Capture reactions with protons, neutrons, and alpha particles

Weller, H. R.; Roberson, N. R.

doi:10.1103/revmodphys.52.699

Cited by 38 publications

(11 citation statements)

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“…Contributions from other than El, Ml and E2 transitions are not expected to be significant near the GDR energy. Measurements of the angular distribution and analysing power for the inverse proton capture reaction 3H(p, Yo)4He are consistent with negligible Ml contributions (as expected since Ml transitions are forbidden to the extent that the 4He ground state belongs to a closed shell configuration) and show that E2 transitions contribute at most 5 % to 0"(1', p) throughout the GDR region (Weller and Roberson 1980). Similar 3He (n,1'o)4He measurements at the single energy Ey = 27·3 MeV suggest even smaller E2 contributions to 0"(1', n) .…”

Section: Simple Argumentmentioning

confidence: 71%

Ratio of the 4He(g, p)3H and 4He(g,n)3He Cross Sections

Barker¹

1984

Aust. J. Phys.

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Recent measurements of the 4He(y, p)3H and 4He(y, n)3He cross sections suggest that their ratio in the giant dipole resonance region is approximately I . 6. This is in marked disagreement with detailed model calculations, which have given a ratio close to unity. We here explain why the calculations yielded this result, by using a simple argument based on independent experimental data and some apparently reasonable assumptions. In order to remove the discrepancy with experiment, it appears to be necessary to relax one of these assumptions and to include contributions from states of higher configurations. A satisfactory fit to the cross sections is then possible, but the required isospinmixing matrix element is much larger than that derived from the Coulomb interaction plus a phenomenological charge-symmetry breaking interaction.

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Section: Simple Argumentmentioning

confidence: 71%

Ratio of the 4He(g, p)3H and 4He(g,n)3He Cross Sections

Barker¹

1984

Aust. J. Phys.

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“…The direct capture model describes the direct capture of a nucleon by a target nucleus with the subsequent emission of a γ ray, as discussed in detail in Refs. [13,14]. In the present case we applied this model to the photodisintegration reaction 9 Be(γ,n 0 ) 8 Be, which is the time-reverse of the capture reaction.…”

Section: Direct Capture Calculationmentioning

confidence: 99%

Polarization asymmetries in theBe9(γ,n0)reaction

et al. 2015

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Measurements of the 9 Be(γ,n 0 ) reaction were performed using nearly 100% linearly polarized, high-intensity, and nearly-monoenergetic γ-ray beams having energies between 5.5 MeV and 15.5MeV at the High Intensity γ-ray Source (HIγS) located at Duke University and Triangle Universities Nuclear Laboratory. Eighteen liquid scintillator detectors were used to measure neutron yields parallel and perpendicular to the plane of beam polarization. Polarization asymmetries, which are the differences between yields observed in detectors located in-plane and out-of-plane divided by their sums, were measured for the neutrons which left the residual nucleus ( 8 Be) in its ground state, termed the n 0 group. Asymmetries between 0.4 to 0.7 were discovered over this energy region in addition to a clear trend of increasing asymmetries with increasing beam energy. A prediction of the polarization asymmetry based on a pure E1 direct capture model shows good agreement with the experimental measurements. These data and the prediction could be of interest for methods that rely on neutron measurements following photofission to identify the presence of special nuclear material.

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“…A considerable interest has been shown in (p, 7) reactions [1][2][3][4]. It seems clear that the direct radiative capture process for proton can compete with the proton transfer reactions as regards the acquisition of detailed information on nuclear structure.…”

Section: Introductionmentioning

confidence: 98%