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
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
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
to 6.3 keV energy range, the data are compatible with the Lindhard theory with a parameter k of 0.162 
(stat + sys).
© The Author(s) 2022
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