Sources of Background Radiation

Question 1

Natural Sources of background radiation

reports no. 160

Answer 1

1. Terrestrial Radiation- from earth natural isotopes with very long half-lives
   Radon (Rn-222 and Thoron (RN-220)
   Radon comes from decay of uranium and thorium
   73% of 310 mrem from background radiation
2. Cosmic radiation- sun and stars send a constant stream.
   11% of 310 mrem
   exposure doubles every 2000 meters of altitude (28mrem/y at sea level)
3. radionuclides in the body - small traces from food and air. C-14, K-40. uranium, radon.
   9% of 310 mrem

Question 2

Appropriate radioisotopes associated with a given a list of consumer products in accordance with NCRP 160

Answer 2

1. Intentional X-ray- Airport luggage inspection <0.5mr/hr at 5 cm

Radioluminous products- Exits signs Tritium (H-3)

2. Tobacco Products- Pb-210 (lead) and Polonium-210 (Po-210)
3. Static eliminators- Po-210
4. Smoke Detectors- Americium-241
5. Building Material - uranium-238, thorium 232
6. Ceramic dinnerware- U-238 20%

Question 3

Total annual collective dose received from background radiation sources in accordance to report 160 and 94

Answer 3

Reports 94- (1987)
360 mrem

Report 160- (2006)
620mrem

difference between the two is increase in mrem from medical