Superconducting Bolometers for the Ricochet Experiment

The Ricochet experiment, located at the research reactor at Institut Laue Langevin

(ILL) in Grenoble, France, is a Coherent Elastic Neutrino-Nucleus Scattering (CEνNS)

observatory that aims to detect reactor neutrinos through low-energy nuclear recoils.

Ricochet has been comissioned at ILL and has been operating since the first half of

2024 with a small array of Ge detectors with heat and ionization readouts. We focus

on the development of the complementary detector array (Q-Array), which uses super-

conducting crystals (e.g. Al, and Sn) of around ∼50 grams as the recoil target and

Manganese-doped Al Transition-Edge-Sensors (TESes) for bolometric readout. We

present and discuss recent R&D data and a corresponding cascade model for parti-

cle interactions and transport in bulk superconductors. The cascade model provides

physical insights towards understanding the data and achieving particle identification

(PID) for nuclear and electron recoil events in a bulk superconductor. Electron recoil

background rejection will be essential for Q-Array to achieve sensitivity to sub-keV

CEνNS signals.