The invention relates to a method for a study of a photon emission source at a site, the method including the steps consisting of: measuring (100) the spectrometric data and the geographic coordinates of the measurement point at a surface point of said site and storing said data in association with said coordinates in a memory; moving (200) the detector to at least one other point of the site and, at each point, repeating the step of measuring and storing; and implementing a deconvolution step (500), using a predetermined detector response function, on all the measured spectrometric surface data, in order to obtain refined spectrometric surface information, said spectrometric surface information enabling the geographic location and the evaluation of the photon emission rate of said source. The invention further relates to a system suitable for implementing the method.