Radiation imaging apparatus and radiation imaging system

A radiation imaging apparatus, comprising:

• a pixel including a conversion element configured to convert radiation into an electric signal, and a switch configured to connect the conversion element to a signal line;
• a readout unit configured to read out a signal that appears in the signal line;
• and
• a signal processing unit,
• wherein the readout unit includes a reset unit configured to reset a potential of the signal line,
• a period during which the readout unit reads out a signal that appears in the signal line includes:
• a first period including an operation in which the potential of the signal line is reset by the reset unit, and thereafter, an operation in which a signal that appears in the signal line in a state in which the switch is not turned on is read out twice, and
• a second period including an operation in which the potential of the signal line is reset by the reset unit, an operation thereafter in which a signal that appears in the signal line in a state in which the switch is not turned on is read out by the readout unit, and thereafter, an operation in which a signal that appears in the signal line due to the switch being turned on is read out, and
• the signal processing unit calculates a difference between a difference between the signal that appears in the signal line due to the switch being turned on in the second period and the signal that appears in the signal line in a state in which the switch is not turned on in the second period, and a difference between the signal read out twice in the first period.