Measurements of the three-body photodisintegration of ³He were performed at the High Intensity γ-ray Source (HIγS). Neutrons emitted in this reaction inside a ³He gas target were detected with seven 12.7 cm diameter liquid scintillator detectors. Time-of-flight (TOF) and pulse-shape discrimination (PSD) techniques were used to identify neutron events. The absolute differential cross sections for the ³ He(γ, n)pp reaction as a function of outgoing neutron scattering angle and energy were determined from the measurements at the incident γ-ray energies of 11.4, 12.8, 13.5, and 14.7MeV to within a precision better than ±6%.

The absolute cross sections at each incident energy are compared to the measurements of Gorbunov [Gor74], phase space calculations, and state-of-the-art three-body calculations. The inclusion of the Coulomb interaction in the three-body problem has been a long-standing challenge in theoretical nuclear physics. The present experimental data were found to be in good agreement with the state-of-the-art theory, which includes a full treatment of the Coulomb interaction between the protons in the final state [Del05].