Abstract: An optical recording apparatus performs an OPC operation with a designated target modulation. A reproduction signal detecting circuit measures, in response to the OPC operation, jitter, amplitude of the reproduction signal and the like. An asymmetry detecting circuit calculates an asymmetry value of the optical disc from the measurements. An RAM temporarily stores the measured reproduction information. A laser power correcting circuit evaluates the calculated asymmetry value, and increases/decreases setting of the target modulation, through a laser power setting circuit. When the asymmetry value comes close to 0, a laser driving circuit performs an overwriting operation (DOW: Direct Over Write) with the current asymmetry value.

Abstract: In radiation detection apparatus apparatus having a plurality of radiation detector each comprising a scintillator which emits light in response to a radiation, and a photodetector which detects an emission intensity of the scintillator; radiation detection apparatus characterized in that the scintillator is made of a layer of phosphor particles, so that the performances of the respective detectors are substantially identical.