Evaluation of (alpha,n) Induced Neutrons as a Background for Dark Matter Experiments

TL;DR

This paper calculates neutron yields and spectra from (alpha,n) reactions in materials used in dark matter detectors, highlighting additional sources like samarium dopants, aiding background modeling for future experiments.

Contribution

It provides detailed neutron yield data from various materials, including samarium, for improved background estimation in dark matter detection.

Findings

Neutron yields from (alpha,n) reactions vary across materials.

Samarium dopants significantly contribute to neutron background.

Results support enhanced Monte Carlo simulations for detector design.

Abstract

Neutrons from ($\alpha$,n) reactions through thorium and uranium decays are important sources of background for direct dark matter detection. The neutron yields and energy spectra from a range of materials that are used to build dark matter detectors are calculated and tabulated. In addition to thorium and uranium decays, we found that $\alpha$ particles from samarium, often the dopant of the window materials of photomultiplier tubes (PMT), are also an important source of neutron yield. The results in this paper can be used as the input to Monte Carlo simulations for many materials that will be used for next generation experiments.