The ³He(α,γ)⁷Be Reaction at Low Energies

Citation

Osborne, John Lawrence (1983) The ³He(α,γ)⁷Be Reaction at Low Energies. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/jjbj-9188. https://resolver.caltech.edu/CaltechTHESIS:10222019-162722254

Abstract

Cross sections for the ³He(α,γ)⁷Be reaction have been measured at several energies from E_cm = 165 to 1200 keV by counting prompt γ rays from a windowless, differentially pumped, recirculating, ³He gas target. The cross-section factor S₃₄(E_cm) and branching ratio γ₁/γ₀ were determined at each energy. Absolute cross sections were measured at E_cm = 947 and 1255 keV by counting the γ rays from the ⁷Be produced in a ³He gas cell with a Ni entrance foil. The inferred zero-energy intercept of the cross-section factor is S₃₄(0) = 0.52 ± 0.03 keV-barn. This value is in good agreement with the previous measurements of Parker and Kavanagh and Nagatani et al., but disagrees substantially with the recently published measurement of Kräwinkel et al. from Münster. The relationship between the present measurements and several theoretical calculations, and the effect of the extrapolated cross section on the solar neutrino problem are discussed.

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