Читать книгу Patty's Industrial Hygiene, Physical and Biological Agents - Группа авторов - Страница 23

The concentration of radioactivity is called the specific activity. Specific activity may be designated in traditional units of curies per unit mass or unit volume. In the SI system, the analogous quantities are given in megabecquerel per kilogram or in megabecquerel per cubic meter.

The specific activity, in Ci/g of a carrier free radioisotope, is given by

(2)

where T_Ra and T_i are the half‐lives, in the same time units, of ²²⁶Ra (T = 1600 years) and of the radioisotope, and A_i is the atomic mass number of the radioisotope. In the case of ¹³¹I, for example whose half‐life is eight days, the specific activity is