Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 69: Neutrino physics without accelerators VI

T 69.2: Talk

Wednesday, March 17, 2021, 16:20–16:35, Ts

Quenching factor measurements for keV range nuclear recoils in germanium — •Aurélie Bonhomme for the CONUS collaboration — Max-Planck-Institut für Kernphysik, 69117 Heidelberg

Coherent elastic neutrino-nucleus scattering (CEvNS) and Dark Matter search experiments are looking for nuclear recoils induced by neutrinos or Weakly Interacting Massive Particles. Their interpretation crucially relies on the understanding of the stopping process of the recoiling ion in the detecting media. In particular for detectors measuring ionization yields, such as high-purity germanium detectors (HPGe), it is of primary importance to know which fraction of the initial energy goes into ionization, while the rest is being dissipated as heat. This quantity, commonly called quenching factor, suffers from large uncertainties in the keV range - the region of interest for reactor-based CEvNS experiments like CONUS.

Recently, a dedicated quenching measurement was carried out by the CONUS group of MPIK in cooperation with the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany. It is expected that the results will significantly reduce the dominant uncertainty of the signal prediction of currently running CEvNS experiments using HPGe detectors. For this measurement, collimated mono-energetic neutron beams obtained via Li(p,n) reactions were used to probe nuclear recoils energies between 0.8 and 6 keV in a thin HPGe target. In this talk, the experimental setup and preliminary insights into the data will be presented.