Search

The predominant branch in the $\ensuremath{\beta}$ decay of $^{34}\mathrm{Ar}$ is the superallowed ${0}^{+}\ensuremath{\rightarrow}\phantom{\rule{0.16em}{0ex}}{0}^{+}$ transition to the ground state of $^{34}\mathrm{Cl}$. To determine its important branching ratio one must first establish the ratios for the competing Gamow-Teller branches based on the measured intensities of $\ensuremath{\gamma}$ rays subsequently emitted from the excited states they populate in $^{34}\mathrm{Cl}$. The strongest of these branches populates the ${1}^{+}$ state at 666 keV in $^{34}\mathrm{Cl}$, which has three possible $\ensuremath{\gamma}$-decay paths. We report here a measurement of the decay of this state, which we populated via resonant proton capture in the reaction $^{33}\mathrm{S}$($p,\ensuremath{\gamma}$)$^{34}\mathrm{Cl}$. We find that the intensity of the 519-keV $\ensuremath{\gamma}$-ray path is 1.46(19)% relative to that of the 666-keV path. This result is critical to new precise measurements of the superallowed decay of $^{34}\mathrm{Ar}$.

The nucleosynthesis path of the γ-process is predominantly governed by the branching points at which the flow of the initial (γ,n) is redirected by either (γ,p) or (γ,α) reactions. In this work, the inverse reactions, proton and α capture on 108Cd were studied in order to aid in verification of the 112Sn isotope as a potential branching point in the γ-process. The results of the first measurement with a γ-summing detector, HECTOR, are compared with previous measurements found in the literature and with NON-SMOKER predictions. The results of this work will provide input for Hauser-Feshbach calculations to obtain the γ induced reaction rates.

The High EffiCiency TOtal absorption spectrometeR (HECTOR) consists of 16 scintillating crystals that are made of thallium-doped sodium iodide (NaI(Tl)). Each of the crystals is coupled to two photomultiplier tubes (PMT) and the detector is oriented to create a cubic array surrounding a target. This cubic array orientation allows for simultaneous measurements of the individual gamma (γ) rays produced during the de-excitation of the reaction products, creating a coverage of nearly 4π steradian. HECTOR was constructed to measure capture reactions relevant for the nucleosynthesis process at low energies. The work presented here focuses on a (p,γ) reaction on 102Pd, one of the p-nuclei produced during the p-process. The experiment was conducted at the University of Notre Dame using the FN tandem accelerator at the Nuclear Science Lab. A highly enriched 102Pd target was bombarded with a proton (p) beam at energies between 3.5 and 8.0 MeV in 200 keV steps. The measured cross section is compared with experimental data found in literature and theoretical models.