Ph.d. degree
Weizmann Institute of Science, Rehovot, Israel, 2023

Andrea Tesi

Supervisor: Shikma Bressler

Development of novel light and charge readout concepts for liquid argon particle detectors

Keywords:

• Noble liquid detectors (scintillation, ionization, double-phase)
• Micropattern gaseous detectors (MSGC, GEM, THGEM, RETHGEM, MHSP, MICROPIC, MICROMEGAS, InGrid, etc)
• Charge transport and multiplication in liquid media

Abstract:

Over the course of the past couple of decades, significant advancements have been made in the field of noble-liquid detectors. Particularly notable are the applications in the domains of neutrino physics and the exploration of dark matter. When particles interact within noble liquids, they produce distinct signatures in the form of light and charge, capable of traversing great distances with minimal losses. This high property, coupled with their exceptional density and potential for expansion, renders noble-liquid detectors highly sought-after for experiments necessitating substantial target masses, negligible background interference, position reconstruction, and high sensitivity to low-energy radiation deposits. The most advanced version of these detectors is the dual-phase Time Projection Chamber (TPC), although concerns persist regarding the scalability of the various signal readout technologies associated with TPCs, particularly in the context of forthcoming multi-ton experiments (Darwin 50 ton LXe, DUNE: 100’s of Kton).

The first part of this thesis work revolves around the innovative concept of the Liquid Hole Multiplier (LHM). The LHM represents a single-element sensor designed to simultaneously detect radiation-induced ionization charges and scintillation light within a noble-liquid detection medium. The underlying principle involves harnessing the phenomenon of electroluminescence (EL) generated in a gas bubble that is confined beneath a perforated electrode coated with Cesium Iodide (CsI) and submerged in the noble liquid. This enables the detection of both ionization electrons and UV-induced photoelectrons, opening up new possibilities for comprehensive radiation detection and analysis. In the second part, two additional concepts for charge multiplication, known as the cryogenic Resistive WELL detector (RWELL) and the cryogenic Resistive Plate WELL detector (RPWELL), were explored. Novel resistive materials, thin films (DLC), or plates (ceramics, thermoplastics), have been engineered for operation at cryogenic temperatures and incorporated into the detector assemblies. It was demonstrated, for the first time at liquid argon temperature, that embedding resistive materials into the detector assemblies results in a performance upgrade and in protection against electrical instabilities.