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.
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.
With an updated, flexible, highly efficient and easily installed system we obtained accurate refractivity (
n−1) values. This system is a refractometer based on a Fabry–Perot interferometer and was ...used to monitor the refractivity of DELPHI RICH Cherenkov radiators near the VUV region. By using a Pt–Ne spectral lamp and improved alignment and temperature control, the refractivities of C
5F
12 and C
4F
10 have been monitored since 1996. With this light source, selected to have large coherence lengths, we can extract the refractivity at several wavelengths from one data set only. The estimated errors of the refractivity measurements are less than 1.2%, and depend on wavelength and the type of gas used. The various parameters affecting the accuracy of the refractometer are also discussed. Finally, results from special sample refractivity measurements of the liquid radiator (C
6F
14) in its gas phase, are presented.
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.
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.
Current achievements of the DELPHI ring imaging Cherenkov detector Adam, W; Albrecht, E; Allen, D ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
03/1996, Letnik:
371, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The DELPHI experiment has already collected 2.5 million Z
0 decays with the ring imaging Cherenkov detector (RICH) operational. This detector, covering most of the solid angle, is designed to perform
...π
K
separation from 0.8 to 20 GeV/
c and K/p separation from 0.8 to 35 GeV/
c. After a brief detector description we discuss the actual operating conditions, the data monitoring and the signal treatment. The collected data from Z
0 decays and the detector response to signals from the calibration system are used to evaluate the performance of the RICH system.
An update of the searches for charginos and neutralinos in DELPHI is presented, based mainly on recent data collected at centre-of-mass energies of 161 GeV and 172 GeV. No signal is found. For a ...sneutrino with mass above 300 GeV/c2 and a mass difference between the chargino and the lightest neutralino above 10 GeV/c2, the lower limit at 95% confidence level on the chargino mass ranges from 84.3 GeV/c2 to the kinematical limit (86.0 GeV/c2), depending on the mixing parameters. The limit decreases for lower chargino-neutralino mass differences. The limit in the case of a light sneutrino is 67.6 GeV/c2, provided that that there is no light sneutrino with a mass within 10 GeV/c2 below the chargino mass. Upper limits on neutralino pair production cross-sections of about a picobarn are derived. The (μ,M2) domain excluded in the MSSM-GUT scenario is determined by combining the neutralino and chargino searches. These results imply a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 24.9 GeV/c2 for tanß >- 1. The search has also been extended to the case where the lightest neutralino is unstable and decays into a photon and a gravitino. imply a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 24.9 GeV/c2 for tanß >- 1. The search has also been extended to the case where the lightest neutralino is unstable and decays into a photon and a gravitino.
Operational experience with the 4π ring imaging Cherenkov detector of DELPHI Adam, W; Albrecht, E; Allen, D ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
06/1995, Letnik:
360, Številka:
1-2
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The ring imaging Cherenkov detector in the DELPHI Experiment at LEP allows hadron identification over a momentum range up to about 40 Gev/c over a near to 4π solid angle. Photons emitted by charged ...particles traversing gas and liquid radiators which are filled with UV-transparent perfluorocarbons, are used for Cherenkov angle reconstruction. Stable operation ensures that the detector is an efficient and powerful instrument. Monitoring of the detector parameters is of utmost importance to achieve good data quality and adequate data processing. The hadron identifying power of the ring imaging Cherenkov detector closely meets the main design values. Computerized control and monitoring features of the different subsystems will be presented. The interplay between detector parameters and the particle separating capacity of the detector will be discussed.
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