Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 18: Search for Dark Matter 1
T 18.1: Talk
Monday, March 4, 2024, 16:00–16:15, Geb. 30.35: HSI
Wafer calorimeter development for the Direct Search Experiment for Light Dark Matter with Superfluid Helium (DELight) — Friedrich Wagner1, Lena Hauswald1, Michael Müller1, Fabienne Bauer1, and •Sebastian Kempf1,2 — 1Institute of Micro- and Nanoelectronic Systems (IMS), Karlsruhe Institute of Technology, Germany. — 2Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, Germany.
The dark matter (DM)-nucleon scattering parameter space of Light Dark Matter (LDM) has been barely probed, as it requires an energy detection threshold as low as a few eV. The "Direct search Experiment for Light dark matter" (DELight) aims investigating this challenging parameter space by using superfluid 4He as target material. Superfluid 4He provides not only a low nuclear mass and a high radiopurity level, but also various signal channels for event classification. For signal detection, DELight will use energy- and time-resolving cryogenic wafer calorimeters with eV-scale energy resolution, some of which will be located above the liquid, while others will be immersed in the superfluid. The detectors will be based on magnetic microcalorimeters (MMCs) that are operated in athermal mode, i.e. the energy of an incident particle is converted into an athermal phonon population that is sensed via normal or superconducting phonon collectors heating up a paramagnetic temperature sensor that is situated in a weak magnetic field. Here, we present our most recent R&D efforts related to detector layout and fabrication technology, both ultimately paving the way towards wafer calorimeters with O(20 eV) energy threshold.
Keywords: Cryogenic microcalorimeter; superfluid helium-4; light dark matter; thermal phonon detectors