Multigap Resistive Plate Chambers (MRPCs) are often used as time-of-flight (TOF) detectors for high-energy physics and nuclear experiments thanks to their excellent time accuracy. For the Compressed ...Baryonic Matter (CBM) TOF system, MRPCs are required to work at particle fluxes on the order of 1–10kHz/cm2 for the outer region and 10–25kHz/cm2 for the central region. Better time resolution will allow particle identification with TOF techniques to be performed at higher momenta. From our previous studies, a time resolution of 25ps has been obtained with a 20-gap MRPC of 140μm gap size with enhanced rate capability. By using a new type of commercially available thin low-resistivity glass, further improvement MRPC rate capability is possible. In order to study the rate capability of the 10-gap MRPC built with this new low-resistivity glass, we have performed tests using the continuous electron beam at ELBE. This 10-gap MRPC, with 160μm gaps, reaches 97% efficiency at 19.2kV and a time resolution of 36ps at particle fluxes near 2kHz/cm2. At a flux of 100kHz/cm2, the efficiency is still above 95% and a time resolution of 50ps is obtained, which would fulfil the requirement of CBM TOF system.
High-rate timing resistive plate chambers with ceramic electrodes Laso Garcia, A.; Kotte, R.; Naumann, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2016, Letnik:
818
Journal Article
Recenzirano
We describe recent advances in developing radiation-hard ceramic resistive plate chambers (CRPCs) with Si3N4/SiC composites. Bulk resistivity measurements for this material for different ...manufacturing processes are reported. The results show that the bulk resistivity ρ can vary between 107and1013Ωcm. The varistor type behaviour of the material is analysed. A comparison with other materials used in timing RPCs is given. We describe the assembly and tests of CRPC prototypes in electron and proton beams. For a prototype with ρ~5×109Ωcm, the efficiency of the detectors is 95% at a flux of 2×105cm−2s−1. The time resolution at the same flux is about 120ps. A prototype with ρ~2×1010Ωcm shows an efficiency of about 85% up to fluxes of 5×104cm−2s−1 with a time resolution better than 80ps. The results are compared with RPC models.
We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics ...measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e+e− invariant mass spectra to elementary p+p data, we observe for e+e− momenta Pee<0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional ρ-like contribution and a decrease of ω yield. These opposite trends are tentatively interpreted as a strong coupling of the ρ meson to baryonic resonances and an absorption of the ω meson, which are two aspects of in-medium modification of vector mesons.
Ceramics high rate timing RPC Naumann, L.; Kotte, R.; Stach, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2011, Letnik:
628, Številka:
1
Journal Article
Recenzirano
A resistive plate counter for timing purposes in the high rate environment of the Compressed Baryonic Matter Experiment has been developed at the Forschungszentrum Dresden-Rossendorf. The detector ...electrodes are made of a ceramics composite whose volume resistivity can be tuned in the production process over five orders of magnitude. The detector prototype has been tested with single electrons of 32
MeV. It shows an all-time high rate capability for electron fluxes up to 5×10
5
s
−1
cm
−2.
High-rate timing RPC with ceramics electrodes Naumann, L.; Kotte, R.; Stach, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2011, Letnik:
635, Številka:
1
Journal Article
Recenzirano
A resistive plate counter for timing purposes in the high-rate environment of the Compressed Baryonic Matter Experiment has been developed at the Forschungszentrum Dresden-Rossendorf. The detector ...electrodes are made of a ceramics composite. Detector tests have been performed with minimum ionizing single electrons, delivered by the electron accelerator ELBE with a time accuracy of few picoseconds. The ceramics RPC shows an all-time high-rate capability for electron fluxes up to
2.7
×
10
5
s
−
1
cm
−
2
.
Radiation hard ceramic RPC development Akindinov, A; Dreyer, J; Fan, X ...
Journal of physics. Conference series,
01/2017, Letnik:
798, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We report recent advances in R&D on the Beam Fragmentation and T0 Counter (BFTC) for the CBM experiment, based on RPCs with floating electrodes made of resistive ceramic material. An optimal value of ...the ceramics bulk resistivity has been determined to be about 5·109 ·cm. RPCs with such electrodes show even characteristics and stable operation under particle fluxes of up to 150 kHz/cm2, with the detection efficiency above 90%.
SiΛvio: A trigger for Λ-hyperons Münzer, Robert; Berger, Martin; Fabbietti, Laura ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2014, Letnik:
745
Journal Article
Recenzirano
Odprti dostop
As online trigger for events containing Λ hyperons in p+p collisions at 3.1GeV a silicon-based device has been designed and built. This system has been integrated close to the target region within ...the FOPI spectrometer at GSI and was also employed as a tracking device to improve the vertex reconstruction of secondary decays. The design of the detector components, read-out, the trigger capability as well as the tracking performance are presented. An enrichment factor of about 14 was achieved for events containing a Λ-hyperon candidate.
About 10 μs after the Big Bang, the universe was filled—in addition to photons and leptons—with strong-interaction matter consisting of quarks and gluons, which transitioned to hadrons at ...temperatures close to kT = 150 MeV and densities several times higher than those found in nuclei. This quantum chromodynamics (QCD) matter can be created in the laboratory as a transient state by colliding heavy ions at relativistic energies. The different phases in which QCD matter may exist depend for example on temperature, pressure or baryochemical potential, and can be probed by studying the emission of electromagnetic radiation. Electron–positron pairs emerge from the decay of virtual photons, which immediately decouple from the strong interaction, and thus provide information about the properties of QCD matter at various stages. Here, we report the observation of virtual photon emission from baryon-rich QCD matter. The spectral distribution of the electron–positron pairs is nearly exponential, providing evidence for a source of temperature in excess of 70 MeV with constituents whose properties have been modified, thus reflecting peculiarities of strong-interaction QCD matter. Its bulk properties are similar to the dense matter formed in the final state of a neutron star merger, as apparent from recent multimessenger observation.
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