An apparatus includes a detector (101) including pixels (201) which converts radiation or light into analog electric signals, a signal processor (105) including a reading circuit (103) which reads an analog electric signal output from the detector (101) and an A/D convertor (104) which converts the analog electric signal into a digital signal, a power-supply unit (106) which applies bias to the detector (101) and the signal processor (105), and a controller (109) which controls at least one of the signal processor (105) and the power-supply unit (106) based on information on an A/D conversion characteristic of the A/D convertor (104) and information on an input analog electric signal to be input to the A/D convertor (104).
