Page 246 - Radiation Safety

Natural Radiation Sources

• Extraterrestrial-primary cosmic rays (outer space) secondary

cosmic rays (interactions between primary ) cosmic rays and

atmosphere

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• Produce cosmogenic radioisotopes: C, T

Cosmic ray dose increases with latitude (influence of

magnetic field, strongest at the poles)

Also increase with altitude (less shielding by

atmosphere),Dose appox. double for every 1500m up to a few

km above the earth. Global yearly avg≈0.4m Sv (Radiation

Saftey,96-00725 IAEA/PI/A47E,1996)

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