First tests of Li$_2$W$_4$ bolometric detectors using MMC sensors for the detection of CE$\nu$NS

International audience; Coherent elastic neutrino-nucleus scattering (CE$\nu$NS), detected for the frst time more than 40 years after its prediction, represents an experimental challenge because of its signature: a single nuclear recoil with energy in the range of 10 eV to a few 10’s keV on average. One of the main features of CE$\nu$NS is its cross section, around two orders of magnitude higher compared with the inverse $\beta$ decay. BASKET (Bolometers At Sub keV Energy Threshold) project aims at investigating cryogenic calorimeters for the CE$\nu$NS detection, able to maintain the background level below the expected signature while being operated in above ground conditions in close vicinity to a nuclear reactor. The main requirements for such detectors are a low enough energy threshold of O(10 eV), and a fast signal rise time in the range of 0.1–1 ms to achieve good timing resolution and hence good mitigation of pile-up events. In this article, we report on the frst tests of a prototype detector coupling a Li$_$2WO$_4$ crystal to a magnetic metallic calorimeter (MMC) thermal sensor