A scanning apparatus including a cylindrical member (12) and an optical system (14) . The cylindrical member rotates about a rotational axis (16) and has an outer surface (18) to support a storage phosphor sample (20) thereon. The optical system moves in translation in a direction (22) parallel to the rotational axis to scan the sample. The optical system comprises an opening (40) , an excitation beam (42) , an integrating member (50) , and a single detector (54) . The excitation beam (42) is directed through the opening (40) to impinge on a sample (20) and cause light to be emitted from the sample. The integrating member (50) reflects the emitted light using an interior three-dimensional polynomial surface providing diffuse reflection. The single detector (54) is disposed adjacent the integrating member (50) for collecting the reflected emitted light.