SiPM super simple spectroscopy

Recently I’ve tested this super simple circuit capable to collect pulses from a SiPM and amplify and pulse-shape them. The pulse shaper Tau constant is 250uSec, this way the resulting shaped pulse could be directly sampled by a PC audio card via Mike input line.

The resulting prototype was made by etching it over a single side bakelite PCB board.

There is no 32-45V power supply for the SiPM polarization. I’ve obtained it by a series of 4x 12V alcaline batteries followed by a linear regulator. SiPM diodes are very sensible to supply noise… batteries in their simplicity provide excellent noise performance.

The shaped pulse looks good and performs well. Tested with my PC soundcard and an 8x8x50mm CsI(Tl) crystal.

FWHM is acceptable. The opamp used must be swapped with something with better bandwidth gain.