Quenching factor measurements of neon nuclei in neon gas

TL;DR

This paper reports the first measurement of the nuclear quenching factor in neon gas at 2 bar using a spherical proportional counter, revealing deviations from theoretical models and demonstrating the feasibility of such measurements at sub-keV energies.

Contribution

First experimental determination of neon nuclear quenching factor at 2 bar using SPCs and neutron beam, with a simple power law model fitting the energy dependence.

Findings

Measured quenching factor parameters: α=0.2801, β=0.0867.

Results do not agree with SRIM or Lindhard theory.

Demonstrated feasibility of sub-keV quenching measurements in gases.

Abstract

The NEWS-G collaboration uses Spherical Proportional Counters (SPCs) to search for weakly interacting massive particles (WIMPs). In this paper, we report the first measurements of the nuclear quenching factor in neon gas at \SI{2}{bar} using an SPC deployed in a neutron beam at the TUNL facility. The energy-dependence of the nuclear quenching factor is modelled using a simple power law: $\alpha$E$_{nr}^{\beta}$; we determine its parameters by simultaneously fitting the data collected with the detector over a range of energies. We measured the following parameters in Ne:CH$_{4}$ at \SI{2}{bar}: $\alpha$ = 0.2801 $\pm$ 0.0050 (fit) $\pm$ 0.0045 (sys) and $\beta$ = 0.0867 $\pm$ 0.020 (fit) $\pm$ 0.006(sys). Our measurements do not agree with expected values from SRIM or Lindhard theory. We demonstrated the feasibility of performing quenching factor measurements at sub-keV energies in gases using SPCs and a neutron beam.