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seeking feedback on PMT abuse / dumb idea

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  • Justin
    (I haven t posted here for about a year, on account of losing my yahoo account, but let s see if this direct email will work). Anyway - anyone want to weigh on
    Message 1 of 2 , Jun 1, 2006
      (I haven't posted here for about a year, on account of losing my yahoo account, but let's see if this direct email will work).

      Anyway - anyone want to weigh on how feasible this photomultiplier tube abuse idea is:

      It's always struck me as a pity that PMTs need to be light-sealed, since they're quite pretty components, it would be nice to be able to show them off. So I'm thinking - since their sensitivity is a function of voltage, perhaps there is a sweet zone of running them at tens of volts instead of a thousand volts, whereby they don't get damaged in visible light, yet you get a signal (not pulses though, so dynode caps would serve no purpose). Ie basically retard a large super sensitive awesome photon detector into something less useful than a lame old photodiode. This could be useful for, uh, geek tech-art?

      My grasp of the hot electron-on-dynode action is insufficient to reliably predict how things might break down when you have virtually no voltage and lots of photons.

      A related question - _why_ are PMTs permanently damaged by too much light - what is the physics behind it - what part of the PMT gets changed? I assume it's something caused by a cascade getting too big, but the current draw is so low and those plates look so substantial that I'm not getting what happens. Does it over-ionise the gas or something?

      Thanks,
      - Justin
    • Tracy Albert
      Hello Justin. Read and memorize this. http://sales.hamamatsu.com/assets/applications/ETD/pmt_handbook_comple te.pdf You may also find the publications posted
      Message 2 of 2 , Jun 1, 2006
        Hello Justin.

        Read and memorize this.


        http://sales.hamamatsu.com/assets/applications/ETD/pmt_handbook_comple
        te.pdf

        You may also find the publications posted here helpful.

        http://sales.hamamatsu.com/index.php?id=13196001

        Enjoy!

        Tracy

        --- In CDV700CLUB@yahoogroups.com, Justin <archvillain@...> wrote:
        >
        > (I haven't posted here for about a year, on account of losing my
        yahoo account, but let's see if this direct email will work).
        >
        > Anyway - anyone want to weigh on how feasible this photomultiplier
        tube abuse idea is:
        >
        > It's always struck me as a pity that PMTs need to be light-sealed,
        since they're quite pretty components, it would be nice to be able to
        show them off. So I'm thinking - since their sensitivity is a
        function of voltage, perhaps there is a sweet zone of running them at
        tens of volts instead of a thousand volts, whereby they don't get
        damaged in visible light, yet you get a signal (not pulses though, so
        dynode caps would serve no purpose). Ie basically retard a large
        super sensitive awesome photon detector into something less useful
        than a lame old photodiode. This could be useful for, uh, geek tech-
        art?
        >
        > My grasp of the hot electron-on-dynode action is insufficient to
        reliably predict how things might break down when you have virtually
        no voltage and lots of photons.
        >
        > A related question - _why_ are PMTs permanently damaged by too much
        light - what is the physics behind it - what part of the PMT gets
        changed? I assume it's something caused by a cascade getting too big,
        but the current draw is so low and those plates look so substantial
        that I'm not getting what happens. Does it over-ionise the gas or
        something?
        >
        > Thanks,
        > - Justin
        >
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