Author:
Baudis L.,Benato G.,Bond E.M.,Chiu P.J.,Elliott S.R.,Massarczyk R.,Meijer S.J.,Müller Y.
Abstract
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.
Subject
Mathematical Physics,Instrumentation