Fabrication and absolute calibration of B-dot probe for magnetic field measurement on a high power laser facility

The fabrication and absolute calibration of a B-dot probe is employed to measure the pulsed magnetic field at the Shenguang-II high power laser facility. Copper enameled silk with a cross section diameter of 0.1 mm is used to wind the one-turn coil with a 1 mm diameter. Two coils are paired and reversely linked to their respective circuits to form a differential B-dot probe that is sealed in and protected by a quartz shell. This B-dot probe is experimentally calibrated and then used to measure the pulsed magnetic field in laser targeting experiments at the Shenguang-II high power laser facility. Signals show a high performance of this B-dot probe. The common mode noise can be effectively canceled out by the differential pair. The magnetic field of over 300 T can be extrapolated at the location close to the target.