Hello. I just got a PMT the glass bulb of which has been broken. Even

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Discussion Overview

The discussion revolves around the feasibility of using a broken photomultiplier tube (PMT) as an electron multiplier, particularly focusing on the implications of the broken glass bulb and the operational requirements for electron multiplication.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether a broken PMT can still function as an electron multiplier with the appropriate electronics.
  • Another participant asserts that a vacuum is essential for PMT operation, implying that a broken bulb negates this possibility.
  • A participant with experience in electron multipliers under high vacuum expresses interest in using the broken PMT, suggesting that if the cathode can remain intact, it might still work.
  • There is a suggestion that if the photo sensing stage is removed, electrons could still be directed to the multiplier, potentially allowing it to function despite the broken casing.
  • One participant expresses uncertainty about whether the PMT can work without modifying the cathode, indicating that the gain is uncertain without further experimentation.
  • A later reply proposes a practical approach to test the setup by adjusting high voltage and gain settings to see if it yields results.

Areas of Agreement / Disagreement

Participants do not reach a consensus. There are competing views on the viability of using the broken PMT, with some arguing against it due to the vacuum requirement and others suggesting it may still work under certain conditions.

Contextual Notes

Limitations include the lack of detailed information on the specific conditions under which the PMT might operate effectively and the assumptions regarding the functionality of the cathode and dynodes.

Who May Find This Useful

Individuals interested in experimental physics, particularly those working with electron multipliers or photomultiplier tubes, may find this discussion relevant.

Ravaner
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Hello. I just got a PMT the glass bulb of which has been broken. Even if performances are not the best, do you think I can use it as an Electron Multiplier (with all convenient electronics) ?
 
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No. Photomultiplier tubes require a vacuum in order to operate. If the glass bulb is broken, it no longer has a vacuum inside.
 


Hi. I'm aware of that ! I work with an Electron Multiplier under high vacuum but as it arrives to end of life and as I've this broken PMT you better understand my question ...
 


Sorry. Then what is your question exactly?
 


Ravaner said:
Hi. I'm aware of that ! I work with an Electron Multiplier under high vacuum but as it arrives to end of life and as I've this broken PMT you better understand my question ...

You want to ask for help, you better talk nicely.

If you are going to install in vacuum, what do you care whether the glass casing is broken or not, it will be in vacuum. If you can remove the photo sensing stage and get the electron to hit the multiplier, it should work. There is no secret with electron multiplier.
 
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My question in fact is about cathode that in case of PMT is photon sensitive to generate electrons. Without removing it and placing all that stuff in high vacuum, will this amount of dynodes work as an electron multiplier. I insist without any dynode replacement. My own EM has suffered during an experiment, and may be this substitution will be a low cost operation for almost identical results.
 


I don't know whether you can make it work without removing the cathode and just let the electrons hit the cathode. There is not enough information to answer whether you have enough gain.

There is only one way to find out, put it in and steer the electrons into the PMT. You have nothing to loose, maybe jack up the high voltage a little, and/or increase the gain of the receiving transimpedance amp and see what happen.
 

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