Speaker
Description
The low energy threshold necessary for the search of nucleus scattering from sub-GeV/c$^2$ light dark matter (LDM) can be achieved nowadays by solid state detectors, with the disadvantage of limited scalability. The DELight experiment plans to overcome this limit by deploying a target of superfluid helium-4 instrumented with magnetic microcalorimeters, recovering the scalability of noble liquid experiments, while reaching low energy thresholds typical of cryogenic semiconductors thanks to its quasiparticle channel. In addition, the light nuclear mass of helium makes it an ideal candidate for LDM searches, allowing DELight to probe masses down to 100 MeV/c$^2$ already during its first phase which will deploy a target of about 1 kg.
As DELight is in its design phase, detailed simulations are of key importance. The current design geometry is implemented in GEANT4, which allows for the propagation and tracking of radiogenic and cosmic background radiation, returning the energy deposition in the sensitive volume. The same framework is also used to simulate the propagation of the different signal quanta from interactions in the helium: photons, excimers, and quasiparticles. In particular, the nature of quasiparticles in superfluid helium-4 renders existing frameworks for their propagation in condensed matter unsuitable. The relative partitioning of the signal into the multiple channels is calculated from measured and calculated cross sections, both for electronic and nuclear recoils.
This talk will focus on the discussion of the simulation framework and the first results towards the optimization and understanding of DELight.
