Speaker
Description
CRESST is an experiment for the direct detection of dark matter, situated at Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It is capable of detecting nuclear recoils down to 10 eV with an impressive sensitivity in the sub-GeV mass region. This is achieved by using cryogenic scintillation crystals as target materials. To separate background from signals a two-channel approach, measuring light and phonos, is utilized. However, the separation capability is poor in the low energy region and it is challenging to distinguish between dark matter interactions and $\beta$, $\gamma$ or $\alpha$-particles.
The background components are considered via simulations with 'ImpCRESST', a Geant4 based simulation code, which is continuously adapted to the setup of CRESST. At the current state, the CRESST background model only considers bulk contaminations and a flat detector surface.
This contribution presents possible effects of surface contamination with radiogenic elements, in combination with the influence of the surface roughness of the detector crystal itself. Because of nuclides decaying inside the crystal in the vicinity of the surface, it is possible that only a share of the energy is placed inside the detector.
As a result, higher energy events can leak into the lower energy range and may affect the simulated background. Since default Geant4 is not capable of simulating a rough surface an extension is developed and the impact of different roughness configurations is studied.
| Submitted on behalf of a Collaboration? | Yes |
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