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Re: [VacuumX] RGA's

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  • chrisoe@aol.com
    Hello all, very interesting proposal. I have tooled around with similar ideas for ion beam and molecular beam experiments some years ago and may still have
    Message 1 of 30 , Mar 1, 2007
      Hello all,
      very interesting proposal. I have tooled around with similar ideas for ion beam and molecular beam experiments some years ago and may still have some notes in an obscure paper pile. From memory the ion source used the filament from a night light/christmas light operating at reduced voltage. The source was essentailly built with glass beads over long threaded studs between the electrodes. The electrodes were bent sheet metal. Then for simpicity and increased sensitivity I converted to API which is unfortunately not feasible in RGA applications.
      For RGA there is a patented source design that should give improved sensitivity. It is a concentric design used in the instruments offered by BALZERS. This design may avoid the need for the costly EM by permitting use of the faraday/electrometer detector.
      A channeltron may however be made by a hobbyist. I remember during my grad work on a HITACHI RMU-6 the japanese engineer using a black graphite paste to repair channeltrons. In a conversation we discovered that this paste could be diluted with acetone and would cover the inside of the glass tube followed by baking out. If anybody has info about the formulation and the conductive coating procedure we should be able to produce something useful without mortgaging the farm.
      An article in NASA tech briefs describes the Quad electronics for a Mini Quadrupole Spectrometer. I remember that is was a relatively simple schematic. I'll look for it.
      I have looked at the sliding rods from discarded scanner to use as Quads. They seem to be precisely ground but for the mounting of the whole assembly I did not trust my skills that it would be sufficiently accurate.
      (My first job was with HP as a masspectrometer specialist aligning and tuning their Dodecapoles - a tricky affair!)
      Lastly I remember a reference to a DIY Masspectrometer project in Scientific American. It may be a good start for a prototype if somebody can locate a copy.
       
      Comments welcome!
       
      Chris




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    • Jim RabidWolf
      Are you talking about aquadag? ... From: chrisoe@aol.com To: VacuumX@yahoogroups.com Sent: Thursday, March 01, 2007 10:26 PM Subject: Re: [VacuumX] RGA s Hello
      Message 2 of 30 , Mar 1, 2007
        Are you talking about aquadag?
        ----- Original Message -----
        Sent: Thursday, March 01, 2007 10:26 PM
        Subject: Re: [VacuumX] RGA's

        Hello all,
        very interesting proposal. I have tooled around with similar ideas for ion beam and molecular beam experiments some years ago and may still have some notes in an obscure paper pile. From memory the ion source used the filament from a night light/christmas light operating at reduced voltage. The source was essentailly built with glass beads over long threaded studs between the electrodes. The electrodes were bent sheet metal. Then for simpicity and increased sensitivity I converted to API which is unfortunately not feasible in RGA applications.
        For RGA there is a patented source design that should give improved sensitivity. It is a concentric design used in the instruments offered by BALZERS. This design may avoid the need for the costly EM by permitting use of the faraday/electrometer detector.
        A channeltron may however be made by a hobbyist. I remember during my grad work on a HITACHI RMU-6 the japanese engineer using a black graphite paste to repair channeltrons. In a conversation we discovered that this paste could be diluted with acetone and would cover the inside of the glass tube followed by baking out. If anybody has info about the formulation and the conductive coating procedure we should be able to produce something useful without mortgaging the farm.
        An article in NASA tech briefs describes the Quad electronics for a Mini Quadrupole Spectrometer. I remember that is was a relatively simple schematic. I'll look for it.
        I have looked at the sliding rods from discarded scanner to use as Quads. They seem to be precisely ground but for the mounting of the whole assembly I did not trust my skills that it would be sufficiently accurate.
        (My first job was with HP as a masspectrometer specialist aligning and tuning their Dodecapoles - a tricky affair!)
        Lastly I remember a reference to a DIY Masspectrometer project in Scientific American. It may be a good start for a prototype if somebody can locate a copy.
         
        Comments welcome!
         
        Chris




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      • John Dykins
        Jim, Isn t it aquadag that is used to coat the inside of the funnel in TV tubes for electrostatic screening? Chris, Interesting filament, great idea. I wonder
        Message 3 of 30 , Mar 2, 2007
          Jim,
          Isn't it aquadag that is used to coat the inside of the funnel in TV
          tubes for electrostatic screening?

          Chris,
          Interesting filament, great idea. I wonder if the material is tungsten?
          Those NASA tech briefs and the BRUKER info could be a good starting
          point. An RMU6 eh, what a beast, good performance in its day though.

          Which HP model were the dodecapoles used on? I would guess an ESI
          model in which they were before the quad rods. I bet they were tricky
          to align.
          I have access to a good library so I will search for the ms article (or
          does anyone have the CD of the Amateur Scientist?)




          Jim RabidWolf wrote:

          > Are you talking about aquadag?
          >
          > ----- Original Message -----
          > *From:* chrisoe@... <mailto:chrisoe@...>
          > *To:* VacuumX@yahoogroups.com <mailto:VacuumX@yahoogroups.com>
          > *Sent:* Thursday, March 01, 2007 10:26 PM
          > *Subject:* Re: [VacuumX] RGA's
          >
          > Hello all,
          > very interesting proposal. I have tooled around with similar ideas
          > for ion beam and molecular beam experiments some years ago and may
          > still have some notes in an obscure paper pile. From memory the
          > ion source used the filament from a night light/christmas light
          > operating at reduced voltage. The source was essentailly built
          > with glass beads over long threaded studs between the electrodes.
          > The electrodes were bent sheet metal. Then for simpicity and
          > increased sensitivity I converted to API which is unfortunately
          > not feasible in RGA applications.
          > For RGA there is a patented source design that should give
          > improved sensitivity. It is a concentric design used in the
          > instruments offered by BALZERS. This design may avoid the need for
          > the costly EM by permitting use of the faraday/electrometer detector.
          > A channeltron may however be made by a hobbyist. I remember during
          > my grad work on a HITACHI RMU-6 the japanese engineer using a
          > black graphite paste to repair channeltrons. In a conversation we
          > discovered that this paste could be diluted with acetone and would
          > cover the inside of the glass tube followed by baking out. If
          > anybody has info about the formulation and the conductive coating
          > procedure we should be able to produce something useful without
          > mortgaging the farm.
          > An article in NASA tech briefs describes the Quad electronics for
          > a Mini Quadrupole Spectrometer. I remember that is was a
          > relatively simple schematic. I'll look for it.
          > I have looked at the sliding rods from discarded scanner to use as
          > Quads. They seem to be precisely ground but for the mounting of
          > the whole assembly I did not trust my skills that it would be
          > sufficiently accurate.
          > (My first job was with HP as a masspectrometer specialist aligning
          > and tuning their Dodecapoles - a tricky affair!)
          > Lastly I remember a reference to a DIY Masspectrometer project in
          > Scientific American. It may be a good start for a prototype if
          > somebody can locate a copy.
          >
          > Comments welcome!
          >
          > Chris
          >
          >
          >
          > ------------------------------------------------------------------------
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          >
          >
          >
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        • Gomez Addams
          ... I m aware that RGA heads are non-trivial, and having seen a few on eBay, I d considered the possibility of buying a head and building the electronics, or
          Message 4 of 30 , Mar 2, 2007
            On Feb 28, 2007, at 8:29 AM, John Dykins wrote:

            > All this in a small package, (the rods need only be about 2 inches
            > long
            > and less than a tenth inch diam) mounted on a vac flange with maybe 10
            > feedthroughs. Metal parts should be stainless steel for non
            > magnetic and
            > other properties.

            I'm aware that RGA heads are non-trivial, and having seen a few on
            eBay, I'd considered the possibility of buying a head and building
            the electronics, or even matching a head to a controller. I've seen
            separate controllers and heads on eBay from time to time.

            I never see complete, working RGAs rigs anywhere except at prices
            which reserve them for corporations and the very well heeled.

            > If you want to pursue this I can go into more detail.
            > An RGA would typically be used for very small vac leaks ( eg if the
            > chamber cannot get better than say 10^-6). For worse leaks I would
            > suggest using the chamber ion gauge and squirt a solvent like
            > methanol
            > methodically on seals, feedthroughs welds etc. The gauge will kick and
            > take a few seconds to recover when the solvent enters a leak. If the
            > pressure is so bad that the ion gauge will not switch on (say
            > 10^-4 or
            > worse) then the pirani/thermocouple gauge could be used.

            This is the problem I have now. I've been unable to find any leak
            using solvents on joints and the like. My system is currently
            waiting for me to machine a new blank-off plate for the top of the
            stack so I can fit a second set of known-good gauge electronics to
            it, to determine whether there really is a leak, or if (as seems
            likely) the gauge electronics that came with the system are wonky.

            - Bill "Gomez" Lemieux

            ..................................................................
            "Do not boast about the tempo of technology. The final, essential
            questions are not altered by technology." -Carl Sonnenschein
          • chrisoe1
            I am not familiar with aquadag. The title for the NASA Tech Brief in 2000 is: Power Supply for Miniature Quadrupole MAss Spectrometer by Jet Propulsion Lab:
            Message 5 of 30 , Mar 2, 2007
              I am not familiar with aquadag.
              The title for the NASA Tech Brief in 2000 is:
              'Power Supply for Miniature Quadrupole MAss Spectrometer' by Jet
              Propulsion Lab: [NASA Tech/Test and Measurement.]

              A simplification of the quadrupole is the monopole mass filter which
              is also a dynamic mass filter based on path stability principles. It
              is essentially one quadrant of the quad cross section but ion
              injection and exit is however in a curved fashion. According to an
              older text book [J. Roboz: Introduction to Masspectroscopy, 1968, pg
              112] this design "is relatively new...is believed to result in a in a
              reduction of electronics requirements as comapred to the quadrupole"
              but on the downside it mentions " ....there is considerable
              controversy at the present time concerning its usefulness in
              comparison with quadrupole."
              Some recent references to these principles have emerged in connection
              with RGA use and it may be interesting again.
              Intersting massfilters are also the various energybalance massfilters
              which were developed in the middle of the last century and can be
              small and were used for RGA purpose. Particularly the
              omegatron and the Syrotron from Varian have my interest due to small
              size and electronic simplicity.

              HP marketed their first MS somewhere in the late 1960's as the HP
              5980 series with the dodecapole as the actual massfilter. It was
              actually a quadrupole with two additional flat electrodes between
              each round rod making the total count of electrodes a round dozen.
              the potential of these electrodes could be adjusted
              sperately to obtain better resolution and/or sensitivity using a
              oscilloscope. Most user however never wanted to touch these controls
              out of fear of making things worse. These were highly interactive
              analog adjustements and there was no default value or 'last entry'
              option to revert to when things got out of hand. When I joined in
              1976 the HP5984 has been introduced and it was a true quadrupole but
              older dodecapoles were still in the field and many needed help.

