That strip to the cathode is probably your getter strip. There are getter materials that are non sputtering, but which are activated and then act as an absorbtive material for the evolved gas. Thorn was a leader in this, which is now used by Phillips in HPS lamps. You will find there is a second cathode lead on the other side ( possibly cut off before the tube base is done) so they can pass a current through the getter strip during evacuation in the oven just before the final sealing is done so there is the least amount of gas present. The dynodes do get hot, they are absorbing all the energy of the primary electron over the minimum required to do the secondary emission. This results in heating of the material. The black is probably the sputtered off cathode material from the tube that was accelerated down to the dynodes from high voltage field, along with fine particles that got sputtered off the preceding anodes and then accumulated there, now turned to a black copper oxide as you opened the tube.
+Michel Dellepere You can see some of the wiring for a PMT in this video where i put together a radiation scintillation probe. th-cam.com/video/rmILTJVbNb4/w-d-xo.html
Thank you, I'm doing a project on night vision and this PMT is a major component of it. Do you think you could have fixed up the tube by finding some way to clean off the dynodes and then replace the tube (and you would obviously have to vacuum out the tube after you reassembled it, )? I'm wondering about this because I'm thinking about trying to assemble my own PMT tube for cheap rather than buying one. Also do you know how much that tube costed/where you got it from?
+J Longworth It's not worth trying to repair a PMT, if you need something cheap i have some PMTs a here, or Sphere in Canada have loads available: www.sphere.bc.ca/test/photo-tubes.html
Hi, I was handling PMTs not attached to any power at room light and was told by an engineer that this damages the tube. I am wondering if this is actually true? I thought that would just be the case if there is voltage applied. Any ideas?
the content in this video is priceless. Thank you for the video and teardown.
Very interesting stuff! Thanks for putting the time and effort into these videos, they're always wonderfully insightful
Silvaentys Fyrerux thank you, hopefully more will come!
Photomultiplier tubes are also founded in night vision goggles but, has a phosphorus anode that turns the electrons into visible light.
That strip to the cathode is probably your getter strip. There are getter materials that are non sputtering, but which are activated and then act as an absorbtive material for the evolved gas. Thorn was a leader in this, which is now used by Phillips in HPS lamps. You will find there is a second cathode lead on the other side ( possibly cut off before the tube base is done) so they can pass a current through the getter strip during evacuation in the oven just before the final sealing is done so there is the least amount of gas present.
The dynodes do get hot, they are absorbing all the energy of the primary electron over the minimum required to do the secondary emission. This results in heating of the material. The black is probably the sputtered off cathode material from the tube that was accelerated down to the dynodes from high voltage field, along with fine particles that got sputtered off the preceding anodes and then accumulated there, now turned to a black copper oxide as you opened the tube.
SeanBZA Thanks Sean, a fountain of knowledge as usual. Any thoughts as to the cause of failure? Thinking most likely it's been blinded.
+DextersLab2013 How would you connect the PMT to a power supply/transformer?
+Michel Dellepere You can see some of the wiring for a PMT in this video where i put together a radiation scintillation probe. th-cam.com/video/rmILTJVbNb4/w-d-xo.html
Nice to know Ludlum uses tubes made in England.
10:20 The rectangular thing on the left side of the glass is not the getter?
Thanks! Provided Enough Information 🙂👍
Is the scintillation crystal covered by beryllium?
Thank you, I'm doing a project on night vision and this PMT is a major component of it. Do you think you could have fixed up the tube by finding some way to clean off the dynodes and then replace the tube (and you would obviously have to vacuum out the tube after you reassembled it, )? I'm wondering about this because I'm thinking about trying to assemble my own PMT tube for cheap rather than buying one. Also do you know how much that tube costed/where you got it from?
+J Longworth It's not worth trying to repair a PMT, if you need something cheap i have some PMTs a here, or Sphere in Canada have loads available: www.sphere.bc.ca/test/photo-tubes.html
DextersLab2013 Thanks!
can we fix a photo multiplier by removing all the gases in it and somehow making the tube free of air yet again?
Vacuum is created while sealing the glass. Reworking the glass under vacuum condition is close to impossible.
@@MsLeguman got the answer two years later😂😂😂thanks tho I really appreciate it
@@AsifAli-yg8kc سلام كيف سيد علي من أي بلد أنت و ما هو اختصاصك أنا مهتم بهذا المنتج
Anode will simply be a plate or what?
Hi may you use this pmt to detect the photon of radio waves ??
Hi, I was handling PMTs not attached to any power at room light and was told by an engineer that this damages the tube. I am wondering if this is actually true? I thought that would just be the case if there is voltage applied. Any ideas?
I don't know TBH, it's an interesting question!
I think the getters are radioactive, so using one in a tube designed to detect radioactivity would not be the best idea
I've heard of radioactive cathodes (thoriated) but never a getter. What are they made of ?
i believe barium
the getter is definitely not radioactive. all that would do is serve to increase the dark noise of the tube and reduce its sensitivity.
@@Muonium1 Dark noise, is that the same as background noise?
@@88njtrigg88 Ya