The present invention relates to a pigment dispersion and a method of producing a pigment dispersion by grinding a grind mixture comprising a pigment, a humectant, water, and a polymeric dispersant. Abrasive jet spray nozzles for spraying abrasive jet water are movably provided on the cutter head. The cartridge also includes a second chamber which communicates with the first chamber in order to collect the water being discharged from the first chamber. A differential detecting circuit 27 detects a level of a magnetooptic signal corresponding to the heat-treated area on the basis of the reflection light amounts of the P wave and the S wave. This serves to prevent passengers and crew members from disabling the system. The maximum concentration of the semiconductor dopant defining the two extensions occurs deeper in the drain extension than in the source extension.