              Comments invited!
              best regards
              Chris

              --- In VacuumX@yahoogroups.com, John Dykins <dykins@...> wrote:
              >
              > Jim,
              > Isn't it aquadag that is used to coat the inside of the funnel in
              TV
              > tubes for electrostatic screening?
              >
              > Chris,
              > Interesting filament, great idea. I wonder if the material is
              tungsten?
              > Those NASA tech briefs and the BRUKER info could be a good starting
              > point. An RMU6 eh, what a beast, good performance in its day though.
              >
              > Which HP model were the dodecapoles used on? I would guess an ESI
              > model in which they were before the quad rods. I bet they were
              tricky
              > to align.
              > I have access to a good library so I will search for the ms article
              (or
              > does anyone have the CD of the Amateur Scientist?)
              >
              >
              >
              >
              > Jim RabidWolf wrote:
              >
              > > Are you talking about aquadag?
              > >
              > > ----- Original Message -----
              > > *From:* chrisoe@... <mailto:chrisoe@...>
              > > *To:* VacuumX@yahoogroups.com <mailto:VacuumX@yahoogroups.com>
              > > *Sent:* Thursday, March 01, 2007 10:26 PM
              > > *Subject:* Re: [VacuumX] RGA's
              > >
              > > Hello all,
              > > very interesting proposal. I have tooled around with similar
              ideas
              > > for ion beam and molecular beam experiments some years ago
              and may
              > > still have some notes in an obscure paper pile. From memory
              the
              > > ion source used the filament from a night light/christmas
              light
              > > operating at reduced voltage. The source was essentailly built
              > > with glass beads over long threaded studs between the
              electrodes.
              > > The electrodes were bent sheet metal. Then for simpicity and
              > > increased sensitivity I converted to API which is
              unfortunately
              > > not feasible in RGA applications.
              > > For RGA there is a patented source design that should give
              > > improved sensitivity. It is a concentric design used in the
              > > instruments offered by BALZERS. This design may avoid the
              need for
              > > the costly EM by permitting use of the faraday/electrometer
              detector.
              > > A channeltron may however be made by a hobbyist. I remember
              during
              > > my grad work on a HITACHI RMU-6 the japanese engineer using a
              > > black graphite paste to repair channeltrons. In a
              conversation we
              > > discovered that this paste could be diluted with acetone and
              would
              > > cover the inside of the glass tube followed by baking out. If
              > > anybody has info about the formulation and the conductive
              coating
              > > procedure we should be able to produce something useful
              without
              > > mortgaging the farm.
              > > An article in NASA tech briefs describes the Quad electronics
              for
              > > a Mini Quadrupole Spectrometer. I remember that is was a
              > > relatively simple schematic. I'll look for it.
              > > I have looked at the sliding rods from discarded scanner to
              use as
              > > Quads. They seem to be precisely ground but for the mounting
              of
              > > the whole assembly I did not trust my skills that it would be
              > > sufficiently accurate.
              > > (My first job was with HP as a masspectrometer specialist
              aligning
              > > and tuning their Dodecapoles - a tricky affair!)
              > > Lastly I remember a reference to a DIY Masspectrometer
              project in
              > > Scientific American. It may be a good start for a prototype if
              > > somebody can locate a copy.
              > >
              > > Comments welcome!
              > >
              > > Chris
              > >
              > >
              > >
              > > --------------------------------------------------------------
              ----------
              > > AOL now offers free email to everyone. Find out more about
              what's
              > > free from AOL at *AOL.com*
              > >
              <http://pr.atwola.com/promoclk/1615326657x4311227241x4298082137/aol?
              redir=http%3A%2F%2Fwww%2Eaol%2Ecom>.
              > >
              > >
              > >
              > >
              > > **************************************
              > > AOL now offers free email to everyone. Find out more about
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              > > free from AOL at http://www.aol.com
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            • Gomez Addams
              ... Well, I just searched the CD-ROM of all Amateur Scientist articles and could not find it, yet I m sure I saw it too! I will try searching the local library
              Message 6 of 30 , Mar 3, 2007
                On Mar 1, 2007, at 9:26 PM, chrisoe@... wrote:

                > Lastly I remember a reference to a DIY Masspectrometer project in
                > Scientific American. It may be a good start for a prototype if
                > somebody can locate a copy.

                Well, I just searched the CD-ROM of all Amateur Scientist articles
                and could not find it, yet I'm sure I saw it too!
                I will try searching the local library system.

                .....................................................................
                "If Edison had a needle to find in a haystack, he would proceed at
                once with the diligence of the bee to examine straw after straw until
                he found the object of his search... I was a sorry witness of such
                doings, knowing that a little theory and calculation would have saved
                him ninety per cent of his labor." - Nikola Tesla
              • Gomez Addams
                ... Yes! It s easy to make too. ... I do, and just looked, but I am sick and just waking up (still drinking my coffee) so I ll look again when I m more awake.
                Message 7 of 30 , Mar 3, 2007
                  On Mar 2, 2007, at 6:38 AM, John Dykins wrote:

                  > Isn't it aquadag that is used to coat the inside of the funnel in TV
                  > tubes for electrostatic screening?

                  Yes! It's easy to make too.

                  > I have access to a good library so I will search for the ms article
                  > (or
                  > does anyone have the CD of the Amateur Scientist?)

                  I do, and just looked, but I am sick and just waking up (still
                  drinking my coffee) so I'll look again when I'm more awake. The Java
                  app for searching the CD isn't the best I've seen.

                  - G.

                  ..........................................................
                  "New and stirring things are belittled because if they are
                  not belittled, the humiliating question arises, 'Why then
                  are you not taking part in them?' " - H. G. Wells
                • jrrymiller
                  Doesn t a CRT have the required filament, cathode and grids in its electron gun to form the basis of the spectrometer emitter. The neck of the cathode ray
                  Message 8 of 30 , Mar 3, 2007
                    Doesn't a CRT have the required filament, cathode and grids in its
                    electron gun to form the basis of the spectrometer emitter. The neck of
                    the cathode ray tube is easily salvaged by drilling a small hole in the
                    HV attachment electrode to relieve the vacuum the the neck can be cut or
                    broken off. For leak detection a tunable detector is not necessary.
                    Only a detector that is positioned to pick up the helium ions. The
                    detector is then some kind of electrometer. (like in a smoke detector) I
                    don't mean to discourage the expirementing with RGA technology.

                    An old computer CRT also has the necessary power supply to suppotr the
                    electron gun.

                    Just some thoughts.

                    Jerry Miller
                  • Jim RabidWolf
                    Yes - Aquadag is the water based version. It s not only used for crt s - it s used in GM tubes and a myriad of other uses (neon glow tubes, etc). Rabid ...
                    Message 9 of 30 , Mar 4, 2007
                      Yes - Aquadag is the water based version. It's not only used for crt's -
                      it's used in GM tubes and a myriad of other uses (neon glow tubes, etc).

                      Rabid

                      ----- Original Message -----
                      From: "John Dykins" <dykins@...>
                      To: <VacuumX@yahoogroups.com>
                      Sent: Friday, March 02, 2007 7:38 AM
                      Subject: Re: [VacuumX] RGA's


                      > Jim,
                      > Isn't it aquadag that is used to coat the inside of the funnel in TV
                      > tubes for electrostatic screening?
                      >
                      > Chris,
                      > Interesting filament, great idea. I wonder if the material is tungsten?
                      > Those NASA tech briefs and the BRUKER info could be a good starting
                      > point. An RMU6 eh, what a beast, good performance in its day though.
                      >
                      > Which HP model were the dodecapoles used on? I would guess an ESI
                      > model in which they were before the quad rods. I bet they were tricky
                      > to align.
                      > I have access to a good library so I will search for the ms article (or
                      > does anyone have the CD of the Amateur Scientist?)
                      >
                      >
                      >
                      >
                      > Jim RabidWolf wrote:
                      >
                      > > Are you talking about aquadag?
                      > >
                      > > ----- Original Message -----
                      > > *From:* chrisoe@... <mailto:chrisoe@...>
                      > > *To:* VacuumX@yahoogroups.com <mailto:VacuumX@yahoogroups.com>
                      > > *Sent:* Thursday, March 01, 2007 10:26 PM
                      > > *Subject:* Re: [VacuumX] RGA's
                      > >
                      > > Hello all,
                      > > very interesting proposal. I have tooled around with similar ideas
                      > > for ion beam and molecular beam experiments some years ago and may
                      > > still have some notes in an obscure paper pile. From memory the
                      > > ion source used the filament from a night light/christmas light
                      > > operating at reduced voltage. The source was essentailly built
                      > > with glass beads over long threaded studs between the electrodes.
                      > > The electrodes were bent sheet metal. Then for simpicity and
                      > > increased sensitivity I converted to API which is unfortunately
                      > > not feasible in RGA applications.
                      > > For RGA there is a patented source design that should give
                      > > improved sensitivity. It is a concentric design used in the
                      > > instruments offered by BALZERS. This design may avoid the need for
                      > > the costly EM by permitting use of the faraday/electrometer
                      detector.
                      > > A channeltron may however be made by a hobbyist. I remember during
                      > > my grad work on a HITACHI RMU-6 the japanese engineer using a
                      > > black graphite paste to repair channeltrons. In a conversation we
                      > > discovered that this paste could be diluted with acetone and would
                      > > cover the inside of the glass tube followed by baking out. If
                      > > anybody has info about the formulation and the conductive coating
                      > > procedure we should be able to produce something useful without
                      > > mortgaging the farm.
                      > > An article in NASA tech briefs describes the Quad electronics for
                      > > a Mini Quadrupole Spectrometer. I remember that is was a
                      > > relatively simple schematic. I'll look for it.
                      > > I have looked at the sliding rods from discarded scanner to use as
                      > > Quads. They seem to be precisely ground but for the mounting of
                      > > the whole assembly I did not trust my skills that it would be
                      > > sufficiently accurate.
                      > > (My first job was with HP as a masspectrometer specialist aligning
                      > > and tuning their Dodecapoles - a tricky affair!)
                      > > Lastly I remember a reference to a DIY Masspectrometer project in
                      > > Scientific American. It may be a good start for a prototype if
                      > > somebody can locate a copy.
                      > >
                      > > Comments welcome!
                      > >
                      > > Chris
                      > >
                      > >
                      > >
                      >
                      ------------------------------------------------------------------------
                      > > AOL now offers free email to everyone. Find out more about what's
                      > > free from AOL at *AOL.com*
                      > >
                      <http://pr.atwola.com/promoclk/1615326657x4311227241x4298082137/aol?redir=ht
                      tp%3A%2F%2Fwww%2Eaol%2Ecom>.
                      > >
                      > >
                      > >
                      > >
                      > > **************************************
                      > > AOL now offers free email to everyone. Find out more about what's
                      > > free from AOL at http://www.aol.com
                      > >
                      > >
                      >
                      >
                      >
                      >
                      >
                      >
                      > Yahoo! Groups Links
                      >
                      >
                      >
                      >
                    • Jim RabidWolf
                      Yes, the required components are there. One of the stranger projects I am considering is refilimenting an on old crt (2AP1) I have that appears to be new,
                      Message 10 of 30 , Mar 4, 2007
                        Yes, the required components are there. One of the "stranger" projects I am
                        considering is refilimenting an on old crt (2AP1) I have that appears to be
                        new, but the filiment is open. Having the necessary vacuum equipment, I
                        think it might be fun to give it a try, There are a number of companies
                        around the specialize in refilimenting/rebuilding kinescope tubes, so I know
                        it can be done. I plan on using a filament from a 6SN7GT as a first try.

