All of the plutonium isotopes, which have a very high
biotoxicity, are man-made and result from various nuclear
activities. Plutonium-241 is a very low-energy beta emitter with
Eβ(max) = (20.8 ± 0.2) keV; Eβ(ave) = (5.23 ± 0.5) keV and a
half-life of (5234 ± 15) that decays primarily to the ground
state of 241Am, an emitter of alpha particles, X and gamma rays
with a half-life of (432.6 ± 0.6) that is much more radiotoxic
than its parent. Quantitation of 241Pu in low-level waste and
environmental samples is of interest because 241Pu is a
precursor of other transuranium nuclides that have longer half-
lives, greater environmental mobility, and greater toxicity. In
addition, 241Pu is the most difficult of the plutonium isotopes
to detect and measure. As a result, radioactivity standards of
241Pu are of great interest for many environmental monitoring
and radioecological studies. A new solution standard of 241Pu
was developed and disseminated as Standard Reference Material
4340B in 2007, during this standardizati