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DELight is a novel experiment to search for light dark matter with a liquid helium target

The "traditional" mass range of dark matter in form of weakly interacting particles (WIMPs) is around 100 GeV/c², the so-called weak scale. However, as no dark matter particle was found so far, low-mass or light dark matter (LDM) has gained more attention recently. The idea is that the dark matter particle is too light to generate a signal in the most sensitive detectors to date, e.g., XENONnT. 

Thus new detector concepts have to be developed to seach for light dark matter. DELight will combine the expertise available at the University of Freiburg, the Karlsruhe Institute of Technology (KIT) and Heidelberg University to design, realize and operate a detector using cryogenic liquid helium (4He) as dark matter target. Already moderate exposures obtained with relatively small detectors will be able to explore far into the not-yet probed LDM parameter space (see image).

The Freiburg Astroparticle Physics Group will contribute to the following aspects of DELight:

  • low-background environment: using our dedicated instruments and expertise to design and build experiments with very low backgrounds
  • site and infrastructure: it is foreseen to install DELight in the Vue-des-Alpes Underground laboratory for its first low-background run. Freiburg has access to this laboratory via its close ties to the University of Bern
  • slow control: we will use our well-established slow control system Doberman to operate and monitor DELight



  • DELight: a Direct search Experiment for Light dark matter with superfluid helium
    B. von Krosigk, K. Eitel, C. Enss, T. Ferber, L. Gastaldo, F. Kahlhoefer, S. Kempf, M. Klute, S. Lindemann, M. Schumann, F. Toschi, K. Valerius