                        Rabid

                        ----- Original Message -----
                        From: "jrrymiller" <gandamiller@...>
                        To: <VacuumX@yahoogroups.com>
                        Sent: Saturday, March 03, 2007 11:01 PM
                        Subject: [VacuumX] Re: RGA's


                        >
                        >
                        > Doesn't a CRT have the required filament, cathode and grids in its
                        > electron gun to form the basis of the spectrometer emitter. The neck of
                        > the cathode ray tube is easily salvaged by drilling a small hole in the
                        > HV attachment electrode to relieve the vacuum the the neck can be cut or
                        > broken off. For leak detection a tunable detector is not necessary.
                        > Only a detector that is positioned to pick up the helium ions. The
                        > detector is then some kind of electrometer. (like in a smoke detector) I
                        > don't mean to discourage the expirementing with RGA technology.
                        >
                        > An old computer CRT also has the necessary power supply to suppotr the
                        > electron gun.
                        >
                        > Just some thoughts.
                        >
                        > Jerry Miller
                        >
                        >
                        >
                        >
                        >
                        >
                        > Yahoo! Groups Links
                        >
                        >
                        >
                        >
                      • chrisoe1
                        Jim, If I understand you correctly, aquadag is used to coat the inside of the CRT or other device for the purpose elstat shielding. Then a low resistance is
                        Message 11 of 30 , Mar 4, 2007
                          Jim,
                          If I understand you correctly, 'aquadag' is used to coat the inside
                          of the CRT or other device for the purpose elstat shielding. Then a
                          low resistance is probably desirable. The Channeltron may have
                          difrferent requirements:
                          It is about 1 to 2 inches long and 1/8 inch diam and bent like a
                          banana with a funnel at the inlet. From front to back is a high
                          voltage and the inner coating of the tube functions as the resistor
                          cascade in the classic SEM. The ion hits the inside of the funnel and
                          knocks out an electron. This is then 'sucked' into the electric field
                          and wanders towards the other end. Due to the bent shape it will
                          collide with the wall where two or more electrons are knocked out and
                          the process repeats itself until the eletroncloud exits and is
                          collected in a faraday cup. The distance of free flight in the tube
                          and the strength of the electric field determines the acceleration
                          until the next collosion with the wall. The process is the same as in
                          a discrete dynode SEM where the acceleration voltage between dynodes
                          is provided by a resistor cascade.
                          I will have to check again but the resistance from front to end is in
                          the Megohms. The voltage is 1 to 3 kV and the current probably in the
                          microamps which is enough to prevent saturation for ion signals in
                          the nanoamps.
                          The above is arguably an non-scientific explanation and somebody may
                          be able to explain the underlying physical principles better
                          permitting a specific design.

                          Regards,
                          Chris


                          --- In VacuumX@yahoogroups.com, "Jim RabidWolf" <unclerabid@...>
                          wrote:
                          >
                          > Yes - Aquadag is the water based version. It's not only used for
                          crt's -
                          > it's used in GM tubes and a myriad of other uses (neon glow tubes,
                          etc).
                          >
                          > Rabid
                          >
                          > ----- Original Message -----
                          > From: "John Dykins" <dykins@...>
                          > To: <VacuumX@yahoogroups.com>
                          > Sent: Friday, March 02, 2007 7:38 AM
                          > Subject: Re: [VacuumX] RGA's
                          >
                          >
                          > > Jim,
                          > > Isn't it aquadag that is used to coat the inside of the funnel in
                          TV
                          > > tubes for electrostatic screening?
                          > >
                          > > Chris,
                          > > Interesting filament, great idea. I wonder if the material is
                          tungsten?
                          > > Those NASA tech briefs and the BRUKER info could be a good
                          starting
                          > > point. An RMU6 eh, what a beast, good performance in its day
                          though.
                          > >
                          > > Which HP model were the dodecapoles used on? I would guess an
                          ESI
                          > > model in which they were before the quad rods. I bet they were
                          tricky
                          > > to align.
                          > > I have access to a good library so I will search for the ms
                          article (or
                          > > does anyone have the CD of the Amateur Scientist?)
                          > >
                          > >
                          > >
                          > >
                          > > Jim RabidWolf wrote:
                          > >
                          > > > Are you talking about aquadag?
                          > > >
                          > > > ----- Original Message -----
                          > > > *From:* chrisoe@... <mailto:chrisoe@...>
                          > > > *To:* VacuumX@yahoogroups.com
                          <mailto:VacuumX@yahoogroups.com>
                          > > > *Sent:* Thursday, March 01, 2007 10:26 PM
                          > > > *Subject:* Re: [VacuumX] RGA's
                          > > >
                          > > > Hello all,
                          > > > very interesting proposal. I have tooled around with
                          similar ideas
                          > > > for ion beam and molecular beam experiments some years ago
                          and may
                          > > > still have some notes in an obscure paper pile. From memory
                          the
                          > > > ion source used the filament from a night light/christmas
                          light
                          > > > operating at reduced voltage. The source was essentailly
                          built
                          > > > with glass beads over long threaded studs between the
                          electrodes.
                          > > > The electrodes were bent sheet metal. Then for simpicity and
                          > > > increased sensitivity I converted to API which is
                          unfortunately
                          > > > not feasible in RGA applications.
                          > > > For RGA there is a patented source design that should give
                          > > > improved sensitivity. It is a concentric design used in the
                          > > > instruments offered by BALZERS. This design may avoid the
                          need for
                          > > > the costly EM by permitting use of the faraday/electrometer
                          > detector.
                          > > > A channeltron may however be made by a hobbyist. I remember
                          during
                          > > > my grad work on a HITACHI RMU-6 the japanese engineer using
                          a
                          > > > black graphite paste to repair channeltrons. In a
                          conversation we
                          > > > discovered that this paste could be diluted with acetone
                          and would
                          > > > cover the inside of the glass tube followed by baking out.
                          If
                          > > > anybody has info about the formulation and the conductive
                          coating
                          > > > procedure we should be able to produce something useful
                          without
                          > > > mortgaging the farm.
                          > > > An article in NASA tech briefs describes the Quad
                          electronics for
                          > > > a Mini Quadrupole Spectrometer. I remember that is was a
                          > > > relatively simple schematic. I'll look for it.
                          > > > I have looked at the sliding rods from discarded scanner to
                          use as
                          > > > Quads. They seem to be precisely ground but for the
                          mounting of
                          > > > the whole assembly I did not trust my skills that it would
                          be
                          > > > sufficiently accurate.
                          > > > (My first job was with HP as a masspectrometer specialist
                          aligning
                          > > > and tuning their Dodecapoles - a tricky affair!)
                          > > > Lastly I remember a reference to a DIY Masspectrometer
                          project in
                          > > > Scientific American. It may be a good start for a prototype
                          if
                          > > > somebody can locate a copy.
                          > > >
                          > > > Comments welcome!
                          > > >
                          > > > Chris
                          > > >
                          > > >
                          > > >
                          > >
                          > ------------------------------------------------------------------
                          ------
                          > > > AOL now offers free email to everyone. Find out more about
                          what's
                          > > > free from AOL at *AOL.com*
                          > > >
                          > <http://pr.atwola.com/promoclk/1615326657x4311227241x4298082137/aol?
                          redir=ht
                          > tp%3A%2F%2Fwww%2Eaol%2Ecom>.
                          > > >
                          > > >
                          > > >
                          > > >
                          > > > **************************************
                          > > > AOL now offers free email to everyone. Find out more about
                          what's
                          > > > free from AOL at http://www.aol.com
                          > > >
                          > > >
                          > >
                          > >
                          > >
                          > >
                          > >
                          > >
                          > > Yahoo! Groups Links
                          > >
                          > >
                          > >
                          > >
                          >
                        • Gomez Addams
                          ... Actually, in a CRT at least, the aquadag coating is the 2nd anode. .............................................................. Once when told that Apple
                          Message 12 of 30 , Mar 5, 2007
                            On Mar 4, 2007, at 5:33 PM, chrisoe1 wrote:

                            > Jim,
                            > If I understand you correctly, 'aquadag' is used to coat the inside
                            > of the CRT or other device for the purpose elstat shielding.

                            Actually, in a CRT at least, the aquadag coating is the 2nd anode.

                            ..............................................................
                            Once when told that Apple Computer bought a CRAY supercomputer
                            to simulate their next Apple computer design, Seymour Cray
                            remarked, "Funny, I am using an Apple to simulate the CRAY-3."
                          • John Dykins
                            Gomez I may be stating the obvious to you, if so forgive me. With no obvious leaks found you might not have a leak at all, it may be that your diff pump is not
                            Message 13 of 30 , Mar 6, 2007
                              Gomez
                              I may be stating the obvious to you, if so forgive me. With no obvious
                              leaks found you might not have a leak at all, it may be that your diff
                              pump is not working well enough. Is the 90 deg elbow that connects to
                              the rotary line warm/hot? I once had a diff that was supplied with the
                              center stack rotated so the hole did not line up with the pump port. The
                              heater was OK, the rotary pump was OK but the pump was stalling due to a
                              high back pressure. A poor chamber pressure and a cool elbow were the
                              only symptoms.

                              Good luck,

                              John



                              Gomez Addams wrote:

                              >
                              > .......
                              > This is the problem I have now. I've been unable to find any leak
                              > using solvents on joints and the like. My system is currently
                              > waiting for me to machine a new blank-off plate for the top of the
                              > stack so I can fit a second set of known-good gauge electronics to
                              > it, to determine whether there really is a leak, or if (as seems
                              > likely) the gauge electronics that came with the system are wonky.
                              >
                              > - Bill "Gomez" Lemieux
                              >
                              > ..................................................................
                              > "Do not boast about the tempo of technology. The final, essential
                              > questions are not altered by technology." -Carl Sonnenschein
                              >
                              >
                            • jrrymiller
                              I have had a similar experience. In fact a careful examination of picture 1 in Jerry Miller s System you can see that the hose connecting the diffusion
                              Message 14 of 30 , Mar 8, 2007
                                I have had a similar experience. In fact a careful examination of
                                picture 1 in "Jerry Miller's System" you can see that the hose
                                connecting the diffusion pump's outlet is collapsed. I was searching
                                for leaks when I finally found this. John is giving you good advice.

                                Jerry Miller
                                --- In VacuumX@yahoogroups.com, John Dykins <dykins@...> wrote:
                                >
                                > Gomez
                                > I may be stating the obvious to you, if so forgive me. With no obvious
                                > leaks found you might not have a leak at all, it may be that your diff
                                > pump is not working well enough. Is the 90 deg elbow that connects to
                                > the rotary line warm/hot? I once had a diff that was supplied with the
                                > center stack rotated so the hole did not line up with the pump port.
                                The
                                > heater was OK, the rotary pump was OK but the pump was stalling due to
                                a
                                > high back pressure. A poor chamber pressure and a cool elbow were the
                                > only symptoms.
                                >
                                > Good luck,
                                >
                                > John
                                >
                                >
                                >
                                > Gomez Addams wrote:
                                >
                                > >
                                > > .......
                                > > This is the problem I have now. I've been unable to find any leak
                                > > using solvents on joints and the like. My system is currently
                                > > waiting for me to machine a new blank-off plate for the top of the
                                > > stack so I can fit a second set of known-good gauge electronics to
                                > > it, to determine whether there really is a leak, or if (as seems
                                > > likely) the gauge electronics that came with the system are wonky.
                                > >
                                > > - Bill "Gomez" Lemieux
                                > >
                                > > ..................................................................
                                > > "Do not boast about the tempo of technology. The final, essential
                                > > questions are not altered by technology." -Carl Sonnenschein
                                > >
                                > >
                                >
                              • Jim RabidWolf
                                I never noticed before - but it is quite clearly pinched off... The only real problem I have right now is the tendency for the pump to spit oil back up through
                                Message 15 of 30 , Mar 8, 2007
                                  I never noticed before - but it is quite clearly pinched off...

