We have produced a beam of high-energy gamma-rays by Compton backscattering of 1064 nm laser photons from 1
GeV electrons circulating in a storage ring. Measuring the energy spectra of the backscattering photons with an HPGe
detector, we have found that the maximum energy of 17:6 MeV and the measured energy spectra show agreement with
the simulation calculations, while the detected photon yields were measured at about 4 103; 2 103 and 3
102 photons s1mA1W1 for the 20, 10 and 2 mmf collimators, respectively. The photon energy widths from the
collimators correspond to 6.6–17:6 MeV; 12.4–17:6 MeV and 17.3–17:6 MeV; respectively. By using these photons, we
measured the total nuclear photoabsorption cross-sections in the E1 giant resonance energy region for 197Au using the
attenuation method and we have demonstrated that the photon attenuation method will be a useful tool for studying
photonuclear reactions.