The DESY ATLAS group is heavily involved in the Phase-II Upgrades of the ATLAS Detector. The Phase-II upgrades will enable ATLAS to fully exploited the increased Luminosity of the High-Luminosity LHC, which is planed for 2022. Each of the two endcaps consists of seven disks with 32 petals each and a total of 50000 readout chips. The petal concept (as well as the closely related stave concept of the Tracker barrel) departs from the classical single module approach and instead integrate up to 15 modules and all associated services into one integrated structure. The goal of the tracker upgrade is to reduce the amount of dead material while at the same time improve the performance of the tracker despite more severe backgrounds.
The DESY group is involved in a wide area of activities ranging from simulation studies, sensor assembly and testing, the overall system design (both mechanical and electrical) to the readout electronics.
The current focus of the group is on the Petalet project, which is to construct a small prototype of an endcap petal to demonstrate the feasibility of several key aspects like the use of wedged shaped sensors and all their implications. DESY is leading the mechanical effort using advanced material like CFC, graphite foams and titanium piping and is involved in the module building effort.
The petalets will be assembled at DESY and extensively tested in the coming year, also making use of our test beam facility on campus
DESY is leading the Silicon Strip Tracker upgrade simulation effort and is focusing on dedicated studies to improve the overall performance of the tracker. The current activities of DESY group involve implementing an accurate description of the endcap geometry, optimizing the number of pixel and strip layers in the upgraded detector, studies involving a potential L1 Track trigger and finally studies involving the b-tagging and vertexing performance.
DESY is responsible for the interface card between the petal/stave and the off-detector electronics and services. This involves a 10 Gbit/s radiation hard fiber link and advanced low-voltage and high-voltage distribution systems like DC-DC converters and High-voltage multiplexing.
DESY is working on the mechanical structure of the petals using composites like CFC to minimize the amount of material in the tracker volume. Using detailed FEA simulations, the performance of the petals in terms of rigidity, stability and heat transport is studied in detail.