|A fact from Image intensifier appeared on Wikipedia's Main Page in the Did you know? column on 9 April 2004. The text of the entry was as follows: "Did you know
- Unless somebody has an objection, I am going to merge this page with Night Vision System. Anybody? Tmaull 17:32, 9 September 2007 (UTC)
Re: Image Intensifier and Night Vision System The original article was moved to NVD (Night Vision Devices) and Merged, however both the IIT page and NVD page tended to create too much cross-over information.
I've re-created this page for Image Intensifier Tubes only, supporting other pages such as specific Night Vision Devices.
I've also delete the original discussion as that only pertains to material merged with NVD.
Within the NVD talk, you'll find comments that related IIT information to other areas has now disappeared, so I recreated this page.
So far I only have the history down, but additional material will cover specifics on all known types of tubes, cover medical and scientific aspects of IITs, deal with Gating and also list specific details of known IITs (eg, MX10160, MX9644 etc).
Reduction or oxidation?
While translating this article for the Dutch Wikipedia, I came across a very strange statement. Under Image intensifier#Generation 2 - The micro-channel plate it says "Reduction of the cesium to cesium oxide in later versions ...".
Well, I am a physicist, not a chemist. But I think I remember enough from earlier chemistry lessons to know that changing an element to its oxide is called oxidation, which is the opposite of reduction.
So I would suggest to change the text to "Oxidation of the cesium to cesium oxide in later versions ...".
Hmmm, you know, you have a point there. The word reduction was used in the original white paper that discussed the method above, but it was probably used incorrectly - I'll recheck the reference material and get around to changing that as needed - Thankyou - —Preceding unsigned comment added by David kitson (talk • contribs) 01:57, 27 March 2010 (UTC)
It would be interesting to include a short explanation why the color green was chosen for use in night vision goggles. — Preceding unsigned comment added by 188.8.131.52 (talk) 10:51, 17 October 2011 (UTC)
An interesting question. Conventional wisdom has it that green is the color we see best, however an evaluation of the phosphor properties seems to contribute to the reasons. In fact, Image intensifiers do come in different colors, even white now ( Photonis Onyx ) - I'll collect the reasons and add them, but it's not specifically science because the original reasons are lost to time. Even now, the US still don't make military intensifiers in other colors, but Europe does. — Preceding unsigned comment added by David kitson (talk • contribs) 22:32, 15 November 2011 (UTC)
Major Update in the works
Time I guess to do this - Expect a lot of changes over the next few months as I add technical content... I have probably left this far too long. Thanks, David Kitson. — Preceding unsigned comment added by David kitson (talk • contribs) 15:31, 5 January 2012 (UTC)
Microchannel plate info Gen 2
I don't know if this is relevant here, but...
I worked for the Niles, IL. Rauland Corp, a subsidiary of Zenith, as a lab technician in 1967 after active duty in the Navy and before U of I. I worked on MCPs there.
Fabrication started with lead glass pipettes that were heated in a vertical oven arrangement where continuous lengths were heated and stretched to shrink the diameter down to somewhere around a millimeter or two, then broken into, I think it was, about 12-15 inch lengths. I think there may have been a second intermediate step where these were somehow combined into secondary, small bundles and stretched, but can't recall the detail.
Then, these were bundled into a large "boule" (rhymes with fool) and placed in another vertical oven that heated it with, as I recall, a weight hanging on the bottom. The boule would stretch, further shrinking the diameters. Slices of this were then made and shaped into about a 1.25 - 1.38 inch diameter, 1/6 inch thick plates. They had somewhere around 1-3 million holes, as I recall.
Another process that I don't recall details of used, I believe just heat, to bring the lead to the inner surfaces of all the holes. This made a very good secondary emission surface. Each electron that entered would "splash off" many in several bounces along the small tubes, thus giving the gain.
The plates were then put into a vacuum dome and Aluminum was evaporated on both faces for the accelerating voltage surfaces. This was done by placing an aluminum pellet into a heating coil in the center of the chamber with MCPs all around the perimeter. The coil was heated in the vacuum and the plates were coated along with a very shiny, mirror-like coating on the inside of the glass bell-dome chamber cover.
For testing, we had a wheel that had places for a number of MCPs inside a 2-1/2 foot diameter vacuum chamber. There was a photo cathode with the electron optics on the rear and lighted image on the back of the chamber and a phosphor screen on the front door right in front of the MCP. The chamber wheel was loaded with the MCPs for testing and the front closed. First, liquid nitrogen cooled "Sorption" (a.k.a. absorption) pumps were used then, a Varian ion pump to pull the vacuum.
Each MCP was rotated in place, the image evaluated and the photo cathode current compared with the screen current to get the gain. As I recall, the gains were on the order of 10,000 to 30,000.
I designed and built a battery powered high voltage supply to make a portable unit for full night vision tube, made in another lab. Rauland made CRTs and other special tubes, such as scan converters, that my Dad developed.
One of the tests I observed was in a large completely dark, windowless interior lab. A single cigarette, when puffed, would illuminate the entire lab enough to read text in the tube.
We had the use of a "Starlight Scope" that we were told was currently used by the military in Viet Nam. It had quite poor resolution and very low gain compared to ours. We were told it had three cascaded, non-MCP (photo cathode and screen) gain tubes.
We were also told that the MCPs also had medical filtering applications and we sent some, I believe, to Canada.