In our systematic research on reactions with weakly bound nuclei at suband nearbarrier energies, we have studied the system 8B+natZr at the sub-barrier energy of 26.5 MeV. Our measurements, performed at the TriSol radioactive beam facility of the University of Notre Dame, include angular distributions of both elastic scattering and breakup, for the determination of the total reaction and breakup cross sections as well as the direct-to-total reaction cross section ratio. Preliminary results of the breakup analysis will be presented, supported by Continuum Discretized Coupling Channel calculations.

Elastic scattering measurements for the reaction 8B+90Zr at the sub-barrier energy of 26.5 MeV (~ 0.9 VC.B.) were carried out in a recent experiment, realized at the TriSol radioactive beam facility of the University of Notre Dame. This experiment was performed in continuation of our previous work studying 8B on the heavier target 208Pb, alongside with breakup measurements for the same reaction. Final goal is the determination of total reaction and breakup cross sections and the deduction of the direct to total cross section ratio. Preliminary experimental data for elastic scattering will be presented and compared with OMP and CDCC calculations.

The 10 MV FN Tandem at the University of Notre Dame's Nuclear Science Laboratory has the option for a second foil stripper halfway down its high energy column. With its utilization, users are able to produce beams with higher energies and/or transmission than single foil stripping alone would be capable of achieving. A discussion of the Schiwietz-Grande, Nikolaev-Dmitriev, and Baudinet-Robinet semi-empirical models used to determine the resulting charge state abundances, as well as how they compare to measured charge state distributions is presented. The advantages of a second foil stripper are discussed alongside measurements of the charge state abundances produced. The potential for more interfering beam species of similar magnetic rigidity is also discussed. It was found that for most of the beams tested, second foil stripping allowed higher energies with higher yields than the single terminal foil stripping alone could achieve which can enhance the capabilities of other laboratories using similar accelerator systems.

The N-15(alpha,gamma)F-19 reaction produces F-19 in asymptotic giant branch (AGB) stars, where the low energy tails of two resonances at E-c.m.=1323 +/- 2 and 1487 +/- 1.7 keV are estimated to contribute about 30% of the total reaction rate in these environments. However, recent measurements have shown discrepancies in the energies, the strengths, and the corresponding alpha widths of these two resonances, resulting in an increase in the systematic uncertainty of the extrapolated cross section to helium burning energies. With this motivation, we have undertaken new measurements of the N-15(alpha,gamma)F-19 at the University of Notre Dame Nuclear Science Laboratory. The setup consisted of an alpha particle beam impinged on a solid (TiN)-N-15 target with gamma-ray spectroscopy accomplished using a high purity germanium detector. Using the Doppler corrected gamma-ray energies, we confirmed the lower resonance energy to be 1321.6 +/- 0.6 keV and found a value for the higher one of 1479.4 +/- 0.6 keV that is more consistent with those found from previous elastic scattering studies. We found that the resonance strengths for both were consistent with most values found in the literature, but a larger alpha width has been recommended for the E-c.m.=1487 keV resonance. The larger alpha width suggests a reaction rate increase of about 15% at temperatures T<0.1 GK relevant to low mass AGB stars. The impact of the increased reaction rate requires further investigations.

The reaction dynamics for the proton halo nucleus $^{8}\mathrm{B}$ $+$ $^{\mathrm{nat}}\mathrm{Zr}$ is explored through an elastic scattering measurement at the sub-Coulomb barrier energy of 26.5 MeV. The differential angular distribution has been measured and the total reaction cross section as well as the interaction distance are derived via an optical model analysis. The present result is combined with relevant values for $^{8}\mathrm{B}$ in comparison with $^{6}\mathrm{He}$, $^{7}\mathrm{Be}$, $^{6,7}\mathrm{Li}$, and $^{16}\mathrm{O}$ on various targets through a consistent optical model analysis at sub- and near-barrier energies. The results demonstrate the proton halo nature of this exotic nucleus, which exhibits larger values for both the total reaction and interaction radii observables, than those determined for the proton-rich radioactive nucleus $^{7}\mathrm{Be}$ as well as for other stable weakly bound projectiles. Similar results are found for the neutron halo nucleus $^{6}\mathrm{He}$. The present elastic scattering results are also described well with continuum-discretized coupled-channels calculations, exhibiting a weak coupling to continuum.

