A low-cost and reliable system is presented which was developed for the gas leak rate measurement of the BIS-Monitored Drift Tubes (MDT) to be used for the Muon Spectrometer of the ATLAS experiment ...at LHC. In order to meet the ATLAS schedule, 100
MDTs are tested simultaneously each time by the developed setup. The method used is based on the measurement of the gas pressure drop in each MDT with respect to the pressure of a gas tight reference tube within a time interval of 48
h and is accomplished with a differential manometer. A high degree of temperature stability and homogeneity is achieved inside two thermally insulated boxes and leads to a satisfactory accuracy for the measurement of the gas leak rates. The developed system is appropriate within the ATLAS specifications for mass production. More than 18500
MDTs have been tested up to now and the obtained results are presented.
ATLAS (a toroidal LHC apparatus) is a general purpose experiment that will start its operation at the large hadron collider (LHC) at CERN in 2007. The ATLAS detector is designed to explore numerous ...physics processes by recording, measuring, and investigating the products emerging from proton-proton collisions at energies up to 14 TeV. High-precision muon momentum measurement (dp/p/spl sim/10% at p/sub T/=1 TeV/c) over large areas using monitored drift tube (MDT) chambers is crucial for the ATLAS experiment. More than 1200 MDT chambers, consisting of approximately 370 000 drift tubes, will provide a total coverage of 5500 m/sup 2/. Three Greek universities have taken the responsibility to construct 130 barrel inner small (BIS)-MDT chambers using 30 000 drift tubes of /spl sim/1.7 m length that have been quality tested before assembly. The design of the muon drift tubes aims at high detection efficiency (>95%) and a spatial single tube resolution of <80 /spl mu/m. This paper describes the cosmic ray test setup, which has been instrumented in order to verify that the BIS-MDT chamber Module-0 fulfills its design requirements. The analysis of its data shows that the chamber meets these requirements; it has low noise levels, uniform drift properties, good spatial resolution, and high particle detection efficiency.
We have measured the response of an array of ATLAS muon spectrometer drift tubes to fast neutrons, produced by a t(d,n)/sup 4/He reaction at the 5.5-MV TANDEM Van de Graaff accelerator of the ...National Centre of Scientific Research "Demokritos." The setup consisted of 24 drift tubes in a 6/spl times/4 arrangement. The neutron energy was 18.3 MeV. The anode wire voltage varied from 2200 to 2800 V. For a neutron flux of about 2.75 kHz/cm/sup 2/, the drift tube sensitivity to 18.3-MeV neutrons ranged from 0.031% to 0.606% for anode voltages between 2200 and 2800 V, respectively.
The ATLAS detector at the Large Hadron Collider at CERN is designed to study the products of proton collisions at energies up to 14 TeV. One of its subdetectors is a high-resolution Muon ...Spectrometer, designed to exploit the physics potential of the collisions. It consists of 1206 monitored drift tube chambers, which have to pass very strict quality criteria. For this purpose dedicated setups have been developed and automated at the National Technical University of Athens. In the present report the results of testing about 10,000 drift tubes are presented. These criteria comprise the anode wire mechanical tension, the high voltage dark current, the anode wire displacement, and the gas leak rate of the endplugs and the cylindrical drift tube.
The hadronic part of the electron structure function F2e has been measured for the first time, using e+e− data collected by the DELPHI experiment at LEP, at centre-of-mass energies of ...s=91.2–209.5 GeV. The data analysis is simpler than that of the measurement of the photon structure function. The electron structure function F2e data are compared to predictions of phenomenological models based on the photon structure function. It is shown that the contribution of large target photon virtualities is significant. The data presented can serve as a cross-check of the photon structure function F2γ analyses and help in refining existing parameterisations.
We have studied the response of an array of ATLAS muon spectrometer drift tubes exposed to a neutron radiation produced by the d(d,n)t reaction at the 5.5 MV TANDEM Van de Graaff accelerator of the ...National Centre of Scientific Research "Demokritos" in Greece. The setup consisted of 24 drift tubes operating with a gas mixture of Ar:CO/sub 2/ (93:7%) at 3 atm absolute pressure. The operating anode wire voltage was 3080 V. The neutron energy varied between 6 and 11 MeV and the neutron flux was adjusted in order to match the expected background neutron flux in the ATLAS hall. In this framework, we present the data analysis with emphasis to the possible mechanisms following the neutron exposure, such as the effect of prompt gamma rays due to the neutron elastic and inelastic scattering in the aluminum drift tube wall, the elastic and inelastic recoils of the gas nuclei, and the emission of gamma rays after activation of the aluminum drift tube wall.
We have measured the response of an array of monitored drift tubes (MDT) to fast neutrons produced by a t(d,n)/sup 4/He reaction at the TANDEM Van de Graaff accelerator of the National Center of ...Scientific Research (NCSR) "Demokritos". The MDT setup consisted of 24 drift tubes operating with a gas mixture of ArCO/sub 2/ (93:7%) at 3 bar absolute pressure. The neutron energy was 18.3 MeV. The operating anode wire voltage varied from 2200 V to 2800 V. The PC based data acquisition system was self-triggered by the OR of all 24 MDT. Data were also taken by triggering on a single tube. The data analysis is presented and the response of the MDT detector to energetic neutrons is discussed with emphasis on the determination of the MDT sensitivity to neutrons.
The study of the MDT chambers performance under the presence of a high neutron and gamma background radiation in a wide neutron energy range is presented in this work. The neutrons were provided by ...the TANDEM Van Der Graaff accelerator of NCSR “Demokritos”. Emphasis was given to the comprehension of all the interactive mechanisms resulting from the presence of the high background radiation, with respect to the neutron energy and the MDT materials. The MDT response to neutrons with energies 0.5–10.0
MeV was determined. A simulation model, based on the Geant4 program, was used to describe the experimental setup and the neutron impact. The simulation results were found to be in good agreement with the experimental results.
Quality control results of the drift tubes for the ATLAS MDT-BIS chambers Alexopoulos, T.; Avramidou, R.; Dris, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2006, Letnik:
560, Številka:
2
Journal Article
Recenzirano
Odprti dostop
ATLAS (A Toroidal LHC ApparatuS) is a general purpose experiment, which will start its operation at the Large Hadron Collider (LHC) at CERN in 2007. The ATLAS detector is designed to study the ...products of proton–proton collisions at c.m.s. energies of up to 14
TeV. Three Greek Universities have taken the responsibility to construct 112 BIS-MDT (Barrel Inner Small) chambers using 29
000 drift tubes of 170
cm length and 3
cm diameter that have been quality tested before assembly. This work describes the Quality Assurance and Quality Control (QA_QC) procedures for the drift tubes, followed at the High Energy Physics Laboratory of the National Technical University of Athens, while emphasis is given on the obtained results for the above mentioned number of tubes.
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