The CNGS project (CERN Neutrinos to Gran Sasso) aims at directly detecting numu-nutau oscillation. An intense muon-neutrino beam (1017numu/day) is generated at CERN and directed towards the Gran ...Sasso National Laboratory, LNGS, in Italy, where the nutau will be detected in large and complex detectors. An overview of the CNGS beam facility is given. The performance of the primary and secondary beam line during beam commissioning and physics operation is discussed. Modifications on the magnetic focusing lenses (horn and reflector) are described.
A dedicated X-ray tomograph has been developed at CERN to control the required wire placement accuracy of better than 20
μm of the 1200 Monitored Drift Tube Chambers which make up most of the ...precision chamber part of the ATLAS Muon Spectrometer. The tomograph allows the chamber wire positions to be measured with a 2
μm statistical and 2
μm systematic uncertainty over the full chamber cross-section of 2.2×0.6
m
2. Consistent chamber production quality over the 4-year construction phase is ensured with a ∼15% sampling rate. Measurements of about 70 of the 650 MDT chambers so far produced have been essential in assessing the validity and consistency of the various construction procedures.
The accuracy of the ATLAS muon X-ray tomograph Avramidou, R; Berbiers, J; Boudineau, C ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2003, 2003-1-00, Letnik:
496, Številka:
1
Journal Article
Recenzirano
A gigantic detector, the ATLAS project, is under construction at CERN for particle physics research at the Large Hadron Collider which is to be ready by 2006. An X-ray tomograph has been developed, ...designed and constructed at CERN in order to control the mechanical quality of the ATLAS muon chambers. We reached a measurement accuracy of 2
μm systematic and 2
μm statistical uncertainties in the horizontal and vertical directions in the working area 220
cm (horizontal)×60
cm (vertical). Here we describe in detail the fundamental approach of the basic principle chosen to achieve such good accuracy. In order to crosscheck our precision, key results of measurements are presented.
For the Large Hadron Collider (LHC), ATLAS, a large general-purpose detector for physics experiment, is under construction. The muon spectrometer of ATLAS is on the scale of a very large industrial ...project: 1200 large monitored drift tubes (MDT) chambers will be built aiming at an exceptional quality in terms of mechanical accuracy, material reliability, assembly, and monitoring. For Quality Control, an X-ray tomograph, monitored by a set of interferometers, has been developed and built at CERN. The tomograph provides an accuracy below 10μm in the determination of the position of each MDT drift tube. First, results have been obtained on MDT prototypes.
An essential part of the Muon Spectrometer of the ATLAS experiment is based on the Monitored Drift Tube (MDT) technology. About 1200 muon drift chambers are being built at 13 institutes all over the ...world. The MDT chambers require an exceptional mechanical construction accuracy of better than 20 /spl mu/m. A dedicated X-ray tomograph has been developed at CERN since 1996 to control the mechanical quality of the chambers. The chamber wire positions are measured with a statistical error of 2 /spl mu/m and a systematic error of 2 /spl mu/m over a working area of 2.2 m /spl times/ 0.6 m. During the construction phase of the MDT chambers, from middle 2000 to mid 2005, the X-ray tomograph is the key tool for ensuring consistent chamber production with a sampling rate of /spl sim/15%. To achieve this program efficiently, an effort for complete automation of the tomograph operation has been underway. Until September 2003, 79 chambers out of 739 chambers produced at 11 of the construction sites have been measured. The X-ray tomograph has proved to be an essential and powerful tool in assessing the validity of the various construction steps.
