Measurement of Energy Resolution with the NEXT-White Silicon Photomultipliers

TL;DR

This paper measures the energy resolution of silicon photomultipliers (SiPMs) in the NEXT-White detector, showing promising results for future SiPM-based readout systems in neutrinoless double beta decay experiments.

Contribution

It provides the first detailed measurement of SiPM energy resolution in the NEXT-White detector, highlighting potential improvements and implications for future detector designs.

Findings

Measured energy resolution of (10.9 ± 0.6)% FWHM with SiPMs

Poor correction methods currently limit resolution accuracy

SiPM noise is negligible with proper noise subtraction

Abstract

The NEXT-White detector, a high-pressure gaseous xenon time projection chamber, demonstrated the excellence of this technology for future neutrinoless double beta decay searches using photomultiplier tubes (PMTs) to measure energy and silicon photomultipliers (SiPMs) to extract topology information. This analysis uses $^{83m}\text{Kr}$ data from the NEXT-White detector to measure and understand the energy resolution that can be obtained with the SiPMs, rather than with PMTs. The energy resolution obtained of (10.9 $\pm$ 0.6) $\%$, full-width half-maximum, is slightly larger than predicted based on the photon statistics resulting from very low light detection coverage of the SiPM plane in the NEXT-White detector. The difference in the predicted and measured resolution is attributed to poor corrections, which are expected to be improved with larger statistics. Furthermore, the noise of the SiPMs is shown to not be a dominant factor in the energy resolution and may be negligible when noise subtraction is applied appropriately, for high-energy events or larger SiPM coverage detectors. These results, which are extrapolated to estimate the response of large coverage SiPM planes, are promising for the development of future, SiPM-only, readout planes that can offer imaging and achieve similar energy resolution to that previously demonstrated with PMTs.