Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!ucbvax!husc6!bbn!aoa!carl
From: carl@aoa.UUCP (Carl Witthoft)
Newsgroups: sci.electronics
Subject: Re: Night vision devices
Keywords: night vision devices, infrared, light amplifiers
Message-ID: <447@aoa.UUCP>
Date: 30 Sep 88 12:00:28 GMT
References: <38669@yale-celray.yale.UUCP>
Reply-To: carl@aoa.UUCP (Carl Witthoft)
Organization: Adaptive Optics Assoc., Cambridge, Mass. USA
Lines: 31

[posters asked about image intensifiers, GenI,GenIII definition]
Take it from someone who regularly buys these things for industrial
use:
"light amplifiers" is a nontechnical term. It could just as easily
be applied to a laser amplifier stage as an image intensifier.
All image intensifier tubes (IIT) convert photons to electrons with
a photocathode (like a photomultiplier tube does), then amplifies
the electron (current) and excites a phosphor screen to generate
secondary photons (like a TV tube).

GenI : old device, still in use.  Electrons are accelerated thru
focus electrodes, 5 to 30 kV, the high energy of the electron allows
a spray of photons to be emitted when the electron hits the phosphor.

GenII: uses a microchannel plate to provide for massive multiplication
of electrons. May or may not have electron focussing electrodes in
front of or behind the MCP. Same cathode & phosphor setup as GenI.

GenIII: like GenII but with GaAs (or other) cathode for extended 
red- infrared response.

Get lots more info from ITT-Indiana or Varo Corp - Plano,TX.


-- 

Alix' Dad ( Carl Witthoft @ Adaptive Optics Associates)
" Axis-navigo, ergo sum."
{ll-xn,spdcc,...}!bbn!aoa!carl
54 CambridgePark Drive, Cambridge,MA 02140 617-864-0201
"disclaimer? I'm not a doctor, but I do have a Master's Degree in Science!"