PROBLEM TO BE SOLVED: To provide an emission system which dispenses with a light guide and an optical fiber required for conventional systems.
SOLUTION: The emission system comprises a light emitting part H including a scintillator and a lens part L. The lens part forms a lens surface on one side. The volumes of the light emitting part and the lens part are formed so that the relationship VH>VL is established, wherein VH is the volume of the light emitting part H and VL is the volume of the lens part. A narrow part R is formed between the light emitting part H and the side of the lens part L opposite to the lens surface. Collimated light is emitted from the lens surface of the lens part L.