Approaches for single channel large area silicon photomultiplier array readout

C M Lavelle,C Chiang,M Nichols,J Osborne,B Brown,W Shanks,A Herschelman,M Cho

doi:10.1063/1.5088503

Abstract

We present the results of experiments applying a large area tiled array of silicon photomultipliers (SiPM) to gamma ray spectroscopy with 50.8 mm diameter NaI(Tl) and CsI(Tl) scintillators and 25.4 mm diameter CeBr3. These scintillators are many times larger than an individual SiPM, the largest of which are 36 mm2 at present. This work compares two methods of summing 64 SiPMs into a single output signal for use with standard charge integration electronics. The methods are a straightforward passive method, which simply combines all anode and cathodes together, and an active method, which employs high bandwidth op-amps in a summing topology. Comparisons are also made to a high quantum efficiency photomultiplier tube (PMT) for both resolution and pulse shape. Resolution and noise floor are satisfactorily comparable to the PMT from 21 keV to 2614 keV. The passive method provides the most straightforward approach, and slightly better energy resolution than the active method. The active method shows a substantially faster pulse rise time and undistorted fall time compared to the passive method.

Highlights

We present the results of experiments applying a large area tiled array of silicon photomultipliers (SiPM) to gamma ray spectroscopy with 50.8 mm diameter NaI(Tl) and CsI(Tl) scintillators and 25.4 mm diameter CeBr3
A number of groups have reported success with larger photosensitive areas using tiled arrays of SiPM arranged in a parallel sum
The key issue we aim to address is the combination of an array of many SiPMs into a single output signal

Summary

Introduction

The silicon photomultiplier (SiPM) is broadly applied in scintillation applications, despite being a relatively recent development.. The silicon photomultiplier (SiPM) is broadly applied in scintillation applications, despite being a relatively recent development.1 These applications include compact portable instrumentation and the type of high channel density measurements conducted in elementary particle physics or medical imaging.. A number of groups have reported success with larger photosensitive areas using tiled arrays of SiPM arranged in a parallel sum.. It is unlikely that the photosensitive area of tiled SiPMs will be able to continue to expand without limit. SiPMs have large detector capacitance, high dark current and significant correlated noise. These effects sum to large levels in tiled arrays

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