The ATLAS collaboration has recently started the construction of its detector for the LHC at CERN. An essential part of its Muon Spectrometer is based on Monitored Drift Tube (MDT) technology. It ...consists of about 1200 large muon drift chambers that will be built at 13 institutes spread all over the world. The MDT chambers require an exceptional mechanical construction accuracy of better than 20 /spl mu/m. The construction quality of the chambers is controlled using X-ray tomography. A dedicated X-ray tomograph has been developed at CERN since 1996. This instrument measures the chamber wire positions with a 2 /spl mu/m statistical and 2 /spl mu/m systematic uncertainty over the full tomograph working area of 2.2 /spl times/ 0.6 m/sup 2/. During the four-year construction phase of the MDT chambers, the X-ray tomograph will be the key tool for ensuring consistent chamber production quality with a sampling rate of /spl sim/15%. To achieve this program efficiently, an effort for complete automation of the tomograph operation is underway. Since mid-2000, first modules from 11 of the construction sites have been measured. Results from this site certification process have demonstrated the essential role of the X-ray tomograph in assessing the validity of the various construction steps.
Horn R&D for 2002-2003 Gilardoni, S; Grawer, G; Maire, G ...
Neutrino Factories and Superbeams,
01/2004, Letnik:
721
Journal Article
Recenzirano
A further step in the horn R&D at CERN has been achieved with the construction of a new power supply, which pulses the horn prototype at 100 kA. This paper reviews the steps leading, during the last ...year, to this goal, and the first mechanical measurements of the horn.
An intense muon-neutrino beam (10 17 Vmu /day) is generated at CERN and directed towards the Gran Sasso National Laboratory,LNGS, in Italy, 732 km from CERN. In the presently approved physics ...programme, it is foreseen to run the CNGS facility with 4.5 middot 10 19 protons per year for five years. During a nominal CNGS cycle, i.e. every 6s, two nominal SPS extractions of 2.4 . 10 13 protons each at 400GeV/c are sent down the proton beam line to the target. The CNGS secondary beam line, starting with the target, has to cope with this situation, which pushes the beam line equipment and instrumentation to the limits of radiation hardness and mechanical stresses during the CNGS operation. An overview of the CNGS secondary beam line is given. Emphasis is on the target, the magnetic focusing lenses (horn and reflector) and the muon monitors. The performance of the secondary beam line during beam commissioning and physics operation is discussed and measurements are compared with simulations.
In this work, we report a detailed experimental study regarding the impact of copper oxide (CuO) secondary phase and heat treatments on the structural, magnetic, and magnetocaloric properties of the ...near-room temperature Pr2∕3Sr1∕3MnO3 (PSMO) magnetic refrigerant. Our investigations are carried out by using structural and microstructural analyses, alongside magnetization measurements. The analysis of X-ray diffraction data of PSMO(95 %)-CuO(5 %) (PSMO-CuO) samples shows the coexistence of both CuO and PSMO phases. Further, the microstructural analysis of PSMO-CuO reveals that the addition of CuO significantly enhances the grains size. On the other hand, the added secondary phase markedly reduces the Curie temperature (Tc) from 293 K for PSMO to about 273 K for PSMO-CuO composite while increasing the magnetocaloric effect. This decrease in Tc is associated with a significant change from 162° to about 156° in the Mn-OII-Mn bond angle respectively. Moreover, performed investigations regarding the role of heat treatments unveil that the observed changes in the structural and magnetic features are mainly driven by the secondary phase that modify grains size and double-exchange interactions in the PSMO compound. Interestingly, our findings demonstrate that the Curie temperature of the PSMO and accordingly its magnetocaloric effect can be tailored by adding small amounts of CuO without need to substitution on cation sites. In the light of obtained results, a multilayered refrigerant composed of PSMO and PSMO-CuO is proposed to cover the magnetic cooling temperature range close to room-temperature. The resulting entropy change remains practically constant between 273 K and 293 K. Such a behavior is highly appreciated from a practical point of view, particularly in cases where the cooling process is carried out by using the AMR and Ericsson cycles.
•The real impact of CuO secondary phase and heat treatment in tailoring the Pr2∕3Sr1∕3MnO3 features is clarified.•The correlation between structural and magnetic ordering parameters in Pr2∕3Sr1∕3MnO3/CuO composite is deeply investigated.•An efficient room temperature multilayered magnetic refrigerant based on Pr2∕3Sr1∕3MnO3/CuO and Pr2∕3Sr1∕3MnO3 is proposed.
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