Design and characterization of AmLi neutron sources for the LZ experiment

TL;DR

This paper details the development and thorough testing of AmLi neutron sources used for calibrating the LZ dark matter detector, including measurements of neutron and gamma emissions and simulation validation.

Contribution

It introduces specifically designed AmLi neutron sources for the LZ experiment and provides comprehensive characterization and validation methods.

Findings

Neutron emission rates accurately measured with $^{3}$He tubes

Gamma emissions characterized using HPGe detector

Monte Carlo simulations validated against experimental data

Abstract

In this paper we describe the development, testing, and characterization of three low-emission rate AmLi neutron sources. The sources are used to calibrate the nuclear recoil response of the LUX-ZEPLIN (LZ) dark matter experiment. The sources' neutron emission rate was measured using $^{3}$He proportional tubes. The sources' gamma emissions were characterized using a high-purity germanium (HPGe) detector. Source-validated GEANT4 Monte Carlo simulations allowed to calibrate the Ge and neutron detector responses.