                                  The only real problem I have right now is the tendency for the pump to spit
                                  oil back up through the inlet - if I don't shut it off, or drop the vacuum
                                  in the system quickly, the vacuum line will quickly fill with oil all the
                                  way up into the bell jar. From looking at it and doing a little research on
                                  the web, it seems to be an endemic problem with the pump version (Savant
                                  VP100 - same as the Edward E2M5) - so I am designing a check ball system
                                  that will automatically block the line when the vacuum stops on the pump
                                  side, but readily open when the pressure on the pump side is less than that
                                  of the bell. (simply a light spring, a large ball bearing, well seated into
                                  an aluminum collar - cut the tube and insert the valve tube.

                                  JRW

                                  ----- Original Message -----
                                  From: "jrrymiller" <gandamiller@...>
                                  To: <VacuumX@yahoogroups.com>
                                  Sent: Thursday, March 08, 2007 3:33 PM
                                  Subject: [VacuumX] Re: RGA's


                                  >
                                  > I have had a similar experience. In fact a careful examination of
                                  > picture 1 in "Jerry Miller's System" you can see that the hose
                                  > connecting the diffusion pump's outlet is collapsed. I was searching
                                  > for leaks when I finally found this. John is giving you good advice.
                                  >
                                  > Jerry Miller
                                  > --- In VacuumX@yahoogroups.com, John Dykins <dykins@...> wrote:
                                  > >
                                  > > Gomez
                                  > > I may be stating the obvious to you, if so forgive me. With no obvious
                                  > > leaks found you might not have a leak at all, it may be that your diff
                                  > > pump is not working well enough. Is the 90 deg elbow that connects to
                                  > > the rotary line warm/hot? I once had a diff that was supplied with the
                                  > > center stack rotated so the hole did not line up with the pump port.
                                  > The
                                  > > heater was OK, the rotary pump was OK but the pump was stalling due to
                                  > a
                                  > > high back pressure. A poor chamber pressure and a cool elbow were the
                                  > > only symptoms.
                                  > >
                                  > > Good luck,
                                  > >
                                  > > John
                                  > >
                                  > >
                                  > >
                                  > > Gomez Addams wrote:
                                  > >
                                  > > >
                                  > > > .......
                                  > > > This is the problem I have now. I've been unable to find any leak
                                  > > > using solvents on joints and the like. My system is currently
                                  > > > waiting for me to machine a new blank-off plate for the top of the
                                  > > > stack so I can fit a second set of known-good gauge electronics to
                                  > > > it, to determine whether there really is a leak, or if (as seems
                                  > > > likely) the gauge electronics that came with the system are wonky.
                                  > > >
                                  > > > - Bill "Gomez" Lemieux
                                  > > >
                                  > > > ..................................................................
                                  > > > "Do not boast about the tempo of technology. The final, essential
                                  > > > questions are not altered by technology." -Carl Sonnenschein
                                  > > >
                                  > > >
                                  > >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > Yahoo! Groups Links
                                  >
                                  >
                                  >
                                  >
                                • John Dykins
                                  Jim Edwards pumps have an anti-suck back seal built in so maybe the Savant does too. In my experience this seal does need replacing every few years. I would
                                  Message 16 of 30 , Mar 9, 2007
                                    Jim
                                    Edwards pumps have an anti-suck back seal built in so maybe the Savant
                                    does too. In my experience this seal does need replacing every few
                                    years. I would put a valve on top of the rotary pump so that there is no
                                    chance of oil contamination on shutdown; cleaning the vac lines is a pain.

                                    John



                                    Jim RabidWolf wrote:

                                    > I never noticed before - but it is quite clearly pinched off...
                                    >
                                    > The only real problem I have right now is the tendency for the pump to
                                    > spit
                                    > oil back up through the inlet - if I don't shut it off, or drop the vacuum
                                    > in the system quickly, the vacuum line will quickly fill with oil all the
                                    > way up into the bell jar. From looking at it and doing a little
                                    > research on
                                    > the web, it seems to be an endemic problem with the pump version (Savant
                                    > VP100 - same as the Edward E2M5) - so I am designing a check ball system
                                    > that will automatically block the line when the vacuum stops on the pump
                                    > side, but readily open when the pressure on the pump side is less than
                                    > that
                                    > of the bell. (simply a light spring, a large ball bearing, well seated
                                    > into
                                    > an aluminum collar - cut the tube and insert the valve tube.
                                    >
                                    > JRW
                                    >
                                    > ----- Original Message -----
                                    > From: "jrrymiller" <gandamiller@...
                                    > <mailto:gandamiller%40verizon.net>>
                                    > To: <VacuumX@yahoogroups.com <mailto:VacuumX%40yahoogroups.com>>
                                    > Sent: Thursday, March 08, 2007 3:33 PM
                                    > Subject: [VacuumX] Re: RGA's
                                    >
                                    > >
                                    > > I have had a similar experience. In fact a careful examination of
                                    > > picture 1 in "Jerry Miller's System" you can see that the hose
                                    > > connecting the diffusion pump's outlet is collapsed. I was searching
                                    > > for leaks when I finally found this. John is giving you good advice.
                                    > >
                                    > > Jerry Miller
                                    > > --- In VacuumX@yahoogroups.com <mailto:VacuumX%40yahoogroups.com>,
                                    > John Dykins <dykins@...> wrote:
                                    > > >
                                    > > > Gomez
                                    > > > I may be stating the obvious to you, if so forgive me. With no obvious
                                    > > > leaks found you might not have a leak at all, it may be that your diff
                                    > > > pump is not working well enough. Is the 90 deg elbow that connects to
                                    > > > the rotary line warm/hot? I once had a diff that was supplied with the
                                    > > > center stack rotated so the hole did not line up with the pump port.
                                    > > The
                                    > > > heater was OK, the rotary pump was OK but the pump was stalling due to
                                    > > a
                                    > > > high back pressure. A poor chamber pressure and a cool elbow were the
                                    > > > only symptoms.
                                    > > >
                                    > > > Good luck,
                                    > > >
                                    > > > John
                                    > > >
                                    > > >
                                    > > >
                                    > > > Gomez Addams wrote:
                                    > > >
                                    > > > >
                                    > > > > .......
                                    > > > > This is the problem I have now. I've been unable to find any leak
                                    > > > > using solvents on joints and the like. My system is currently
                                    > > > > waiting for me to machine a new blank-off plate for the top of the
                                    > > > > stack so I can fit a second set of known-good gauge electronics to
                                    > > > > it, to determine whether there really is a leak, or if (as seems
                                    > > > > likely) the gauge electronics that came with the system are wonky.
                                    > > > >
                                    > > > > - Bill "Gomez" Lemieux
                                    > > > >
                                    > > > > ..................................................................
                                    > > > > "Do not boast about the tempo of technology. The final, essential
                                    > > > > questions are not altered by technology." -Carl Sonnenschein
                                    > > > >
                                    > > > >
                                    > > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    > > Yahoo! Groups Links
                                    > >
                                    > >
                                    > >
                                    > >
                                    >
                                    >
                                  • Gomez Addams
                                    For those who don t recall, the issue with my system is that I can t get the ion gauge to come on, and I don t know whether the pressure really is to high (the
                                    Message 17 of 30 , Mar 9, 2007
                                      For those who don't recall, the issue with my system is that I can't
                                      get the ion gauge to come on, and I don't know whether the pressure
                                      really is to high (the T/C gauges bottom out) or the ion gauge
                                      electronics are out of whack.

                                      My system is a Veeco VE-300 general purpose laboratory vacuum cart,
                                      often used for solder evaporators and other systems. It's a lot like
                                      this one, except I don't have a bell jar:

                                      http://www.nanotech.ucsb.edu/NanotechNew/equipment/Equipment%20Images/
                                      solder_evap.jpg


                                      On Mar 6, 2007, at 1:51 PM, John Dykins wrote:

                                      > Gomez
                                      > I may be stating the obvious to you, if so forgive me. With no
                                      > obvious
                                      > leaks found you might not have a leak at all, it may be that your diff
                                      > pump is not working well enough.

                                      Entirely possible.

                                      > Is the 90 deg elbow that connects to the rotary line warm/hot?

                                      Yes! Although I'm not sure how much its temp differs from the rest
                                      of the
                                      bottom of the pump.

                                      > I once had a diff that was supplied with the
                                      > center stack rotated so the hole did not line up with the pump port.

                                      That - in and of itself - is definitely not the problem, because I
                                      tore apart the pump, cleaned it aggressively, and reassembled it. I
                                      specifically recall carefully aligning the ejector holes with the
                                      foreline.

                                      What concerns me is that the interior of the DP looked like it had
                                      been electropolished when it was new. When I got it, it had shiny
                                      walls... except where The Crud was baked on. "The Crud" was a rock
                                      hard black layer of who-knows-what, but I assumed it was cooked oil -
                                      it had probably been dived to ambient with hot petroleum-based or
                                      Octoil oil in it. (Veeco says it is supposed to use DC-704, which is
                                      supposed to be somewhat resistant to burning but I got this system
                                      from a college, and strange abusive things happen to equipment in
                                      college labs.)

                                      My helper and I were convinced The Crud had to go, so I tried soaking
                                      it (for days each) in every solvent I could lay my hands on -
                                      acetone, toluene, xylene, alcohols, all to no avail. Eventually, I
                                      decided to sandblast it out (using glass beads, actually).
                                      That got the pump and the stack parts nice and clean, but of course,
                                      the walls were no longer shiny, they are now a matte finish.

                                      After that, I washed the interior and stack with hot water and
                                      detergent, then rinsed with hot distilled water, dried everything
                                      with a heat gun, then rinsed with anhydrous methanol, dried with the
                                      heat gun again, reassembled, and filled with 100mL of DC-704, which
                                      is what the spec supposedly calls for. (it's a rather small pump).

                                      > The heater was OK, the rotary pump was OK but the pump was stalling
                                      > due to a
                                      > high back pressure. A poor chamber pressure and a cool elbow were the
                                      > only symptoms.

                                      Huh. Not sure that's the case here.

                                      The heater had an odd plate between the heating element and the
                                      bottom of the pump - one side was curved convex, as if to apply more
                                      heat to the center of the DP than the edges. I suppose this could
                                      make sense, although I don't know whether it is normal. Since I had
                                      to replace the heater wiring with high-heat wire and new connectors,
                                      I had all of that apart too, which is how I saw the odd plate. The
                                      odd plate was also rusty, so I cleaned it up. It was so corroded
                                      that I can't be 100% certain the curvature was original!

