There was a lot of work done on GEN III NV devices. They use GaAs photocathodes w/ high QE. The same photocathode works for PMTs.
Detecting single photons is duck soup w/ a PMT. With modest cooling, you can get the dark count down to 1/minute or better. -John ================= > On Fri, Feb 14, 2014 at 7:45 AM, J. Forster <[email protected]> wrote: > >> You should not denigrate PhotoMultiplier tubes. >> >> They are virtually perfect, almost noiseless, detectors. With the right >> photocathode, they are capable of QEs >50%, spectral response from the >> VUV >> to near IR, and dark counts <1 PPS, with maximum count rates >10 MPPS. >> Thay can easily have current gains of >10E+6 >> > > Really? I used to work on photon-counting systems for photometric > astronomy. As I recall, the best quantum efficiency I had ever seen was > around 21%. Which cathode material are you talking about? > > Conversely I remember working on current amps for photodiodes. The > photodiodes I was playing with had QEs of 90% but, of course, they had no > current gain. Detecting individual photoelectrons is a challenge. > > Yeah, PM tubes are very cool devices, especially if you cool them to > reduce > the emission of thermal electrons. ;-) > > -- > Brian Lloyd, WB6RQN/J79BPL > 706 Flightline Drive > Spring Branch, TX 78070 > [email protected] > +1.916.877.5067 > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
