Elastic Scattering of 11.5—17.7-Mev Photons by Au Measured with a Bremsstrahlung Monochromator

The external electron beam of the University of Illinois 25-Mev betatron and a post-bremsstrahlung electron spectrometer are used to provide a time coincidence which selects monochromatic photons with an energy resolution of 0.67%. For this resolution and an electron beam current of 3×${10}^{-9\mathrm{}}$ amp, the maximum photon intensity is about 1.5×${10}^5$/sec for each electron detector placed in the spectrometer.