Photomultiplier Tubes camera build

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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Thu Oct 20, 2016 11:45 am

Back at it i tested the inverter on the PMT today ...the pmt load dropped the voltage by 50 volts so running on 12 volts -1050 the voltage is clean too had no problems at all ..this makes life easier...

I will test the video sync mixer today second half see how that gos ....i want it to now run off batteries so will work on that too after i find out it does what i want ....
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sat Oct 22, 2016 6:01 pm

Got side tracked on working out how to power the PMT camera idea from either my bench top or experimental battery supply and inverter ...
I needed a dual 12 volt supply so 2 9 volt batteries are hooked up as 2 18 volt supplies which i am regulating to a dual 12 volt ...
Managed to get every thing to fit .
Worth a shot to try ..
I have hedge my bets here so it can run also off my PMT bench power supply via 4 sockets which i can plug into my power supply which i was also working on today adding that hard ware to the back of the large can that houses the pmt tube ,motor control and video sync mixer board ...show that another day .
Still have to solder the battery supply to the plug feeds the PMT can .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Tue Oct 25, 2016 7:32 pm

Heres the PMT can power supply sockets and controls the work i am up to.
Wiring is still a bit of a mess and i still have to add a led which i will have to light proof from the back and a connector for an audio jack ..might put in another socket for my oscilloscope and a multi position switch wired to different test points in the circuit so i can view what i can't get at any more when its inside the can .
Might also be wise to have a fine tuning of the motor control if the battery pack works well enough ,so just thinking of things to add before i do a Nipkow test with the PMT .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Oct 30, 2016 5:01 pm

More wiring mess today but only way to move on is have a control panel...looks like i will have to put a bit of touch up paint :|
Not easy mounting stuff in the end of a can i have found out time consuming it is ...a few changes to the position of controls to get them to fit when mounting .
Hope i get some results that would be nice ~! :roll:
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Fri Nov 04, 2016 11:08 pm

Another day more wiring .......all that's left is soldering up the sync led indicator and hooking up the nipkow motor and the PMT to this ....power supply tests seem good on the battery and inverter to camera circuit board....
Changed the multi test signal switch the older one i had for years seemed a bit intermittent so i now have 6 test points with the new one,that's the 6 colour wires on the back of the main board.
Hope to do a Test run very soon i need to check each test point once more if every thing cooperates i will switch on the PMT .
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Re: Photomultiplier Tubes camera build

Postby ppppenguin » Sat Nov 05, 2016 1:59 am

I'm rather late to this party but I have a copy of the EMI Photomultiplier catalogue from 1970. I've scanned and uploaded the relevant pages for the 9524.

Many years ago I worked with PMTs in Cintel telecines and elsewhere. The HT needs to be very smooth indeed but you'd probably get away with an inverter and plenty of smoothing. This is easy at the low currents involved. The voltage needs to be very finely adjustable to vary the sensitivity. And of course it needs to be very stable. The cheap and cheerful answer for lab work used to be a string of type 126 90V batteries. Not really an option now but I suppose you could fit a lot of PP3s together :D

In an earlier post I saw a circuit with a string of zeners feeding the dynodes. This feels instinctively wrong as you want the dynode voltages to track the overall voltage. You might well use a 150V zener from the cathode to the first dynode as recommended in some EMI notes. Otherwise the current in the dynode chain wants to be at least 10x the anode current. The mean anode current should rarely be more than 100uA so a few mA down the chain is about right.

Hope this helps.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sat Nov 05, 2016 7:12 pm

ppppenguin wrote:I'm rather late to this party but I have a copy of the EMI Photomultiplier catalogue from 1970. I've scanned and uploaded the relevant pages for the 9524.


OH any one can join my party when ever you want :wink: Thanks for the scans this is very helpful there are so many different PMT's but very few data related to the ones i own so again big thanks for this !

Many years ago I worked with PMTs in Cintel telecines and elsewhere. The HT needs to be very smooth indeed but you'd probably get away with an inverter and plenty of smoothing.


Well when i started i tried some inverters from china and the rf noise was dreadful but the inverter i am trying here seems very good ...i have designed the project to work from either a bench top supply i know the DC is free of any noise but a touch more deadly than the battery inverter idea ...any case the supply will at least work from the bench top which has been tested non stop for a week .

This is easy at the low currents involved. The voltage needs to be very finely adjustable to vary the sensitivity. And of course it needs to be very stable. The cheap and cheerful answer for lab work used to be a string of type 126 90V batteries. Not really an option now but I suppose you could fit a lot of PP3s together :D


That battery supply from your old work would be be deadly as well i should think but i see if you had them and the space why not .....

i hope my camera works at all but the reason i want a small portable inverter also and same for the battery supply is i think it would be different to make a portable NBTV camera ...its does not have to work for long just enough for proof of concept ...

I
n an earlier post I saw a circuit with a string of zeners feeding the dynodes. This feels instinctively wrong as you want the dynode voltages to track the overall voltage. You might well use a 150V zener from the cathode to the first dynode as recommended in some EMI notes. Otherwise the current in the dynode chain wants to be at least 10x the anode current. The mean anode current should rarely be more than 100uA so a few mA down the chain is about right.


OK i will not use that idea in future work i have been happy with the simple resistor chain ,i will use the 9524s for the next project on PMT's as i have 2 of those they are smaller than my RCA tube i am using here ...new to them and never been able to get my hands on one till this year i really like experimenting with them .


