Characterization of photon-emitting wide area reference sources

► A procedure to calibrate photon-emitting wide area reference sources has been developed. ► The requirements introduced by the recent revision of ISO standard 8769 are discussed. ► A Monte Carlo approach is used to calculate the photon flux for a given activity distribution. ► The position dependent efficiency map of a large NaI detector is measured by a motorized XY stage. ► The uniformity of the activity distribution is reconstructed from a digital autoradiography.