Image Intensifier Tube DEP 80D100

[ArVo]

Hallo,

my question might be slightly off topic - because it is not about thermal imaging. But I did not find a better place to post it:

Does anyone of you have some information about an image intensifier tube from DEP, 80D100 ? It seems to be a second generation image intensifier tube with adjustable gain. And it looks older than todays much smaller image intensifier tubes. (Maybe 1980ies to 1990ies?)

I am searching for some kind of data sheet, with some general technical specifications like signal-to-noise ratio, EBI, resolution etc. (The tube seems to look quite similar to a XX1420. Or is this even just another designation for the same tube? But I do not have any information about the XX1420 tube, either.)

Maybe you also know a better forum especially suited to this more vintage kind of night vision stuff?

Many thanks in advance and with best regards
Arne

[Lambda]

Hi ArVo

At least about the XX 1420 some sparse infos...

https://www.ar15.com/forums/armory/Looking_for_info_advice_about_some_tubes__newbie_inside__/18-384502/

https://patentimages.storage.googleapis.com/48/5a/c3/70741c37fddfd3/US4862257.pdf  (see col. 4, l. 65 - col. 5, l.1)

While keeping on investigating for further elements for the DEP 80D100 tube...

Best regards.

[Lambda]

Hi ArVo.

One question, where did you find such reference "80D100".... ?

[ArVo]

Hallo Lambda,

thank you for your first hints! "80D100" is printed onto the tube, at the screen end:



In the past there was a german forum about night vision technology with a huge base of knowledge, also of this kind of older stuff. But sadly that forum closed some time ago.

Best regards
Arne

[NeoWang]

It seems not just simple gen2 intensifier, XX1420 is a mix-connect intensifier, whitch means it has a gen1 tube connect to a gen2 tube inside. photocathode of a gen1 tube connect to screen of gen2 tube to enhance gain of hole unit.this type of tube usually get good gain(around 20000~60000 FL/FC) and resolution（41-57lp,usually 8 or 12 μm MCP）at that time,but not that good sigal-noise(3-8,most of product lower than 5). if you want to know more about mix connect tube, you can read this file, all XX1380 series is mix-connect tube
http://bitsavers.trailing-edge.com/components/philips/_dataBooks/1986_T13_Philips_Image_intensifiers_and_Infrared_detectors.pdf

[Fraser]

NeoWang,

That Philips data book is an excellent resource for SPRITE thermal imaging sensor data as well as I.I.T’s. Thank you for linking to it 

Fraser

[ArVo]

Thank you for the informations about this type of image intensifier tube, NeoWang!

I can confirm that the SNR of my tube is quite low, which becomes very prominent with maximum gain in very low light situations. I have two MX-9644 tubes in different conditions to compare the XX1420 to, but both seem to perform slightly better, regarding SNR. What might be the benefit of putting the gen 1 stage behind the gen 2 stage when it will amplify the higher noise level of the microchannel plate, too? From my basic understanding, would it not be better to put a gen 2 stage behind a gen 1 stage to achieve a higher SNR?

Best regards
Arne

[NeoWang]

well, sigle stage gen1 also has lot's of noise in low light condition, infact if you put a sigle stage gen 1 in test a chanber to measurement it's signal to noise, it will not give any result, SN of sigle stage gen1 in test enviroment (put 1.08*10^-4lux 2856k luminance in φ0.2mm area of photocathode) is less than 1. as i know this is because gen1 usually has very bad photocathode sensitivity in about 10-200μA/lm. so if you connect gen2 into gen1's screen, the perfprmance of whole tube will get worse.
 early gen2 photocathode sensitivity is around 400-500, it can do much better to sampling low light signal. and after a gen2 tube intensify the light in it's screen, gen1's photocathode can be work in a much better condition, that's where gen1 tube can take advantage of it's low noise feature.
SN of image intensifier will dynamic change in defferent light condition and because there is no mcp inside gen1 ,the only noise source is photocathde and noise signal of photocathode basically just affect by temp, in low light condition useful signal become very low because of low photocathode sensitivity and noise signal unchagen, and electrostaic feild can't provide enougth gain to separated useful signal from noise signal.
E.G,for a gen 1 tube which has 100μA/lm photocathode sensitivity, a photon hit photocathode and emission an photoelectorn has 1.1keV energy, energy of electron emission by photocathode noise is 1keV , let's say feild gain is around 50, so useful signal after electrostaic intensify will be 55keV and noise will be 50KeV, 5Kev is theres defferent.
In gen2 tube, it has 400μA/lm sensitivity and emission photoelectron energy will be 4.4keV, noise emission is also 1kev. and hypothesis the MCP multiplication ratio is 500. ignore feild gain because double close gen2 basiclly has no feild gain. when the electron reach to screen, electron cause by light signal will be 500pcs of electoron with 4.4kev energy in each electron, which has 4.4*500=2200kev total energy, noise electron will be 500pcs of 1kev electron, total energy is 500kev, ther energy defference of noise signal and light signal will be 1700Kev, energy of light signal is 4.4 times of noise signal and 4.4 will be the Signal to Noise.

[NeoWang]

In case to compare early electron lens inverter gen2 tube, MX9916, and mix-connect tube has double closed gen2 tube for first stage and gen1 tube for second stage, i can't really say which one will be better in SN, but one thing is for sure, ususally double closed tube will has better photocathode sensitivity, this may be benifit to SN. and first stage of mix-connect tube usually will get lower MCP drive votage, this will reduce gain of MCP but also reduce MCP noise, for mix-connect tube, second stage can provide 10-100 times of gain so gain will not be a big question for first stage, but for MX9644, it only has one stage and most of gain is depend on MCP, so MCP noise might be larger.
anyway, compare two kinds of gen2 tube need to do some real mesument, and the result decided everything.

[ArVo]

Hallo NeoWang,

thank you very much for your detailed explanation regarding the SNR behaviour of gen 1 and gen 2 image intensifiers!
In the meantime I tried to photograph the seemingly higher SNR of my tube in question vs a well performing MX-9610 in an AN-VVS2 periscope. I took photos through the ocular of both of them with the same exposure settings in the dark, with both tubes at maximum gain while the objectives were covered, so no light should have entered the tubes. The exposure time in both cases was set to 1 second, so the photo should have "integrated" the noise over this time period. While the photograph of the MX-9610 screen results in a rather calm and dark picture, in comparison the photograph of the other tubes screen shows many of the bright scintillation events at maximum gain. I am not sure which could be the reason for the much stronger scintillation in that tube.



Today I pulled the tube out of the night vision device to check for a part number. And indeed, there is a number printed on its side: 080F37300 .



Google found some information in some kind of NATO part number lists, where it is listed as part of "Optical Sighting and Ranging equipment" from the Netherlands. Sadly I could not find any more detailed information for this part number up to now.

Many thanks and best regards
Arne

[mawyatt]

NeoWang,

That Philips data book is an excellent resource for SPRITE thermal imaging sensor data as well as I.I.T’s. Thank you for linking to it 

Fraser

Just noticed this, isn't that ITT and not IIT?

Best,