Hope this helps.


Yes you have data sheets are like gold !
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Re: Photomultiplier Tubes camera build

Postby ppppenguin » Sun Nov 06, 2016 8:47 am

Glad I could help.

Actually 10x 126 batteries wouldn't be a very big or heavy lump. But dangerous as you suggested. I suppose up to 100x PP3 isn't totally absurd. You're unlikely to need more than 900V.

Many years ago ISTR making a very simple flyback inverter to power a vidicon or plumbicon tube. I don't have any details now but it was pretty crude. I think it gave about 800V which I stabilised with a string of zeners. You might get some decent results wth an old diode split LOPT driven by a very modest amount of switched power. I've kept a couple of old CRT PC monitors to provide not just the LOPT but also the drive circuits.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Nov 06, 2016 9:15 am

ppppenguin wrote:Glad I could help.

Actually 10x 126 batteries wouldn't be a very big or heavy lump. But dangerous as you suggested. I suppose up to 100x PP3 isn't totally absurd. You're unlikely to need more than 900V.

Many years ago ISTR making a very simple flyback inverter to power a vidicon or plumbicon tube. I don't have any details now but it was pretty crude. I think it gave about 800V which I stabilised with a string of zeners. You might get some decent results wth an old diode split LOPT driven by a very modest amount of switched power. I've kept a couple of old CRT PC monitors to provide not just the LOPT but also the drive circuits.



Thanks Jeff I have gone with 4 9 volt batteries the motor i am using is very small ,not sure how long they would run this but should be at least a few minutes before it runs down to below the 12 volt regulators ..

But again the inverter and battery supply are not really needed i can run this off my bench supply as i started out to do just would be nice to run portable if it can ...

MY tube seems to run from negative 900 to 1200 volts ...degrades in signal a lot below 900....i was reading lab guys flying spot scanner experiment just sticking a PMt in front of a tv he had to reduce the PMT voltage to 250 volts due to the amount of light to get a correct tv signal .

Pity you don't have any information on the vidicon and plumbicon tube experiments you did left very little experiments on these these days Troy on this forum has many different image tubes he'd be interested in what you got up to as i am sure others me too .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Fri Nov 11, 2016 1:58 pm

I have been lucky till now i found my Trany BC109 was faulty in the video sync mixer i ended up replacing that with a 2n2222..so thats working now
Just been looking at every thing to make sure the thing out puts something at least .
Its looking good for a Test run with the PMT i think it will be a little disassembled as far as the front nipkow and back can for a test

The sync photo is what i am getting out of R9 and R10...theres a little bit of noise which i don't see on the CRT scope i think its just this crappy PC scope with my knocked together probe any case its good for testing in the house .

So this is about it as far as construction gos just have to try it with the PMT in the next day or 2 ...my only worry is that it will pick up the light from the opto reflecting switch and or i have missed something about the optics side ....i will find out soon .
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Last edited by Harry Dalek on Fri Nov 11, 2016 9:30 pm, edited 2 times in total.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Fri Nov 11, 2016 8:33 pm

Had a bit more time this afternoon than i tend to so ....
I have hooked every thing up ready for a test run tonight just waiting for it to get dark may have problems with the room lighting don't know ...don't even know what to expect i just feel safer as i can turn lights on and off and see how it gos may get strobing from what i have read i will try it in day light when i know something is happening image wise.
I will run the PMT from a low voltage and work my way up see if i can get it to show any thing ...as i said in the last post i will have to run it looking like this for now ,no point putting it together till i know it is working
Trying the bench power supply tonight first as i started this project to do ....Fingers crossed
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Fri Nov 11, 2016 10:00 pm

I have just been doing a test run no real changes to adjustment i have been able to see a ruff iron cross drawing from my test card via a little torch for the light source and running the pmt on 630 volts negative this is very promising .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Fri Nov 11, 2016 11:14 pm

Tonights a good night if any thing so far its a proof of concept still very very ruff results but i have not adjusted a thing apart from trying to move the test card in front of the lens in focus .

Just using this Iron cross drawing i used on my flying spot camera go a few moons ago this time its a little more ruff but i could clearly see it as i moved it about in front of the lens .

I am out putting the video signal to my laptop and using Gary's Big picture to view it live sorry video results are so poor once again hard trying to keep it in focus in the light and film in the other hand least i got something to show tonight ...

Looks like a have some improving to do but very happy its going and this time 3rd time lucky on a direct light camera boy they are hard ....
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sat Nov 12, 2016 11:31 am

Test this morning i have got better results in room light very dull day... see the nbtv letters in my test card and iron cross

My hand in the other small viewer..and the little pig toy last video ...

Still a little washed out ,from the little time i got this going i see the advice on adjusting the high negative is one way to get the camera to work at least close to see something viewable also adjusting the light level to the object is another way ,still working on 630 volts negative just above its starting to work voltage of 500 volts .

Just been using room light today which to me is amazing how sensitive it is it does need a touch more light or voltage to get the correct shading levels.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Nov 13, 2016 10:42 am

Today i am going to adjust the camera some more i can see my sync pulse is perhaps to wide i have an adjustment on ic2 for the pulse width.

i will also have a look at the high voltage negative and preamp level and do some more video tests.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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