Determination of a spatial gain distribution of a scintillator

A radiation detector device comprising:

• a primary radiation from a primary radiation source having a first radiation path;
• a secondary radiation from a secondary radiation source having a second radiation path;
• a reflection sheet that is transparent for the primary radiation and which reflects the secondary radiation;
• a light guide plate adjacent and face-to-face with the reflection sheet, the light guide plate comprising an elongated prism sheet to distribute and to change the direction of the secondary radiation;
• a radiation director plate adjacent and face-to-face with the light guide plate, the radiation director plate comprising an elongated prism sheet to distribute and to change the direction of the secondary radiation, wherein the elongated prisms of the light guide plate extend in a direction perpendicular to the direction of the elongated prisms in the radiation director;
• a substrate plate adjacent and face-to-face with the radiation director plate, wherein the first radiation path passes through the reflection sheet, the light guide plate, the radiation director, and the substrate;
• a scintillator adjacent to the substrate for receiving the primary radiation passing through the substrate, wherein the scintillator produces in response to the primary radiation a converted primary radiation having a spatial primary gain distribution image, wherein the radiation director directs the secondary radiation perpendicular to the scintillator surface, wherein the scintillator receives the secondary radiation for generating an image of a spatial secondary gain distribution of the scintillator for the secondary radiation, wherein the spatial secondary gain distribution image corresponds to a spatial primary gain distribution image of the scintillator for the primary radiation;
• a photo detector adjacent to the scintillator, wherein the photo detector is provided for reading a converted primary radiation generated by the scintillator in response to the primary radiation and for reading the spatial secondary gain distribution image from the scintillator;
• wherein the first radiation path is perpendicular to the scintillator surface, wherein the secondary radiation source is arranged to be outside of the first radiation path and supported by the reflection sheet on the side opposite from the incoming primary radiation, wherein the reflection sheet, the light guide plate, and the radiation director distribute the secondary radiation by multiple reflections and changes of direction across a surface that corresponds to the photo detector surface, and wherein the primary radiation and the secondary radiation are irradiated onto a common surface portion of the scintillator.