Alpha-Decay Properties of Neutron-Deficient Isotopes of Emanation

Abstract

Isotopes of emanation (element 86) with 126 or fewer neutrons were prepared at the Heavy Ion Linear Accelerator by bombardment of platinum, gold, mercury, and thallium targets with $^{16}\mathrm{O}$, $^{14}\mathrm{N}$, and $^{12}\mathrm{C}$ nuclei. Several techniques were developed for isolation of the gaseous products. Si(Au) surface-barrier detectors were used to measure $\ensuremath{\alpha}$ particles emitted by emanation isotopes and by their polonium and astatine daughters. Mass- number assignments of new isotopes of mass 201 through 205 were based on genetic relationships and on excitation functions. The probable nature of the isomerism observed in $^{203}\mathrm{Em}$ is discussed. Properties of isotopes with masses 206 through 212 were confirmed.