Apparatus and method to determine a position of a radiation source

An apparatus for detecting a radiation source includes a collimator configured to have an optical path for converging radiation formed therein, a radiation sensor provided at the end of the optical path and configured to measure the intensity of radiation incident on the optical path, a rotation driving unit connected to the collimator and configured to rotate the collimator up and down and left and right, movement means configured to move the collimator and the rotation driving unit along the surface of land, a position tracking unit provided within the collimator and configured to track a current position and to measure a distance moved by the movement means, and a radiation position information processing unit configured to obtain direction information and information about the distance to the radiation source based on a maximum intensity of radiation, measured by the radiation sensor, and the movement distance.