Design and fabrication of magnetic measurement system with Hall elements for muon transport solenoid of COMET experiment

COMET is the experiment, which is currently under construction at J-PARC, to search for muon-to-electron conversion process using intense pulsed proton beam produced in J-PARC main ring as the primary beam. The COMET superconducting magnet system in Phase-1 consists of a pion capture solenoid, a muon transport solenoid, and a detector solenoid. A 90-degree-curved muon transport path consists of 18 superconducting solenoid magnets with a magnetic field at 3 T and 16 superconducting dipole magnet coils for orbit correction with a magnetic field at 0.06 T. To measure the magnetic field distribution generated by these superconducting magnets, we have designed a magnetic field measurement system consisting of two 3-axis Hall probes. In this paper, we report the design and construction of the magnetic field measurement system. (author)