SABRE and the Stawell Underground Physics Laboratory Dark Matter Research at the Australian National University

L J Bignell,J Wu,H Timmers,G J Lane,M S Rahman,O Lennon,C Simenel,F Nuti,E Barberio,I Mahmood,Y Y Zhong,M B Froehlich,N J Spinks,A Wallner,A E Stuchbery,L Wang

doi:10.1051/epjconf/202023201002

Abstract

The direct detection of dark matter is a key problem in astroparticle physics that generally requires the use of deep-underground laboratories for a low-background environment where the rare signals from dark matter interactions can be observed. This work reports on the Stawell Underground Physics Laboratory – currently under construction and the first such laboratory in the Southern Hemisphere – and the associated research program. A particular focus will be given to ANU’s contribution to SABRE, a NaI:Tl dark matter, direct detection experiment that aims to confirm or refute the long-standing DAMA result. Preliminary measurements of the NaI:Tl quenching factor and characterisation of the SABRE liquid scintillator veto are reported.

Highlights

Understanding the nature of dark matter is a major goal of modern physics
Most experiments search for an excess of interaction events beyond known backgrounds in an active detector volume, that may be due to galactic dark matter
There are a number of NaI:Tl based detectors currently operating, including COSINE and ANAIS, that have recently reported their first annual modulation searches [6, 7]; in both cases they are not yet sensitive enough to confirm or refute the DAMA result

Summary

Introduction

Understanding the nature of dark matter is a major goal of modern physics. There is a distinct possibility that dark matter is an as-yet undiscovered fundamental particle; there are several avenues being explored that target the direct detection of particle dark matter [1]. There are a number of NaI:Tl based detectors currently operating, including COSINE and ANAIS, that have recently reported their first annual modulation searches [6, 7]; in both cases they are not yet sensitive enough to confirm or refute the DAMA result. Both of these detectors are located in the Northern Hemisphere, whereas a measurement in both hemispheres can control for seasonal effects to verify the astrophysical origin of any modulation in a DAMA-like. The full SABRE design and expected sensitivity is outlined in Refs. [13, 14], and is expected to confirm or refute the DAMA result at 5σ significance within 3 years of operation

Quenching Factor Measurements

Veto Scintillator Characterisation

Optical Absorbance

Light Yield

Compatibility Tests

Future Work