Description
Recent advances in the detection of very low energy signals opened up new possibilities to study coherent elastic neutrino-nucleus scattering (CEνNS) or to detect low mass dark matter candidates. Their observation relies on the detection of the recoiling nuclei in the keV energy range. Therefore, a deep understanding of the detector response to nuclear recoils in this energy range is needed for the interpretation of the data. For detectors relying on the detection of ionization signals, one quantity of specific interest is the ionization quenching factor defined as the ratio of the ionization energy generated by nuclear recoils over the one generated by electron recoils of the same energy.
A dedicated measurement of this factor was carried out at the PTB facility in Braunschweig (Germany) to support the on-going experimental program of CONUS, aiming at detecting CEνNS at reactor site. Nuclear recoils were produced in a thin high-purity germanium target with a very low energy threshold via irradiation with 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. With measured quenching factors between 0.16 and 0.23 for nuclear recoils ranging from 0.4 keV to 6.3keV, the data are compatible with the Lindhard theory with a parameter k of 0.162 ± 0.004 (stat+sys). This poster will present this measurement and the analysis in details.
| Collaboration | CONUS |
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