Photofission of ^{<span class="cmr-7">238</span>}U Induced by a Quasi-monochromatic, Compton Backscattered <span class="cmmi-10">γ</span> Beam

Abstract

The photofission cross-section of 238 U was measured in the sub-barrier energy region as a function of the γ energy using, for the first time, a monochromatic, high-brilliance, Compton backscattered γ beam. This prototype experiment was performed at the HIγS gamma beam facility of the Duke University at Durham (North Carolina, US) using the 238 U(γ, f ) reaction at a beam energy varied between E γ = 4.7-6.0 MeV and with an energy resolution of ∆E = 150-200 keV (∆E/E ≈ 3%). The photofission cross-section was determined down to E * = 4.7 MeV. Indications of transmission resonances have been observed at excitation energies of E * = 5.1 and 5.6 MeV with moderate amplitudes.