The CBM RICH project Adamczewski-Musch, J.; Becker, K.-H.; Belogurov, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
766
Journal Article
Recenzirano
The Compressed Baryonic Matter (CBM) experiment will study the properties of super dense nuclear matter by means of heavy ion collisions at the future FAIR facility. An integral detector component is ...a large Ring Imaging Cherenkov detector with CO sub(2) gas radiator, which will mainly serve for electron identification and pion suppression necessary to access rare dileptonic probes like e super(+)e super(-) decays of light vector mesons or J/ psi psi . We describe the design of this future RICH detector and focus on results obtained by building a CBM RICH detector prototype tested at CERN-PS.
Event reconstruction in the RICH detector of the CBM experiment at FAIR Adamczewski, J.; Becker, K.-H.; Belogurov, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
766
Journal Article
Recenzirano
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.
The CBM experiment at the future FAIR facility will explore nuclear matter at high net-baryon densities. One of the key observables is di-leptons as they penetrate the created matter without further ...strong interactions. A gaseous RICH detector in a standard projective geometry using spherical mirrors is one of two detector elements for the required electron identification. The mirror system consists of about 72 trapezoidal mirror tiles. Any misalignment between the tiles relative to the nominal common spherical surface leads to reduction of the reconstruction efficiency of Cherenkov rings and deterioration of their resolution. To determine tolerances in mirror misalignment extensive simulation and measurement studies were carried out. Pure CO sub(2) will be used as radiator gas. Gas contamination, mainly moisture and Oxygen, reduces the number of detected photons per ring and worsens the quality of reconstructed Cherenkov rings. Therefore a study was carried out to determine tolerances in radiator gas contamination.
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 sub(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.
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.
Tests of the CBM Rich readout and Daq prototype Adamczewski-Musch, J.; Akishin, P.; Becker, K. -H. ...
Physics of particles and nuclei letters,
11/2017, Letnik:
14, Številka:
6
Journal Article
Recenzirano
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.
Abstract We present a measurement of the cosmic-ray spectrum above 100 PeV using the part of the surface detector of the Pierre Auger Observatory that has a spacing of 750 m. An inflection of the ...spectrum is observed, confirming the presence of the so-called second-knee feature. The spectrum is then combined with that of the 1500 m array to produce a single measurement of the flux, linking this spectral feature with the three additional breaks at the highest energies. The combined spectrum, with an energy scale set calorimetrically via fluorescence telescopes and using a single detector type, results in the most statistically and systematically precise measurement of spectral breaks yet obtained. These measurements are critical for furthering our understanding of the highest energy cosmic rays.
The RICH detector of the CBM experiment Adamczewski-Musch, J.; Akishin, P.; Becker, K.-H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2017, Letnik:
876
Journal Article
Recenzirano
The CBM-RICH detector is designed to identify electrons with momenta up to 8GeV/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.
Abstract The hybrid design of the Pierre Auger Observatory allows for the measurement of the properties of extensive air showers initiated by ultra-high energy cosmic rays with unprecedented ...precision. By using an array of prototype underground muon detectors, we have performed the first direct measurement, by the Auger Collaboration, of the muon content of air showers between $$2\times 10^{17}$$ 2×1017 and $$2\times 10^{18}$$ 2×1018 eV. We have studied the energy evolution of the attenuation-corrected muon density, and compared it to predictions from air shower simulations. The observed densities are found to be larger than those predicted by models. We quantify this discrepancy by combining the measurements from the muon detector with those from the Auger fluorescence detector at $$10^{{17.5}}\, {\mathrm{eV}} $$ 1017.5eV and $$10^{{18}}\, {\mathrm{eV}} $$ 1018eV . We find that, for the models to explain the data, an increase in the muon density of $$38\%$$ 38% $$\pm 4\% (12\%)$$ ±4%(12%) $$\pm {}^{21\%}_{18\%}$$ ±18%21% for EPOS-LHC, and of $$50\% (53\%)$$ 50%(53%) $$\pm 4\% (13\%)$$ ±4%(13%) $$\pm {}^{23\%}_{20\%}$$ ±20%23% for QGSJetII-04, is respectively needed.
Single photon test bench for series tests of HAMAMATSU H12700 MAPMTs Adamczewski-Musch, J.; Akishin, P.; Becker, K.-H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2017, Letnik:
876
Journal Article
Recenzirano
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.
•Valuable MAPMT characteristics retrievable from single photon test bench.•The HAMAMATSU H12700 is more efficient than the HAMAMATSU H8500 at ∼460nm.•First H12700 shows a gradient in the single photon detection efficiency in X-direction.
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