Abstract: A photonic radiation detection device includes a collimator, a detector, and localization means for determining information relative to the localization of a photon interaction with the detector material. In at least one previously selected acquisition configuration, a degree of pixelation in the detection plane is greater than 1 and a collimator-detector distance (C) is greater than one tenth of the septal height (h) of the collimator where the septal height is a maximum dimension of the collimator in a direction orthogonal to the frontal detection plane. In one instance, the septal wall thickness (e) is one of about 0.1 or less than about 0.1 of the channel width (w). In another instance, the collimator-detector distance is greater than h/(2(w/e?1)). A dimensioning method includes, for at least one given spatial frequency, calculating and comparing merit indicator values for different acquisition configurations of a structural model of the detection device.