Detector hardware

The design of straw tube detector modules developed for the PANDA Forward Tracker is
presented. One module consists of 32 straws with 10mm diameter, arranged in two staggered
layers, and has a very low material budget of only 8:8 x10^-4 X0. The overpressure of the working gas
mixture of 1 bar makes the module self-supporting and enables the use of lightweight and compact
support frames. Detection planes in the Forward Tracker consist of modules mounted closely,
without gaps, next to each other on a support frame. A module can be mounted and dismounted
from the frame without the need to remove the neighborig modules, enabling fast repairs. Technical
details of the detector design and the assembly procedure of the straw tubes and the straw modules
as well as results of performed tests of the modules are given.

Invited talk at DIRC2017: Workshop on fast Cherenkov detectors, Castle Rauischholzhausen, Germany, Aug 7-9, 2017.

The first major assembly stage of the barrel part of the electromagnetic calorimeter of the PANDA experiment at the future FAIR facility by assembling one single barrel slice segment will be presented. The calorimeter is composed of two endcaps and a barrel covering the major part of the solid angle consisting of more than 11.300 tapered PbWO4 crystals. Each scintillator module is readout via two large area avalanche photo diodes connected to custom made ASIC-preamplifier. The construction of the first segment comprises a full length slice beam holding in total 18 module blocks. Each block consists of a matrix of 4x10 crystals. The assembly procedure of single detector modules, module blocks and the overall slice segment, respectively will be discussed. Test results of single components and fully assembled detector modules will be discussed and compared with earlier prototype in-beam and lab tests. Supported by BMBF, GSI and HIC for FAIR.

In this thesis the prototype system for processing of the signals generated in the
straw tube trackers of the PANDA spectrometer is proposed, built and evaluated. The
full processing chain of signal consists of programmable readout electronics, configware
and analysis methods. The proposed readout is based on the front end electronics,
equipped with the configurable PASTTRECv1 ASIC (PANDA STT REadout Chip
version 1 Application Specific Integrated Circuit) and the readout board (TRBv3 - Trigger
Readout Board version 3) acting as data concentrator and time measurement device.
The readout system performs full chain of data processing consisting of analog
shaping, digital conversion and data transmission. A dedicated analysis methods have
been developed to extract track position and a particle energy deposit in the detectors.
Dedicated tests of the system by means of the cosmic rays and proton beams have
been performed. The results prove that the spatial resolution better than 150 m can
be achieved. Furthermore, particle identification based on time over threshold method
can be successfully applied in the momentum region below 800 MeV/c. The last but
not least goal was to show that it is possible to realize complete readout system based
on the concept presented in this thesis which is capable of cope with the hit rates of the
PANDA spectrometer.

The envisaged physics program of the PANDA (antiProton ANnihilation at Darmstadt) experiment at the future Facility for Antiproton and Ion Research (FAIR) requires excellent particle identification over the full solid angle. The Endcap Disc DIRC (EDD) will cover forward polar angles between 5 and 22◦ and is one of three dedicated subdetectors for the identification of charged hadrons and the separation of pions and kaons in particular. DIRC stands for Detection of Internally Reflected Cherenkov light and implies that the emitted Cherenkov photons are trapped inside the radiator by total internal reflection.
The central part of each DIRC detector is its optical system which is responsible for a lowloss and angle-preserving transport of the Cherenkov photons. The work at hand experimentally addresses several objectives in connection with the optical components and the system as a whole. Radiator prototypes were evaluated with high precision and adapted specifications were identified based on the results. The imaging performance of the Focusing Elements (FELs) was verified and different options regarding the coupling of the individual components were evaluated. In addition a radiation hardness study of a new fused silica material provided an insight into the long term behavior of induced defects and confirmed the material to be suitable for high energy physics experiments.
A conceptual design for the mechanical integration was developed featuring a rigid optical system which is mounted into a cross-like structure. In this context the spatial constrains for the holding structure and the FELs were identified and an assembly procedure was developed. The existing prototype was revised and newly developed concepts were integrated and tested.
Furthermore a data analysis of an earlier prototype test at a mixed hadron beam at CERN was carried out. It was the first evaluation of an EDD prototype which consisted of optical components made of fused silica only and had highly segmented MCP-PMTs (Micro-Channel Plate PhotoMultiplier Tubes) for the photon detection. A single photon resolution down to 5.68 mrad could be achieved and a good agreement with Monte-Carlo predictions was reached. At 3 GeV/c a 5σ separation of pions and protons was accomplished using a single MCP-PMT column.