Speaker
Description
The low-mass region of the dark matter (DM) parameter space remains largely unexplored, as detecting Light Dark Matter (LDM) requires both nuclear recoil thresholds below 100 eV and an approach capable of large exposures. The Direct search Experiment for Light dark matter (DELight) aims to address this challenge by using superfluid helium-4 as a target material, exploiting its low nuclear mass, intrinsic radiopurity, as well as its dual photon and quasiparticle signal channels. Detection will be performed using Large-Area Cryogenic Microcalorimeters (LAMCALs). The latter are athermal detectors based on Magnetic Microcalorimeter (MMC) technology which offer excellent energy resolution and detection thresholds of a few eV.
As a first step in this direction, a dedicated R&D cell has been developed to study the operation of thermal MMCs fabricated on a 5 mm × 5 mm silicon substrate, submerged in superfluid helium. In this setup, a small copper cell (300 ml) is cooled down to ~10 mK inside a ³He/⁴He dilution refrigerator and filled with ⁴He. The primary goal is to establish stable MMC operation in this environment, while also beginning to explore the signal channels relevant for DELight, namely the detection of UV photons and of quasiparticles in the superfluid. This contribution presents the current status and recent developments of this R&D cell.
| Main Contribution topic | Direct detection |
|---|---|
| Secondary contribution topic | Light Dark Matter |