PROBLEM TO BE SOLVED: To allow the measurement of a beam shape and the detection of a radiation arrival position for X-rays, gamma rays, and charged particle radiation without requiring a transmitter.
SOLUTION: In the radiation arrival position detection system, a radiation device is configured as follows. It comprises an emission part H including a scintillator and a lens part L. The lens part is provided with a lens surface on one side. The volumes of the emission part H and the lens part L are formed so that they have the relationship VH>VL, wherein VH is the volume of the emission part H and VL is the volume of the lens part L. A narrow part R is formed between the emission part H and the side of the lens part L opposite to the lens surface. The optical axis of the emission part H and that of the lens part L are parallel to each other. An array is configured which consists of an arrangement of a plurality of the radiation devices so that their lens surfaces are arranged in a row on a plane. The spatial distribution of the emission intensity of the scintillator is measured as an image.