Research Group Ketzer

In our group we develop fast and high precision detectors to detect traces of charged particles. So-called Micropattern Gas Detectors (MPGD) use gas as the active medium and microscopic structures created by photo-lithography and etching techniques to amplify and read out the electrical signals. The two most prominent variants of MPGD are Gas Electron Multipliers (GEM) and Micro Mesh Gaseous Structures (Micromegas), both of which are used in our research. Time Projection Chambers (TPC), which use GEMs as gain structures, are a new and powerful technique developed by our group to record 3-D movies of particle collisions. Advanced readout electronics are an integral part of any particle detector. Signals generated in the detector have to be further amplified, processed and digitized. High-speed application-specific integrated circuits (ASICs) are used for this purpose. In our group we perform research to understand, adapt and improve the performance of MPGDs for high particle rates as they occur in particle accelerators.

The Ketzer group is responsible for the small-area tracking system of the COMPASS experiment at CERN, which consists of 22 large-area planar GEM detectors and up to 6 smaller GEM detectors with pixel readout. The group is currently developing new GEM detectors for the AMBER experiment, which will incorporate novel self-triggering readout electronics. The group was also instrumental in the development of the world's largest TPC at ALICE at the LHC. A similar GEM TPC is also planned for the CBELSA/TAPS experiment at ELSA. Furthermore, GEM detectors from the group will be used in the NA64 experiment at CERN, which is searching for so-called dark photons, possible candidates for dark matter.