George Herold wrote:
> Well I did a bit better than that ~ 20k photons. But I think I'm
> finally getting my head around the issues. I really care about C and
> the voltage noise.
> I measured about 0.2 mVrms of noise but only 1 Meg ohm Rf
Well, one of the interesting things is to test the amp without
the detector, then with the detector with no bias and then with
reverse bias on the detector. The lowest noise will be with no
detector (detector capacitance increases noise gain, and also there
is thermal noise generated in the junction.) This is worst
with the detector un-biased, you can watch the noise drop
dramatically with even a few Volts of reverse bias.
Rf really only controls the time it takes to recover to baseline.