Study of nuclear recoils in liquid argon with monoenergetic neutrons

TL;DR

This study investigates nuclear recoil responses in liquid argon using monoenergetic neutrons to improve understanding for dark matter detector development, focusing on scintillation yields and pulse shapes.

Contribution

It introduces an experimental setup for studying nuclear recoils in liquid argon with monoenergetic neutrons, providing new data on scintillation properties relevant to dark matter detection.

Findings

First results on scintillation yields from nuclear recoils

Analysis of pulse shape differences between nuclear and electronic recoils

Insights into excimer state populations in liquid argon

Abstract

For the development of liquid argon dark matter detectors we assembled a setup in the laboratory to scatter neutrons on a small liquid argon target. The neutrons are produced mono-energetically (E_kin=2.45 MeV) by nuclear fusion in a deuterium plasma and are collimated onto a 3" liquid argon cell operating in single-phase mode (zero electric field). Organic liquid scintillators are used to tag scattered neutrons and to provide a time-of-flight measurement. The setup is designed to study light pulse shapes and scintillation yields from nuclear and electronic recoils as well as from {\alpha}-particles at working points relevant to dark matter searches. Liquid argon offers the possibility to scrutinise scintillation yields in noble liquids with respect to the populations of the two fundamental excimer states. Here we present experimental methods and first results from recent data towards such studies.