We have written a Fortran program BCVEGPY, which is an event generator for the hadronic production of the B-c meson through the dominant hard subprocess gg --> B-c(B-c(*)) + b + c. To achieve a ...compact program, we have written the amplitude of the subprocess with the particle helicity technique and made it as symmetric as possible, by decomposing the gluon self couplings and then applying the symmetries. To check the program, various cross sections of the subprocess have been computed numerically and compared with those in the literature. BCVEGPY is written in a PYTHIA-compatible format, thus it is easy to implement in PYTHIA.
The electromagnetic (e.m.) calorimeter of the ATLAS experiment for the Large Hadron Collider will be a sampling liquid argon accordion calorimeter. To achieve sufficient energy resolution, it is ...necessary to correct for the energy loss in the material upstream of the calorimeter. For this purpose, a separate presampler detector fixed on the inner face of the e.m. calorimeter, in the same cryostat, is being built by the ATLAS collaboration. Two presampler sectors have already been built and tested in their final version. The geometry of the detector and the various steps of its construction are reviewed. The hardware performance of the detector measured both at CERN and at the ISN-Grenoble (specific test bench) is discussed. It is concluded that the presampler will adequately fulfill its role for future operation at the CERN Large Hadron Collider.
A two-dimensional laser-wire scanner for electron accelerators Bosco, A.; Price, M.T.; Blair, G.A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2008, Letnik:
592, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A two-dimensional laser-wire scanner capable of measuring the transverse charge profiles of an electron (or positron) bunch has been constructed at the PETRA accelerator in DESY. The development of ...the system is explained in this paper, along with descriptions of its photon detector and laser system. Results of transverse profile scans are presented for both horizontal and vertical directions. The measurement error is 1.3% from a multi-scan measurement in the vertical direction, where single scans can be performed in less than 50
s.
The construction and assembly of the two half barrels of the ATLAS central electromagnetic calorimeter and their insertion into the barrel cryostat are described. The results of the qualification ...tests of the calorimeter before installation in the LHC ATLAS pit are given.
The ATLAS Inner Detector consists of three sub-systems, the Pixel Detector at the innermost radius, the Semi-Conductor Tracker at intermediate radii, and the Transition Radiation Tracker (TRT) at the ...outermost radius in front of the electromagnetic calorimeter. The TRT provides a combination of continuous tracking with many projective measurements based on individual drift-tubes (or straws) and of electron identification based on radiator fibres or foils interleaved between the straws themselves. This paper describes the current status of design and construction of the various components of the TRT: the assembly of the barrel modules has recently been completed, that of the end-cap wheels is well underway, and the on-detector front-end electronics is in production. The detector modules and front-end electronics boards will be integrated together over the next year, the barrel and end-cap TRT parts will be assembled and tested with their SCT counterparts during 2005 and installation and commissioning in the ATLAS pit will take place at the end of 2005 and the beginning of 2006.
Performance of the ATLAS electromagnetic calorimeter end-cap module 0 Ballansat, J; Bazan, A; Beaugiraud, B ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2003, Letnik:
500, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The construction and beam test results of the ATLAS electromagnetic end-cap calorimeter pre-production module 0 are presented. The stochastic term of the energy resolution is between 10% and
12.5%
...GeV
1/2
over the full pseudorapidity range. Position and angular resolutions are found to be in agreement with simulation. A global constant term of 0.6% is obtained in the pseudorapidity range 2.5<
η<3.2 (inner wheel).
Performance of the ATLAS electromagnetic calorimeter barrel module 0 Aubert, B.; Ballansat, J.; Beaugiraud, B. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2003, Letnik:
500, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The construction and performance of the barrel pre-series module 0 of the future ATLAS electromagnetic calorimeter at the LHC is described. The signal reconstruction and performance of ATLAS-like ...electronics has been studied. The signal to noise ratio for muons has been found to be 7.11±0.07. An energy resolution of better than
9.5%
GeV
1/2/
E
(sampling term) has been obtained with electron beams of up to
245
GeV
. The uniformity of the response to electrons in an area of Δ
η×Δ
φ=1.2×0.075 has been measured to be better than 0.8%.
The ATLAS Transition Radiation Tracker (TRT) performance depends critically on the choice of the active gas and on its properties. The most important operational aspects, which have led to the final ...choice of the active gas for the operation of the TRT at the LHC design luminosity, are presented. The TRT performance expected at these conditions is reviewed, including pile-up effects at high luminosity.
A simulation study to evaluate the required computing resources for a research exploitation of the Large Hadron Collider (LHC) has been performed. The evaluation was done as a case study, assuming ...existence of a Nordic regional centre and using the requirements for performing a specific physics analysis as a yard-stick. Other input parameters were: assumption for the distribution of researchers at the institutions involved, an analysis model, and two different functional structures of the computing resources.
ATLAS Transition Radiation Tracker test-beam results Akesson, T.; Arik, E.; Baker, K. ...
2nd Workshop on Advanced Transition Radiation Detectors for Accelerator and Space Applications,Bari, Italy,2003-09-04 - 2003-09-07,
2004, Letnik:
522, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Several prototypes of the Transition Radiation Tracker for the ATLAS experiment at the LHC have been built and tested at the CERN SPS accelerator. Results from detailed studies of the straw-tube hit ...registration efficiency and drift-time measurements and of the pion and electron spectra without and with radiators are presented.
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