Speaker
Description
The Ricochet experiment measures coherent elastic neutrino-nucleus scattering (CEνNS) of reactor antineutrinos at the ILL (Grenoble, France), using germanium cryogenic calorimeters with neutron transmutation doped germanium thermistors. Dual phonon-ionization readout enables nuclear-recoil identification and efficient electron-recoil rejection. Since commissioning in 2024, Ricochet has scaled from 3 to a full 18-detector array, with the addition of detectors featuring inter-digitized electrodes providing improved surface-event rejection. A critical challenge for CEνNS detection is the irreducible background from reactor-related and cosmogenic neutrons. We present an in-situ measurement of the low-energy nuclear recoil background rate obtained during the commissioning phase.