PERFORMANCE OF LHC MAIN DIPOLES FOR BEAM OPERATION

At present about 90 % of the main dipoles for the LHC have been manufactured and one of the three cold mass assemblers has already completed the production. 85 % of the 1232 dipoles needed for the tunnel have been tested and accepted. In this paper we mainly deal with the performance results: the quench behaviour, the magnetic field quality, the electrical integrity quality and the geometry features will be summarized. PRODUCTION AND QUALITY Production has now reached over 1100 Cold Masses of the 1232 CMs to be installed and is expected to be completed by the end of October 2006 (1). Cold tests on the remaining ~ 200 CMs are expected to finish by the end of 2006. During CM production the quality at the Cold Mass Assembler factories is assured by an extensive plan, which is an integral part of the technical specification. Early detection of faults during the assembly procedure is provided by a magnetic field measurement at room temperature. A total of 18 cases have been found (2), with 4 faults in the assembly, and 14 non-conform components. Magnetic measurements at room temperature have also been used to locate the position of electrical shorts for 18 cases (3). Among them, 12 occurred in the inner layer and 4 on the outer one. In all cases the shorts were in the coil heads. After delivery to CERN, tests and measurements in operating (cryogenic) conditions are done to qualify the magnets. These tests are on the geometry, electrical integrity, quench behaviour and magnetic field quality.