The CBM (Compressed Baryonic Matter) experiment constructed at FAIR (Facility for Anti-proton and Ion Research) at GSI, Darmstadt, Germany, will provide unique research opportunities to explore the phase diagram of nuclear matter. As one of the core detectors in the CBM experiment, the Time-of-Flight (TOF) system applies the MRPC (Multi-gap Resistive Plate Chamber) for a precise particle identification for all the incident charged hadrons. The CBM-TOF will be operated at an ion beam intensity up to 109/s, which means the particle fluxes on the TOF wall can reach an unprecedentedly high rate of 30 kHz/cm2. Almost half of the MRPC counters are from the inner region of the TOF wall, and they will be assembled with the low-resistive glass which enables them to work under such high rate. This is the first time of the large scale application of the low-resistive glass MRPCs into the nuclear and high-energy physics experiments. It is especially important to study on the production and test procedure to keep the good performance of all these counters. For this mass production, we have developed a set of specified manufacturing procedure and quality control method to guarantee the performance of all the counters. A newly developed method to check the uniformity of the gas gap with help of the projection imaging technique has been first applied. Until now, 73 MRPCs have been produced for the eTOF project in the BESII detector upgrade at STAR and the TOF system of mini-CBM. Tested by cosmic ray in a system based on TRB, all the produced counters show a stable performance of above 95% efficiency and below 90 ps time resolution. The study on the mass production of the low-resistive plate chamber will provide experience for wide application of MRPC into the high rate experiments in the future. In this paper, the counter design, manufacturing procedures, quality control methods and test results for this MRPC counter are described in a detailed way.

The free streaming readout concept of the CBM experiment imposes to the Multi-Strip Multi-Gap RPCs (MSMGRPCs) developed for the CBM-TOF wall a very good matching of the characteristic impedance of the signal transmission line (corresponding to a single strip) to the input impedance of the front-end electronics in order to reduce fake signals produced by reflections. The design of the MSMGRPC prototype described here exploits in an innovative way the advantage of a strip structure for the readout and the high voltage electrodes, the impedance of the signal transmission line being adjusted independent of the detector granularly. The new design allows to built MSMGRPCs with the impedance corresponding to a single strip matched to the input impedance of the front end electronics. The prototype was tested in-beam at CERN-SPS with reaction products of a 30.A GeV Pb beam colliding onto a Pb target, in conditions rather similar in terms of energy and multiplicity with those expected at SIS100/FAIR. The obtained performance of 62 +/- 3 ps system time resolution and 97% efficiency shows that the new developed prototype meets the challenging requirements for the inner zone of the CBM-TOF wall.

The Compressed Baryonic Matter (CBM) spectrometer aims to study strongly interacting matter under extreme conditions. The key element providing hadron identification at incident energies between 2 and 11AGeV in heavy-ion collisions at the SIS100 accelerator is a Time-of-Flight (TOF) wall covering the polar angular range from 2.5 degrees-25 degrees and full azimuth. CBM is expected to be operational in the year 2024 at the Facility for Anti-proton and Ion Research (FAIR) in Darmstadt, Germany. The existing conceptual design foresees a 120 m(2) TOF-wall composed of Multi-gap Resistive Plate Chambers (MRPC) which is subdivided into a high rate region, a middle rate region and a low rate region. The MRPC3b Multistrip-MRPCs, foreseen to be integrated in the low rate region, have to cope with charged particle fluxes up to 1 kHz/cm(2) and therefore will be constructed with thin float glass (0.28 mm thickness) as resistive electrode material. In the scope of the FAIR phase 0 program it is planned to install about 36% of the MRPC3b counters in the east endcap region of the STAR experiment at BNL as an upgrade for the Beam Energy Scan campaign (BESII) in 2019/2020.

The Time Of Flight (TOF) subsystem is one of the main detectors of the CBM experiment. The TOF wall in conjunction with Silicon Tracking System (STS) is foreseen to identify charged hadrons, i.e. pions, kaons and protons, with a full azimuthal coverage at 2.5 degrees - 25 degrees polar angles. A system time resolution of at least 80 ps, including all contributions, such as electronics jitter and the resolution of the time reference system, is required. Such a performance should be maintained up to a counting rate larger than 30 kHz/cm(2) at the most inner region of TOF wall. Our R&D activity has been focused on the development of two-dimensional position sensitive Multi-gap Resistive Plate Counter (MRPC) prototypes for the forward region of the CBM-TOF subdetector, the most demanding zone in terms of granularity and counting rate. The in-beam tests using secondary particles produced in 30 GeV/u Pb ion collisions on a Pb target at SPS - CERN aimed to test the performance of these prototypes in conditions similar to the ones expected at SIS100 at FAIR. The performance of the prototypes is studied in conditions of exposure of the whole active area of the chamber to high multiplicity of reaction products. The results show that this type of MRPC fulfill the challenging requirements of the CBMTOF wall. Therefore, such an architecture is recommended as basic solution for CBM-TOF inner zone.

