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A 64-channel readout and data-acquisition module is described in detail. It consists of an H12700 multianode photomultiplier tube, four PADIWA preamplifier boards, and a TRB v3 card that perform the functions of a time-to-digital converter and a data concentrator. The software modules that are necessary for operation of the prototype are described. The inter-channel delays are calibrated. The drift of individual delays does not exceed 0.5 ns for the entire measurement time. The spectra of the “time over threshold” (ToT) are investigated. The influence of periodic noise pickups and the need to improve circuit designs are revealed. The timing properties of the wavelength shifter and its effect on the detection efficiency for Cherenkov rings are investigated. The most intense component is characterized by a decay time of 1.1 ns and there are components with characteristic times of 3.8 and 45 ns. The influence of single-electron spectrum features on the detection efficiency for photoelectrons and the probability of false hits are determined. The total time resolution of 131 channels is 1.1 ns (FWHM). The results make it possible to use the investigated system of readout and data acquisition in the CBM experiment. Nevertheless, the elimination of the revealed shortcomings will provide the efficiency margin and improve the reliability of the system during long-term operation.

The CBM-RICH detector is designed to identify electrons with momenta up to 8 GeV/c and high purity as this is essential for the CBM physics program. The detector consist of a CO2-gaseous radiator, a spherical mirror system, and Multi-Anode PhotoMultiplier Tubes (MAPMT) of type H12700 from Hamamatsu as photon detectors. The detector concept was verified through R&D studies and a laterally scaled prototype. The results were summarized in a TDR, in which open issues were defined concerning the readout electronics, the shielding of the magnetic stray field in the MAPMT region, the radiation hardness of the MAPMT sensors, and the mechanical holding structure of the mirror system. In this article an overview is given on the CBM RICH development with focus on those open issues.

The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility will investigate the QCD phase diagram at high net baryon densities and moderate temperatures in A+A collisions from 2 to 11 AGeV (SIS100). Electron identification in CBM will be performed by a Ring Imaging Cherenkov (RICH) detector and Transition Radiation Detectors (TRD). A real size prototype of the RICH detector was tested together with other CBM groups at the CERN PS/T9 beam line in 2014. For the first time the data format used the FLESnet protocol from CBM delivering free streaming data. The analysis was fully performed within the CBMROOT framework. In this contribution the data analysis and the event reconstruction methods which were used for obtained data are discussed. Rings were reconstructed using an algorithm based on the Hough Transform method and their parameters were derived with high accuracy by circle and ellipse fitting procedures. We present results of the application of the presented algorithms. In particular we compare results with and without Wavelength shifting (WLS) coating.

The HADES RICH detector is designed for efficient electron identification (electron momenta up to few GeV) in relativistic heavy ion collisions, and successfully in operation since 1999 at the SIS18 accelerator facility, GSI, Darmstadt, Germany. It uses a gaseous photon detector with reflective CsI cathode deposited on the MWPC pad plane. The CBM experiment at the future FAIR facility in Darmstadt will install a RICH detector utilizing 1100 Hamamatsu H12700 Multianode Photomultiplier tubes. In a joint effort the HADES RICH photon detector will be replaced by a subset of these MAPMTs together with a new FPGA-TDC based readout chain resulting in a significant improvement of e + e − - pair reconstruction efficiency for near future measurement campaigns.

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-proton and Ion Research (FAIR) will investigate the phase diagram of strongly interacting matter at high net-baryon density and moderate temperature in A+A collisions. One of the key detectors of CBM to explore this physics program is a Ring Imaging CHerenkov (RICH) detector for electron identification. For a high performance of the RICH detector precise mirror alignment is essential. A three-step correction cycle has been developed, which will be discussed: First a qualitative, fast check of the mirror positions, second a quantitative determination of possible misalignments and third a software correction routine, allowing a proper functioning of the RICH under misalignment conditions.

The CBM RICH detector is an integral component of the future CBM experiment at FAIR, providing efficient electron identification and pion suppression necessary for the measurement of rare dileptonic probes in heavy ion collisions. An overview of the CBM RICH readout and DAQ system prototype is given, consisting of the PADIWA preamplifier-discriminator board, the TDC-HUB board TRBv3, and DAQ and analysis code in the CbmRoot framework. The laboratory setup built for studying the timing characteristics of the readout chain and the analysis results obtained using the laboratory measurements are presented. The fine time calibration and inter-channel delay correction techniques and their implementation and effect are discussed.

