If very high gain is needed ( 10 5 to 10 6 ), certain APDs ( single-photon avalanche diodes ) can be operated with a reverse voltage above the APD's breakdown voltage.
22.
Measuring elements of static relays have been successfully and economically built up from diodes, zener diodes, avalanche diodes, unijunction transistors, p-n-p and n-p-n bipolar transistors, field effect transistors or their combinations.
23.
This histogram can then be fit to an exponential function that contains the exponential lifetime decay function of interest, and the lifetime parameter can accordingly be extracted . 16 ~ 64 multichannel PMT systems have been commercially available, whereas the recently demonstrated CMOS single-photon avalanche diode ( SPAD )-TCSPC FLIM systems can offer additional low-cost options.
