Am-241

Am-241 is isotope of Americium.

Mass: 241.056829144 amu

Halflife: 432.2 y

Energy of alpha decay (dominant):  7.543272 MeV

Using
\( \rm ^{241}_{~94}Pu \xrightarrow[15~y]{\beta^-,~ 21\,KeV} {} ^{241}_{~95}Am \xrightarrow[432.7\,y]{\alpha,\, 4.959\,MeV} {}^{237}_{~96}Np \xrightarrow[2.4 \times 10^6\,y]{\alpha,~4.958 \,MeV} \mathrm{^{233}_{91}Pa} ~.\,.\,. \)

Am-241 is considered as the important component of the nuclear waste and dominant contaminante since come tens or years after a nuclear catastrophe.