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The occurrence of octupole shapes in even-mass neutron-rich Ba isotopes has been well established. However, the situation with the odd-mass Ba and odd or odd-odd La nuclei around them is not so clear. In order to shed light on these less-studied isotopes, a fast-timing experiment was performed using the GRIFFIN spectrometer at TRIUMF-ISAC. A wealth of excited-state lifetimes in the 100 ps to few ns range have been measured in $^{144,145,146}\mathrm{Ba}$ and $^{145,146}\mathrm{La}$ populated in the ${\ensuremath{\beta}}^{\ensuremath{-}}$ and ${\ensuremath{\beta}}^{\ensuremath{-}}\text{\ensuremath{-}}n$ decay of $^{145,146}\mathrm{Cs}$. The results do not allow one to draw firm conclusions about the possible octupole deformation of these nuclei but suggest different spin and parity assignments than previous works. This work highlights the need for more detailed study of the odd and odd-odd isotopes in this region to properly understand their structure.

Spectroscopy of doubly magic $^{132}_{50}$Sn$_{82}$ has been performed with the GRIFFIN spectrometer at TRIUMF-ISAC following the $\beta$ decay of $^{132}_{49}$In$_{83}$. The analysis has allowed for the placement of a total of 70 transitions and 29 excited states in $^{132}$Sn. Detailed spectroscopy has also been performed on $^{131}$Sb, resulting from the $\beta$ decay of $^{131}$Sn, produced from the $\beta$-delayed neutron decay of $^{132}$In. Measurement of $\gamma$-rays in both $^{131}$Sn and $^{131}$Sb has led to the determination of the $\beta$-delayed neutron emission probability, $P_{n}$, from $^{132}$In. This is the first time the $P_{n}$ has been measured for this nucleus using $\gamma$ spectroscopy, and the new value of 12.3(4)% is consistent with the most recent $\beta-n$ counting experiment. Additionally, $\gamma$-$\gamma$ angular correlations have been performed in $^{132}$Sn, supporting the spin assignments of several excited states. Novel ab initio calculations are presented which describe several of the excited states, and these are compared to the experimental spectrum.

Lifetimes of ${2}_{1}^{+}$ and ${4}_{1}^{+}$ states as well as some negative-parity and nonyrast states in $^{188--200}\mathrm{Hg}$ were measured using $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ electronic fast timing techniques with the ${\mathrm{LaBr}}_{3}(\mathrm{Ce})$ detector array of the GRIFFIN spectrometer. The excited states were populated in the $\ensuremath{\epsilon}/{\ensuremath{\beta}}^{+}$ decay of ${J}^{\ensuremath{\pi}}={7}^{+}/{2}^{\ensuremath{-}}\phantom{\rule{0.28em}{0ex}}^{188--200}\mathrm{Tl}$ produced at the TRIUMF-ISAC facility. The deduced $B(E2)$ values are compared to different interacting boson model predictions. The precision achieved in this paper over previous ones allows for a meaningful comparison with the different theoretical models of these transitional Hg isotopes, which confirms the onset of state mixing in $^{190}\mathrm{Hg}$.

The half-lives of three β-decaying states of 13149In82 have been measured with the GRIFFIN γ-ray spectrometer at the TRIUMF-ISAC facility to be T1/2(1/2−)=328(15)ms, T1/2(9/2+)=265(8)ms, and T1/2(21/2+)=323(55)ms, respectively. The first observation of γ rays following the βn decay of 131In into 130Sn is reported. The β-delayed neutron emission probability is determined to be P1n=12(7)% for the 21/2+ state and 2.3(3)% from the combined 1/2− and 9/2+ states of 13149In82 observed in this experiment. A significant expansion of the decay scheme of 131In, including 17 new excited states and 35 new γ-ray transitions in 13150Sn81 is also reported. This leads to large changes in the deduced β-branching ratios to some of the low-lying states of 131Sn compared to previous work with implications for the strength of the first-forbidden β transitions in the vicinity of doubly magic 13250Sn82. (Less)

Internal conversion coefficients have been measured for transitions in 110Pd to allow the determination of electric monopole (E0) transition strengths. Excited states were populated through inelastic alpha scattering and the SPICE+TIGRESS detectors at TRIUMF-ISAC-II were used to detect the emitted gamma rays and internal conversion electrons. The E0 transition strengths are found to be small and are consistent with the expectation for transitions from a K = 2 band to the K = 0 ground-state band in the axial rotor model.

A high-precision half-life measurement for the superallowed Fermi ${\ensuremath{\beta}}^{+}$ emitter $^{22}\mathrm{Mg}$ was performed at the TRIUMF-ISAC facility using a $4\ensuremath{\pi}$ proportional gas counter. The result of ${T}_{1/2}=3.87400\ifmmode\pm\else\textpm\fi{}0.00079$ s is a factor of 3 more precise than the previously adopted world average and resolves a discrepancy between the two previously published $^{22}\mathrm{Mg}$ half-life measurements.

The $\ensuremath{\beta}$-decay half-lives of $^{128--130}\mathrm{Cd}$ have been measured with the newly commissioned GRIFFIN $\ensuremath{\gamma}$-ray spectrometer at the TRIUMF-ISAC facility. The time structures of the most intense $\ensuremath{\gamma}$ rays emitted following the $\ensuremath{\beta}$ decay were used to determine the half-lives of $^{128}\mathrm{Cd}$ and $^{130}\mathrm{Cd}$ to be ${T}_{1/2}=246.2\phantom{\rule{0.16em}{0ex}}(21)$ ms and ${T}_{1/2}=126\phantom{\rule{0.16em}{0ex}}(4)$ ms, respectively. The half-lives of the $3/{2}^{+}$ and $11/{2}^{\ensuremath{-}}$ states of $^{129}\mathrm{Cd}$ were measured to be ${T}_{1/2}(3/{2}^{+})=157\phantom{\rule{0.16em}{0ex}}(8)$ ms and ${T}_{1/2}(11/{2}^{\ensuremath{-}})=147\phantom{\rule{0.16em}{0ex}}(3)$ ms. The half-lives of the Cd isotopes around the $N=82$ shell closure are an important ingredient in astrophysical simulations to derive the magnitude of the second $r$-process abundance peak in the $A\ensuremath{\sim}130$ region. Our new results are compared with recent literature values and theoretical calculations.