Recent results from the PANDA DIRC detectors

The PANDA experiment at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR), Darmstadt, Germany, will address fundamental questions of hadron physics using p̄p annihilations. Excellent Particle Identification (PID) over a large range of solid angles and particle momenta will be essential to meet the objectives of the rich physics program. Charged PID in the target region will be provided by a combination of two DIRC (Detection of Internally Reflected Cherenkov light) counters. The Barrel DIRC, covering the polar angle range of 22-140 degrees, will provide π/K separation power of at least 3 standard deviations (s.d.) for charge particle momenta up to 3.5 GeV/c. The design of the Barrel DIRC features narrow radiator bars made from synthetic fused silica, an innovative multi-layer spherical lens focusing system, a prism-shaped synthetic fused silica expansion volume, and an array of lifetime-enhanced Microchannel Plate PMTs (MCP-PMTs) to detect the location and arrival time of the Cherenkov photons. The novel Endcap Disc DIRC will be placed in forward region, covering polar angles from 5 to 22 degree, and is designed to provide 3 s.d. π/K separation up to 4 GeV/c. It is constructed out of four optically isolated quadrants, each comprising a synthetic fused silica radiator plate, focusing optics, and a compact readout region with finely-segmented MCP-PMTs. Detailed Monte-Carlo simulations were performed and reconstruction methods were developed to study the performance of both DIRCs. We will discuss the status of the technical design and present recent results of the design validation using prototypes in mixed hadron beams at CERN and DESY

The PANDA Barrel DIRC Detector

The PANDA detector at the international accelerator Facility for Antiproton and IonResearch in Europe (FAIR) near GSI, Darmstadt, Germany will address fundamental questionsof hadron physics.Excellent Particle Identification (PID) over a large range of solid angles andparticle momenta will be essential to meet the objectives of the rich physics program,which includes charmonium spectroscopy, the search for hybrids and glueballs, and thestudy of the interaction of hidden and open charm particles with nucleons and nuclei.Charged PID for the barrel section of the target spectrometer will be provided bya DIRC (Detection of Internally Reflected Cherenkov light) detector.This counter will cover the angular range of 22-140 degrees and will need to cleanlyseparate charged pions from kaons for momenta between 0.5 GeV/c and 3.5 GeV/c with aseparation power of at least 3 standard deviations.The design of the PANDA Barrel DIRC detector is based on the successful BABARDIRC and the SuperB FDIRC R&D with several important improvements to optimize theperformance for PANDA, such as a focusing lens system, fast timing, and a compact fusedsilica prism as expansion region.We will discuss the baseline design of the PANDA Barrel DIRC, based on narrow barsmade of synthetic fused silica, and a complex multi-layer spherical lens system,and the potentially cost-saving design option using wide fused silica plates andwill present the result of tests of a large system prototype with a mixedhadron beam at CERN

The PANDA DIRC Detectors

The PANDA experiment at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR), under construction near GSI, Darmstadt, Germany, will address fundamental questions of hadron physics. Excellent Particle Identification (PID) over a large range of solid angles and particle momenta will be essential to meet the objectives of the rich physics program. Charged PID for the PANDA target spectrometer will be provided by two innovative RICH counters using the DIRC (Detection of Internally Reflected Cherenkov light) technology.The Barrel DIRC will cover the polar angle range of 22-140 degrees and cleanly separate charged pions from kaons for momenta between 0.5 GeV/c and 3.5 GeV/c with a separation power of at least 3 standard deviations (s.d.). The design is based on the successful BABAR DIRC and the SuperB FDIRC R&D with several important improvements to optimize the performance for PANDA, such as wider and shorter radiator bars, a spherical focusing lens system, fast timing, a compact fused silica prism as expansion region, and lifetime-enhanced Microchannel-Plate PMTs (MCP-PMTs) for photon detection.The Endcap Disc DIRC (EDD) will separate pions from kaons with momenta up to 4 GeV/c and polar angles between 5 and 22 degrees with a separation power of 3 s.d. or more. The EDD consists of four optically isolated quadrants, each comprising a synthetic fused silica radiator plate of 2 cm thickness, focusing optics along the outer edge to convert the angle information into a position information, and a compact readout region. The intrinsic contribution of a chromatic error is reduced by an optical filter and an adapted photocathode. High-resolution MCP-PMTs will be used in connection with a fast ASIC-based readout to record events.We will discuss the technical design of the two PANDA DIRC detectors and the results of the design validation using prototypes in hadronic particle beams at DESY and at CERN