A prototype of the Micromegas detector with 30 × 30 mm2 active area and the resistive anode was developed and produced at DLNP JINR using a bulk Micromegas technological process and a diamond-like ...carbon resistive layer on a polyimide substrate. The prototype is considered as an option for the future upgrade of the readout chambers for the Time Projection Chamber of the Multi-Purpose Detector experiment at the NICA collider. The performance of the prototype of the Micromegas detector was studied using a 55Fe radioactive source and an Ar:CO2 (90:10) gas mixture. The dependencies of the gas gain and the energy resolution on applied high voltage are obtained. The detector works stably up to the gas gain of 30,000. For the gas gain of 10,000 the resolution for the line 5.9 keV of the 55Fe source is 22%. The robustness of the detector prototype to electric discharges was demonstrated by accumulating about 10,000 discharge events at a gas gain of 40,000 without any visible impact on the operation of the prototype.
Photons produced in pp interactions at 450 GeV/c were detected by reconstructing the e+e− pairs of photon conversions in a 1 mm thick lead sheet placed in front of the MWPCs of the OMEGA spectrometer ...at CERN. A soft photon signal 4.1±0.8 times the inner bremsstrahlung prediction was observed in the forward rapidity region (yc.m.s.⩾1.2), thus extending the domain of the anomalous soft photon effect seen already in K+p, π+p and π−p interactions.
In this Letter we present additional experimental characteristics of anomalous soft photon radiation observed in π−p interactions at 280 GeV/c in the CERN experiment WA91, together with a ...re-calculated ratio of the observed direct soft photon signal to the expected level of the hadronic inner bremsstrahlung, which is found to be 5.3±1.0. The other presented characteristics, energy dependence and angular distributions of direct soft photons, show the similarity of the observed signal to the expected hadronic bremsstrahlung behaviour.
A PMT-Block test bench Adragna, P.; Antonaki, A.; Boudagov, I. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2006, Letnik:
564, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is housed in a unit, called
PMT-Block. The PMT-Block is a compact instrument comprising a light mixer, a PMT together with its ...divider and a
3-in-1 card, which provides shaping, amplification and integration for the signals. This instrument needs to be qualified before being assembled on the detector. A PMT-Block test bench has been developed for this purpose. This test bench is a system which allows fast, albeit accurate enough, measurements of the main properties of a complete PMT-Block. The system, both hardware and software, and the protocol used for the PMT-Blocks characterization are described in detail in this report. The results obtained in the test of about 10
000 PMT-Blocks needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile Calorimeter are also reported.
An analysis of the centrally produced
π
+
π
− and
π
+
π
−
π
+
π
− mass spectra from the WA76 and WA91 experiments is presented, which shows that in the
π
+
π
−
π
+
π
− channel there are two new ...states, the
f
0(1450) and
f
2(1900). There is another new state in the
π
+
π
− channel with
M = 1497 ± 30 MeV and
Γ = 199 ± 30 MeV, which is compatible with the
f
0(1520) observed by the Crystal Barrel experiment. Another interpretation is discussed, where the 1450 and 1497 GeV structures are explained as being due to an interference effect between the
f
0(1365) and
f
0(1520).
We describe the detectors and trigger system used in the CERN WA92 experiment. The experiment was designed to study the production and decay of beauty particles from 350 GeV/
c
π
− interactions in ...copper and tungsten targets. Charged particle tracking is performed using the omega spectrometer. Silicon microstrip detectors are used to provide precise tracking information in the region of the production and the decay of heavy-flavoured particles and to trigger on the resulting high impact parameter tracks. The precision of vertex reconstruction corresponds to ±3.7% of the mean B-decay proper lifetime. Lepton and high transverse momentum hadron signals are also used in the trigger, which accepts 23% of B-decays and rejects 98.4% of non-beauty interactions.
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