Embodiments of a radiation detector and subassemblies thereof are provided having a scintillator with a face and a reflector constructed and arranged to redirect a majority of light leaving the face of the scintillator at an angle within a range of 45 to 135 degrees compared to the direction in which the light was traveling when it left the face. In other embodiments a method is provided including receiving radiation into a scintillator having a face, producing light with the scintillator in response to the radiation, allowing at least a portion of the light to leave the face, and reflecting a majority of the light leaving the face at an angle within a range of 45 to 135 degrees compared to the direction in which the light was traveling when it left the face with a reflector. Other embodiments are directed to a reflector including a plurality of prisms having a first face and a second face with a barrier on the first face.