Simulations of neutron background in a time projection chamber relevant to dark matter searches

TL;DR

This paper presents detailed simulations of neutron backgrounds in a dark matter time projection chamber, analyzing sources, propagation, and suppression methods to assess detector sensitivity limits.

Contribution

It provides new simulation data on neutron backgrounds from various sources and evaluates suppression techniques for gaseous dark matter detectors.

Findings

Neutron backgrounds from rock and detector components are quantified.

Neutron suppression methods can effectively reduce background levels.

Sensitivity to WIMP interactions can reach (1 - 3) x 10^{-8} pb with current techniques.

Abstract

Presented here are results of simulations of neutron background performed for a time projection chamber acting as a particle dark matter detector in an underground laboratory. The investigated background includes neutrons from rock and detector components, generated via spontaneous fission and (alpha, n) reactions, as well as those due to cosmic-ray muons. Neutrons were propagated to the sensitive volume of the detector and the nuclear recoil spectra were calculated. Methods of neutron background suppression were also examined and limitations to the sensitivity of a gaseous dark matter detector are discussed. Results indicate that neutrons should not limit sensitivity to WIMP-nucleon interactions down to a level of (1 - 3) x 10^{-8} pb in a 10 kg detector.