Neutral bremsstrahlung and excimer electroluminescence in noble gases and its relevance to two-phase dark matter detectors

TL;DR

This paper investigates neutral bremsstrahlung and excimer electroluminescence mechanisms across all noble gases, providing theoretical calculations of yields and spectra to enhance two-phase dark matter detector technology.

Contribution

It extends previous work on argon to all noble gases, offering a comprehensive theoretical analysis of electroluminescence mechanisms relevant to dark matter detection.

Findings

Neutral bremsstrahlung contributes to electroluminescence in all noble gases.

Calculated EL yields and spectra for NBrS and excimer emissions.

Results inform the development of more effective two-phase dark matter detectors.

Abstract

Proportional electroluminescence (EL) is the physical effect used in two-phase detectors for dark matter searches, to optically record (in the gas phase) the ionization signal produced by particle scattering in the liquid phase. In our previous work the presence of a new EL mechanism, namely that of neutral bremsstrahlung (NBrS), was demonstrated in two-phase argon detectors both theoretically and experimentally, in addition to the ordinary EL mechanism due to excimer emission. In this work the similar theoretical approach is applied to all noble gases, i.e. overall to helium, neon, argon, krypton and xenon, to calculate the EL yields and spectra both for NBrS and excimer EL. The relevance of the results obtained to the development of two-phase dark matter detectors is discussed.