Neutron emission spectrum from gold excited with 16.6 MeV linearly polarized monoenergetic photons

The neutron-emission spectrum from a 197Au target excited with a 16.6 ±0.2 MeV, monoenergetic, linearly polarized photon beam was measured using the time-of-flight method at the NewSUBARU-BL01. Two components were clearly detected in the neutron spectrum produced by photonuclear reactions. One component [component (A)] shows an evaporation-like spectrum with energies up to 4 MeV. The spectrum of the other component [component (B)] is shaped like a bump and energies ≥4 MeV. The intensity of the component (A) does not show any definite angular dependence, whereas, that of the component (B) follows the relation [a+ b cos(2Θ)] as a function of the angle Θ between the polarization and detector directions.