Design Features and Performance of a 10 T Twin Aperture Model Dipole for LHC

A twin-aperture superconducting (sc) dipole model has been designed in collaboration with Finnish and Swedish Institutions and built at CERN. The cable critical current was attained at a central field of 10.5 T at a temperature of 1.77 K after three training quenches only. This model has shown a very good quench performance as well as a robust mechanical behavior over several thermal cycles. This p aper will discuss the design, the innovations of the mechanical structure, and the results obtained during the intensive campaigns of tests

Design and Manufacture of a Large-Bore 10 T Superconducting Dipole for the CERN Cable Test Facility

A large-bore 10 T superconducting dipole magnet was designed and fabricated in close cooperation between CERN and HMA Power Systems. The dipole has a length of about 1.7 m and an aperture of 88 mm and is composed of two two-layer poles wound with NbTi cables cooled to 1.9 K to reach magnetic inductions close to 10 T. This dipole will be installed at the CERN cable test facility and used as a background field magnet to test LHC superconducting cables. In its large aperture up to four cable samples can be tested at the same time. The mechanical design of the magnet is such that coil prestress variations between warm and cold conditions are kept within 20 MPa. A short model was also built and cooled down in order to check and confirm with test results the mechanical behavior of the dipole. Magnetic measurements, at room temperature, were performed upon its arrival at CERN prior to installation in the test facility. The dipole was recently cooled down and tested. This paper will discuss the design, the main manufacturing steps and the initial test results

Design, Manufacturing Aspects and Performance of Recent 10 m Long Model Dipole Superconducting Magnets for the LHC Project

A number of twin aperture, 10 m long, model dipole magnets for the LHC Project have been built and tested. With regard to the models of the first generation, the inner coil diameter and the intra-beam distance were increased from 50 to 56 mm and from 180 to about 194 mm, respectively. Also with regard to the previous models, a 5-block (instead of a 6-block) coil cross-section was chosen and the wid th of the Rutherford cable was reduced from 17 mm to 15 mm. The coils were manufactured and collared in Industry, the assembly of their magnetic circuit and cold mass were carried out at CERN. The ind ividual design and manufacturing features of each of these magnets are described and the results of their warm and cold magnetic measurement are presented and discussed

Performance of the LHC Final Prototype and First Pre-series Superconducting Dipole Magnets

Within the LHC cryo-dipole program, six full-scale superconducting prototypes of final design were built in collaboration between Industry and CERN, followed by launching the manufacture of pre-series magnets. Five prototypes and the first of the pre-series magnets were tested at CERN. This paper reviews the main features and the performance of the cryo-dipoles tested at 4.2 K and 1.8 K. The results of the quench training, conductor performance, magnet protection, sensitivity to ramp rate and field characteristics are presented and discussed in terms of the design parameters

Design, Manufacturing Status, First Results of the LHC Main Dipole Final Prototypes and Steps towards Series Manufacture

This paper reports about the program of six LHC superconducting main dipole final prototypes and the steps towards series manufacture. The above program, launched in summer 1998, relies on collared coils manufactured by industry and cold masses assembled at the CERN Magnet Assembly Facility. Following design, stability and robustness studies, the magnet design for series manufacture features a "6-block" coil and austenitic steel collars. A general description of the magnet with its main components is given and the main working parameters and the most important manufacturing features are presented. Results of mechanical and magnetic measurements are given as well as the performances of the first prototype. A comparison with results from the previous generation of dipole magnet models and prototypes is also made. Finally an outlook towards series manufacture is given

Manufacturing features and performances of long models and first prototype for the LHC project

This paper reports about the 10-m-long models and one 15-m-long prototype. Their main design features are a 5-block coil cross section, an intra-beam distance of 194 mm at room temperature and a 15-mm-wide superconducting cable. The collared coil of the 10-m-long models were built in Industry and the assembly of the magnetic circuit and cold mass was done at CERN while the 15-m-long prototype was entirely made in Industry. Manufacturing features, assembly steps and quench performances of each magnet are presented. Results of magnetic measurements taken in the course of magnet assembly, during and after the cold test campaigns are also given

Test results on the long models and full scale prototypes of the second generation LHC arc dipoles

With the test of the first full scale prototype in June-July 1998, the R&D on the long superconducting dipoles based on the LHC design of 1993-95 has come to an end. This second generation of long magnets has a 56 mm coil aperture, is wound with 15 mm wide cable arranged in a 5 coil block layout. The series includes four 10 m long model dipoles, whose coils have been wound and collared in industry and the cold mass assembled and cryostated at CERN, as well as one 15 m long dipole prototype, manufactured totally in industry in the framework of a CERN-INFN collaboration for the LHC. After a brief description of particular features of the design and of the manufacturing, test results are reported and compared with the expectations. One magnet reached the record field for long model dipoles of 9.8 T but results have not been well reproducible from magnet to magnet. Guidelines for modifications that will appear in the next generation of long magnets, based on a six block coil design, are indicated in the conclusions. (10 refs)

Manufacture and Performance of the LHC Main Dipole Final Prototypes

This paper reports about the program of six LHC main dipole final prototypes. This program, launched in summer 1998, relies on industrially manufactured collared coils and cold masses assembled at the CERN Magnet Assembly Facility. The magnet design for series manufacture features a "6-block" coil and austenitic steel collars, following design, stability and robustness studies. Results of mechanical and magnetic measurements are given and discussed, as well as the performances of the prototypes measured so far

Final Prototypes, First Pre-series Units and Steps Towards Series Production of the LHC Main Dipoles

The LHC, a 7 TeV proton collider presently under construction at CERN, requires 1232 superconducting dipole magnets, featuring a nominal field of 8.33 T inside a cold bore tube of 50 mm inner diameter and a magnetic length of 14.3 m. This paper summarises the results of the program of the six LHC main dipole final prototypes and presents the performance measurements of the first magnets of the 90 pre-series units currently under manufacture by industry. Results of geometric and magnetic measurements are given and discussed. Finally, the major milestones towards the dipole magnets series manufacture are given and commented

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011