Optimization for manufacturing spare coils for the bending magnet DB2 at J-PARC MUSE

A dipole magnet, called DB2, is installed in Decay muon beamline (D-line) of MLF in J-PARC. Muon beams generated by muon target are bent in the angle of 40 degrees by the DB2 after passing through the solenoid magnet, and transferred to experimental areas. As the DB2 has used over 40 years since its production, we plan to make the spare coils. However, it is difficult to get a hollow conductor with the same cross-sectional shape as existing coil. So we decided to make the coil by using a hollow conductor with same the nominal cross section and external dimensions as the existing coil. For this reason, we came to optimize the parameter of DB2. (author)