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J-PARC Correctors


Japan is constructing a 50 Gev, high intensity proton accelerator at a site near the Japanese high energy research laboratory, KEK. The project is called J-PARC (Japan Proton Accelerator Research Complex). The site is at Tokai and is part of the Japanese Atomic Energy Research Institute (JAERI). KEK and JAERI are jointly responsible for its construction.

J-PARC will serve many uses. One of the uses will be to produce neutrinos that will be directed toward a detector located in Kamiokande, Japan. The neutrinos will be produced when protons are extracted from J-PARC and are directed by magnets in a beam line to strike a target. Further information about the neutrino experiment is available.

KEK and the BNL Superconducting Magnet Division are working together to produce the superconducting magnets for the proton beam line. KEK is producing the principal magnets, which will have a novel “combined function” coil that will bend and focus the proton beam at the same time. One area of cooperation between KEK and BNL is to jointly review some of the detailed features of the design, since some of the concepts used in the design were established during the construction of the magnets for RHIC.

The other area of cooperation is to construct superconducting correction coils for the beam line. Dipole correction coils are definitely needed. It may also be desirable to have quadrupole correction available. If so, this correction would be provided in the form of combined function correctors. All correctors will be constructed at BNL using coil design software integrated with a precise, automatic winding machine. This CAD/CAM facility is now being used to make new insertion region (IR) magnets for the electron-positron collider BEPC II in Beijing, China (SMD BEPC work). In the past, the machine made IR magnets for an upgrade of the HERA IR regions at DESY in Hamburg, Germany (SMD HERA work).

The work at BNL is being funded by the U.S. – Japan Collaboration. During JFY03 (April 1, 2003 – March 31, 2004), BNL is building prototype dipole and combined function correctors in a beam tube supplied by KEK. These correctors will be installed and tested in the prototype main coil that is being built at KEK.

prototype dipole and combined function 

Prototype dipole and combined function correctors in a beam tube

For more information contact Peter Wanderer.