Ronald D. Macfarlane

A system for studying accelerator-produced short-lived alpha emitters☆

Abstract A target assembly and detection system is described which has applications for studying accelerator-produced short-lived alpha activities with good efficiency and excellent alpha particle resolution. The system is simple and fast and allows for the continuous recording of alpha particle spectra at the same time the activity is produced.

ALPHA DECAY PROPERTIES OF SOME TERBIUM AND DYSPROSIUM ISOTOPES NEAR THE 82- NEUTRON CLOSED SHELL

Abstract The half-lives and alpha particle energies of Tb149m, Tb151, Dy150, Dy151, Dy152 and Dy153 have been measured with greater precision than previously reported. Alpha branching ratios for these nucleides were also obtained using direct counting techniques.

Dysprosium-154, a long-lived α-emitter

Abstract Gadolinium oxide, enriched in 154 Gd, was bombarded with 48 MeV α-particles to form dysprosium isotopes. α-Pulse-analysis of the chemically separated dysprosium resulted in the observation of a new weak α-activity of 2·85 ± 0·05 MeV energy. This activity was assigned to 154 Dy on the basis of a rough excitation function and consideration of α-decay systematics of the neighbouring dysprosium isotopes. The α-half-life was calculated as approximately 1 × 10 6 years by estimating the amount of 154 Dy produced and comparing it with the α-count rate. A lower limit of 10 years for the β-decay half life was established on the basis of the absence of the prominent γ-radiation of 154 Tb in the photon spectrum.