The $\overline{{\rm{P}}}\mathrm{ANDA}$ (anti-Proton ANnihiliation at DArmstadt) experiment will be one of the four flagship experiments at the new international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. $\overline{{\rm{P}}}\mathrm{ANDA}$ will address fundamental questions of hadron physics and quantum chromodynamics using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c and a design luminosity of up to 2 × 1032 cm−2 s−1. Excellent particle identification (PID) is crucial to the success of the $\overline{{\rm{P}}}\mathrm{ANDA}$ physics program. Hadronic PID in the barrel region of the target spectrometer will be performed by a fast and compact Cherenkov counter using the detection of internally reflected Cherenkov light (DIRC) technology. It is designed to cover the polar angle range from 22° to 140° and will provide at least 3 standard deviations (s.d.) π/K separation up to 3.5 GeV/c, matching the expected upper limit of the final state kaon momentum distribution from simulation. This documents describes the technical design and the expected performance of the $\overline{{\rm{P}}}\mathrm{ANDA}$ Barrel DIRC detector. The design is based on the successful BaBar DIRC with several key improvements. The performance and system cost were optimized in detailed detector simulations and validated with full system prototypes using particle beams at GSI and CERN. The final design meets or exceeds the PID goal of clean π/K separation with at least 3 s.d. over the entire phase space of charged kaons in the Barrel DIRC.

A real size prototype of the CBM RICH detector was tested in beam at CERN in November 2014 with new readout electronics. A detailed analysis of the timing characteristics of the readout chain will be presented in this article. Results of the time precision measurements for several subsets of all channels and the stability of the fine time calibration will be discussed. The obtained sub-nanosecond time precision allows also to investigate the effect on timing when using additional wavelength-shifting films on top of the MAPMT windows.

In 2015 1100 Multi-Anode Photo-Multipliers (MAPMTs) of type HAMAMATSU H12700 were ordered to equip the photon detection plane of the CBM-RICH and HADES-RICH detectors. Both experiments aim to study the properties of dense matter produced in heavy ion collisions. To measure the characteristics of all ordered MAPMTs and give feedback to the manufacturer, a test bench was built at the University of Wuppertal. This paper describes the working principle of the test bench and compiles the measurements of the first 400 H12700 MAPMTs delivered. The average characteristics of the H12700 gathered from these measurements are discussed and compared to measurements of the HAMAMATSU H8500.

The next generation of high-luminosity experiments requires excellent particle identification detectors which calls for Imaging Cherenkov counters with fast electronics to cope with the expected hit rates. A Barrel DIRC will be used in the central region of the Target Spectrometer of the planned PANDA experiment at FAIR. A single photo-electron timing resolution of better than 100 ps is required by the Barrel DIRC to disentangle the complicated patterns created on the image plane. R&D studies have been performed to provide a design based on the TRB3 readout using FPGA-TDCs with a precision better than 20 ps RMS and custom frontend electronics with high-bandwidth pre-amplifiers and fast discriminators. The discriminators also provide time-over-threshold information thus enabling walk corrections to improve the timing resolution. Two types of frontend electronics cards optimised for reading out 64-channel PHOTONIS Planacon MCP-PMTs were tested: one based on the NINO ASIC and the other, called PADIWA, on FPGA discriminators. Promising results were obtained in a full characterisation using a fast laser setup and in a test experiment at MAMI, Mainz, with a small scale DIRC prototype.

