John Doty wrote: > On Aug 23, 2008, at 12:48 PM, John Griessen wrote: >> 120 deg F is plenty good, and the amount of near IR in >> that temperature surface is >> enough to see with a CCD I bet. > > Nope. Quantum efficiency of silicon detectors drops like a rock just > beyond 1 µm wavelength: the radiation just goes right through without > interacting. Indeed, Si wafers make excellent entrance windows for > for thermal IR detectors. > > A 350 K blackbody emits ~271 µW/mm^2 of thermal radiation, but only > ~4.4 fW/mm^2 of that is short of 1 µm.
Dang! Thanks for educating me. > On the other hand, a 350 K component is pretty easy to find with your > finger... And to think I've forgotten that much since working for SBRC making detector related circuits! Silicon having 1 µm cutoff window properties is a great memory aid. Won't forget that relation now, thanks, John Griessen _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