                                      The original mechanical was a Cenco Hyvac-7, which seemed to pull a
                                      decent vacuum (10-3 without much time) but needed a new shaft seal.
                                      My helper gave me a Hyvac-14 which did not leak, so I used that
                                      instead. More mechanical = better, right? It has been flushed and
                                      has new oil in it.

                                      I am still focused on an unrelated project, but I should reach a good
                                      (or at least, unavoidable) stopping point with that in a few weeks or
                                      a month or two at which point I can turn back to this vacuum system.
                                      What I plan to do next is machine a new blank-off plate for the top
                                      of the stack (where the bell jar plate would go if it were installed)
                                      to accept some spare gauges, then I can verify whether the factory
                                      gauge electronics on my system are working right. If not, Joy!
                                      Because I can easily tweak the Veeco gauge system against the known
                                      good gauges. If they are working right, then I have a leak or a
                                      pumping problem to track down.

                                      Any more thoughts?

                                      - Gomez


                                      .....................................................
                                      A long memory is the most subversive idea in America.
                                    • Gomez Addams
                                      Hee-hee. My DP is connected to the mechanical by a very short length of brand new 1/2 wall gum rubber vacuum tubing from Duniway. It hasn t collapsed yet.
                                      Message 18 of 30 , Mar 9, 2007
                                        Hee-hee. My DP is connected to the mechanical by a very short length
                                        of brand new 1/2" wall gum rubber vacuum tubing from Duniway. It
                                        hasn't collapsed yet.

                                        On Mar 8, 2007, at 2:33 PM, jrrymiller wrote:

                                        > I have had a similar experience. In fact a careful examination of
                                        > picture 1 in "Jerry Miller's System" you can see that the hose
                                        > connecting the diffusion pump's outlet is collapsed. I was searching
                                        > for leaks when I finally found this. John is giving you good advice.
                                        >
                                        > Jerry Miller
                                        > --- In VacuumX@yahoogroups.com, John Dykins <dykins@...> wrote:
                                        >>
                                        >> Gomez
                                        >> I may be stating the obvious to you, if so forgive me. With no
                                        >> obvious
                                        >> leaks found you might not have a leak at all, it may be that your
                                        >> diff
                                        >> pump is not working well enough. Is the 90 deg elbow that connects to
                                        >> the rotary line warm/hot? I once had a diff that was supplied with
                                        >> the
                                        >> center stack rotated so the hole did not line up with the pump port.
                                        > The
                                        >> heater was OK, the rotary pump was OK but the pump was stalling
                                        >> due to
                                        > a
                                        >> high back pressure. A poor chamber pressure and a cool elbow were the
                                        >> only symptoms.
                                        >>
                                        >> Good luck,
                                        >>
                                        >> John
                                        >>
                                        >>
                                        >>
                                        >> Gomez Addams wrote:
                                        >>
                                        >>>
                                        >>> .......
                                        >>> This is the problem I have now. I've been unable to find any leak
                                        >>> using solvents on joints and the like. My system is currently
                                        >>> waiting for me to machine a new blank-off plate for the top of the
                                        >>> stack so I can fit a second set of known-good gauge electronics to
                                        >>> it, to determine whether there really is a leak, or if (as seems
                                        >>> likely) the gauge electronics that came with the system are wonky.
                                        >>>
                                        >>> - Bill "Gomez" Lemieux
                                        >>>
                                        >>> ..................................................................
                                        >>> "Do not boast about the tempo of technology. The final, essential
                                        >>> questions are not altered by technology." -Carl Sonnenschein
                                        >>>
                                        >>>
                                        >>
                                        >
                                        >
                                        >
                                        >
                                        >
                                        >
                                        > Yahoo! Groups Links
                                        >
                                        >
                                        >

                                        ..............................................
                                        A conservative is a liberal who's been mugged.
                                        A libertarian is a conservative who's been arrested.
                                      • Jim RabidWolf
                                        Well, I rebuilt the pump and there isn t one, unfortunately. That s why I m building the check ball valve to stop it. I was reading on a Neon site, a gentelman
                                        Message 19 of 30 , Mar 9, 2007
                                          Well, I rebuilt the pump and there isn't one, unfortunately. That's why I'm
                                          building the check ball valve to stop it.

                                          I was reading on a Neon site, a gentelman with the same pump was bemoaning
                                          the problem. Edwards sells a check valve to solve the problem, but at the
                                          price of around $300, I'll build my own, thank you very much.

                                          The problem has to do with the way the low vacuum stage valve is
                                          constructed - it's merely a flapper valve of rubber - the high vacuum valve
                                          seal is a spring loaded button.


                                          ----- Original Message -----
                                          From: "John Dykins" <dykins@...>
                                          To: <VacuumX@yahoogroups.com>
                                          Sent: Friday, March 09, 2007 7:17 AM
                                          Subject: Re: [VacuumX] Re: RGA's


                                          Jim
                                          Edwards pumps have an anti-suck back seal built in so maybe the Savant
                                          does too. In my experience this seal does need replacing every few
                                          years. I would put a valve on top of the rotary pump so that there is no
                                          chance of oil contamination on shutdown; cleaning the vac lines is a pain.

                                          John



                                          Jim RabidWolf wrote:

                                          > I never noticed before - but it is quite clearly pinched off...
                                          >
                                          > The only real problem I have right now is the tendency for the pump to
                                          > spit
                                          > oil back up through the inlet - if I don't shut it off, or drop the vacuum
                                          > in the system quickly, the vacuum line will quickly fill with oil all the
                                          > way up into the bell jar. From looking at it and doing a little
                                          > research on
                                          > the web, it seems to be an endemic problem with the pump version (Savant
                                          > VP100 - same as the Edward E2M5) - so I am designing a check ball system
                                          > that will automatically block the line when the vacuum stops on the pump
                                          > side, but readily open when the pressure on the pump side is less than
                                          > that
                                          > of the bell. (simply a light spring, a large ball bearing, well seated
                                          > into
                                          > an aluminum collar - cut the tube and insert the valve tube.
                                          >
                                          > JRW
                                          >
                                          > ----- Original Message -----
                                          > From: "jrrymiller" <gandamiller@...
                                          > <mailto:gandamiller%40verizon.net>>
                                          > To: <VacuumX@yahoogroups.com <mailto:VacuumX%40yahoogroups.com>>
                                          > Sent: Thursday, March 08, 2007 3:33 PM
                                          > Subject: [VacuumX] Re: RGA's
                                          >
                                          > >
                                          > > I have had a similar experience. In fact a careful examination of
                                          > > picture 1 in "Jerry Miller's System" you can see that the hose
                                          > > connecting the diffusion pump's outlet is collapsed. I was searching
                                          > > for leaks when I finally found this. John is giving you good advice.
                                          > >
                                          > > Jerry Miller
                                          > > --- In VacuumX@yahoogroups.com <mailto:VacuumX%40yahoogroups.com>,
                                          > John Dykins <dykins@...> wrote:
                                          > > >
                                          > > > Gomez
                                          > > > I may be stating the obvious to you, if so forgive me. With no obvious
                                          > > > leaks found you might not have a leak at all, it may be that your diff
                                          > > > pump is not working well enough. Is the 90 deg elbow that connects to
                                          > > > the rotary line warm/hot? I once had a diff that was supplied with the
                                          > > > center stack rotated so the hole did not line up with the pump port.
                                          > > The
                                          > > > heater was OK, the rotary pump was OK but the pump was stalling due to
                                          > > a
                                          > > > high back pressure. A poor chamber pressure and a cool elbow were the
                                          > > > only symptoms.
                                          > > >
                                          > > > Good luck,
                                          > > >
                                          > > > John
                                          > > >
                                          > > >
                                          > > >
                                          > > > Gomez Addams wrote:
                                          > > >
                                          > > > >
                                          > > > > .......
                                          > > > > This is the problem I have now. I've been unable to find any leak
                                          > > > > using solvents on joints and the like. My system is currently
                                          > > > > waiting for me to machine a new blank-off plate for the top of the
                                          > > > > stack so I can fit a second set of known-good gauge electronics to
                                          > > > > it, to determine whether there really is a leak, or if (as seems
                                          > > > > likely) the gauge electronics that came with the system are wonky.
                                          > > > >
                                          > > > > - Bill "Gomez" Lemieux
                                          > > > >
                                          > > > > ..................................................................
                                          > > > > "Do not boast about the tempo of technology. The final, essential
                                          > > > > questions are not altered by technology." -Carl Sonnenschein
                                          > > > >
                                          > > > >
                                          > > >
                                          > >
                                          > >
                                          > >
                                          > >
                                          > >
                                          > >
                                          > > Yahoo! Groups Links
                                          > >
                                          > >
                                          > >
                                          > >
                                          >
                                          >






                                          Yahoo! Groups Links
                                        • John Dykins
                                          The diff pump elbow, at the junction of the L , which may be one or two inches from the wall of the diff., should be quite hot to touch, maybe only a few
                                          Message 20 of 30 , Mar 9, 2007
                                            The diff pump elbow, at the junction of the "'L", which may be one or
                                            two inches from the wall of the diff., should be quite hot to touch,
                                            maybe only a few seconds before it is painful. In contrast the bottom of
                                            the diff will give a severe burn. I just measured the elbow temp on my
                                            4" & 6" Edwards Diffstak models, it was 190-200 deg F. The bottom of the
                                            diffs was around 480 deg F. I am using Santovac 5 but the boiling points
                                            for the silicones are only slighly less

                                            One way I test a diff and an ion gauge and also eliminate the
                                            chamber, is mount the ion gauge to flat plate and put the plate on top
                                            of the diff flange with an O ring seal.( Is this what you are going to
                                            do with your new flange?) That way there are only two seals to worry
                                            about and the pump down time is short. Edwards do a "Co-Seal" O ring
                                            which grips the special O ring on the outside so you don't have to
                                            machine a groove in the plate. If the surfaces are good enough you do
                                            not need bolts either.

                                            Re diff pump crud, I am not surprised with what you found. Even with a
                                            synthetic ether oil like Santovac5 I have found it on a 10 year old
                                            diff. You certainly did a thorough job on the cleaning.

                                            One thought, is the diff heating element in good contact with the bottom
                                            flange?

                                            Even with good diff and rotary pump sizing, the length and especially
                                            the diameter of the pump lines (diff to chamber as well as rotary to
                                            diff) can be the limiting factor for pump down time or ultimate
                                            vacuum with a gas load.



