Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 18: Search for Dark Matter 1

T 18.4: Talk

Monday, March 4, 2024, 16:45–17:00, Geb. 30.35: HSI

Evaporated Gold Thin-Films on NaI Crystals for remoTES based Detectors — •Kilian Heim for the COSINUS collaboration — Max-Planck-Institut für Physik, Garching, Deutschland

The COSINUS (Cryogenic Observatory for SIgnals seen in Next generation Underground Searches) experiment aims for a model-independent cross-check of the dark matter signal claimed to be observed by the DAMA/LIBRA experiment. Starting its first operational phase at the end of 2024, COSINUS will use the same target material as the DAMA/LIBRA experiment, namely sodium iodide (NaI). The NaI crystals will be operated as cryogenic calorimeters, enabling a dual channel readout of both a scintillation and phonon signal.

The readout of the phonon signal is done with a transition edge sensor (TES), but due to the low melting point and hygroscopicity of the NaI crystal, the TES cannot be deposited directly on the crystal. Therefore, the novel remoTES setup is applied, which locates the TES on a separate wafer, linked to a gold pad on the crystal.

Currently, the circular gold pad is cut from a gold foil and then glued onto the crystal. As a next step, the evaporation of gold on the crystal is investigated, which could enhance the reproducibility and signal strength of the TES. In this contribution, I want to highlight the advantages of an evaporated gold pad and present first results from the way towards an improved detector setup.

Keywords: Dark Matter; cryogenic calorimeters; quantum sensors; Sodium Iodide; COSINUS