The use of High Purity Germanium detectors operated in ionization mode at cryogenic temperatures is investigated as an external background mitigation solution for bolometers used in rare-event search experiments. A simple experimental setup with very partial coverage, running a 52-g Li2WO4 bolometer sandwiched in-between two 2-cm thick High Purity Germanium cylindrical detectors in a dry cryostat, shows promising rejection to environmental gammas and atmospheric muons backgrounds. The acquired data are used together with a Monte Carlo simulation of the setup to extract the main contributions to the external backgrounds expected in an above ground experiment, such as e.g.~current and future experimental efforts targeting the detection of coherent elastic neutrino-nucleus scattering at reactor facilities. Based on all these results, a 4π coverage similar veto system achieving a O(10 keV) energy threshold is expected to achieve a ≳ 70 \% and a ≳ 97 \% rejection power for gamma-like and muon-like events, respectively.
@article{arxiv.2401.09837,
title = {Prototyping a High Purity Germanium cryogenic veto system for a bolometric detection experiment},
author = {Chloé Goupy and Stefanos Marnieros and Beatrice Mauri and Claudia Nones and Matthieu Vivier},
journal= {arXiv preprint arXiv:2401.09837},
year = {2025}
}