                                            Gomez Addams wrote:

                                            > For those who don't recall, the issue with my system is that I can't
                                            > get the ion gauge to come on, and I don't know whether the pressure
                                            > really is to high (the T/C gauges bottom out) or the ion gauge
                                            > electronics are out of whack.
                                            >
                                            > My system is a Veeco VE-300 general purpose laboratory vacuum cart,
                                            > often used for solder evaporators and other systems. It's a lot like
                                            > this one, except I don't have a bell jar:
                                            >
                                            > http://www.nanotech.ucsb.edu/NanotechNew/equipment/Equipment%20Images/
                                            > <http://www.nanotech.ucsb.edu/NanotechNew/equipment/Equipment%20Images/>
                                            > solder_evap.jpg
                                            >
                                            > On Mar 6, 2007, at 1:51 PM, John Dykins wrote:
                                            >
                                            > > Gomez
                                            > > I may be stating the obvious to you, if so forgive me. With no
                                            > > obvious
                                            > > leaks found you might not have a leak at all, it may be that your diff
                                            > > pump is not working well enough.
                                            >
                                            > Entirely possible.
                                            >
                                            > > Is the 90 deg elbow that connects to the rotary line warm/hot?
                                            >
                                            > Yes! Although I'm not sure how much its temp differs from the rest
                                            > of the
                                            > bottom of the pump.
                                            >
                                            > > I once had a diff that was supplied with the
                                            > > center stack rotated so the hole did not line up with the pump port.
                                            >
                                            > That - in and of itself - is definitely not the problem, because I
                                            > tore apart the pump, cleaned it aggressively, and reassembled it. I
                                            > specifically recall carefully aligning the ejector holes with the
                                            > foreline.
                                            >
                                            > What concerns me is that the interior of the DP looked like it had
                                            > been electropolished when it was new. When I got it, it had shiny
                                            > walls... except where The Crud was baked on. "The Crud" was a rock
                                            > hard black layer of who-knows-what, but I assumed it was cooked oil -
                                            > it had probably been dived to ambient with hot petroleum-based or
                                            > Octoil oil in it. (Veeco says it is supposed to use DC-704, which is
                                            > supposed to be somewhat resistant to burning but I got this system
                                            > from a college, and strange abusive things happen to equipment in
                                            > college labs.)
                                            >
                                            > My helper and I were convinced The Crud had to go, so I tried soaking
                                            > it (for days each) in every solvent I could lay my hands on -
                                            > acetone, toluene, xylene, alcohols, all to no avail. Eventually, I
                                            > decided to sandblast it out (using glass beads, actually).
                                            > That got the pump and the stack parts nice and clean, but of course,
                                            > the walls were no longer shiny, they are now a matte finish.
                                            >
                                            > After that, I washed the interior and stack with hot water and
                                            > detergent, then rinsed with hot distilled water, dried everything
                                            > with a heat gun, then rinsed with anhydrous methanol, dried with the
                                            > heat gun again, reassembled, and filled with 100mL of DC-704, which
                                            > is what the spec supposedly calls for. (it's a rather small pump).
                                            >
                                            > > The heater was OK, the rotary pump was OK but the pump was stalling
                                            > > due to a
                                            > > high back pressure. A poor chamber pressure and a cool elbow were the
                                            > > only symptoms.
                                            >
                                            > Huh. Not sure that's the case here.
                                            >
                                            > The heater had an odd plate between the heating element and the
                                            > bottom of the pump - one side was curved convex, as if to apply more
                                            > heat to the center of the DP than the edges. I suppose this could
                                            > make sense, although I don't know whether it is normal. Since I had
                                            > to replace the heater wiring with high-heat wire and new connectors,
                                            > I had all of that apart too, which is how I saw the odd plate. The
                                            > odd plate was also rusty, so I cleaned it up. It was so corroded
                                            > that I can't be 100% certain the curvature was original!
                                            >
                                            > The original mechanical was a Cenco Hyvac-7, which seemed to pull a
                                            > decent vacuum (10-3 without much time) but needed a new shaft seal.
                                            > My helper gave me a Hyvac-14 which did not leak, so I used that
                                            > instead. More mechanical = better, right? It has been flushed and
                                            > has new oil in it.
                                            >
                                            > I am still focused on an unrelated project, but I should reach a good
                                            > (or at least, unavoidable) stopping point with that in a few weeks or
                                            > a month or two at which point I can turn back to this vacuum system.
                                            > What I plan to do next is machine a new blank-off plate for the top
                                            > of the stack (where the bell jar plate would go if it were installed)
                                            > to accept some spare gauges, then I can verify whether the factory
                                            > gauge electronics on my system are working right. If not, Joy!
                                            > Because I can easily tweak the Veeco gauge system against the known
                                            > good gauges. If they are working right, then I have a leak or a
                                            > pumping problem to track down.
                                            >
                                            > Any more thoughts?
                                            >
                                            > - Gomez
                                            >
                                            > .....................................................
                                            > A long memory is the most subversive idea in America.
                                            >
                                            >
                                          • Jim RabidWolf
                                            There are other ways to tell what the vacuum is - can you still get a glow from an electric discharge? You can rig up a simple TC guage and find out if you re
                                            Message 21 of 30 , Mar 9, 2007
                                              There are other ways to tell what the vacuum is - can you still get a glow
                                              from an electric discharge? You can rig up a simple TC guage and find out if
                                              you're getting to 10^-3, bro


                                              ----- Original Message -----
                                              From: "Gomez Addams" <gomez@...>
                                              To: <VacuumX@yahoogroups.com>
                                              Sent: Friday, March 09, 2007 8:32 AM
                                              Subject: Re: [VacuumX] RGA's


                                              For those who don't recall, the issue with my system is that I can't
                                              get the ion gauge to come on, and I don't know whether the pressure
                                              really is to high (the T/C gauges bottom out) or the ion gauge
                                              electronics are out of whack.

                                              My system is a Veeco VE-300 general purpose laboratory vacuum cart,
                                              often used for solder evaporators and other systems. It's a lot like
                                              this one, except I don't have a bell jar:

                                              http://www.nanotech.ucsb.edu/NanotechNew/equipment/Equipment%20Images/
                                              solder_evap.jpg


                                              On Mar 6, 2007, at 1:51 PM, John Dykins wrote:

                                              > Gomez
                                              > I may be stating the obvious to you, if so forgive me. With no
                                              > obvious
                                              > leaks found you might not have a leak at all, it may be that your diff
                                              > pump is not working well enough.

                                              Entirely possible.

                                              > Is the 90 deg elbow that connects to the rotary line warm/hot?

                                              Yes! Although I'm not sure how much its temp differs from the rest
                                              of the
                                              bottom of the pump.

                                              > I once had a diff that was supplied with the
                                              > center stack rotated so the hole did not line up with the pump port.

                                              That - in and of itself - is definitely not the problem, because I
                                              tore apart the pump, cleaned it aggressively, and reassembled it. I
                                              specifically recall carefully aligning the ejector holes with the
                                              foreline.

                                              What concerns me is that the interior of the DP looked like it had
                                              been electropolished when it was new. When I got it, it had shiny
                                              walls... except where The Crud was baked on. "The Crud" was a rock
                                              hard black layer of who-knows-what, but I assumed it was cooked oil -
                                              it had probably been dived to ambient with hot petroleum-based or
                                              Octoil oil in it. (Veeco says it is supposed to use DC-704, which is
                                              supposed to be somewhat resistant to burning but I got this system
                                              from a college, and strange abusive things happen to equipment in
                                              college labs.)

                                              My helper and I were convinced The Crud had to go, so I tried soaking
                                              it (for days each) in every solvent I could lay my hands on -
                                              acetone, toluene, xylene, alcohols, all to no avail. Eventually, I
                                              decided to sandblast it out (using glass beads, actually).
                                              That got the pump and the stack parts nice and clean, but of course,
                                              the walls were no longer shiny, they are now a matte finish.

                                              After that, I washed the interior and stack with hot water and
                                              detergent, then rinsed with hot distilled water, dried everything
                                              with a heat gun, then rinsed with anhydrous methanol, dried with the
                                              heat gun again, reassembled, and filled with 100mL of DC-704, which
                                              is what the spec supposedly calls for. (it's a rather small pump).

                                              > The heater was OK, the rotary pump was OK but the pump was stalling
                                              > due to a
                                              > high back pressure. A poor chamber pressure and a cool elbow were the
                                              > only symptoms.

                                              Huh. Not sure that's the case here.

                                              The heater had an odd plate between the heating element and the
                                              bottom of the pump - one side was curved convex, as if to apply more
                                              heat to the center of the DP than the edges. I suppose this could
                                              make sense, although I don't know whether it is normal. Since I had
                                              to replace the heater wiring with high-heat wire and new connectors,
                                              I had all of that apart too, which is how I saw the odd plate. The
                                              odd plate was also rusty, so I cleaned it up. It was so corroded
                                              that I can't be 100% certain the curvature was original!

                                              The original mechanical was a Cenco Hyvac-7, which seemed to pull a
                                              decent vacuum (10-3 without much time) but needed a new shaft seal.
                                              My helper gave me a Hyvac-14 which did not leak, so I used that
                                              instead. More mechanical = better, right? It has been flushed and
                                              has new oil in it.

                                              I am still focused on an unrelated project, but I should reach a good
                                              (or at least, unavoidable) stopping point with that in a few weeks or
                                              a month or two at which point I can turn back to this vacuum system.
                                              What I plan to do next is machine a new blank-off plate for the top
                                              of the stack (where the bell jar plate would go if it were installed)
                                              to accept some spare gauges, then I can verify whether the factory
                                              gauge electronics on my system are working right. If not, Joy!
                                              Because I can easily tweak the Veeco gauge system against the known
                                              good gauges. If they are working right, then I have a leak or a
                                              pumping problem to track down.

                                              Any more thoughts?

                                              - Gomez


                                              .....................................................
                                              A long memory is the most subversive idea in America.






                                              Yahoo! Groups Links
                                            • gomez@owlhouse.org
                                              ... I haven t tried touching it for long, the elbow gets plenty hot despite having a few heat sink fins on it. In contrast the bottom of ... I need to get a
                                              Message 22 of 30 , Mar 9, 2007
                                                > -----Original Message-----
                                                > From: John Dykins [mailto:dykins@...]
                                                > Sent: Friday, March 9, 2007 06:46 PM
                                                > To: VacuumX@yahoogroups.com
                                                > Subject: Re: [VacuumX] RGA's
                                                >
                                                > The diff pump elbow, at the junction of the "'L", which may be one or
                                                > two inches from the wall of the diff., should be quite hot to touch,
                                                > maybe only a few seconds before it is painful.

                                                I haven't tried touching it for long, the elbow gets plenty hot despite having a few heat sink fins on it.

                                                In contrast the bottom of
                                                > the diff will give a severe burn. I just measured the elbow temp on my
                                                > 4" & 6" Edwards Diffstak models, it was 190-200 deg F. The bottom of the
                                                > diffs was around 480 deg F.

                                                I need to get a reasonably accurate (hah, emission isn't constant!) non-contact pyrometer or maybe just an accurate contact thermometer module that I can plug into a VOM.

                                                > I am using Santovac 5 but the boiling points
                                                > for the silicones are only slighly less
                                                >
                                                > One way I test a diff and an ion gauge and also eliminate the
                                                > chamber, is mount the ion gauge to flat plate and put the plate on top
                                                > of the diff flange with an O ring seal.( Is this what you are going to
                                                > do with your new flange?)

                                                The new flange I'm going to make is for the top of the whole system. I have a blank-off plate on there now. I could just adapt the one that's on it now, I suppose, but then it would be more challenging to seal after I make a great hole in it for an ion gauge socket.

                                                My goal is to find out whether the gauges are working right before I disassemble anything again. I have already gone over the thing many times with various solvents looking for leaks visible on a TC gauge, to no avail.

                                                So the top of this system is the top of a butterfly valve, which is on top of a LN2 cold trap, which is on top of the DP. I can blank off the DP later if I think I really do have a leak somewhere.

