John Doty says: > Nope. Quantum efficiency of silicon detectors drops like a rock just > beyond 1 ?m wavelength: the radiation just goes right through without > interacting. Indeed, Si wafers make excellent entrance windows for > for thermal IR detectors. v > A 350 K blackbody emits ~271 ?W/mm2 of thermal radiation, but only > ~4.4 fW/mm2 of that is short of 1 ?m. With very fast optics, > cryogenic temperatures, a state of the art scientific CCD, the > extremely low noise video chains I design for astronomy, and rigorous > exclusion of every optical photon, you might be able to see > something. With commercial/industrial technology, not a chance. > > On the other hand, a 350 K component is pretty easy to find with your > finger...
So how do they do this (answer in the last URL)? http://www.x20.org/thermal/ http://www.temperatures.com/tivendors.html http://www.opticsplanet.net/heat-seekers-termal-imagers.html http://en.wikipedia.org/wiki/Thermography John Perry _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user