Armory Sponsor
Posted: 4/13/2015 5:19:25 PM EDT
| I know we can make a gen 1 cascade device by aligning 3 gen 1 tubes, but has anyone ever tried to put two gen 3 tubes together to see what happens? I was thinking if the front tube was set at low gain so a clean signal went into the second tube and then the gain on the second tube can be turned up to boost the signal that way. I'm sure it's been thought of before and there's a reason why it doesn't work. I'd love to hear about it. |
|
I am by no means an expert on this, but I would expect this is not done for the following reasons:
1) It is not needed for a gen3 device 2) It is bad for the gen3 device if it is exposed to any visible light (the front device would be emmittting an image that was bright enough to degrade the rear device) |
|
They already did something similar. Gen 3+1 25mm tube. Had the most gain of any tube I have ever used. It is a rare tube to find. They used to make wild tubes but cost and standardization kind of killed that. Now everything is about what we can mass produce cost effective but still performs acceptably. I am sure some special tubes are made for covert long range surveillance and special forces but these are not made in any bulk and are most likely very expensive.
Filmless tubes are still commonly used for high end needs. |
|
They do cascade the MCP internally when required to achieve this output, without the optical losses, but the MCP noise is still increased. With 2 stages of MCP, you can visualize singe photons, although if you manually cascade two Gen3 devices ( just hold them together ) you can do this anyway. And what Dino said was absolutely correct. Gen3+1 cascaded a Gen3 and a Gen1 stage - the Gen1 stage was used as a low-noise amplifier and provided significant gain. They were most commonly used to spot aircraft in the SNS ( Stinger Night Sight ) - but also had some other uses. However they cost significantly more than a normal Gen3 tube to make. Regards David |
|
Quoted: That's very interesting. Have any of you actually tried putting two tubes together (powered of course) and looked through? I would imagine it would be a good idea to turn the gain down fully on both tubes to begin with. Yes, some of us have done it - You need to have optical parts to do it so use a couple of monoculars... Just stick them together... And use in very dark conditions. Usually we do it to visualize the level of dark current while covering up the photocathode with foil. You'll see individual scintillation caused by thermionic electron emission. Regards David. |
|
Quoted: i think,cascading can be done through matching fiber optic surfaces. is it possible to stack gen3 tubes that have glass input and concave FO output? Not really, because most Gen3 don't have fiber optic plates for the input window, and glass windows ( or curved FO windows ) require optical parts - eg, the monocular lenses. So putting two monoculars together achieves the same outcome. Regards David |
Armory Sponsor