Radiation detector

A radiation detector that detects spatial distribution of a first radiation and a second radiation, the radiation detector comprising:

• a plurality of optical transducers that converts the first radiation to a first light having a first wavelength, and converts the second radiation to a second light having a second wavelength;
• a shielding unit that is arranged between the optical transducers to shield the first radiation, the second radiation, the first light, and the second light;
• a plurality of first photoelectric converters that corresponds to each of the optical transducers, and outputs a first electrical signal based on intensity of the first light;
• and
• a plurality of second photoelectric converters that corresponds to each of the optical transducers, and outputs a second electrical signal based on intensity of the second light.