The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.

The ATLAS Experiment at the CERN Large Hadron Collider

This paper describes the ATLAS experiment as installed in i ts experimental cavern at point 1 at CERN. It also presents a brief overview of the expec ted performance of the detector.

http://absimage.aps.org/image/SES08/MWS_SES08-2008-020010.pdf

Parton distributions with LHC data

A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H→γγ and H→ZZ→4l decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is mH=125.09±0.21 (stat)±0.11 (syst)  GeV.

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Combined Measurement of the Higgs Boson Mass in pp Collisions at √s=7 and 8 TeV with the ATLAS and CMS Experiments

The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.

/pdf/the-atlas-simulation-infrastructure-gw5d3ea9bf.pdf

The ATLAS Simulation Infrastructure

This paper describes the Heat and Radiation Shield (HRS). It serves to protect the superconducting coils of the Mu2e Production Solenoid (PS) from the intense radiation generated by the 8 GeV kinetic energy primary proton beam striking the production target within the warm bore of the PS. This shield also protects the coils in the far upstream end of the Transport Solenoid (TS), a straight section of coils called TS1, at the exit from the PS. The HRS aperture should allow the maximum stopping rate of negative muons in the Detector Solenoid stopping target. Requirements to the Heat and Radiation Shield are discussed in the paper. Work supported by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. § Corresponding author. Email: vspron@fnal.gov

Requirements for the Mu2e Production Solenoid Heat and Radiation Shield

The purpose of this document is to define the specifications for the structure fabrication and assembly of MQXFA series magnets to be used by the US High-Luminosity LHC Accelerator Upgrade Project (AUP). Magnets fabricated according to these specifications are expected to allow MQXFA magnets to meet the MQXFA Functional Requirements Specification. These specifications for the fabrication of MQXFA series magnets are based on the R&D performed by the US LHC Accelerator Research Program (LARP) and the development performed by AUP, in collaboration with CERN, through fabrication and test of pre-series coils and magnets.

/pdf/mqxfa-series-magnet-production-specification-2jfeultx.pdf

MQXFA Series Magnet Production Specification

Fermi National Accelerator Laboratory has been developing a new generation of superconducting accelerator magnets based on niobium tin (Nb3Sn). The performance of these magnets is influenced by thermo-magnetic instabilities, known as flux jumps, which can lead to premature trips of the quench detection system due to large voltage transients or quenches at low current. In an effort to better characterize and understand these instabilities, a system for capturing fast voltage transients was developed and used in recent tests of R&D model magnets. A new automated voltage spike analysis program was developed for the analysis of large amount of voltage-spike data. We report results from the analysis of large statistics data samples for short model magnets that were constructed using MJR and RRP strands having different sub-element size and structure. We then assess the implications for quench protection of Nb3Sn magnets.

Analysis of Voltage Spikes in Superconducting ${\rm Nb}_{3}{\rm Sn}$ Magnets

Pushing accelerator magnets beyond 10 T holds a promise of future upgrades to machines like the Large Hadron Collider (LHC) at CERN. Nb{sub 3}Sn conductor is at the present time the only practical superconductor capable of generating fields beyond 10 T. In support of the LHC Phase-II upgrade, the US LHC Accelerator Research Program (LARP) is developing a large bore (120 mm) IR quadrupole (HQ) capable of reaching 15 T at its conductor peak field and a peak gradient of 219 T/m at 1.9 K. While exploring the magnet performance limits in terms of gradient, forces and stresses the 1 m long two-layer coil will demonstrate additional features such as alignment and accelerator field quality. In this paper we summarize the design and report on the magnet construction progress.

Design and Construction of a 15 T, 120 mm Bore Ir Quadrupole Magnet for LARP

A new practically long copper stabilized Rapid-Heating Quenching and Transformation (RHQT) Nb3Al strand is presented, which is being developed and manufactured at the National Institute of Material Science (NIMS) in Japan. It has achieved a non-copper Jc of 1000 A/mm2 at 15 T at 4.2K, with a copper over non-copper ratio of 1.04, and a filament size about 50 µm. Using this strand the feasibility study of a 15 T dipole magnet is presented. For this study a Rutherford cable with 28 Nb3Al strands of 1 mm diameter will be fabricated early in 2006. A block-type magnet is designed using ROXIE, and the stress and strain in the coil is estimated and studied with the characteristics of the Nb3Al strand. The advantages and disadvantages of the Nb3Al cable are compared with the prevailing Nb3Sn cable from the point of view of stress-strain, and possible effects on Jc due to cabling is presented. The Nb3Al coil of the magnet, which will be made by wind and react method, has to be heat treated at 800 degree C for 10 hours. As preparation for the 15 T magnet design, a series of tests on strands and Rutherford cables is presented.

Giorgio Ambrosio

Papers

Requirements for the Mu2e Production Solenoid Heat and Radiation Shield

MQXFA Series Magnet Production Specification

Analysis of Voltage Spikes in Superconducting ${\rm Nb}_{3}{\rm Sn}$ Magnets

Design and Construction of a 15 T, 120 mm Bore Ir Quadrupole Magnet for LARP

Feasibility Study for 15-Tesla Magnet using Rapid-Heating Quenching and Transformation Nb3Al Strand