Development of magnetic jB sensor

Kasai, Satoshi; Nakayama, Takahide*; Ishitsuka, Etsuo   

The improved mechnical sensor, jB has been desiged and developed. Materials of a load cell (strain gauge and sensor beam) and sensing coil/frame are selected to be neutron resistance. In order to reduce temperature drift of the sensor signal, four strain gauges with the same electrical property and geometrical size are bonded on the sensor beam by AlO spraying process. These gauges form an electrical bridge circuit. The zero-level drift of the output of the load cell was reduced to about 1/20 compared with the old sensor. Non-linearity of the output of load cell and sensitivity of the jB sensor was observed. The deviation of sensitivity from the fitting line was less than 7 % in high magnetic field region. The sensitivity of the sensor was gradually decreased by about 30 % at neutron fluence of (1.82.8)10 n/m in high magnetic field region.