Alpha decay spectroscopy of neutron-deficient astatine, radon and francium nuclei using a gas-filled separator

Abstract

Alpha particle decay properties (alpha particle energy and half-life) of neutron-deficient astatine, radon and francium isotopes are studied in this thesis. These nuclei in the close vicinity of the proton drip-line were produced using three different heavy-ion-induced fusion-evaporation reactions. The reactions were 141Pr(56Fe, xn)197-xAt, 169Tm(35Cl, xn)204-xRn, 170Yb(35Cl, xn)205-xFr and the beam particles were delivered by the K = 130 MeV heavy ion cyclotron of the Accelerator Laboratory of the Department of Physics, University of Jyvaskylii. The gas-filled recoil separator RITU was used to separate reaction products from the primary beam. The method of time and position correlated alpha particle decay chains were used for analysing the experimental data. Nine previously unpublished alpha particle transition from five different isotopes (193,194,195At, 197Rn and 200Fr) were observed in the present work. Measured alpha particle energies and half-lives are compared with the systematics of heavier isotopes and with theoretical predictions. The systematics of isomerism and shell model intruder states are also shown.