T. Grahn

Studies of pear-shaped nuclei using accelerated radioactive beams

There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are ‘octupole deformed’, that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on 220Rn and 224Ra show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental studies of atomic electric-dipole moments that might reveal extensions to the standard model.

α decay studies of the nuclides U 218 and U 219

Very neutron deficient uranium isotopes were produced in fusion evaporation reactions using

Decay studies of Au 170 , 171 , Hg 171 – 173 , and Tl 176

^{40}\mathrm{Ar}

In-beam spectroscopy using the JYFL gas-filled magnetic recoil separator RITU

ions on

Analysis methods of safe Coulomb-excitation experiments with radioactive ion beams using the GOSIA code

^{182}\mathrm{W}

Discovery of 157 W and 161 Os

targets. The gas-filled recoil separator RITU was employed to collect the fusion products and to separate them from the scattered beam and other reaction products. The activities were implanted into a position sensitive silicon detector after passing through a gas-counter system. The isotopes were identified using spatial and time correlations between the implants and the decays. Two

Coulomb shifts and shape changes in the mass 70 region

\ensuremath{\alpha}

In-beam and decay spectroscopy of very neutron deficient iridium nuclei

-decaying states, with

Heavy Element Spectroscopy At JYFL

{E}_{\ensuremath{\alpha}}=(8612\ifmmode\pm\else\textpm\fi{}9)

Spectroscopic factor and proton formation probability for the d3/2 proton emitter 151mLu

keV and