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[en] The low-energy structures of the mirror nuclei ²¹Ne and radioactive ²¹Na have been examined by using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of ∼5x10⁶ ions/s were accelerated to 1.7 MeV/A and Coulomb excited in a 0.5 mg/cm^2natTi target. Scattered beam and target particles were detected by the segmented Si detector BAMBINO, while γ rays were observed by using two TIGRESS HPGe clover detectors perpendicular to the beam axis. For each isobar, Coulomb excitation from the (3/2)⁺ ground state to the first excited (5/2)⁺ state was observed and B(E2) values were determined by using the 2⁺→0⁺ de-excitation in ⁴⁸Ti as a reference. The φ segmentation of BAMBINO was used to deduce tentative assignments for the signs of the mixing ratios between the E2 and M1 components of the transitions. The resulting B(E2)↑ values are 131±9 e² fm⁴ (25.4±1.7 W.u.) for ²¹Ne and 205±14 e² fm⁴ (39.7±2.7 W.u.) for ²¹Na. The fit to the present data and the known lifetimes determined E2/M1 mixing ratios and B(M1)↓ values of δ=(-)0.0767±0.0027 and 0.1274±0.0025 μ_N² and δ=(+)0.0832±0.0028 and 0.1513±0.0017 μ_N² for ²¹Ne and ²¹Na, respectively (with Krane and Steffen sign convention). By using the effective charges e_p=1.5e and e_n=0.5e, the B(E2) values produced by the p-sd shell model are 30.7 and 36.4 W.u. for ²¹Ne and ²¹Na, respectively. This analysis resolves a significant discrepancy between a previous experimental result for ²¹Na and shell-model calculations

[en] Levels in ^186,188Os have been investigated using the (³He,d) reaction with 30 MeV ³He beams. Absolute level-population cross sections have been determined, and angular distributions measured between 5 deg. and 50 deg. The 4₃⁺ levels are observed to be some of the strongest populated states below 2 MeV excitation energy, and the magnitudes of the 5/2⁺[402]_π+3/2⁺[402]_π configuration extracted are in line with quasiparticle-phonon model predictions which state that the lowest-lying K^π = 4⁺ band is predominantly a hexadecapole excitation

[en] The structures of ₃⁺ states in Os have been debated over several decades. Based on measured B(E2) values they were interpreted in ^186-192Os as K^π = 4⁺ two-phonon vibrations, whereas inelastic scattering, and (t,α) work imply a hexadecapole phonon description. To clarify the nature of these K^π = 4⁺ bands in ^186,188Os, we performed a (³He,d) reaction on ^185,187Re targets using 30 MeV ³He beams and a Q3D spectrograph. Absolute cross sections were obtained for excited states up to 3 MeV at 9 angles from 5 deg. to 50 deg. Results indicate a significant (5/2)⁺[402]_π+(3/2)⁺[402]_π component in agreement with quasiparticle phonon model predictions for a single hexadecapole phonon structure.

[en] The low-energy structure of the proton dripline nucleus ²⁰Na has been studied using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. A 1.7-MeV/nucleon ²⁰Na beam of ∼5x10⁶ ions/s was Coulomb excited by a 0.5-mg/cm^2natTi target. Scattered beam and target particles were detected by the BAMBINO segmented Si detector while γ rays were detected by two TIGRESS HPGe clover detectors set perpendicular to the beam axis. Coulomb excitation from the 2⁺ ground state to the first excited 3⁺ and 4⁺ states was observed, and B(λL) values were determined using the 2⁺→0⁺ de-excitation in ⁴⁸Ti as a reference. The resulting B(λL)↓ values are B(E2;3⁺→2⁺)=55±6 e² fm⁴ (17.0±1.9 W.u.), B(E2;4⁺→2⁺)=35.7±5.7 e² fm⁴ (11.1±1.8 W.u.), and B(M1;4⁺→3⁺)=0.154±0.030 μ_N² (0.086±0.017 W.u.). These measurements provide the first experimental determination of B(λL) values for this proton dripline nucleus of astrophysical interest.

[en] The scattering of 30 MeV ³He from a ¹⁸⁵Re target has been investigated. The measured elastic scattering is in disagreement with calculations using common optical model parameter sets found in the literature. A new optical model parameter set has been determined that reproduces the data for both the elastic and the inelastic scattering channels

[en] Excited states in the N=Z-2 nucleus ⁴⁴V have been observed for the first time. The states have been identified through particle-γ-γ coincidence relationships and comparison with analog states in the mirror nucleus ⁴⁴Sc. Mirror energy differences have been extracted and compared to state-of-the-art shell-model calculations which include charge-symmetry-breaking forces. Observed decay pattern asymmetries between the mirror pair are discussed in terms of core excitations, electromagnetic spin-orbit effects and isospin mixing.

[en] The most recent isospin-symmetry-breaking corrections, δc, of Towner and Hardy for superallowed Fermi β-decay transitions, have included the opening of specific core orbitals. This change has resulted in significant deviations in some of the δc factors from their previous calculations, and an improved agreement of the individual corrected Ft values with the overall world average of the 13 most precise cases. While this is consistent with the conserved-vector-current (CVC) hypothesis of the Standard Model, these new calculations must be thoroughly tested, and guidance must be given for the improvement of calculations for the upper-pf shell nuclei. Using the (d,t) reaction mechanism to probe the single neutron wavefunction overlap, information regarding the relevant shell-model configurations needed in the calculation can be determined. An experiment was therefore performed with a 22 MeV polarized deuterium beam from the MP tandem Van de Graaff accelerator in Munich, Germany. Using the Q3D magnetic spectrograph, and a cathode-strip focal-plane detector, outgoing tritons were analyzed at 9 angles between 10⁰ and 60⁰, up to an excitation energy of 4.8 MeV. This proceeding reports the motivational and experimental details for the ⁶⁴Zn(d,t)⁶³Zn transfer work presented.

[en] The TRIUMF-ISAC Gamma-Ray Escape Suppressed Spectrometer (TIGRESS) is a state-of-the-art γ-ray spectrometer being constructed at the ISAC-II radioactive ion beam facility at TRIUMF. TIGRESS will be comprised of twelve 32-fold segmented high-purity germanium (HPGe) clover-type γ-ray detectors, with BGO/CsI(Tl) Compton-suppression shields, and is currently operational at ISAC-II in an early-implementation configuration of six detectors. Results have been obtained for the first experiments performed using TIGRESS, which examined the A = 20, 21, and 29 isotopes of Na by Coulomb excitation.

[en] The 8π spectrometer, installed at the TRIUMF-ISAC facility, was the world's most sensitive γ-ray spectrometer dedicated to β-decay studies. A description is given of the 8π spectrometer and its auxiliary detectors including the plastic scintillator array SCEPTAR used for β-particle tagging and the Si(Li) array PACES for conversion electron measurements, its moving tape collector, and its data acquisition system. The recent investigation of the decay of "1"2"4Cs to study the nuclear structure of "1"2"4Xe, and how the β-decay measurements complemented previous Coulomb excitation studies, is highlighted, including the extraction of the deformation parameters for the excited 0"+ bands in "1"2"4Xe. As a by-product, the decay scheme of the (7"+) "1"2"4Cs isomeric state, for which the data from the PACES detectors were vital, was studied. Finally, a description of the new GRIFFIN spectrometer, which uses the same auxiliary detectors as the 8π spectrometer, is given. (paper)