The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility will investigate the QCD phase diagram at high net-baryon densities and moderate temperatures. One of the key signatures will be di-leptons emitted from the hot and dense phase in heavy-ion collisions. Measuring di-electrons, a high purity of identified electrons is required in order to suppress the background. Electron identification in CBM will be performed by a Ring Imaging Cherenkov (RICH) detector and Transition Radiation Detectors (TRD). In order to access the foreseen rare probes, the detector and the data acquisition have to handle interaction rates up to 10 MHz. Therefore, the development of fast and efficient event reconstruction algorithms is an important and challenging task in CBM. In this contribution event reconstruction and electron identification algorithms in the RICH detector are presented. So far they have been developed on simulated data but could already be tested on real data from a RICH prototype testbeam experiment at the CERN-PS. Efficient and fast ring recognition algorithms in the CBM-RICH are based on the Hough Transform method. Due to optical distortions of the rings, an ellipse fitting algorithm was elaborated to improve the ring radius resolution. An efficient algorithm based on the Artificial Neural Network was implemented for electron identification in RICH. All algorithms were significantly optimized to achieve maximum speed and minimum memory consumption.

Electron identification in the Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) will be performed using a gaseous RICH detector. Due to the UV transparency of the CO 2 radiator, a high photon detection efficiency of the PMTs in use at small wavelengths is favourable. The use of wavelength shifting (WLS) films aims at increasing the integral quantum efficiency of the photon sensors. WLS films absorb UV photons and re-emit photons at longer wavelengths where the quantum efficiency of common photocathodes is higher. As photon sensors, multianode PMTs (MAPMTs) with bialkali or superbialkali photocathodes and UV-extended windows are envisaged. We present quantum efficiency measurements with and without WLS coating for different types of MAPMTs as well as results from a beam test at the CERN PS. An increased photon yield was observed when using WLS films. In addition, we discuss the effect of WLS films on the spatial resolution of MAPMTs.

The RICH detectors of the existing HADES spectrometer and CBM experiment (to be built at FAIR) will use 64 channel Multi-Anode PMTs. We designed a complete set of digitizing electronics, consisting of analog and digital front-end modules, power supply and data concentrator cards plugged into a backplane carrying 3 × 2 MAPMTs on the front side, and all readout modules on the backside. These contain all necessary supply electronics, preamplifiers and FPGA-based TDC as well as the digital data and trigger handling logic and an optical transceiver. We present the electronics along with first performance test results.

The main task of the future Compressed Baryonic Matter experiment (CBM), to be operated at the FAIR facility at GSI, Darmstadt, is the exploration of the properties of super-dense nuclear matter. The search for in-medium modifications of hadrons, the study of the transition from dense hadronic matter to quark-gluon matter, and the possible location of a critical endpoint in the QCD phase diagram of strongly interacting matter are the most important physics goals of CBM. Detailed measurements of di-leptons stemming from low-mass vector-mesons and charmonium have a large potential to shed light on the existence of such effects. The Ring Imaging Cherenkov detector of the CBM experiment aims at a clean and efficient electron identification. It is foreseen to use CO2 as radiator gas and equip the detector with a focussing mirror system and multi-anode photomultiplier tubes as photon detector. In this paper we present selected results of R&D studies and beam test measurements of the detector prototype performed in fall 2011 and 2012 at the CERN/PS with a mixed electron-pion beam.

One of the most important aspects of particle identification experiments is the digitisation of time, amplitude and charge data from detectors. These conversions are mostly undertaken with Application Specific Integrated Circuits (ASICs). However, recent developments in Field Programmable Gate Array (FPGA) technology allow us to use commercial electronic components for the required Front-End Electronics (FEE) and to do the digitisation in the FPGA. It is possible to do Time-of-Flight (ToF), Time-over-Threshold (ToT), amplitude and charge measurements with converters implemented in FPGA. We call this principle come & kiss: use COmplex ComMErcial Elements & Keep It Small and Simple.

A high precision ( < 14 ps RMS time resolution) and high channel density ( ~ 256 channels) Time to Digital Converter (TDC) module (realized in FPGAs) with integrated DAQ is presented. The data is transported over up to 8 Gigabit-Ethernet or optical links with up to 3 Gb/s. Slow-Control information is transported over the same links. It can be attached directly to the detector, which allows the elimination of long cables and crate systems. The full 256 channel TDCs are expected to use approximately 30 W electrical power. The module size is 20 cm by 23 cm. Power is provided by a galvanically isolated 48 V low noise power supply. AddOn-boards adapt to the special needs of the detector to be read out, e.g. containing Charge to Width (Q2W) FEE for PMT readout.