Commissioning Results of Superconducting Magnet System for the Neutrino Beam Line
The first commissioning of a magnet system for the neutrino beam line in the J-PARC has been performed from January to March, 2009. The magnet system could be cooled down successfully in 9 days. RRRs of all the magnets and joint resistances in the magnet string were measured to be reasonable values. The magnet string composed of 28 superconducting combined function magnets could be excited up to 5000 A after several shutdown tests without a spontaneous quench. A quench protection scheme with a magnet safety system developed by CEA/SACLAY were verified to work properly. As for beam commissioning, the proton beams could pass through the arc section including the superconducting magnet string on the first attempt, and the magnet protection system were verified to work quite well even in a beam induced quench test.
Test Results of Superconducting Combined Function Magnets for the J-PARC Neutrino Beam Line
Superconducting combined function magnets for the J-PARC (Japan Proton Accelerator Research Complex) neutrino experiment have been successfully developed at High Energy Accelerator Research Organization, KEK. The first prototype magnet reassembled for the quench protection studies, and the cold test result indicated that the eight quench protection heaters are effective for the safe protection of the magnet. Three production magnets have been fabricated and tested at 4.5 K, 1 atm, in a vertical cryostat, and the excellent excitation and quench performances are observed. In the field measurement during cold tests, all the magnets indicated the field qualities good enough to fulfill the specification. The field measurement at room temperature has been also performed with the three production magnets for checking the dipole field component. The results are consistent with the computation.
Design of the Second Series of LHC Prototype Dipole Magnet Cryostats
An initial series of six LHC 10 m long prototype dipole magnets and cryostats have been manufactured by European Industry. The assembled cryo-magnets were tested singly and connected in series in a test string at CERN between March 1994 and December 1996. During the same period, an evolution in the requirements for LHC cryogenics distribution has lead project management to adopt a seChapaute cryo-distribution line running Chapaullel to the LHC machine.1 The former standard LHC half-cell, made up of a short straight section unit and four 10 m dipoles, has been discarded and replaced with one composed of a short straight section unit and three 15 m dipoles. The new 15 m LHC dipole magnet cryostats are described. These units house the dipole magnet cold mass, which stands on three low heat in-leak support columns, and is enclosed within an actively cooled radiation screen operating at 4.5–20 K and an actively cooled thermal shield operating at 50–75 K.