The reaction dynamics for the proton halo nucleus 8 B + nat Zr is explored through an elastic scattering measurement at the sub-Coulomb barrier energy of 26.5 MeV. The differential angular distribution has been measured and the total reaction cross section as well as the interaction distance are derived via an optical model analysis. The present result is combined with relevant values for 8 B in comparison with 6 He, 7 Be, 6 , 7 Li, and 16 O on various targets through a consistent optical model analysis at sub- and near-barrier energies. The results demonstrate the proton halo nature of this exotic nucleus, which exhibits larger values for both the total reaction and interaction radii observables, than those determined for the proton-rich radioactive nucleus 7 Be as well as for other stable weakly bound projectiles. Similar results are found for the neutron halo nucleus 6 He. The present elastic scattering results are also described well with continuum-discretized coupled-channels calculations, exhibiting a weak coupling to continuum.

The Mg-25,Mg-26(alpha, n)Si-28,Si-29 reactions have been shown to be influential to Al-26 production in massive stars. The previously measured data sets for these reactions have discrepant results, and further study is warranted. The first measurements are reported of the total reaction cross sections of these reactions using direct recoil detection. The results are in good agreement with previous data sets based upon differential cross section studies. Astrophysical reaction rates based on the experimental data are reported and are within a factor of 1.5 of previous statistical model estimates.

A quasielastic scattering study of the 7Be + natZr system was performed at five sub- and near- Coulomb barrier energies, namely, 20.6, 22.1, 23.7, 27.3, and 28.2 MeV (Elab C.b.= 24.3 MeV). Differential angular distributions were measured in the angular ranges & AP;20 degrees to 63 degrees and 111 degrees to 154 degrees and were considered in an optical model approach, to define the energy dependence of the potential as well as to determine the total reaction cross sections. The real part of the optical potential was found to be energy independent in most of the energy range, with a weak trend of a dispersion augmentation at the lowest energy point. Total reaction cross sections were found to be compatible with phenomenological predictions, validating the choice of our potential. Fusion cross sections were also calculated, taking into account the obtained potential, and were found to compare well with experimental results of 7Li on the medium mass target of 124Sn. The measured quasielastic scattering cross sections were reasonably well reproduced by continuum-discretized coupled-channel calculations. These calculations indicated a modest, but not negligible, coupling to the continuum effect.

Accelerator Mass Spectrometry (AMS) with 53Mn has geological applications as a chronometer for exposure and burial times for discontinuously deposited sediments. It has also been used to search for evidence of recent supernovae events, and proposed as a proxy to monitor the variation in the galactic cosmic ray spectrum over time. The current sensitivity limit amongst active facilities is 53Mn/55Mn = 3 x 10-13 while a sensitivity of 53Mn/55Mn = 1 x 10-13 is necessary to fully exploit 53Mn's capabilities. At the University of Notre Dame's Nuclear Science Laboratory (NSL), a 10 MV tandem accelerator and a Browne-Buechner Spectrograph operated as a gas-filled magnet were used to separate 53Mn from 53Cr. Samples covering ranges of 53Mn/55Mn = 10-10 - 10-8 were measured for the first time at the NSL using various settings resulting in a background level of 53Mn/55Mn = 6.2(3) x 10-11. Analysis of the results, descriptions of experimental settings, and further explorations will be presented in this paper.

As the scope of Accelerator Mass Spectrometry (AMS) expands, there is an increased need to extend the capability of isobaric separation to the medium-heavy mass region. Existing AMS facilities are limited in their ability to separate radioactive nuclei in the A = 100-200 range of interest from their neighboring stable isobars, as such measurements require higher energies than available in most facilities. ATLAS is one of the highest energy system used for AMS based experiments and has enabled isobaric discrimination for medium to heavy nuclides, notably via the Gas-Filled Magnet technique. A preparatory experiment performed in November, 2019, successfully demonstrated isobaric separation of 92Zr-92Mo using the Argonne Gas-Filled Analyzer (AGFA) with high magnetic rigidity. Since that time, MONICA, an eight-anode ionization chamber that measures both energy loss and position with two sets of split anodes, has been developed to aid in AMS experiments at AGFA and has undergone four commissioning runs at the Nuclear Science Laboratory at the University of Notre Dame utilizing Si, Fe/Ni, and Mn beams. This report presents the AGFA AMS run (November 2019) and the subsequent commissioning runs of the MONICA detector, including preliminary measurements on the long-lived isotopes 39Ar (268 y) and for the first time on 42Ar (33 y).