Absolute differential cross sections for double–photon Compton scattering

The differential cross sections for double-photon Compton scattering were measured as functions of independent final-photon energy with the two detectors placed at 90° to the incident beam and 135° to each other. The energy of the incident photons was 661.65 keV as produced by an 8 Ci (1 Ci = 37 GBq) 137 Cs radioactive source. Many systematic effects contributing to true events have been taken into account. The measured energy spectra of two...