Timing resolution performance comparison for fast and standard outputs of SensL SiPM

A new silicon photomultiplier (SiPM) with a unique fast output signal feature was recently introduced by SensL. For a SiPM device with 3×3 mm² sensitive area, the single photo electron response from the fast output is less than 2 ns wide compared with 50 ns width observed at the standard output. Using the fast readout signal, a coincidence resolving time (CRT) of 190 ps (FWHM - full width at half maximum) was measured with a 3×3×10 mm³ LYSO crystal optically coupled to the SiPM mounted on the SensL MicroFB-SMA evaluation board. Applying additional C-R high pass filters to the standard SiPM output, we shortened the SPE response from 50 ns to 3 ns width and measured CRT values similar to those obtained with fast output signals. We have studied the effect of external filtering on CRT with two SensL 3×3 mm² devices with different microcell sizes (35 μm and 50 μm). For both devices studied, we demonstrated similar CRT performance between the fast output and standard output with optimized pulse shaping filter. However, for applications requiring simultaneous measurement of intensity and timing of light pulses, the availability of a separate fast output directly from the sensor is convenient because it reduces the need for additional circuits and provides CRT performance equal to external filters optimized for the standard outputs.