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Calibration sources for the LEGEND-200 experiment


Baudis, L; Benato, G; Bond, E M; Chiu, P J; Elliott, S R; Massarczyk, R; Meijer, S J; Müller, Y (2023). Calibration sources for the LEGEND-200 experiment. Journal of Instrumentation, 18(02):P02001.

Abstract

In the search for a monochromatic peak as the signature of neutrinoless double beta decay an excellent energy resolution and an ultra-low background around the Q-value of the decay are essential. The LEGEND-200 experiment performs such a search with high-purity germanium detectors enriched in 76Ge immersed in liquid argon. To determine and monitor the stability of the energy scale and resolution of the germanium diodes, custom-made, low-neutron emission 228Th sources are regularly deployed in the vicinity of the crystals. Here we describe the production process of the 17 sources available for installation in the experiment, the measurements of their alpha- and gamma-activities, as well as the determination of the neutron emission rates with a low-background LiI(Eu) detector operated deep underground. With a flux of (4.27±0.60stat±0.92syst)×10−4 n / (kBq⋅s), approximately one order of magnitude below that of commercial sources, the neutron-induced background rate, mainly from the activation of 76Ge, is negligible compared to other background sources in LEGEND-200.

Abstract

In the search for a monochromatic peak as the signature of neutrinoless double beta decay an excellent energy resolution and an ultra-low background around the Q-value of the decay are essential. The LEGEND-200 experiment performs such a search with high-purity germanium detectors enriched in 76Ge immersed in liquid argon. To determine and monitor the stability of the energy scale and resolution of the germanium diodes, custom-made, low-neutron emission 228Th sources are regularly deployed in the vicinity of the crystals. Here we describe the production process of the 17 sources available for installation in the experiment, the measurements of their alpha- and gamma-activities, as well as the determination of the neutron emission rates with a low-background LiI(Eu) detector operated deep underground. With a flux of (4.27±0.60stat±0.92syst)×10−4 n / (kBq⋅s), approximately one order of magnitude below that of commercial sources, the neutron-induced background rate, mainly from the activation of 76Ge, is negligible compared to other background sources in LEGEND-200.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Scopus Subject Areas:Physical Sciences > Instrumentation
Physical Sciences > Mathematical Physics
Uncontrolled Keywords:Mathematical Physics, Instrumentation
Language:English
Date:1 February 2023
Deposited On:18 Feb 2023 15:59
Last Modified:30 Jan 2024 02:43
Publisher:IOP Publishing
ISSN:1748-0221
OA Status:Hybrid
Publisher DOI:https://doi.org/10.1088/1748-0221/18/02/p02001
  • Content: Published Version
  • Language: English
  • Licence: Creative Commons: Attribution 4.0 International (CC BY 4.0)