# Characterization of a silicon photo-multiplier array with summing board as a photo-multiplier tube replacement in organic scintillator assemblies

## TL;DR

This study demonstrates that summing outputs from silicon photomultiplier arrays can match traditional photomultiplier tubes in energy, timing, and pulse-shape discrimination for organic scintillator detectors, offering a compact alternative.

## Contribution

It introduces a method to replace photomultiplier tubes with summed silicon photomultiplier arrays in scintillator assemblies, showing comparable performance.

## Key findings

- Silicon photomultiplier arrays achieve 13.6% energy resolution at 341 keVee.
- Timing resolution of 277 ps in the 100-400 keVee range.
- Pulse-shape discrimination figure-of-merit of 2.21 in the 230-260 keVee range.

## Abstract

We report on the energy, timing, and pulse-shape discrimination performance of cylindrical 5 cm diameter x 5 cm thick and 7 cm diameter x 7 cm thick {\it trans}-stilbene crystals read out with the passively summed output of three different commercial silicon photo-multiplier arrays. Our results indicate that using the summed output of an 8x8 array of SiPMs provides performance competitive with photo-multiplier tubes for many neutron imaging and correlated particle measurements: for the 5x5 cm crystal read out with SensL's ArrayJ-60035\_64P-PCB, which had the best overall properties, we measure the energy resolution as 13.6$\pm$1.8\% at 341 keVee, the timing resolution in the 100--400 keVee range as 277$\pm$34 ps, and the pulse-shape discrimination figure-of-merit as 2.21$\pm$0.03 in the 230--260 keVee energy range. These results enable many scintillator-based instruments to enjoy the size, robustness, and power benefits of silicon photo-multiplier arrays as replacement for the photo-multiplier tubes that are predominantly used today.