MPGDs in Compton imaging with liquid-xenon

TL;DR

This paper discusses the development of a liquid-xenon time-projection chamber for 3 gamma imaging, utilizing MPGDs for detecting scintillation and ionization signals, with preliminary results and future detector plans.

Contribution

It introduces a novel liquid-xenon TPC for 3 gamma imaging and explores the use of MPGDs and gaseous photomultipliers for signal detection.

Findings

Successful detection of scintillation signals with vacuum photomultiplier.

Preliminary results from a THGEM-based gaseous photomultiplier.

Feasibility of using MPGDs in liquid xenon for nuclear imaging.

Abstract

The interaction of radiation with liquid xenon, inducing both scintillation and ionization signals, is of particular interest for Compton-sequences reconstruction. We report on the development and recent results of a liquid-xenon time-projection chamber, dedicated to a novel nuclear imaging technique named "3 gamma imaging". In a first prototype, the scintillation is detected by a vacuum photomultiplier tube and the charges are collected with a MICROMEGAS structure; both are fully immersed in liquid xenon. In view of the final large-area detector, and with the aim of minimizing dead-zones, we are investigating a gaseous photomultiplier for recording the UV scintillation photons. The prototype concept is presented as well as preliminary results in liquid xenon. We also present soft x-rays test results of a gaseous photomultiplier prototype made of a double Thick Gaseous Electron Multiplier (THGEM) at normal temperature and pressure conditions.