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 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_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 2022, in the context of the worldwide efforts to explore high-density QCD matter.

The MRPC has been widely applied in the high-energy physics experiments in recent decades for its excellent timing performance and good efficiency. The Compressed Baryonic Matter (CBM) experiment at FAIR plans to build its TOF system based on the MRPCs, aiming at a good hadron identification. The CBM-TOF will work at a very high particle flux rate (similar to 30 kHz/cm(2)) condition, and the long-time exposure to such high-rate ionizing radiation will lead to severe gas aging problem on the MRPC. In order to improve the gas interchange inside the MRPC, we designed a new structure of self-sealed MRPC. It has a much smaller gas volume, which may accelerate the exchange process between the fresh and the polluted gas. The preparation time before the MRPC could work is also largely shortened. A prototype of self-sealed MRPC was produced in Tsinghua University, and it was tested in the CERN SPS Nov 2015 beam test organized by the CBM-TOF group. It showed around 98% efficiency and 60 ps time resolution. Due to the rate limit of 10 kHz/cm(2) in this beam test, we cannot make judgement on its performance under extremely high rate. Therefore further studies have to be performed under higher rate in order to study the capability of improving the gas exchange speed of this more flexible and operable sealed MRPC. This will allow that MRPC to be better suited for the high rate environment of TOF system while operating in the experiment.

The Compressed Baryonic Matter (CBM) experiment has decided to use the Multi-gap Resistive Plate Chambers(MRPC) technology to build its Time-Of-Flight (TOF) wall. CBM-TOF requires a rate capability over 20kHz/cm2 for inner region. A 10-gap pad-MRPC assembled with low resistive glass is designed to construct this area. The prototypes, which consist of 10×0.22mm gas gaps and 2×8 20mm×20mm readout pads, require fewer electronic channels compared to the strip design. A timing resolution of around 60ps and an efficiency above 98% were obtained in a cosmic test and a beam test taken in 2014 October GSI beam time. The results show that the real-size prototypes fulfill the requirements of the CBM-TOF.

Two dimensional position sensitive timing MGMSRPC prototypes were developed for the low polar angles of the CBM - TOF wall. Four MGMSRPC counters were arranged in a staggered geometrical configuration along the z direction, with overlap along and across the strips, in order to define a basic architecture for the inner zone of the CBM-TOF wall. This configuration was tested with mixed electron-pion beam at CERN-PS and with reaction products resulted from the heavy ion induced reactions at SIS18 - GSI Darmstadt and SPS - CERN. The performance of the basic architecture in conditions close to the ones expected for their operation in the inner zone o the CBM - TOF wall at SIS100/FAIR will be presented.

The GEM-TPC detector will be part of the standard Super-FRS detection system, as tracker detectors at several focal stations along the separator and its three branches.

In the CBM (Compressed Baryonic Matter) experiment constructed at the Facility for Anti-proton and Ion Research (Fair) at GSI, Darmstadt, Germany, MRPC(Multi-gap Resistive Plate Chamber) is adopted to construct the large TOF (Time-of-Flight) system to achieve an unprecedented precision of hadron identification, benefiting from its good time resolution, relatively high efficiency and low building price. We have developed a kind of double-ended readout strip MRPC. It uses low resistive glass to keep good performance of time resolution under high-rate condition. The differential double stack structure of 2x4 gas gaps help to reduce the required high voltage to half. There are 24 strips on one counter, and each is 270mm long, 7mm wide and the interval is 3mm. Ground is placed onto the MRPC electrode and feed through is carefully designed to match the 100 Ohm impedance of PADI electronics. The prototype of this strip MRPC has been tested with cosmic ray, a 98% efficiency and 60ps time resolution is gotten. In order to further examine the performance of the detector working under higher particle flux rate, the prototype has been tested in the 2014 October GSI beam time and 2015 February CERN beam time. In both beam times a relatively high rate of 1 kHz/cm2 was obtained. The calibration is done with CBM ROOT. A couple of corrections has been considered in the calibration and analysis process (including time-walk correction, gain correction, strip alignment correction and velocity correction) to access actual counter performances such as efficiency and time resolution. An efficiency of 97% and time resolution of 48ps are obtained. All these results show that the real-size prototype is fully capable of the requirement of the CBM-TOF, and new designs such as self-sealing are modified into the strip counter prototype to obtain even better performance.

Multi-gap RPC prototypes with a multi-strip-electrode readout were developed for the small polar angle region of the CBM-TOF subdetector, the most demanding zone in terms of granularity and counting rate. The prototypes are based on using low resistivity (∼ 1010 Ω·cm) glass electrodes for performing in high counting rate environment. The strip width/pitch size was chosen such to fulfill the impedance matching with the front-end electronics and the granularity requirements of the innermost zone of the CBM-TOF wall. The in-beam tests using secondary particles produced in heavy ion collisions on a Pb target at SIS18—GSI Darmstadt and SPS—CERN were focused on the performance of the prototypes in conditions similar to the ones expected at SIS100/FAIR. An efficiency larger than 98% and a system time resolution in the order of 70–80 ps were obtained in high counting rate and high multiplicity environment.

