Page 920 - Radiation Safety

Procedure in Working with Sealed
Procedure in Working with Sealed

Sources
Sources

• Time, shielding and distance

 Time, shielding and distance are three principles of methods of control that can

be incorporated into engineering as well as management controls of radiation
hazard.

 Longer exposure times means higher dose of exposure and vice versa.

 Thickness, density as well as types of materials (Z number) determine the

effectiveness of shield against a particular radiation quality. Generally thicker
material increases the attenuation of radiation intensity. High Z materials (e.g.
Pb) are effective in attenuating electromagnetic radiation (e.g. gamma and x-
rays). Low Z materials (e.g. H) are effective in attenuating neutron sources.

 Inverse square law is used to reduce dose through distance.