                                                > Re diff pump crud, I am not surprised with what you found. Even with a
                                                > synthetic ether oil like Santovac5 I have found it on a 10 year old
                                                > diff. You certainly did a thorough job on the cleaning.

                                                Thanks. We tried. During the final stages, we degreased many parts (like brass plumbing, but certainly not the o-rings!) with toluene and handled everything that had been de-greased with gloves to keep our fingerprints / moisture off them. We thought we were being careful. Similar methods and practices got my friend's _home_built_from_scratch_ system working beautifully.

                                                > One thought, is the diff heating element in good contact with the bottom
                                                > flange?

                                                I think so.

                                                > Even with good diff and rotary pump sizing, the length and especially
                                                > the diameter of the pump lines (diff to chamber as well as rotary to
                                                > diff) can be the limiting factor for pump down time or ultimate
                                                > vacuum with a gas load.

                                                Diff to chamber can't be made shorter unless I remove the cold trap, which I am disinclined to do, I will probably want it for my intended applications.

                                                The foreline to mechanical path is as short as I can make it also. IIRC, the hose is about 4" long. I will take a picture of the bottom (pump area) of the system when I get home tonight. (slacking off at the office now)

                                                regards,
                                                - Bill "Gomez" Lemieux
                                              • gomez@owlhouse.org
                                                ... There s no bell jar. It is an all metal system. ... I think I ve already mentioned that I intend to do that. But it s not all that trivial without
                                                Message 23 of 30 , Mar 9, 2007
                                                  > -----Original Message-----
                                                  > From: Jim RabidWolf [mailto:unclerabid@...]
                                                  > Sent: Friday, March 9, 2007 07:31 PM
                                                  > To: VacuumX@yahoogroups.com
                                                  > Subject: Re: [VacuumX] RGA's
                                                  >
                                                  > There are other ways to tell what the vacuum is - can you still get a glow
                                                  > from an electric discharge?

                                                  There's no bell jar. It is an all metal system.

                                                  > You can rig up a simple TC guage and find out if
                                                  > you're getting to 10^-3, bro

                                                  I think I've already mentioned that I intend to do that. But it's not all that trivial without changing the configuration. Since I don't know whether the TC gauges on the system are trustworthy (not the two different tubes, which are probably fine, but the single gauge electronics they share) I need to add a new TC to the system. To do that, I need a place to put it. That place will be a new hole in the blank-off plate, or a new plate, and while I'm at it, I may as well add a socket for an ion tube...


                                                  > ----- Original Message -----
                                                  > From: "Gomez Addams" <gomez@...>
                                                  > To: <VacuumX@yahoogroups.com>
                                                  > Sent: Friday, March 09, 2007 8:32 AM
                                                  > Subject: Re: [VacuumX] RGA's
                                                  >
                                                  >
                                                  > For those who don't recall, the issue with my system is that I can't
                                                  > get the ion gauge to come on, and I don't know whether the pressure
                                                  > really is to high (the T/C gauges bottom out) or the ion gauge
                                                  > electronics are out of whack.
                                                  >
                                                  > My system is a Veeco VE-300 general purpose laboratory vacuum cart,
                                                  > often used for solder evaporators and other systems. It's a lot like
                                                  > this one, except I don't have a bell jar:
                                                  >
                                                  > http://www.nanotech.ucsb.edu/NanotechNew/equipment/Equipment%20Images/
                                                  > solder_evap.jpg
                                                  >
                                                  >
                                                  > On Mar 6, 2007, at 1:51 PM, John Dykins wrote:
                                                  >
                                                  > > Gomez
                                                  > > I may be stating the obvious to you, if so forgive me. With no
                                                  > > obvious
                                                  > > leaks found you might not have a leak at all, it may be that your diff
                                                  > > pump is not working well enough.
                                                  >
                                                  > Entirely possible.
                                                  >
                                                  > > Is the 90 deg elbow that connects to the rotary line warm/hot?
                                                  >
                                                  > Yes! Although I'm not sure how much its temp differs from the rest
                                                  > of the
                                                  > bottom of the pump.
                                                  >
                                                  > > I once had a diff that was supplied with the
                                                  > > center stack rotated so the hole did not line up with the pump port.
                                                  >
                                                  > That - in and of itself - is definitely not the problem, because I
                                                  > tore apart the pump, cleaned it aggressively, and reassembled it. I
                                                  > specifically recall carefully aligning the ejector holes with the
                                                  > foreline.
                                                  >
                                                  > What concerns me is that the interior of the DP looked like it had
                                                  > been electropolished when it was new. When I got it, it had shiny
                                                  > walls... except where The Crud was baked on. "The Crud" was a rock
                                                  > hard black layer of who-knows-what, but I assumed it was cooked oil -
                                                  > it had probably been dived to ambient with hot petroleum-based or
                                                  > Octoil oil in it. (Veeco says it is supposed to use DC-704, which is
                                                  > supposed to be somewhat resistant to burning but I got this system
                                                  > from a college, and strange abusive things happen to equipment in
                                                  > college labs.)
                                                  >
                                                  > My helper and I were convinced The Crud had to go, so I tried soaking
                                                  > it (for days each) in every solvent I could lay my hands on -
                                                  > acetone, toluene, xylene, alcohols, all to no avail. Eventually, I
                                                  > decided to sandblast it out (using glass beads, actually).
                                                  > That got the pump and the stack parts nice and clean, but of course,
                                                  > the walls were no longer shiny, they are now a matte finish.
                                                  >
                                                  > After that, I washed the interior and stack with hot water and
                                                  > detergent, then rinsed with hot distilled water, dried everything
                                                  > with a heat gun, then rinsed with anhydrous methanol, dried with the
                                                  > heat gun again, reassembled, and filled with 100mL of DC-704, which
                                                  > is what the spec supposedly calls for. (it's a rather small pump).
                                                  >
                                                  > > The heater was OK, the rotary pump was OK but the pump was stalling
                                                  > > due to a
                                                  > > high back pressure. A poor chamber pressure and a cool elbow were the
                                                  > > only symptoms.
                                                  >
                                                  > Huh. Not sure that's the case here.
                                                  >
                                                  > The heater had an odd plate between the heating element and the
                                                  > bottom of the pump - one side was curved convex, as if to apply more
                                                  > heat to the center of the DP than the edges. I suppose this could
                                                  > make sense, although I don't know whether it is normal. Since I had
                                                  > to replace the heater wiring with high-heat wire and new connectors,
                                                  > I had all of that apart too, which is how I saw the odd plate. The
                                                  > odd plate was also rusty, so I cleaned it up. It was so corroded
                                                  > that I can't be 100% certain the curvature was original!
                                                  >
                                                  > The original mechanical was a Cenco Hyvac-7, which seemed to pull a
                                                  > decent vacuum (10-3 without much time) but needed a new shaft seal.
                                                  > My helper gave me a Hyvac-14 which did not leak, so I used that
                                                  > instead. More mechanical = better, right? It has been flushed and
                                                  > has new oil in it.
                                                  >
                                                  > I am still focused on an unrelated project, but I should reach a good
                                                  > (or at least, unavoidable) stopping point with that in a few weeks or
                                                  > a month or two at which point I can turn back to this vacuum system.
                                                  > What I plan to do next is machine a new blank-off plate for the top
                                                  > of the stack (where the bell jar plate would go if it were installed)
                                                  > to accept some spare gauges, then I can verify whether the factory
                                                  > gauge electronics on my system are working right. If not, Joy!
                                                  > Because I can easily tweak the Veeco gauge system against the known
                                                  > good gauges. If they are working right, then I have a leak or a
                                                  > pumping problem to track down.
                                                  >
                                                  > Any more thoughts?
                                                  >
                                                  > - Gomez
                                                  >
                                                  >
                                                  > .....................................................
                                                  > A long memory is the most subversive idea in America.
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  > Yahoo! Groups Links
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  > Yahoo! Groups Links
                                                  >
                                                  >
                                                  >
                                                  >
                                                • Jim RabidWolf
                                                  Well, that s what I was saying - the electronics are mystifyingly simple - merely a matter of current - Worst case, I can throw together a rough unit for you -
                                                  Message 24 of 30 , Mar 9, 2007
                                                    Well, that's what I was saying - the electronics are mystifyingly simple -
                                                    merely a matter of current - Worst case, I can throw together a rough unit
                                                    for you - wouldn't be extremely accuracte, but enough to tell you - I also
                                                    have a spare NRC 720 laying around - the ion section needs work, but the TC
                                                    sections are fine.

                                                    ----- Original Message -----
                                                    From: <gomez@...>
                                                    To: <VacuumX@yahoogroups.com>
                                                    Sent: Friday, March 09, 2007 5:20 PM
                                                    Subject: Re: [VacuumX] RGA's