Multi-gapResistive Plate Chambers (MRPCs) [1] with multi-strip readout are considered to be the optimal detector candidate for the Time-of-Flight (ToF) wall in the Compressed Baryonic Matter (CBM) experiment. In the R&D phase MRPCs with different granularities, low-resistive materials and high voltage stack configurations were developed and tested. Here, we focus on two prototypes called HD-P2 and THU-strip, both with strips of 27 cm length and low-resistive glass electrodes. The HD-P2 prototype has a single-stack configuration with 8 gaps while the THU-strip prototype is constructed in a double-stack configuration with 2 x 4 gaps. The performance results of these counters in terms of efficiency and time resolution carried out in a test beam time with heavy-ion beam at GSI in 2014 are presented in this proceeding even though the incident particle flux of a few hundred Hz/cm(2) does not meet the real CBM conditions (between 1.5 kHz/cm(2) and 10 kHz/cm(2) for these counters).

A full-size float-glass MRPC prototype for the peripheral part of the time-of-flight (ToF) wall of the future Compressed Baryonic Matter (CBM) experiment is presented. In a cosmicray test, a time resolution of 40ps (including contributions from discrimination and digitization electronics) was observed. The detection efficiency was found to be above 98%. In these respects, the MRPC prototype surpasses the criteria formulated by the CBM collaboration. The analysis algorithm applied to the MRPC raw data is described in detail clustering correlated MRPC hits and correcting for various dependencies.

Charged hadron identification in the Compressed Baryonic Matter experiment (CBM) is realized via the Time-of-Flight method [1]. For this purpose the CBM-ToF collaboration designed a Time-of-Flight wall composed of Multi-gap Resistive Plate Chambers (MRPCs). Due to the high interaction rate in CBM of 10 MHz the key challenge is the development of high rate MRPCs above 25 kHz/cm2 which become possible after the development of low resistive glass with extremely good quality. In this article we present the actual conceptual design of the ToF-wall which is subdivided in three parts namely the outer wall, the inner wall and the forward zone that are discussed in detail.

Two important parametrizations of momentum-dependent nucleonic fields, proposed for the simulations of central heavy-ion collisions, one by Gale et al. and the other by Welke et al., suffer from practical limitations. The first gives rise to mean fields isotropic in momentum, even when underlying momentum distributions are anisotropic, making descriptions of early nonequilibrium stages of collisions unrealistic. The second parametrization gives rise to anisotropic mean fields, but is computationally expensive, because the mean field has to be computed separately for every location of a nucleon in phase space, through folding. Here we construct a parametrization of the nucleonic mean field that yields an anisotropic mean field for an anisotropic momentum distribution and is inexpensive computationally. To demonstrate the versatility of our parametrization, we take the case of results from the parametrization by Welke et al. and attempt to approximate them. In arriving at a suitable anisotropic mean-field potential, we draw, on one hand, from the idea behind the parametrization of Gale et al., of a separable expansion of the potential energy, and, on the other, from the idea of a parallel expansion of the energy and mean field in anisotropy. We show that using our novel parametrization we can qualitatively and partially quantitatively reproduce the features of the mean-field parametrization of Welke et al.. This opens up the possibility of exploring the effects of mean-field anisotropy in collisions, without the penalty of computational cost behind the folding parametrization.

Development of novel therapy strategies is one of the major pressing topics of clinical oncology to overcome drug resistance of tumors. Artesunate (ART) is an anti-malarial drug, which also exerts profound cytotoxic activity towards cancer cells. We applied a gene-hunting approach using microarray-based transcriptome-wide mRNA expression profiling and COMPARE analyses. We identified a set of genes, whose expression was associated either with high IC50 values or low IC50 values for ART. Therefore, these genes may function as resistance or sensitivity factors for response of tumor cells towards ART. This viewpoint is conceivable for genes involved in ribosomal activity, drug transport, cellular antioxidant defense, apoptosis, cell proliferation, cell cycle progression etc. An investigation of underlying signal transduction by pathway analysis suggested a role of the signaling pathways related to tumor necrosis factor (TNF) and the tumor suppressor p53. On the other hand, there were genes without obvious functional link to cellular response to ART, such as genes involved in the survival of cochlear outer and inner hair cells etc. We proved the hypothesis that ART influences the activity of transcription factors regulating downstream genes involved or not involved in response of cancer cells towards ART. This would explain the identification of genes with and without obvious relation to the cytotoxic activity of ART by microarray and COMPARE analyses. By analysis of the binding motifs for the transcription factors c-Myc and Max, we indeed found that 53 of 56 genes contained one or more binding sites for c-Myc/Max upstream of the gene-location. We conclude that c-Myc and Max-mediated transcriptional control of gene expression might contribute to the therapeutic effects of ART in cancer cells, but may also confer unwanted side effects by affecting therapy-unrelated genes.