Parts | Days | Selection | Search | Updates | Downloads | Help
MON: Monday Contributed Sessions
MON 10: Standard Model and Beyond
MON 10.6: Talk
Monday, September 8, 2025, 15:30–15:45, ZHG103
Shaping DELight: signal propagation in superfluid helium-4 — •Francesco Toschi, Eleanor Fascione, and Belina von Krosigk — Kirchhoff-Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany
Large dual-phase noble liquid TPCs strongly constrain the parameter space for dark matter candidates above the GeV/c2 but can barely explore lighter candidates. Probing this low-mass regime requires ultra-low energy thresholds, which solid-state cryogenic detectors can reach by measuring phonons. However, their small target masses limit exposure and cannot scale in a monolithic way. The Direct search Experiment for Light dark matter (DELight) will use a superfluid helium-4 target instrumented with large area microcalorimeters (LAMCALs), combining the low threshold of phonon-based detection with the scalability of noble liquids. This allows DELight to explore masses down to below 100 MeV/c2 with just 1 kg d of exposure.
DELight is in its design phase, and detailed simulations play a central role in informing the design and construction of the final detector. This talk will present the current GEANT4 simulation framework, with particular focus on the propagation of the different signal quanta deriving from an energy deposition in superfluid helium-4: photons, excimers, and quasiparticles, i.e. phonons and rotons. In particular, the role of quasiparticle collection efficiency in motivating the choice of a high aspect ratio (or ’pancake’) geometry for the detector cell will be discussed.
Keywords: DELight collaboration; superfluid helium; magnetic microcalorimeter; dark matter; GEANT4