Armory Sponsor
Posted: 7/26/2007 5:16:39 AM EDT
|
Okay guys, got another info request for you. he For your info you can see the specs at this site below XR-5 2nd gen tube specs They list minimum lifetime at 15,000 hrs, but I was looking for the sensitivity curves over the lifetime of the tube if it's out there. |
| I heard from many people that they were in the 7500 to 8000 hour range. I believe they advertise 5000 hours but I saw some posts with someone talking to Ed Wilcox and I am pretty sure they were the figures. Its just a couple thousand hours shy of a Gen 3 tube. I don't think I can put 10,000 hours on my tube in the rest of my life so I just don't worry about it much. Hope this helps. |
|
Thanks for that info DinoSnyder. They've come a long way with 2nd generation going by the specs. I used to have sensitivity curves over the lifetime of 3rd gen tubes and the older DEP XD-4 tube. And the interesting thing aboout the curves is that the DEP tubes maintained more sensitivity and performance over the lifetime of the tube vs. gen 3. Mind you this was DEP's literature, but I was interested to see how these new autogated gen 2 XR-5's compared with Pinnacle tubes. |
| I would be interested to see a study about just how much a tube does degrade over time be it a US Gen 3 or a DEP tube. I know the tube rates at 10,000 hours but I would be interested to see how well the tube performs at say 9000 hours from the specs when it was new.Maybe even a tube with 100 hours that was used very little buy a consumer over a 10 year period.I am sure age and use are a factor Would the dif be drastic? I just don't know and have never seen a study by anyone that does.I am sure someone somewhere has this info (ITT) but nobody is forthcoming on the information. It may be out there but I have just never run across it ! Vic do you know?? |
|
Okay, found it he For Gen 3 tubes the ion barrier film was introduced not to extend life time of these devices beyond that of Gen 2, but to prevent an immediate decay of the GaAs photocathode. This photocathode is extremely sensitive to ion feedback as the top layer of Cesiumoxide is oly a few monolayers thisk and can easily be sputtered away. The drop in sensitivity per removed layer is orders of magnitude higher than for S25 photocathodes. The chart I have for the Super Gen 2 vs. Gen 3 shows both starting at 100% relative sensitivity. At 2,000 hrs Gen 3 is at 90% Super Gen 2 is at 95% At 4,000 hrs Gen 3 is at 80% Super Gen 2 is at 90% At 6,000 hrs Gen 3 is at 77% Super Gen 2 is at 83% At 8,000 hrs Gen 3 is at 64% Super Gen 2 is at 77% At 10,000 hrs Gen 3 is at 60% Super Gen 2 is at 75% Image Quality: A Gen.2 tube provides nicer images than a Gen. 3 tube: the images of Gen 3 tubes are more "cloudy". The reason for the latter is the etching down of the GaAs photocathode to a thickness of a few micrometers in an acid liquid which is a very difficult to control process. The scenes to which image intensifiers are exposed are often very dynamic. Also under these conditions they have to provide an image of good quality. In addition to the normal requirements like little shading, no Fixed Pattern Noise (FPN) and a limited number of spots, this sets extra requirements with respect to the image quality under these conditions. We will show that the Super Gen tubes have advantages compared to a Gen 3 tube under these dynamic conditions. Image Burn In: It is of course very important that any image burn in be avoided. In Gen 2 tubes image burn in is primarily caused by ion feedback which etches the photocathode. Thanks to the unique DEP tube manufacturing process there is only a little ion feedback in the DEP tubes which means that until rather bright light-level conditions are experienced, No burning occurs. In gen 3 image intensifiers burn in occurs at the ion barrier film and therefore this tube is much more susceptible to burn in. Clamp Operation: At higher light levels the Photocathode/MCD voltage will drop to the so called clamp value in order to maintain an image on the screen. For Gen 3 tubes this clamp value is close to the film threshold value. So, very small thickness variations in the film will lead to large non-uniformities. This may totally spoin the image. A Super Gen. tube has no ion barrier film and hence will not have these problems. Bright Spots: Pinholes in the film will appear as bright sopts in the image at high light levels. Again, in Super Gen tubes these bright spots will not be present because there is no film. And that's all I have for now, if anyone can help add this info please feel free to post it. |
|
An excellent question 1paintball, I can tell you that the XD-4 is at a disadvantage under the conditions you mentioned. The XR-5 Autogated is literally running neck and neck with the Pinnacle tubes though under those conditions. XR-5 Specs Above is a data sheet of the XR-5, a lot of the figures are very close to the U.S. Pinnacle Tubes in regards to resolution, Signal to Noise, and lifetime, even the Photocathode response is rated minimum 700 uA/lm and this is without an ion barrier film. I see they even came out with a Black and White Phosphor version of these tubes called Onyx, specs are here I find it rather facinating that the European countries opted to keep advancing on 2nd gen technology to the limit that it has, while we here in the U.S. abandoned it and focused all efforts on the 3rd gen technology. I'm still trying to find a photo comparison of these tubes vs. 3rd gen to see the differences EDIT: Found a Review of a law enforcement test of Gen 3 Pinnacle vs DEP 2nd gen SHD3 tube Link is Here Comparison between SHD-3 XD-5 and XR-5 is Here The paper lists the XR-5 light levels as 10-6 to 10 to the fifth or Full Sunlight |
|
Slow day for me, found some more info XD-4 vs Gen 3 Omni IV paper is here |
|
Hey 1paintball, After firing a few questions to DEP Photonis it seems that not only is the XD-4 at a disadvantage, but the XR-5 as well under extremely dark conditions. The European standard uses a different light test when coming up with the signal to noise ratio and the microlux test uses a brighter light than we use here in the U.S. for testing tubes. I can see where the XR-5's have some advantages and would be a nice choice if there is skyglow from a nearby city, or a few lights here and there, but these things just can't compare to the Pinnacle tubes when it comes to creating an image under the darkest of conditions. |
Dont think so, from what ive seen/know its the SHD-3 thats SHP. HTH, Dave. |
|
Armory Sponsor