Search

The 8 spectrometer, located at TRIUMF-ISAC, was the world's most powerful spectrometer dedicated to β-decay studies until its decommissioning in early 2014 for replacement with the GRIFFIN array. An integral part of the 8π spectrometer was the Pentagonal Array for Conversion Electron Spectroscopy (PACES) consisting of 5 Si(Li) detectors used for charged-particle detection. PACES enabled both γ - e- and e- - e- coincidence measurements, which were crucial for increasing the sensitivity for discrete e- lines in the presence of large backgrounds. Examples from a 124Cs decay experiment, where the data were vital for the expansion of the 124Csm decay scheme, are shown. With sufficient statistics, measurements of conversion coefficients can be used to extract the E0 components of Jπ → Jπ transitions for J ≠ 0, which is demonstrated for data obtained in 110In → 110Cd decay. With knowledge of the shapes of the states involved, as obtained, for example, from the use of Kumar-Cline shape invariants, the mixing of the states can be extracted. [ABSTRACT FROM AUTHOR]

A program of high-precision superallowed Fermi β decay studies is being carried out at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. Recent high-precision branching ratio measurements for the superallowed decays of 74Rb and 26Alm, as well as a half-life measurement for 26Alm that is the most precise half-life measurement for any superallowed emitter to date, are reported. These results provide demanding tests of the theoretical isospin symmetry breaking corrections in superallowed Fermi β decays. [ABSTRACT FROM AUTHOR]