Operation of a dual-phase xenon detector with wavelength sensitivity from ultraviolet to infrared

TL;DR

This paper demonstrates a dual-phase xenon detector sensitive to UV and IR wavelengths, revealing IR scintillation signals that could improve detection and background rejection in rare event searches.

Contribution

It reports the first observation of IR electroluminescence in a dual-phase xenon detector and analyzes its timing and dependence on electric fields.

Findings

IR signals are coincident with UV scintillation and electroluminescence.

IR emission has a distinct time response from previous alpha particle studies.

IR scintillation could enhance signal identification in future detectors.

Abstract

Xenon, in both its gaseous and liquid phase, offers excellent scintillation and ionization properties, making it an ideal target medium for rare event searches. We report on measurements performed with a dual-phase xenon time projection chamber sensitive to wavelengths from 170 nm to 1700 nm. In addition to the well-established ultraviolet (UV) scintillation, we observe coincident signals in a photomultiplier tube sensitive to infrared (IR) light, associated with both prompt scintillation in the liquid and electroluminescence in the gas. We study the time response of the IR signals and their dependence on the applied amplification field in the gas. Our findings support the observation of IR emission from electroluminescence and reveal a time response distinct from that previously reported for $\alpha$-particles in gas. The results suggest that IR scintillation could provide enhanced signal identification and background rejection in future xenon-based detectors.