Ground-State (p,n) Reactions in Mirror Nuclei and the Quasielastic Model of (p,n) Reactions

Abstract

The Al 27 (^,#)Si 27 , Si 29 (p,n)V®, and ~P u (p,n)S u ground-state reactions have been measured using poly ethylene "long counters." Absolute cross sections and angular distributions were obtained from 0° to 160° at 10° intervals. The measured angular distributions were compared with the predictions of an optical-model calculation, using an optical potential suggested by Lane, which is a function of the isotopic spins of the incident proton and target nucleus. Since the ground-state (p,n) reactions were measured below the threshold for the excited state, the proton incident energies were between 5.8 and 7.6 MeV. Because of this low proton energy, the optical-model calculations include both Coulomb effects of distortion of the proton wave and the Coulomb energy difference between the incoming proton and the outgoing neutron. Fair agreement between the theoretical and experimental results was obtained for Si 29 and P 31 using a surface interaction for the imaginary and isobaric parts of the optical potential. Furthermore, the angular distributions from these two nuclei wefe quite similar in structure, in agreement with the twin-reaction hypothesis of Bloom, Glendenning, and Moszkowski. The neutron angular distributions from Al 27 are quite different in structure from those obtained from Si 29 and P 31 , and attempts to fit them with the optical-model calculation were not successful. A calculation based on distorted-wave single-particle excitation with charge-exchange was also. carried out. The results of this calculation agree with those of the optical model for Si 29 and P 31 . For the Al 27 reaction the results of the DWBA calculation are different from those of the optical model, since in the former calculation momentum transfers greater than zero are included; however, neither calculation fitted the Al 27 data.

Study of the 15N(p,n)15O reaction as a monoenergetic neutron source for the measurement of differential scattering cross sections

“…This is not in agreement with the data in DROSG-2000 which show a minimum at E p = 6.58 MeV and a maximum at E p = 6.65 MeV. The present data are compared with an angular distribution measured by Hansen et al [16] for E p = 6.65 MeV which shows a larger 0° differential cross section. The data points at E p = 6.62 MeV by Murphy et al and 6.65 MeV by Hansen et al determine the shape of the 0° excitation function in this energy range in the code DROSG-2000 (see figure 3).…”

“…Because of the strong variation of the angular distribution with projectile energy, the proton energy has to be carefully chosen to achieve a large neutron yield. In addition to the present data, angular distributions by Jones et al [12] and Hansen et al [16]…”

Seasonal and interannual variability of sedimentation and organic matter distribution in the Buor-Khaya Gulf: the primary recipient of input from Lena River and coastal erosion in the southeast Laptev Sea

“…The character of the vertical structure was evaluated by the Hanssen-Rattray ( S) parameter determined as a function of the salinity deviation at the bottom and at the surface to the average vertical deviation (Hansen et al, 1966).…”

N=90region: The decay ofEu154toKulp1, Wood2, Krane3 et al. 2004Phys. Rev. C

“…Based upon the ␥ ray intensities listed in Table I and conversion coefficient data (values listed in [2] are used where available or computed using HSICC [26]), the intensity [27]). From this we deduce that the states at 123 and 371 keV primarily are populated indirectly by ␥ rays from levels higher in the decay scheme.…”

“…balance for the 123 keV level indicates an excess of ͑10.6± 0.9͒% (cf. from observation of direct ␤ decay: 9.2± 1.5%[27] and 10.8± 1.2%[28]). The 371 keV level has an excess of 0.19± 0.05% (cf.…”