Low energy recoil detection with a spherical proportional counter

TL;DR

This paper demonstrates the capability of the spherical proportional counter to detect low energy nuclear recoils in the keV range, using neutron sources and simulations to evaluate its performance for neutrino and dark matter detection.

Contribution

The study provides experimental results and simulation insights into the low energy detection capabilities of the SPC, highlighting its potential for neutrino and dark matter research.

Findings

Successful detection of keV recoil energies with the SPC.

Energy resolution of 9% at 5.9 keV X-ray line.

Simulation results support experimental observations.

Abstract

We present low energy recoil detection results in the keV energy region, from measurements performed with the Spherical Proportional Counter (SPC). An ${}^{241}Am-{}^{9}{Be}$ fast neutron source is used in order to obtain neutron-nucleus elastic scattering events inside the gaseous volume of the detector. The detector performance in the $keV$ energy region was resolved by observing the $5.9\ keV$ line of a ${}^{55}Fe$ X-ray source, with energy resolution of $9\%$ ($\sigma$). The toolkit GEANT4 was used to simulate the irradiation of the detector by an ${}^{241}Am-{}^{9}{Be}$ source, while SRIM was used to calculate the Ionization Quenching Factor (IQF). The GEANT4 simulated energy deposition spectrum in addition with the SRIM calculated quenching factor provide valuable insight to the experimental results. The performance of the SPC in low energy recoil detection makes the detector a good candidate for a wide range of applications, including Supernova or reactor neutrino detection and Dark Matter (WIMP) searches (via coherent elastic scattering).