The Panda experiment, currently under construction at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, addresses fundamental questions in hadron and nuclear physics via interactions of antiprotons with nucleus / nuclei. The High Energy Storage Ring will provide an antiproton beam with a momentum range of 1.5 – 15 GeV/c and an average collision rate of 20~MHz on a fixed target. Due to a missing hardware trigger and a continuous data acquisition in the \panda experiment, a highly advanced online analysis is needed to achieve an online data reduction of a factor 100 – 1000 before storage. A missing collision time (\t0), high interaction rates and overlapping event data in the sub detector systems further increases the difficulty of the event reconstruction.
The Barrel Time-of-Flight detector (Barrel TOF) for Panda, being developed at the Stefan Meyer Institute, will be one of the key components in Panda to determine the origin time of particle tracks, to ensure a disentanglement of overlapped hits from neighboring collisions and to provide information about \t0. Another important task of the Barrel TOF is to provide particle identification (PID) for charged particles together with the Cherenkov-based PID detectors, which is especially important for particle momenta below 700 MeV. In order to achieve a time resolution of < 100 ps, required for the mentioned disentanglement of the data, while keeping a minimal material budget, the detector will be realized as a barrel-shaped scintillator tile hodoscope. It covers the central region of the detector with a diameter of about 1~m and a length of about 2~ m. The sensitive area of about 6~ m² consists of 1920 scintillating tiles with a dimension of 90 x 30 x 5 mm³ each, readout by 8 Silicon Photomultipliers (SiPMs), with 4 on each end connected in series. The signal transmission lines are embedded in a multilayer PCB backplane. It also serves as the mechanical frame to minimize the material budget. During beam tests a single tile time resolution of about 55 ps in standard deviation has been achieved.
It was a crucial and challenging task to implement the Barrel TOF in the simulation framework, PandaRoot. This allowed the optimization of the detector geometry using Monte Carlo simulations and the investigation of the requirements for the readout electronics and led to the described design. In the second phase the performance of the Barrel TOF was evaluated and optimized for the entire experiment. For this purpose software algorithms based on the Barrel TOF system were developed and implemented in PandaRoot, i.e. triggering, event sorting, start time reconstruction and particle identification. Among other work this allowed the submission of the Technical Design Report for the Barrel TOF in February 2017 to FAIR, which has been accepted. After this the developed and implemented algorithms as well as the acquired knowledge were used to advance the general \panda reconstruction chain. Together with our international collaborators the first steps towards a dynamical tracking and event reconstruction algorithm, which combines the signal of all sub detector systems of Panda, were developed.
This is the written proceeding for the LEAP 2018 Conference, that was held in Paris.
It will be published in 'Hyperfine interaction'. To be sent before May 16, 2018.
The \PANDA experiment is a core project of the future Facility for
Antiproton and Ion Research (FAIR) at GSI in Darmstadt. It will investigate
antiproton-proton annihilations on nucleons and nuclei with the aim to explore fundamental
questions in the non-perturbative regime of QCD as the origin of the hadron mass. The multi-purpose
detector is currently under construction. The intense and high quality anti-proton beam will span
the momentum range between 1.5 and 15 GeV/$c$. Properties of hadrons, leptons, and photons in the final states
will be determined with very high precision. A rich physics program including the study of resonances in the charmonium and open charm region, electromagnetic form factors, and hypernuclear physics is planned. The worldwide collaboration gathers today more than 450 physicists from 60 institutions in 19 countries. An overview of the \PANDA experiment is given, focussing on aspects of the physics program that will be investigated as soon as the facility becomes operational.
In this paper different propagation methods for the extraploation of tracks from the STT to the EMC are studied and a new, momentum and particle type dependent quality cut was introduced to improve the completness and the purity of charged candidates.
The PANDA experiment, currently under construction at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, addresses fundamental questions in hadron and nuclear physics via interactions of antiprotons with nuclei. It will be installed at the High Energy Storage Ring (HESR), which will provide an antiproton beam with a momentum range of 1.5 - 15 GeV/c and enables a high average interaction rate on the fixed target of 2 x 10^7 events/s. The PANDA experiment adopts a continuous data acquisition and the expected data rate transmitted to a high-bandwidth computing network will be in the order of 200 GB/s. However, in order to select very rare physics processes, an indiscriminate hardware trigger does not suffice. Instead, an online software-based data selection system will be used to achieve a data reduction of a factor 100 - 1000. This demands a highly advanced online analysis due to the high interaction rate which has to deal also with overlapping event data. Scalability and parallelization of the reconstruction algorithms are therefore a particular focus in the development process. An simulation framework called PandaRoot is used to develop and evaluate different reconstruction algorithms for event building, tracking and particle identification as well as to further optimize the detector performance. An overview about PandaRoot and the requirements on the event reconstruction algorithms is presented and algorithms for the event time reconstruction currently under development are discussed.