The Electric Field Dependence of Single Electron Emission in the PIXeY Two-Phase Xenon Detector

TL;DR

This paper investigates how electric fields influence single electron emissions in a dual-phase xenon detector, revealing the underlying mechanisms and their dependence on the applied electric field.

Contribution

It provides the first detailed measurement of the electric field dependence of single electron backgrounds, including the Fowler-Nordheim effect, in a dual-phase xenon detector.

Findings

Single electron background increases with electric field strength.

Fowler-Nordheim effect significantly contributes to electron emission.

Photoionization also affects the background levels.

Abstract

Dual phase xenon detectors are widely used in experimental searches for galactic darkmatter particles. The origin of single electron backgrounds following prompt scintillation and proportional scintillation signals in these detectors is not fully understood, although there has been progress in recent years. In this paper, we describe single electron backgrounds in ${}^{83m}Kr$ calibration events and their correlation with drift and extraction fields, using the Particle Identification in Xenon at Yale (PIXeY) dual-phase xenon time projection chamber. The single electron background induced by the Fowler-Nordheim (FN) effect is measured, and its electric field dependence is quantified. The photoionization of grids and impurities by prompt scintillation and proportional scintillation also contributes to the single electron background.