
Glossary
(modifi ed from Eisler 1994, 2007
a
and Wikipedia 2011
b
)
Actinides. Elements of atomic numbers 89 to 103: actinium, thorium,
protactinium, uranium, neptunium, americium, curium, berkelium,
californium, einsteinium, fermium, mendelevium, nobelium,
lawrencium (Ac, Th, Pa, U, Np, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lw).
Activity. The activity of a radioactive material is the number of
nuclear disintegrations per unit time. Up to 1977, the accepted unit
of activity was the curie (Ci), equivalent to 37 billion disintegrations/
second (d/s)—a number that approximated the activity of 1 gram of
radium-226. The present unit of activity is the becquer ...