Proceedings (PRO)

The Barrel DIRC of the PANDA experiment at FAIR will cleanly
separate pions from kaons for the physics program of PANDA. Innovative solutions
for key components of the detector sitting in the strong magnetic eld of the compact
PANDA target spectrometer as well as two reconstruction methods were developed
in an extensive prototype program. The technical design and present results from
the test beam campaigns at the CERN PS in 2017 and 2018 are discussed.

The PANDA experiment at the future Facility for Antiproton and Ion Research (FAIR) will address
fundamental questions of hadron physics with unprecedented precision.
To reach this goal excellent Particle Identification (PID) is essential over a large range of particle momenta and solid angles.
Most of the phase space will be covered by two innovative DIRC (Detection of Internally Reflected Cherenkov light) detectors.
The Endcap Disc DIRC and Barrel DIRC will cover the polar angle range from 5 to 22$^\circ$ and 22 to 140$^\circ$, respectively.
Both detectors rely on high precision optical components, lifetime-enhanced Microchannel Plate PMTs (MCP-PMTs), and fast readout electronics.

The DIRC detectors of the PANDA experiment at FAIR will use multi-anode MCP-PMTs as photon sensors. After long and extensive R&D work
the performance parameters of the recent 2'' MCP-PMT models are converging towards the required values. The lifetime of most ALD-coated
MCP-PMTs is well surpassing the DIRC requirements with the best tube currently reaching >22 C/cm2 without aging. The performance of the most advanced MCP-PMTs from PHOTONIS and Hamamatsu fulfill basically all requirements with a highlight being the high DQE of almost 30% for the PHOTONIS 9002108. The improvements of the latest MCP-PMT models compared to former tubes are emphasized in this paper. In addition, some performance features of a recently developed 2'' MCP-PMT by Photek Ltd are presented and discussed.

The PANDA experiment will be one of the pillars of the new Facility for Antiproton and Ion Research (FAIR), which is currently under construction in Darmstadt, Germany. PANDA will be a fixed-target experiment which will allow the study of non-perturbative phenomena of the strong interaction. These will be probed in antiproton-proton collisions in the momentum range of 1.5 - 15 GeV/c. Within the PANDA physics program, strangeness production will be addressed through pbar p - > Ybar Y processes. Measurements of the pbar p-> Sigmabar Lambda channel for its comparison with the existing data of the Lambdabar Lambda channel are highly encouraged to study the role of isospin symmetry in hadron production dynamics. This work consists on a simulation study focusing on the feasibility of measuring the pbar p -> Sigmabar Lambda channel at PANDA.

d.o.i.: 10.1088/1748-0221/13/01/c01043

d.o.i.: 10.1109/NSSMIC.2017.8533084

The PANDA experiment represents the central part of the hadron physics
programme at the new Facility for Antiproton and Ion Research (FAIR) under
construction at GSI/Darmstadt (Germany). The multi-purpose PANDA detector in
combination with an intense and high-quality antiproton beam allows for coverage
of a broad range of different aspects of QCD, and it is best suited for charmonium
spectroscopy. We present a comprehensive PANDA Monte Carlo simulation study for
precision resonance energy scan measurements, using the example of the charmonium-like
$X(3872)$ state discussed to be exotic. Apart from the proof of principle for
natural decay width and line-shape measurements of very narrow resonances, the
achievable sensitivities are quantified for the concrete example of the $X(3872)$.
The discussed measurement is uniquely possible with a $\bar{p}p$ annihilation
experiment such as PANDA at FAIR.

At the international FAIR laboratory, an upcoming significant enlargement of the GSI installations near Darmstadt, Germany, the PANDA antiproton experiment will investigate fundamental questions of hadron physics in the charm quark energy range. Antiprotons in the 1.5 to15 GeV/c momentum range will interact with gas jet or pellet fixed targets. The Endcap Disc DIRC (Detection of Internally Reflected Cherenkov light) covers the forward endcap solid angle of the PANDA target spectrometer to positively identify charged kaons. Monte-Carlo simulations indicate that from 1 up to 4 GeV/c one can achieve kaon-pion separation with a separation power of at least 3 standard deviations. For the upcoming CERN test beam in August 2018 the read-out electronics has been upgraded to the TOFPET-ASIC Version 2.

Microchannel-plate (MCP) PMTs were identified as the only suitable photon sensors for the two DIRC detectors of the PANDA experiment at FAIR. As the long-standing aging problem of MCP-PMTs was recently overcome by coating the MCP pores with an atomic layer deposition (ALD) technique, further improved 2-inch MCP-PMTs were investigated. The best PHOTONIS device has reached a lifetime of >20 C/cm2 integrated anode charge without any sign of aging. Also the newly developed 2-inch MCP-PMTs of Hamamatsu are maturing and are usable in high rate environments. The status of our long-term lifetime measurements and the performance parameters of the currently most advanced ALD-coated MCP-PMTs from PHOTONIS and Hamamatsu are presented. In addition, first results obtained with a new quality assurance setup for MCP-PMTs are discussed. This setup consists of a high performance DAQ system to measure the response of >=64 anode pixels simultaneously. The system allows to study and quantify background parameters like position dependent dark count rates and ion afterpulsing as well as temporal and spacial distributions of recoil electrons and the effects of electronic and charge-sharing crosstalk among the anode pixels.