what are the main source of radiation
Exposure from terrestrial radiation. The composition of the earth's crust is a major source of natural radiation. The main contributors are natural deposits of uranium, potassium and thorium which, in the process of natural decay, will release small amounts of ionizing radiation.-rays: X-rays are a form of radiation similar to gamma radiation but they are produced mainly by artificial means rather than from radioactive substances. Neutron radiation: Neutron radiation occurs when neutrons are ejected from the nucleus by nuclear fission and other processes.