The Alpha-Particles of Radium

Abstract

The abundance of ${\alpha }_{188}$ of ${\mathrm{Ra}}^{226}$ was determined with an alpha-particle spectrograph to be 5.7±0.3 percent. The nomenclature ${\alpha }_{188}$ refers to the alpha-group populating the excited level of the residual nucleus which is 188 kev above the ground state.