Determination of responses of liquid xenon to low energy electron and nuclear recoils using the PandaX-II detector

TL;DR

This paper systematically calibrates the responses of the PandaX-II liquid xenon detector to low energy electron and nuclear recoils, providing empirical models that accurately describe the light and charge yields within specified energy ranges.

Contribution

It presents the first comprehensive calibration of PandaX-II's responses to low energy recoils using multiple sources and drift fields, with empirical models fitting the data well.

Findings

Calibrated electron recoil responses from 1-25 keV.

Calibrated nuclear recoil responses from 4-80 keV.

Developed empirical models with quantified uncertainties.

Abstract

We report a systematic determination of the responses of PandaX-II, a dual phase xenon time projection chamber detector, to low energy recoils. The electron recoil (ER) and nuclear recoil (NR) responses are calibrated, respectively, with injected tritiated methane or $^{220}$Rn source, and with $^{241}$Am-Be neutron source, within an energy range from $1-25$ keV (ER) and $4-80$ keV (NR), under the two drift fields of 400 and 317 V/cm. An empirical model is used to fit the light yield and charge yield for both types of recoils. The best fit models can well describe the calibration data. The systematic uncertainties of the fitted models are obtained via statistical comparison against the data.