The neutron-induced reaction cross sections of (242)mAm were measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. A new neutron-capture cross section was determined, and the absolute scale was set according to a concurrent measurement of the well-known (242)mAm(n, f) cross section. The (n,gamma) cross section was measured from thermal energy to an incident energy of 1 eV at which point the data qualitywas limited by the reaction yield in the laboratory. Our new (242)mAmfission cross sectionwas normalized to ENDF/B-VII. 1 to set the absolute scale, and it agreed well with the (n, f) cross section reported by Browne et al. (1984) from thermal energy to 1 keV. The average absolute capture-to-fission ratio was determined from thermal energy to E-n = 0.1 eV, and it was found to be 26(4)% as opposed to the ratio of 19% from the ENDF/B-VII. 1 evaluation.

The Am-242 metastable isomer's neutron-induced destruction mechanisms were studied at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array with a compact parallel-plate avalanche counter. New Am-242m neutron-capture cross sections were determined from 100 meV to 10 keV, and the absolute scale was set with respect to a concurrent measurement of the well-known Am-242m neutron-induced-fission cross section. The new fission cross section spans an energy range from 100 meV to 1 MeV and was normalized to the ENDF/B-VII. 1 evaluated cross section to set the absolute scale. Our Am-242m(n, f) cross section agrees well with the cross section of Browne et al. [Phys. Rev. C 29, 2188 (1984)] over this large energy interval. The new neutron-capture cross sectionmeasurement complements and agrees well with our recent results reported below 1 eV in Buckner et al. [Phys. Rev. C 95, 024610 (2017)]. This new work comprises the most comprehensive study of Am-242m(n,.) above thermal energy. Neutron-induced resonance energies and parameters were deduced with the SAMMY R-matrix code for incident neutron energies up to 45 eV, and the new average inverted right perpendicular(gamma) is 13% higher than the evaluated average. width.

Angle averaged cross sections for the mutual of the 0(2)(+), 6.05 MeV excited state of O-16 have been measured over the center of mass energy region 30.0-43.5 MeV in steps of 200-400 keV. The excitation function is dominated by three wide structures centered at center of mass energies 33.0, 37.0, and 40.5 MeV. A spin assignment for an angular distribution measurement at 37.0 indicates the dominant spins of this exit channel are smaller than the spins that dominate the resonances observed in the single excitation to the 0(2)(+), 6.05 MeV excited state of O-16 at comparable center of mass energies. This result is consistent with preliminary coupled channel calculations.

Angle averaged cross sections for the mutual excitation of the ${0}_{2}^{+},$ 6.05 MeV excited state of ${}^{16}\mathrm{O}$ have been measured over the center of mass energy region 30.0--43.5 MeV in steps of 200--400 keV. The excitation function is dominated by three wide structures centered at center of mass energies 33.0, 37.0, and 40.5 MeV. A spin assignment for an angular distribution measurement at 37.0 indicates the dominant spins of this exit channel are smaller than the spins that dominate the resonances observed in the single excitation to the ${0}_{2}^{+},$ 6.05 MeV excited state of ${}^{16}\mathrm{O}$ at comparable center of mass energies. This result is consistent with preliminary coupled channel calculations.

A differentially pumped windowless Ne-20 gas target was used to measure angle averaged excitation functions for binary decay of the Si-28+Ne-20 reaction into low-lying states of Si-28+Ne-20, Mg-24+Mg-24, and S-32+O-16, and for binary decay of the Mg-24+Ne-20 reaction into low-lying states of Mg-24+Ne-20 and Si-28+O-16. The Si-28+Ne-20 measurements span the region of excitation energy in Cr-48 from 50.6 to 67.7 MeV (Si-28 beam energies from 87.2 to 128.2 MeV). The reaction Mg-24+Ne-20 was investigated over a region in Ti-44 from 48.75 to 71.0 MeV (Mg-24 beam energies from 70.8 to 119.75 MeV). Angular distribution measurements were made for Ne-20(Si-28,Mg-24)Mg-24 at excitation energy=56.22 MeV and for Ne-20(Mg-24,O-16)Si-28 at excitation energy=53.02 and 57.75 MeV. Both systems display evidence of statistically significant correlated resonance phenomena, but the resonances are dominated by spins comparable to the grazing angular momenta of the respective entrance channels, and are not analogs of the molecular configurations that dominate the Mg-24(Mg-24, Mg-24*)Mg-24* reactions.

Angular correlations between deuterons and alphas in the reaction C-12(N-14,d)Mg-24*(alpha)Ne-2(g.s) at beam energies of 30, 33, 36, and 42 MeV have been used to investigate the reaction mechanism. Evidence for possible C-12 Cluster transfer to the 13.45 MeV 6+ state in Mg-24 is presented. The transfer of C-12(2+) clusters seems to be the dominant process. In addition to the correlation measurements, deuteron angular distributions were measured at 33 and 42 MeV and an excitation function at a lab angle of 8-degrees was obtained between 30 MeV and 45 MeV in 3 MeV steps. The angular correlations, deuteron angular distributions, and the excitation function were fitted using the finite range distorted wave Born approximation (FRDWBA) and the Hauser-Feshbach formalism of compound nucleus formation.

ln a search for high spin resonances in {sup 36}Ar, we have measured excitation functions of elastic and inelastic scattering of {sup 16}O+{sup 20}Ne. The experiment was performed using a differentially pumped gas target. Excitations involving the {sup 16}O(O{sub 2}{sup +}, 6.05MeV) state are of particular interest because of the strong deformation. A segmented Si detector with an area of 24 cm{sup 2} and a thickness of 0.5mm was used to detect the e{sup -} and e{sup +} emitted from the pair decay of that state. The gas cell for the target was constructed from thin walled aluminum parts to minimize the sensitivity to the nearby (3{sup -}) state. Angle averaged cross sections for excitations in 0 to 10 MeV were obtained for the energy range 35MeV{le}E{sub lab}{le}75MeV in 500keV steps. Pronounced structure has been identified in most channels. There appears to be no strong correlation between the structure observed in excitation of the momentum matched 6.13MeV (31-) state and momentum mismatched 6.05MeV (O{sub 2}{sup +}) state. Angular distribution measurements to determine some of the spin values are currently under way.

Previous studies of the elastic and single-O{sub 2}{sup +} exit channels of {sup 16}O+{sup 16}O have shown pronounced structure. Resonance spins in these spin zero exit channels may be measured directly with angular distributions. In the present work, the mutual-O{sub 2}{sup +} excitation function has been measured for E{sub Lab}= 60-80 MeV, well above the Coulomb barrier. Recoil coincidences were observed with silicon surface barrier detectors, one of which was mounted in a gas E-{Delta}E telescope during a portion of the experiment. Both the {Delta}E and flight time information were used to to identify the reaction channel. To discriminate against background processes that are unresolved in energy, especially those involving the {sup 16}O(3{sup -}) state, the e{sup +}e{sup -} decay of the {sup 16}O(O{sub 2}{sup +}) was observed with two large, ion-implanted silicon detectors. A minimum of three, perhaps four, electron detector signals in coincidence with the heavy ion trigger were required to exclusively determine the cross section of interest. The low intrinsic noise of these passivated detectors in conjunction with custom-built pre-amplifiers allowed the e{sup {plus_minus}} minimum ionization peak to be well resolved from the electronic noise.