Alignment in a Warm Measurement of the J-PARC Combined Function Magnet.

A magnetic field measurement under a warm condition for a prototype of superconducting combined function magnet (SCFM) in a J-PARC was performed. In this measurement, the magnet was aligned on an alignment-line defined by a laser beam by referring alignment markers on the magnet shell and laser beam position markers on the alignment-line. Each process of alignment and measurement was performed within ±0.05 mm accuracy. To identify the precise magnetic field distribution in the SCFM, we developed a position-monitoring system of a magnetic sensor (rotating coil), which consisted of a laser also used as the alignment-line and a position-sensitive detector mounted on the rotating coil. By using this position monitor, we identified displacements of the rotating coil to ±0.06 ham accuracy. Finally, we succeeded to identify the measured positions of the magnetic field in the prototype SCFM within the required tolerance of ±0.3 mm. [ABSTRACT FROM AUTHOR]