Direct measurement of the ionization quenching factor of nuclear recoils in germanium in the keV energy range

A. Bonhomme; H. Bonet; C. Buck; J. Hakenmüller; G. Heusser; T. Hugle; M. Lindner; W. Maneschg; R. Nolte; T. Rink; E. Pirovano; H. Strecker

doi:10.1140/epjc/s10052-022-10768-1

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2022) 82: 815
https://doi.org/10.1140/epjc/s10052-022-10768-1

Regular Article - Experimental Physics

Direct measurement of the ionization quenching factor of nuclear recoils in germanium in the keV energy range

A. Bonhomme¹^a, H. Bonet¹, C. Buck¹, J. Hakenmüller¹, G. Heusser¹, T. Hugle¹, M. Lindner¹, W. Maneschg¹, R. Nolte², T. Rink¹, E. Pirovano² and H. Strecker¹

¹ Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
² Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116, Brunswick, Germany

^a aurelie.bonhomme@mpi-hd.mpg.de, conus.eb@mpi-hd.mpg.de

Received: 16 February 2022
Accepted: 30 August 2022
Published online: 14 September 2022

Abstract

This article reports the measurement of the ionization quenching factor in germanium for nuclear recoil energies in the keV range. Precise knowledge of this factor in this energy range is highly relevant for coherent elastic neutrino-nucleus scattering and low mass dark matter searches with germanium-based detectors. Nuclear recoils were produced in a thin high-purity germanium target with a very low energy threshold via irradiation using monoenergetic neutron beams. The energy dependence of the ionization quenching factor was directly measured via kinematically constrained coincidences with surrounding liquid scintillator based neutron detectors. The systematic uncertainties of the measurements are discussed in detail. With measured quenching factors between 0.16 and 0.23 in the 0.4 keV $_{nr}$ $_{nr}$ to 6.3 keV $_{nr}$ $_{nr}$ energy range, the data are compatible with the Lindhard theory with a parameter k of 0.162 $\pm 0.004$ $\pm \,0.004$ (stat + sys).

© The Author(s) 2022

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