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Within the ERC-funded project ULTIMATE, we perform R&D towards the ultimate dark matter detector based on a dual-phase liquid xenon TPC. Such detector, maybe realized within the DARWIN framework, will have a target mass of ~40t of liquid xenon. Its sensitivity will start to be limited by coherent neutrino-nucleus interactions, a background which cannot be reduced by shielding.

The ULTIMATE team consists of 2 professors, 1 PostDoc, 3 PhD students and several BSc and MSc students. We address the following questions:

  • How can we achieve the strict Rn-background requirements for DARWIN?
    →We study an alternative detector design and work on improved material selection
  • How can we reduce the neutron background originating from PTFE?
    →The (no so) simple trick is to use less and cleaner PTFE.
  • Can we improve the design of the TPC to reduce these backgrounds?
    →We are currently investigating this question.
  • Are there better alternatives to the dual-phase charge readout?
    → An approach where the scintillation light is created in the liquid might solve some known problems.
  • Which (non-WIMP) science channels can be addressed by DARWIN?
    →We are making detailed background studies to estimate DARWIN's sensitivity for WIMPs and other dark matter candidates and also focus on neutrino science.
  • Which shields are required for DARWIN?
    →This is an important question to select the site of a real experiment.


Some of these projects are pursued in our new laboratory in Freiburg. This unique building was re-furbished for our group recently and provides ideal conditions for large- and small-scale prototypes. It is equipped with a small class ISO-6 cleanroom.

Fotos: Oliver Kern (, Architect: Roger Gerber
Please click on images to enlarge them.


The photo below shows one of our team members in the cleanroom, putting together a small-scale liquid xenon time projection chamber which shows some features that have never been tested before.

The project is funded by an ERC Consolidator Grant from the European Commission, project number 724320. erc.png