December 2023

Journal

Multisite event discrimination for the majorana demonstrator

By:
Alvis, S. I.; Arnquist, I.; Avignone Iii, Frank T; Bertrand Jr, Fred E; Green, Matthew P; Radford, David C; Shanks, Benjamin E; Varner Jr, Robert L; Wilkerson, John F; Yu, Chang-Hong
Journal Name:
Physical Review C
Page Number:
65501
Volume:
99
Issue Number:
6
Publication Date:
December 27, 2023
View DOI Listing:
https://doi.org/10.1103/PhysRevC.99.065501

Abstract

The Majorana Demonstrator is searching for neutrinoless double-beta decay (0νββ) in 76Ge using arrays of point-contact germanium detectors operating at the Sanford Underground Research Facility. Background results in the 0νββ region of interest from data taken during construction, commissioning, and the start of full operations have been recently published. A pulse shape analysis cut applied to achieve this result, named AvsE, is described in this paper. This cut is developed to remove events whose waveforms are typical of multisite energy deposits while retaining (90±3.5)% of single-site events. This pulse shape discrimination is based on the relationship between the maximum current and energy, and tuned using 228Th calibration source data. The efficiency uncertainty accounts for variation across detectors, energy, and time, as well as for the position distribution difference between calibration and 0νββ events, established using simulations.