PANDA Annual Report 2019

The PANDA Experiment, which is located at the High Energy Storage Ring at the FAIR accelerator center in Darmstadt, Germany, is optimized for questions of hadron physics. With this detector it will be possible to discover new states and measure their line shapes as well as the line shapes of already known states very precisely. To normalize the energy scan measurements exact knowledge of the luminosity is required. The luminosity at PANDA will be determined from the angular distribution of elastical antiprotonm proton scattering. In order to achieve an absolute measuring accuracy of 5% , the tracks of the scattered antiprotons will be measured by four planes of thinned silicon detectors (HV-MAPS). HV-MAPS are pixel sensors with integrated readout electronics. They will be operated with a reverse voltage of 60 volts to increase their radiation hardness. The four detector planes consist of CVD-diamonds on which the sensors are clued. To reduce the multiple scattering the detector is operated in a vacuum. The concept of the luminosity detector is presented and technical aspects such as the vacuum system, cooling, electronics, and sensors are discussed, as well as insights into data analysis.

The PANDA experiment at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR) near GSI, Darmstadt, Germany will address fundamental questions of hadron physics. Excellent particle identification is required to achieve the PANDA physics goals. Hadronic particle identification (PID) in the PANDA target spectrometer will be delivered by two DIRC (Detection of Internally Reflected Cherenkov light) counters. The Barrel DIRC will cover the polar angle range of 22−140 degree and is designed to provide pion/kaon separation for momenta between 0.5 GeV/c and 3.5 GeV/c with a separation power of at least 3 standard deviations. Several reconstruction algorithms have been developed to determine the performance of the detector. The "geometrical reconstruction" determines the Cherenkov angle relying primarily on the position of the detected photons. The "time imaging", however, utilizes both position and time measurements by directly performing the maximum likelihood fit. GEANT4 simulations and experimental data from prototype tests at the CERN PS were used to optimize the performance of the algorithms. We will discuss detailed aspects of both reconstruction approaches.