A radioactive substance detection device that detects a radioactive substance being present in a specified direction. A radiation detection element having a thickness that stops and detects a characteristic X-ray arriving from a radioactive substance being present in the specified direction that radiates both gamma rays and the characteristic X-rays, and allows the gamma ray arriving from the radioactive substance to pass through. A screening body having a thickness that screens out characteristic X-rays of radiation which arrives from directions other than the specified direction and allows gamma rays of radiation which arrives from directions other than the specified direction to pass through.
展开▼
