Feasibility Study to use Neutron Capture for an Ultra-low Energy Nuclear-recoil Calibration in Liquid Xenon

TL;DR

This study explores using neutron capture in liquid xenon to calibrate ultra-low energy nuclear recoils, aiming to improve sensitivity in light WIMP detection for dark matter searches.

Contribution

It demonstrates the feasibility of using neutron capture for ultra-low energy calibration in liquid xenon detectors, enabling better detection of light WIMPs.

Findings

Recoil energies up to 0.3 keVnr can be imparted during neutron capture.

Calibration of scintillation and ionization yields below 0.3 keVnr is achievable.

This method enhances sensitivity for light WIMP searches.

Abstract

The feasibility of an ultra-low energy nuclear-recoil measurement in liquid xenon using neutron capture is investigated for a small (sub-kilogram) liquid xenon detector that is optimized for a high scintillation gain, and a pulsed neutron source. The measurement uses the recoil energies imparted to xenon nuclei during the de-excitation process following neutron capture, where promptly emitted $\gamma$ cascades can provide the nuclei with up to $0.3$ keV$_\text{nr}$ of recoil energy due to conservation of momentum. A successful calibration of scintillation photon and ionization electron yields below this energy will contribute to a greater sensitivity for liquid xenon experiments in searches for light WIMPs.