Long-Term Characterization of Prototype Silicon Photomultipliers in Liquid Xenon

Presenter: Zihan Rao

Faculty Sponsor: Andrea Pocar

School: UMass Amherst

Research Area: Physics

Session: Poster Session 6, 4:15 PM - 5:00 PM, Auditorium, A40

ABSTRACT

The search for neutrinoless double beta decay is one of today’s most compelling challenges in physics, as its observation would confirm the Majorana nature of neutrinos and provide crucial insights into their absolute masses. A fermion is said to be a Majorana when it coincides with its antiparticle. If this were true for neutrinos, the discovery of neutrinoless double beta decay could help to reveal the reason why we live in a matter-dominated universe in which antimatter is almost absent. In support of this quest, detectors such as the nEXO (next Enriched Xenon Observatory) experiment are under development. My research focuses on the operation and analysis of a Liquid Xenon Cryogenic System at Andrea Pocar’s lab at UMass Amherst - a xenon liquefaction prototype setup run as part of the nEXO R&D. A critical function of the system is to test silicon photomultipliers (SiPMs) in liquid xenon, thereby supporting the development of detectors for nEXO.

My contributions span the operation of the LXe cryogenic system and the waveform analysis of silicon photomultipliers. An SiPM is a highly sensitive light detector capable of resolving single photons. Key performance parameters include single-photon (SPE) resolution, breakdown voltage, dark count rate, and correlated avalanche probability. 

In my work, I characterize the long-term behavior of prototype SiPMs by measuring breakdown voltage and gain in vacuum, gaseous nitrogen, and most importantly in liquid xenon (LXe), and study how xenon scintillation light propagates in an nEXO-like detector configuration.

RELATED ABSTRACTS