Development of a dual-phase xenon time projection chamber prototype for the RELICS experiment

TL;DR

This paper reports on the design, construction, and successful operation of a prototype dual-phase xenon TPC for the RELICS experiment, demonstrating key performance metrics and validating core technologies for neutrino detection.

Contribution

It introduces a prototype that validates the detector concept and technical feasibility for the full-scale RELICS neutrino detection experiment.

Findings

Achieved a sub-keV energy threshold with a single electron gain of 34.30 PE/e$^-$.

Successfully detected 0.27 keV decay events from $^{37}$Ar.

Developed and validated data analysis and simulation frameworks for future use.

Abstract

The RELICS (REactor neutrino LIquid xenon Coherent elastic Scattering) experiment aims to detect coherent elastic neutrino-nucleus scattering from reactor antineutrinos using a dual-phase xenon time projection chamber. To validate the detector concept and ensure technical reliability for the full-scale experiment, a dedicated prototype was designed, constructed, and operated. This work presents an overview of the design, construction, and operational performance of the prototype, with emphasis on its major subsystems, including the TPC, cryogenic and xenon purification systems, slow control, and data acquisition. During operation, the detector demonstrated the capability to achieve a sub-keV energy threshold required for the RELICS physics program, as reflected by a measured single electron gain of 34.30~$\pm$~0.01~(stat.)~PE/e$^-$ and the successful detection of 0.27~keV L-shell decay events from $^{37}$Ar. In addition, essential data analysis techniques and simulation frameworks were developed and validated, establishing the methodological foundation for future RELICS operations. The successful construction and operation of this prototype confirm the feasibility of the core technologies and provide a crucial experimental basis for the final RELICS detector.