Neutron spectroscopy with N${}_2$-filled high-pressure large-volume spherical proportional counters

Abstract

Precise in-situ measurements of the neutron flux in underground laboratories is crucial for direct dark matter searches, as neutron induced backgrounds can mimic the typical dark matter signal. The development of a novel neutron spectroscopy technique using Spherical Proportional Counters is investigated. The detector is operated with nitrogen and is sensitive to both fast and thermal neutrons through the ${}^{14}$N(n, $\hat{I}\pm$)${}^{11}$B and ${}^{14}$N(n, p)${}^{14}$C reactions. This method holds potential to be a safe, inexpensive, effective, and reliable alternative to ${}^3$He-based detectors. Measurements of fast and thermal neutrons from an Am-Be source with a Spherical Proportional Counter operated at pressures up to 2 bar at Birmingham are discussed.

4 pages, 5 figures, International Conference on Technology and Instrumentation in Particle Physics (TIPP2021)