Speaker
Description
Searches for light dark matter and studies of coherent elastic neutrino-nucleus scattering require detector technologies with energy thresholds in the 10-100 eV regime. While cryogenic calorimeters are a leading technology in this domain, a precise calibration of their response to sub-keV nuclear recoils remains a central experimental challenge. The CRAB collaboration has developed a novel, direct, and model-independent calibration method based on nuclear recoils induced by the radiative capture of thermal neutrons. Following successful proof-of-concept measurements at TU Munich – including the first observation of a monoenergetic 112.5 eV peak from $^{182}$W recoils and the observation of two $^{27}$Al nuclear recoil peaks at 575 eV and 1145 eV – the project is now preparing for its high-precision phase.
For this purpose, a dedicated calibration facility has recently been established at the TU Vienna TRIGA reactor, delivering a pure, low-intensity thermal neutron beam to target detectors operated inside a wet dilution refrigerator. Stable cryostat operation over month-long timescales and detector baseline resolutions below 5 eV have since been demonstrated. These achievements open a broad physics program probing the response of cryogenic detectors to sub-keV nuclear recoils with unprecedented precision and directly comparing it $\textit{in situ}$ to electron recoils induced in the same energy range. The latest results and the experimental strategy of the CRAB collaboration will be presented.
| Main Contribution topic | Direct detection |
|---|---|
| Secondary contribution topic | Instrumentation for Dark Matter |