Scintillation and Ionization Responses of Liquid Xenon to Low Energy Electronic and Nuclear Recoils at Drift Fields from 236 V/cm to 3.93 kV/cm

TL;DR

This study provides new measurements of scintillation and ionization yields in liquid xenon for low energy electronic and nuclear recoils across various drift fields, improving data accuracy for dark matter detector calibration.

Contribution

The paper presents the first comprehensive measurements of low energy recoil responses in liquid xenon at multiple drift fields, with results that refine existing models and offer better calibration data.

Findings

Nuclear recoil responses agree with NEST model predictions.

Electronic recoil ionization yields are higher than NEST predictions by about 5 e$^-$/keV$_{ee}$.

New recombination parameters are derived from the data.

Abstract

We present new measurements of the scintillation and ionization yields in liquid xenon for low energy electronic (about 3--7 keV$_{ee}$) and nuclear recoils (about 8--20 keV$_{nr}$) at different drift fields from 236 V/cm to 3.93 kV/cm, using a three-dimensional sensitive liquid xenon time projection chamber with high energy and position resolutions. Our measurement of signal responses to nuclear recoils agrees with predictions from the NEST model. However, our measured ionization (scintillation) yields for electronic recoils are consistently higher (lower) than those from the NEST model by about 5 e$^-$/keV$_{ee}$ (ph/keV$_{ee}$) at all scanned drift fields. New recombination parameters based on the Thomas-Imel box model are derived from our data. Given the lack of precise measurement of scintillation and ionization yields for low energy electronic recoils in liquid xenon previously, our new measurement provides so far the best available data covering low energy region at different drift fields for liquid xenon detectors relevant to dark matter searches.