Glass resistive plate chambers for a semi-digital HCAL Bedjidian, M.; Ianigro, J.-P.; Kieffer, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
The Particle Flow Algorithm (PFA) concept is one of the main features of the future ILC experiments. This implies a highly granular hadronic calorimeter. A 1cm2 segmentation can be obtained using ...semi-digital embedded electronics together with an efficient gas detector. The Glass RPC is an excellent candidate that was successfully used in the BELLE experiment. To apply the PFA efficiently it is necessary to reduce the detector dead zones while keeping it as thin as possible. We have designed and constructed very thin GRPCs for which the number and volume of spacers as well as the area of the gas-tight frame are minimized. New resistive coatings were used to reduce cross-talk. Attempts to improve on the high voltage connection were made and novel gas distribution schemes were tested.
A detailed study of J/
ψ,
ψ′ and Drell-Yan production in S-U collisions has been performed by experiment NA38 at the CERN SPS. This paper presents production cross sections and their centrality ...dependence, based on the largest sample of S-U events collected by the experiment.
Absolute J/
ψ and
ψ
′ production cross sections have been measured at the CERN SPS, with 450 GeV/
c protons incident on a set of C, Al, Cu and W targets. Complementing these values with the results ...obtained by experiment NA51, which used the same beam and detector with H and D targets, we establish a coherent picture of charmonia production in proton-induced reactions at SPS energies. In particular, we show that the scaling of the J/
ψ cross section with the mass number of the target, A, is well described as A
α
, with
α
ψ
=0.919±0.015. The ratio between the J/
ψ and
ψ
′ yields, in our kinematical window, is found to be independent of A, with
α
ψ
′
−
α
ψ
=0.014±0.011.
The charged particle multiplicity distribution dNch/dη has been measured by the NA50 experiment in Pb–Pb collisions at the CERN SPS. Measurements were done at incident energies of 40 and 158 GeV per ...nucleon over a broad impact parameter range. The multiplicity distributions are studied as a function of centrality using the number of participating nucleons (Npart), or the number of binary nucleon–nucleon collisions (Ncoll). Their values at midrapidity exhibit a power law scaling behaviour given by Npart1.00 and Ncoll0.75 at 158 GeV. Compatible results are found for the scaling behaviour at 40 GeV. The width of the dNch/dη distributions is larger at 158 than at 40 GeV/nucleon and decreases slightly with centrality at both energies. Our results are compared to similar studies performed by other experiments both at the CERN SPS and at RHIC.
The production of the J/
ψ and
ψ
′ charmonia states has been studied, through their dimuon decay, in proton, Oxygen and Sulphur induced reactions, by the NA38 experiment at the CERN SPS. The proton ...data was collected with beams of 200 and 450 GeV, while the ion beams had an energy of 200 GeV per incident nucleon. The J/
ψ production cross-section per nucleon-nucleon collision exhibits a remarkably continuous pattern, as a function of the product of the mass numbers of the interacting nuclei, from pp up to S-U reactions. The same pattern is observed within S-U collisions, as a function of the collision centrality. While in p-A interactions both charmonia states exhibit the same A-dependence, in S-U collisions the
ψ
′ production is very strongly suppressed.
J/
ψ and
ψ′ production cross-sections are measured in pp and pd collisions at 450 GeV/
c at the CERN-SPS. The Drell-Yan cross section for muon pairs in the mass range 4.3–8.0 GeV/
c
2 is also ...determined in the same experiment.
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