D.S. Flynn

Cross sections and reaction rates forNa23(p, n)Mg23,Al27(p, n)Si27,Al27(α, n)P30,Si29(α, n)S32, andSi30(α, n)S33

The total neutron production cross sections for the /sup 23/Na(p,n)/sup 23/Mg, /sup 27/Al(p,n)/sup 27/Si, /sup 27/Al(..cap alpha..,n)/sup 30/P, /sup 29/Si(..cap alpha..,n)/sup 32/S, and /sup 30/Si(..cap alpha..,n)/sup 33/S reactions have been measured for bombarding energies from threshold to 6.3 MeV. The neutron detector was a 60-cm diameter sphere of polyethylene with eight /sup 10/BF/sub 3/ counters and was insensitive to the angle and energy of the emitted neutrons. Cross sections for inverse reactions have been obtained using the principle of detailed balance. The data have been used to determine parameters for statistical model calculations to facilitate extrapolation of cross sections to higher bombarding energies. These reactions are relevant to problems of nucleosynthesis and stellar evolution and to studies of radiation damage. Nucleosynthesis reaction rates, N/sub A/(sigmav), were determined for the reactions studied and are tabulated for temperatures ranging from 0.4 x 10/sup 9/ to 10.0 x 10/sup 9/ K.

A simple calibration procedure for in-beam gamma-ray spectroscopy

Abstract The absolute gamma-ray yields from 2 MeV protons on a 0.3 cm thick, 99.99% pure aluminum target have been determined to an accuracy of about 4%. Such data are useful for in-beam gamma-ray studies as an overall, secondary calibration and in elemental analysis using proton-induced gamma-ray emission (PIGME).

The proton‐90Zr interaction at sub‐coulomb proton energies

Measurements have been made of proton elastic scattering differential cross sections for proton scattering at 135° and 165° from 2 to 7 MeV, of inelastic scattering cross sections for proton scattering from 3.9 to 5.7 MeV, and of the radiative capture cross sections from 1.9 to 5.7 MeV detecting primary and cascade gamma rays. Optical potentials with Hauser‐Feshbach and coupled‐channel models have been used to analyze the data. This analysis yields an energy dependent absorptive potential of W=2.63+.73 whose mean value of 5 MeV at Ep=4 MeV is consistent with previously reported, but anomalously small values. The diffuseness of the real potential is .54 fm, which is consistent with values found for 92Zr and 94Zr. The adopted model values are used to deduce a total proton strength function which displays the features of both the 3s and the 3p single particle resonances.

Reactions rates of (p,n) and (α,n) reactions important to nucleosynthesis

The use of a 6 MV Van de Graaff accelerator for the studies of (p,n) and (α,n) reactions in intermediate mass nuclei is described with particular emphasis on the measurement of proton strength functions in the atomic-mass range from 88 to 124. The neutrons are detected in a 60-cm-diameter polyethylene sphere detector with an efficiency which is independent of energy for neutrons having energies between 30 keV and 2.5 MeV. In some cases, cross sections for the inverse reactions have been obtained using the principle of detailed balance. Nucleosynthesis reaction rates NA (σv) have been determined in most cases. The (p,n) reaction studies are of interest in establishing reaction systematics for p-process nuclei.

Cross sections and reaction rates for NA-23(p, n) Mg-23, Al-27(p, n) Si-27 Al-27(alpha, n) P-30, Si-29(alpha, n) S-32, and si-30(alpha, n) S-33

The total neutron production cross sections for the /sup 23/Na(p,n)/sup 23/Mg, /sup 27/Al(p,n)/sup 27/Si, /sup 27/Al(..cap alpha..,n)/sup 30/P, /sup 29/Si(..cap alpha..,n)/sup 32/S, and /sup 30/Si(..cap alpha..,n)/sup 33/S reactions have been measured for bombarding energies from threshold to 6.3 MeV. The neutron detector was a 60-cm diameter sphere of polyethylene with eight /sup 10/BF/sub 3/ counters and was insensitive to the angle and energy of the emitted neutrons. Cross sections for inverse reactions have been obtained using the principle of detailed balance. The data have been used to determine parameters for statistical model calculations to facilitate extrapolation of cross sections to higher bombarding energies. These reactions are relevant to problems of nucleosynthesis and stellar evolution and to studies of radiation damage. Nucleosynthesis reaction rates, N/sub A/(sigmav), were determined for the reactions studied and are tabulated for temperatures ranging from 0.4 x 10/sup 9/ to 10.0 x 10/sup 9/ K.

Cross sections and reaction rates for /sup 23/Na(p,n) /sup 23/Mg, /sup 27/Al(p,n) /sup 27/Si, /sup 27/Al(. cap alpha. ,n) /sup 30/P, /sup 29/Si(. cap alpha. ,n) /sup 32/S, and /sup 30/Si(. cap alpha. ,n) /sup 33/S

The total neutron production cross sections for the /sup 23/Na(p,n)/sup 23/Mg, /sup 27/Al(p,n)/sup 27/Si, /sup 27/Al(..cap alpha..,n)/sup 30/P, /sup 29/Si(..cap alpha..,n)/sup 32/S, and /sup 30/Si(..cap alpha..,n)/sup 33/S reactions have been measured for bombarding energies from threshold to 6.3 MeV. The neutron detector was a 60-cm diameter sphere of polyethylene with eight /sup 10/BF/sub 3/ counters and was insensitive to the angle and energy of the emitted neutrons. Cross sections for inverse reactions have been obtained using the principle of detailed balance. The data have been used to determine parameters for statistical model calculations to facilitate extrapolation of cross sections to higher bombarding energies. These reactions are relevant to problems of nucleosynthesis and stellar evolution and to studies of radiation damage. Nucleosynthesis reaction rates, N/sub A/(sigmav), were determined for the reactions studied and are tabulated for temperatures ranging from 0.4 x 10/sup 9/ to 10.0 x 10/sup 9/ K.