Signatures of muonic activation in the Majorana Demonstrator

Abstract

Experiments searching for very rare processes such as neutrinoless double-beta decay require a detailed understanding of all sources of background. Signals from radioactive impurities present in construction and detector materials can be suppressed using a number of well-understood techniques. Background from in-situ cosmogenic interactions can be reduced by siting an experiment deep underground. However, the next generation of such experiments have unprecedented sensitivity goals of 10${}^{28}$ years half-life with background rates of 10${}^{-5}$cts/(keV kg yr) in the region of interest. To achieve these goals, the remaining cosmogenic background must be well understood. In the work presented here, Majorana Demonstrator data is used to search for decay signatures of meta-stable germanium isotopes. Contributions to the region of interest in energy and time are estimated using simulations, and compared to Demonstrator data. Correlated time-delayed signals are used to identify decay signatures of isotopes produced in the germanium detectors. A good agreement between expected and measured rate is found and different simulation frameworks are used to estimate the uncertainties of the predictions. The simulation campaign is then extended to characterize the background for the LEGEND experiment, a proposed tonne-scale effort searching for neutrinoless double-beta decay in ${}^{76}$Ge.

14 pages, 12 figures

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• The Sanford Underground Research Facility at Homestake
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• Cosmogenic Activation of Germanium Used for Tonne-Scale Rare Event Search Experiments
• Measurement of neutron-proton capture in the SNO+ water phase
• A detection system to measure muon-induced neutrons for direct Dark Matter searches
• Cosmogenic Neutron Production at the Sudbury Neutrino Observatory

Cited by in corpus (4)

• Final Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of ${}^{76}$Ge to Excited States of ${}^{76}$Se
• Experimental study of 13C(α,n)16O reactions in the Majorana Demonstrator calibration data
• Rare multi-nucleon decays with the full data sets of the Majorana Demonstrator
• Examining LEGEND-1000 cosmogenic neutron backgrounds in Geant4 and MCNP