Robert Weis

Metallic Magnetic Calorimeters

In recent years there has been important progress in Astro- and Particle Physics,which has led to a deeper understanding of the fundamental properties of matter and the nature of the universe. Much of the experimental progress was only possible due to technological developments in other areas, like optics, electronics and computer science. In the vein of these developments the new technology of cryogenic particle detectors are about to make important contributions to a wide range of astrophysics experiments. Examples are the search for dark matter, the observation of the cosmic microwave background  and several projects in x-ray astronomy. But not only in astrophysics experiments such detectors have high potential, there are also attractive application possibilities in atomic and nuclear physics.

Direct Determination of the Neutrino Mass

The determination of the absolute scale of the neutrino masses is one of the most challenging questions in particle physics. Different approaches are followed to achieve a sensitivity on neutrino masses in the sub-eV range. We develop cryogenic detectors for several large scale neutrino mass experiments like ECHo, MARE and AMoRe.

High Resolution X-Ray Spectroscopy

Two-dimensional arrays of x-ray detectors (maXs-20, maXs-200) with ultrahigh resolution are developed and produced based upon the concept of magnetic calorimeters. Applications of such detectors are X-ray astronomy and spectroscopy of highly charged ions at GSI and at EBIT fascilities. 

Detectors for Energetic Molecular Fragments

Novel large area cryogenic detectors are being developed for the spectroscopy of molecular fragments and are planned to be used at the cryogenic storage ring (CSR) at the Max-Planck Institute of Nuclear Physics. At the CSR  fast and cold molecular ions are stored and the recombination processes with electrons are studied.

DC-SQUID Development for Reading Out MMMs

For the direct readout of magnetic calorimenters, dc-SQUIDS and dc-SQUID arrays are developed that can be operated a mK-temperatures and are optimally suited for MMC detectors. Here not only the paramters for coupling are optimized, but also resudual heating effects and 1/f noise are reduced. 

Development of Multiplexing Schemes for Magnetic Calorimeters

The parallel readout of systems with large number of cryogenic detectors requires the use of multiplexing techniques. Basic properties of the detectors like the energy resolution and the detector speed should not be degraded significantly by multiplexing. Based on rf-SQUIDs we are developing a novel multiplexing scheme that is specially optimised for our applications.

Process Development for Micro-Structuring of Detectors

The production of state of the art micro-calorimeters requires the use of micro-structuring techniques. In many cases novel processes have to be developed in order to lay down and structure the necessary materials.