Fast Cherenkov and scintillation detectors based on microchannel-plate photomultiplier tubes and silicon photomultipliers are being developed for application in the multi-purpose detector and ...baryonic matter at the Nuclotron experiments with the heavy ion beams at the Joint Institute for Nuclear Research. The aim of the detectors is the fast triggering of nucleus–nucleus collisions with high efficiency and to generate the start signal with picosecond time resolution for time-of-flight measurements. The detectors provide a time resolution better than 50 ps and can operate in the strong magnetic field of the experimental facilities.
Two fast interaction trigger systems based on fast detectors with MCP-PMTs and SiPMs readout have been developed for fixed target experiment Baryonic Matter at Nuclotron and collider experiment ...Multi-Purpose Detector at Laboratory of High Energy Physics, Joint Institute for Nuclear Research. These detectors provide the effective L0 trigger for nucleus–nucleus collisions and the start pulse T0 for TOF detectors with picosecond time resolution. Important requirement to the detectors is good operation in a strong magnetic field.
•L0 trigger systems for heavy ion experiments at JINR are described.•The MCP-PMTs and SiPMs are used for readout in Cherenkov and scintillation detectors.•The detectors operate in a strong magnetic field.•T0 pulse with picosecond time resolution is produced for TOF detectors.
The High Acceptance DiElectron Spectrometer (HADES) has been recently commissioned at GSI Darmstadt. It has been designed to study hadron properties inside nuclear matter via measurements of ...dielectron decays in proton, pion and heavy ion induced reactions in
1
−
2
AGeV
energy range. We report first preliminary results on invariant masses of
e
+
e
−
pairs measured in
12C +
12C collisions at
E
=
2
AGeV
and compare them to simulations based on UrQMD transport model. In summary we present and discuss planned experiments.
During the 1996 lead run time, CERES has accumulated 42 million events, corresponding to a factor of 5 more statistics than in 1995 and 2.5 million events of a special photon-run. We report on the ...results of the low-mass e
+e
−-pair analysis. Since the most critical item is the poor signal-to-background ratio we also discuss the understanding of this background, in absolute terms, with the help of a detailed Monte Carlo simulation. We show preliminary results of the photon analysis and summarize the results of the hadron analysis preliminarily reported on already at QM'97 1.
We report preliminary results of the first measurement of low-mass electron pairs in 160 GeV/nucleon PbAu collisions at central rapidities in a wide multiplicity range. This work is the continuation ...of our systematic studies on pair production in p-Be, p-Au and SAu interactions. The motivation for this effort derives from a new source of lowmass dileptons recently observed in SAu and S-W collisions by CERES and HELIOS/3, respectively. The results obtained in the analysis of the PbAu data confirm our previous finding that pair production in the mass range 0.2 < m
ee
< 1.5 GeV/
c
2 is enhanced over the contributions from hadron decays while no significant excess could be observed for m
ee
≲ 2m
π
. A comparison of the results for different multiplicity bins favours a non-linear dependence of the e
+e
−-yield on the accompanying charged particle densities.
Differential triangular flow, v3(pT), of negative pions is measured at sNN=17.3 GeV around midrapidity by the CERES/NA45 experiment at CERN in central PbAu collisions in the range 0–30% with a mean ...centrality of 5.5%. This is the first measurement as a function of transverse momentum of the triangular flow at SPS energies. The pT range extends from about 0.05 GeV/c to more than 2 GeV/c. The triangular flow magnitude, corrected for the HBT effects, is smaller by a factor of about 2 than the one measured by the PHENIX experiment at RHIC and the ALICE experiment at the LHC. Within the analyzed range of central collisions no significant centrality dependence is observed. The data are found to be well described by a viscous hydrodynamic calculation combined with an UrQMD cascade model for the late stages.
The HADES tracking system Müntz, C.; Markert, J.; Agakichiev, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Volume:
535, Issue:
1
Journal Article
Peer reviewed
Open access
The HADES dielectron spectrometer has recently launched its physics program at the heavy ion synchrotron SIS at GSI Darmstadt. The spectroscopy of vector mesons in heavy ion collisions via their ...dielectron decay channel makes great demands on the HADES tracking system regarding acceptance and spatial resolution. The tracking system is formed out of 24 low-mass, trapezoidal multi-layer drift chambers providing about
30
m
2
of active area. Low multiple scattering in the in total four planes of drift chambers before and after the magnetic field is ensured by using helium-based gas mixtures and aluminum cathode and field wires. First in-beam performance results are contrasted with expectations from simulations. Emphasis is placed on the energy loss information, exploring its relevance regarding track recognition.
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