The Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-proton and Ion Research (FAIR) complex will investigate the phase diagram of strongly interacting matter at high baryon ...density and moderate temperatures created in A+A collisions. For the SIS100 accelerator, the foreseen beam energy will range up to 11 AGeV for the heaviest nuclei. One of the key detector components required for the CBM physics program is the Ring Imaging CHerenkov (RICH) detector, which is developed for efficient and clean electron identification and pion suppression. An important aspect to guarantee a stable operation of the RICH detector is the alignment of the mirrors. A qualitative alignment control procedure for the mirror system has been implemented in the CBM RICH prototype detector and tested under real conditions at the CERN PS T9 beamline. Collected data and results of image processing are reviewed and discussed. In parallel a quantitative method using recorded data has also been employed to compute mirror displacements of the RICH mirrors. Results based on simulated events and the limits of the method are presented and discussed as well. If mirror misalignment is detected, it can be subsequently included and rectified by correction routines. A first correction routine is presented and a comparison between misaligned, corrected and ideal geometries is shown.
The Compressed Baryonic Matter (CBM) experiment is a dedicated heavy ion collision experiment at the FAIR facility. It will be one of the first HEP experiments which works in a triggerless mode: data ...received in the DAQ
from the detectors will not be associated with events by a hardware trigger anymore. All raw data within a giventime period will be collected continuously in containers, so-called time-slices. The task of the reconstruction algorithms is to create events out of this raw data stream. In this contribution, the optimization of the reconstruction software in the RICH detector to the free-streaming data flow is presented. The implementation of ring reconstruction algorithms which use time measurements of the hits as an additional parameter is discussed.
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.
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Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high ...temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (
s
N
N
=
2.7--4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (
μ
B
>
500
MeV), effects of chiral symmetry, and the equation of state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2024, in the context of the worldwide efforts to explore high-density QCD matter.
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, Volume:
14, Issue:
6
Journal Article
Peer reviewed
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.
Status of the CBM and HADES RICH projects at FAIR Adamczewski-Musch, J.; Akishin, P.; Bendarouach, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2020, Volume:
952
Journal Article
Peer reviewed
The upgraded HADES RICH detector, as well as the future CBM RICH detector, will both use the same Hamamatsu H12700 Multianode PMTs read out by the newly developed DiRICH FPGA-TDC readout chain for ...MAPMTs and MCPs. The upgrade of the HADES RICH photon detector has meanwhile been completed, and we are now looking forward to the upcoming physics run in spring 2019. A brief overview on the status of both detector projects is given and supplemented with the recent test-beam results which confirmed the functionality of the DiRICH development before the start of the mass-production of all DiRICH components needed for the HADES RICH upgrade.
Wavelength-shifting (WLS) films of p-terphenyl have been applied by means of dip-coating on the entrance window of the H12700 multi anode photomultiplier (MAPMT) in order to enhance the UV ...sensitivity. Using coated and uncoated MAPMTs in a CBM RICH testbox in a proton testbeam at the COSY accelerator, an enhancement of the number of hits per ring of 15%–20% depending on cuts has been observed. Due to new fast readout electronics of the RICH detector for the CBM/ HADES experiments, the time response of p-terphenyl has been measured to show a decay constant of 2.35 ns. This compares well with time-resolved fluorescence measurements of the films.
•Sensitivity of H12700 MAPMTs extended to UV wavelengths with p-terphenyl films.•Application to Ring Imaging Cherenkov (RICH) Detectors.•Increase in number of hits per ring due to wavelength-shifting films by 15%–20%.•Fast decay time (2.35 ns) measured with CBM/HADES RICH readout electronics.•Good agreement between CBM/HADES RICH and time-resolved fluorescence measurements.
The Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-proton and Ion Research (FAIR) complex will explore the phase diagram of strongly interacting matter at high baryon ...density and moderate temperatures in A+A collisions. The energy spectrum will start at 2 AGeV/c and extend up to 11 AGeV/c for the heaviest nuclei at the SIS 100 accelerator set-up. To explore the physics program of CBM, a RICH detector will be employed for electron identification and pion suppression in a momentum range up to 8 GeV/c. Mirror alignment is a key issue for a proper detector operation. The final conceptual design for a monitoring system of the alignment of the mirrors of the CBM RICH detector will be introduced. It consists of a fast qualitative check of the alignment as well as two different methods to derive quantitative numbers for misalignments. A software correction cycle had been developed which, once applied allows to get back to physics performances as in an ideally aligned case.
•A hardware-based method used to quantify mirror rotations is presented.•Errors up to 2.75% of the applied rotation are observed for a vertical rotation.•Errors up to 14.25% of the applied rotation are observed for a diagonal rotation.•A correction cycle correcting ring-track distance with misaligned mirrors is shown.•Software improvements in ring-track matching and electron ID efficiencies are seen.
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, Volume:
876
Journal Article
Peer reviewed
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.
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, Volume:
876
Journal Article
Peer reviewed
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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