The Bending Magnets for the Proton Transfer Line of CNGS

The project "CERN neutrinos to Gran Sasso (CNGS)", a collaboration between CERN and the INFN (Gran Sasso Laboratory) in Italy, will study neutrino oscillations in a long base-line experiment. High-energy protons will be extracted from the CERN SPS accelerator, transported through a 727 m long transfer line and focused onto a graphite target to produce a beam of pions and kaons and subsequently neutrinos. The transfer line requires a total of 78 dipole magnets. They were produced in the framework of an in-kind contribution of Germany via DESY to the CNGS project. The normal conducting dipoles, built from laminated steel cores and copper coils, have a core length of 6.3 m, a 37 mm gap height and a nominal field range of 1.38 T - 1.91 T at a maximum current of 4950 A. The magnet design was a collaboration between CERN and BINP. The half-core production was subcontracted to EFREMOV Institute; the coil fabrication, magnet assembly and the field measurements were concluded at BINP in June 2004. The main design issues and results of the acceptance tests, including mechanical, electrical and magnetic field measurements, are discussed

The bending magnets for the LHC injection transfer lines

Two injection transfer lines, each about 2.8 km long, with 51 and 107 degree horizontal deflection, are being built to transfer protons at 450 GeV from the Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC). A total of 360 dipole magnets are required; they have been produced in the framework of the contribution of the Russian Federation to the construction of the LHC. The classical dipoles, built from laminated steel cores and copper coils, have a core length of 6.3 m, 25 mm gap height and a nominal field of 1.81 T at a current of 5270 A. The magnet design was made in collaboration between CERN and BINP. An unusual design has been chosen for the coils to cope with the limited voltage from the available power supplies. All magnets in each of the two lines will be powered in series. The coil is composed of overlapping, but electrically insulated, half coils of 3 1/2 turns each. Thus, the power connections for IN and OUT are placed on opposite magnet ends. Short copper braids are used to connect all upper or lower half coils in series and the whole string can be powered without power consuming cable links running alongside the magnets. Precautions are taken to avoid transmission line effects and hazards from differences in voltage between upper and lower half coil. Advantages and drawbacks of this concept are discussed as well as results of the acceptance test including mechanical, electrical and magnetic field measurements. Fabrication and measurement of the magnets at BINP, with the half core production subcontracted to EFREMOV, have been finished in June 2001. (9 refs)