                                                    >
                                                    > > -----Original Message-----
                                                    > > From: Jim RabidWolf [mailto:unclerabid@...]
                                                    > > Sent: Friday, March 9, 2007 07:31 PM
                                                    > > To: VacuumX@yahoogroups.com
                                                    > > Subject: Re: [VacuumX] RGA's
                                                    > >
                                                    > > There are other ways to tell what the vacuum is - can you still get a
                                                    glow
                                                    > > from an electric discharge?
                                                    >
                                                    > There's no bell jar. It is an all metal system.
                                                    >
                                                    > > You can rig up a simple TC guage and find out if
                                                    > > you're getting to 10^-3, bro
                                                    >
                                                    > I think I've already mentioned that I intend to do that. But it's not all
                                                    that trivial without changing the configuration. Since I don't know whether
                                                    the TC gauges on the system are trustworthy (not the two different tubes,
                                                    which are probably fine, but the single gauge electronics they share) I need
                                                    to add a new TC to the system. To do that, I need a place to put it. That
                                                    place will be a new hole in the blank-off plate, or a new plate, and while
                                                    I'm at it, I may as well add a socket for an ion tube...
                                                    >
                                                    >
                                                    > > ----- Original Message -----
                                                    > > From: "Gomez Addams" <gomez@...>
                                                    > > To: <VacuumX@yahoogroups.com>
                                                    > > Sent: Friday, March 09, 2007 8:32 AM
                                                    > > Subject: Re: [VacuumX] RGA's
                                                    > >
                                                    > >
                                                    > > For those who don't recall, the issue with my system is that I can't
                                                    > > get the ion gauge to come on, and I don't know whether the pressure
                                                    > > really is to high (the T/C gauges bottom out) or the ion gauge
                                                    > > electronics are out of whack.
                                                    > >
                                                    > > My system is a Veeco VE-300 general purpose laboratory vacuum cart,
                                                    > > often used for solder evaporators and other systems. It's a lot like
                                                    > > this one, except I don't have a bell jar:
                                                    > >
                                                    > > http://www.nanotech.ucsb.edu/NanotechNew/equipment/Equipment%20Images/
                                                    > > solder_evap.jpg
                                                    > >
                                                    > >
                                                    > > On Mar 6, 2007, at 1:51 PM, John Dykins wrote:
                                                    > >
                                                    > > > Gomez
                                                    > > > I may be stating the obvious to you, if so forgive me. With no
                                                    > > > obvious
                                                    > > > leaks found you might not have a leak at all, it may be that your diff
                                                    > > > pump is not working well enough.
                                                    > >
                                                    > > Entirely possible.
                                                    > >
                                                    > > > Is the 90 deg elbow that connects to the rotary line warm/hot?
                                                    > >
                                                    > > Yes! Although I'm not sure how much its temp differs from the rest
                                                    > > of the
                                                    > > bottom of the pump.
                                                    > >
                                                    > > > I once had a diff that was supplied with the
                                                    > > > center stack rotated so the hole did not line up with the pump port.
                                                    > >
                                                    > > That - in and of itself - is definitely not the problem, because I
                                                    > > tore apart the pump, cleaned it aggressively, and reassembled it. I
                                                    > > specifically recall carefully aligning the ejector holes with the
                                                    > > foreline.
                                                    > >
                                                    > > What concerns me is that the interior of the DP looked like it had
                                                    > > been electropolished when it was new. When I got it, it had shiny
                                                    > > walls... except where The Crud was baked on. "The Crud" was a rock
                                                    > > hard black layer of who-knows-what, but I assumed it was cooked oil -
                                                    > > it had probably been dived to ambient with hot petroleum-based or
                                                    > > Octoil oil in it. (Veeco says it is supposed to use DC-704, which is
                                                    > > supposed to be somewhat resistant to burning but I got this system
                                                    > > from a college, and strange abusive things happen to equipment in
                                                    > > college labs.)
                                                    > >
                                                    > > My helper and I were convinced The Crud had to go, so I tried soaking
                                                    > > it (for days each) in every solvent I could lay my hands on -
                                                    > > acetone, toluene, xylene, alcohols, all to no avail. Eventually, I
                                                    > > decided to sandblast it out (using glass beads, actually).
                                                    > > That got the pump and the stack parts nice and clean, but of course,
                                                    > > the walls were no longer shiny, they are now a matte finish.
                                                    > >
                                                    > > After that, I washed the interior and stack with hot water and
                                                    > > detergent, then rinsed with hot distilled water, dried everything
                                                    > > with a heat gun, then rinsed with anhydrous methanol, dried with the
                                                    > > heat gun again, reassembled, and filled with 100mL of DC-704, which
                                                    > > is what the spec supposedly calls for. (it's a rather small pump).
                                                    > >
                                                    > > > The heater was OK, the rotary pump was OK but the pump was stalling
                                                    > > > due to a
                                                    > > > high back pressure. A poor chamber pressure and a cool elbow were the
                                                    > > > only symptoms.
                                                    > >
                                                    > > Huh. Not sure that's the case here.
                                                    > >
                                                    > > The heater had an odd plate between the heating element and the
                                                    > > bottom of the pump - one side was curved convex, as if to apply more
                                                    > > heat to the center of the DP than the edges. I suppose this could
                                                    > > make sense, although I don't know whether it is normal. Since I had
                                                    > > to replace the heater wiring with high-heat wire and new connectors,
                                                    > > I had all of that apart too, which is how I saw the odd plate. The
                                                    > > odd plate was also rusty, so I cleaned it up. It was so corroded
                                                    > > that I can't be 100% certain the curvature was original!
                                                    > >
                                                    > > The original mechanical was a Cenco Hyvac-7, which seemed to pull a
                                                    > > decent vacuum (10-3 without much time) but needed a new shaft seal.
                                                    > > My helper gave me a Hyvac-14 which did not leak, so I used that
                                                    > > instead. More mechanical = better, right? It has been flushed and
                                                    > > has new oil in it.
                                                    > >
                                                    > > I am still focused on an unrelated project, but I should reach a good
                                                    > > (or at least, unavoidable) stopping point with that in a few weeks or
                                                    > > a month or two at which point I can turn back to this vacuum system.
                                                    > > What I plan to do next is machine a new blank-off plate for the top
                                                    > > of the stack (where the bell jar plate would go if it were installed)
                                                    > > to accept some spare gauges, then I can verify whether the factory
                                                    > > gauge electronics on my system are working right. If not, Joy!
                                                    > > Because I can easily tweak the Veeco gauge system against the known
                                                    > > good gauges. If they are working right, then I have a leak or a
                                                    > > pumping problem to track down.
                                                    > >
                                                    > > Any more thoughts?
                                                    > >
                                                    > > - Gomez
                                                    > >
                                                    > >
                                                    > > .....................................................
                                                    > > A long memory is the most subversive idea in America.
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    > > Yahoo! Groups Links
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    > > Yahoo! Groups Links
                                                    > >
                                                    > >
                                                    > >
                                                    > >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    >
                                                    > Yahoo! Groups Links
                                                    >
                                                    >
                                                    >
                                                    >
                                                  • Gomez Addams
                                                    ... Ooops, sorry if I didn t make myself clear about the check gauge systems I intend to use to test the Veeco system. I have a spare (old, but known good,
                                                    Message 25 of 30 , Mar 11, 2007
                                                      On Mar 9, 2007, at 8:56 PM, Jim RabidWolf wrote:

                                                      > Well, that's what I was saying - the electronics are mystifyingly
                                                      > simple -
                                                      > merely a matter of current - Worst case, I can throw together a
                                                      > rough unit
                                                      > for you - wouldn't be extremely accuracte, but enough to tell you -
                                                      > I also
                                                      > have a spare NRC 720 laying around - the ion section needs work,
                                                      > but the TC
                                                      > sections are fine.

                                                      Ooops, sorry if I didn't make myself clear about the "check" gauge
                                                      systems I intend to use to test the Veeco system.
                                                      I have a spare (old, but known good, even if it does use tube
                                                      electronics!) gauge system (both ion and TC) and if I don't trust
                                                      that, there's always the system my friend has.

                                                      So I'm set for gauges. The only thing holding me up is time. I
                                                      could have worked on it this weekend for example (or more likely,
                                                      worked on the other project which is ahead of the vacuum system) if I
                                                      weren't ridiculously sick. *sigh*

                                                      - Bill "Gomez" Lemieux

                                                      ...........................
                                                      Insert pithy aphorism here.
                                                    • Jim RabidWolf
                                                      Dude - I take 200mg a day of morophine for the nerve and back pain - eat vicodin like it was candy - I understand. Uncle Rabid got started as my fallback a few
                                                      Message 26 of 30 , Mar 11, 2007
                                                        Dude - I take 200mg a day of morophine for the nerve and back pain - eat
                                                        vicodin like it was candy - I understand. Uncle Rabid got started as my
                                                        fallback a few years ago because, at 55, I'm seriously looking at the day
                                                        coming very soon when I can't work my regular job.


                                                        ----- Original Message -----
                                                        From: "Gomez Addams" <gomez@...>
                                                        To: <VacuumX@yahoogroups.com>
                                                        Sent: Sunday, March 11, 2007 10:55 AM
                                                        Subject: Re: [VacuumX] RGA's


                                                        >
                                                        > On Mar 9, 2007, at 8:56 PM, Jim RabidWolf wrote:
                                                        >
                                                        > > Well, that's what I was saying - the electronics are mystifyingly
                                                        > > simple -
                                                        > > merely a matter of current - Worst case, I can throw together a
                                                        > > rough unit
                                                        > > for you - wouldn't be extremely accuracte, but enough to tell you -
                                                        > > I also
                                                        > > have a spare NRC 720 laying around - the ion section needs work,
                                                        > > but the TC
                                                        > > sections are fine.
                                                        >
                                                        > Ooops, sorry if I didn't make myself clear about the "check" gauge
                                                        > systems I intend to use to test the Veeco system.
                                                        > I have a spare (old, but known good, even if it does use tube
                                                        > electronics!) gauge system (both ion and TC) and if I don't trust
                                                        > that, there's always the system my friend has.
                                                        >
                                                        > So I'm set for gauges. The only thing holding me up is time. I
                                                        > could have worked on it this weekend for example (or more likely,
                                                        > worked on the other project which is ahead of the vacuum system) if I
                                                        > weren't ridiculously sick. *sigh*
                                                        >
                                                        > - Bill "Gomez" Lemieux
                                                        >
                                                        > ...........................
                                                        > Insert pithy aphorism here.
                                                        >
                                                        >
                                                        >
                                                        >
                                                        >
                                                        >
                                                        > Yahoo! Groups Links
                                                        >
                                                        >
                                                        >
                                                        >
                                                      • Gomez Addams
                                                        ... Yikes! All I ve got is a bad cold which turned into bronchitis and is threatening to turn into pneumonia. But a week or two from now, it will be gone.
                                                        Message 27 of 30 , Mar 11, 2007
                                                          On Mar 11, 2007, at 1:21 PM, Jim RabidWolf wrote:

                                                          > Dude - I take 200mg a day of morophine for the nerve and back pain
                                                          > - eat
                                                          > vicodin like it was candy - I understand.

                                                          Yikes! All I've got is a bad cold which turned into bronchitis and
                                                          is threatening to turn into pneumonia. But a week or two from now,
                                                          it will be gone. I'm very sorry to hear that. My wife had a bad hip
                                                          for years, so I'm at least familiar with what living with chronic
                                                          pain can be like.

                                                          > Uncle Rabid got started as my
                                                          > fallback a few years ago because, at 55, I'm seriously looking at
                                                          > the day
                                                          > coming very soon when I can't work my regular job.
                                                          >
                                                          >
                                                          > ----- Original Message -----
                                                          > From: "Gomez Addams" <gomez@...>
                                                          > To: <VacuumX@yahoogroups.com>
                                                          > Sent: Sunday, March 11, 2007 10:55 AM
                                                          > Subject: Re: [VacuumX] RGA's
                                                          >
                                                          >
                                                          >>
                                                          >> On Mar 9, 2007, at 8:56 PM, Jim RabidWolf wrote:
                                                          >>
                                                          >>> Well, that's what I was saying - the electronics are mystifyingly
                                                          >>> simple -
                                                          >>> merely a matter of current - Worst case, I can throw together a
                                                          >>> rough unit
                                                          >>> for you - wouldn't be extremely accuracte, but enough to tell you -
                                                          >>> I also
                                                          >>> have a spare NRC 720 laying around - the ion section needs work,
                                                          >>> but the TC
                                                          >>> sections are fine.
                                                          >>
                                                          >> Ooops, sorry if I didn't make myself clear about the "check" gauge
                                                          >> systems I intend to use to test the Veeco system.
                                                          >> I have a spare (old, but known good, even if it does use tube
                                                          >> electronics!) gauge system (both ion and TC) and if I don't trust
                                                          >> that, there's always the system my friend has.
                                                          >>
                                                          >> So I'm set for gauges. The only thing holding me up is time. I
                                                          >> could have worked on it this weekend for example (or more likely,
                                                          >> worked on the other project which is ahead of the vacuum system) if I
                                                          >> weren't ridiculously sick. *sigh*
                                                          >>
                                                          >> - Bill "Gomez" Lemieux
                                                          >>
                                                          >> ...........................
                                                          >> Insert pithy aphorism here.
                                                          >>
                                                          >>
                                                          >>
                                                          >>
                                                          >>
                                                          >>
                                                          >> Yahoo! Groups Links
                                                          >>
                                                          >>
                                                          >>
                                                          >>
                                                          >
                                                          >
                                                          >
                                                          >
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                                                          ...................................
                                                          "Patience comes to those who wait."
                                                          - Too Much Coffee Man
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