SiPMs coated with TPB : coating protocol and characterization for NEXT

TL;DR

This paper presents a protocol for coating silicon photomultipliers with TPB to enable detection of xenon scintillation light at 175 nm, crucial for background rejection in neutrinoless double beta decay experiments.

Contribution

It introduces a new coating protocol for SiPMs with TPB and characterizes their performance in the UV-VUV range for use in NEXT.

Findings

Successful coating protocol for SiPMs with TPB.

Enhanced sensitivity of SiPMs in the UV-VUV range.

Validated performance of coated SiPMs for xenon scintillation detection.

Abstract

Silicon photomultipliers (SiPM) are the photon detectors chosen for the tracking readout in NEXT, a neutrinoless {\beta}{\beta} decay experiment which uses a high pressure gaseous xenon time projection chamber (TPC). The reconstruction of event track and topology in this gaseous detector is a key handle for background rejection. Among the commercially available sensors that can be used for tracking, SiPMs offer important advantages, mainly high gain, ruggedness, cost-effectiveness and radio-purity. Their main drawback, however, is their non sensitivity in the emission spectrum of the xenon scintillation (peak at 175 nm). This is overcome by coating these sensors with the organic wavelength shifter tetraphenyl butadienne (TPB). In this paper we describe the protocol developed for coating the SiPMs with TPB and the measurements performed for characterizing the coatings as well as the performance of the coated sensors in the UV-VUV range.