Large-mass, low-threshold sapphire detector for rare event searches

TL;DR

This paper presents a novel 100 g sapphire detector with ultra-low energy threshold designed for rare event searches like low-mass dark matter and CENNS, demonstrating promising resolution and sensitivity.

Contribution

Introduction of a first-of-its-kind sapphire detector with low energy threshold and large mass for rare event detection in dark matter and neutrino experiments.

Findings

Achieved baseline recoil energy resolution of 18 eV.

Successfully resolved low energy calibration lines.

Demonstrated sensitivity for low-energy rare interactions.

Abstract

Low mass nuclear recoil dark matter and coherent-elastic-neutrino-nucleus-scattering (CENNS) searches confront similar challenges in choosing ultra-low threshold and large-mass detectors. We report experimental results from the first-of-its-kind 100 g single-crystal sapphire detector design with a diameter of 76 mm and thickness of 4 mm. The detector is designed to be sensitive for low-energy rare interactions with an intention to investigate the low mass region of dark matter phase-space and search for CENNS at the reactor site. Sapphire is a crystal of aluminum oxide (Al2O3) and has been found to be a good candidate for light mass spin-dependent dark matter search experiments due to its lower atomic mass compared to other detector materials such as germanium and silicon. Using the data collected from the test facility at Texas A&M University, we were able to resolve low energy lines from calibration sources and estimated that our newly developed sapphire detector has a baseline recoil energy resolution of 18 eV. These detectors are operated at 0 V with the phonon-assisted detection providing a quenching-free low-threshold operation.