Hinds Instruments offers an avalanche diode photodetector module that is optimized for use with the PEM and low light levels. It is less expensive, safer, more rugged and easier to use than a photomultiplier tube (PMT).
The gain is adjustable and the bandwidth is DC to 450 kHz, making it useful for circular dichroism experiments and other polarization measurements that involve small, fast (PEM frequency) signals.
Hinds designed the module using an avalanche photodiode that is sensitive to a minimum 5 microWatt (at maximum gain) signal and is usable from 200 1000 nm. While it is not sensitive enough for photon counting, it is well suited for most other applications that previously required a PMT. Unlike a PMT, it does not require the expense or large footprint of a high voltage power supply.