Photoelectric conversion device and optical detection system

An optical detection system comprising:

• a photoelectric conversion device comprising a plurality of pixels each including
• a photoelectric conversion unit configured to output a signal based on incidence of a photon, the photoelectric conversion unit including an avalanche photodiode configured to multiply a charge resulting from the incidence of the photon by avalanche multiplication,
• a counter configured to count the signal output from the photoelectric conversion unit, and
• a pixel output circuit configured to control output of a count counted by the counter;
• a data line connected to the plurality of pixels;
• and
• a reception circuit configured to receive a pixel signal output from the plurality of pixels via the data line,
• wherein an off-leakage current of a first transistor constituting the reception circuit is lower than that of a second transistor constituting the pixel output circuit,
• wherein the photoelectric conversion device is configured to record time information about when the count of the counter reaches a predetermined value, and
• wherein the optical detection system further includes an acquisition apparatus configured to acquire a predicted count based on the time information.