The ATLAS-Experiment

With a length of 46m and a total weight of 7000t, the ATLAS detector is one of the four largest particle detectors at the Large Hadron Collider (LHC) at the European Research Center for Particle Physics (CERN) in Geneva, Switzerland. In order to operate such a large experiment, about 5500 scientists, technicians, engineers and administrators from all over the world work hand in hand to understand the unsolved questions of the universe. As part of this collaboration our group conducts significant research and development contributions to the tau reconstruction, the measurement of the Standard Model and the high luminosity upgrade of the ATLAS pixel detector.

Reconstruction of Tau-Leptons

Both, the tau decay-mode classification as well as the precise knowledge of the decay topology play an essential part in physics analyses. Therefore, software used for decay reconstruction is continuously optimized and extended. Within these efforts, neural networks play a prominent role and progressively replace conventional algorithms used to process big data.

Probing the Standard-Model

The Standard Model has a set of free experimentally determined parameters. Precision measurements hone in on weak points in the theory. The discovery of the Higgs boson in 2012 opened the door for another series of parameter measurements that hasn't yet concluded.

Physics beyond the Standard-Model

The Standard Model provides a theoretical basis for about 5% of known matter. In order to get a better understanding of the remaining 95% alternative models are investigated. One promising hypothesis looks for leptoquarks - particles that couple to leptons as well as quarks.

The High-Luminosity LHC and the ATLAS Inner Tracker Upgrade

In effort to increase the number of collisions, the High-Luminosity LHC (HL-LHC) encompases vast upgrades of the accelerator and the detectors planned for 2029. The HL-LHC will increase the number of collisions in the ATLAS detector by a factor of 10 which is why, the inner tracking detector has to be replaced by a completely new detector, the Inner Tracker (ITk). This detector will consist of several layers of silicon strip detectors as well as silicon pixel detectors.

Prototypes of the ITk Pixel-Detector

The ITk pixel detector, based on state-of-the-art semiconductor technology, is based on new concepts of detector design and integration that have not been used in any major particle detector setup. The components of the detector, from individual pixel modules to larger detector structures, are tested in detail using in-house developed prototypes.

Detector integration and Quality Control of the ITk Pixel-Detector

After completion of the development phase, the individual carrier structures of the ITk pixel detector will be assembled and tested within the different clusters in the ATLAS collaboration. These structures will then be shipped to CERN, where the final assembly and integration of the complete pixel detector into the ATLAS detector will take place. As part of the German cluster, pixel modules as well as carrier structures equipped with pixel modules for the ITk pixel detector are produced and tested in Bonn.