Scatter spectroscopy

In high flux density ionizing photon fields, it is usually difficult to measure photon spectra with Ge(Li) or Si(Li) semiconductor radiation detectors. A method which is an extension of that reported by Unsworth and Greening has been developed to sample scattered photons from a photon beam. A thin sheet of low atomic number material is placed in the photon beam and is observed by a collimated detector from some convenient angle, θ, away from the beam direction. Only a small fraction of the photons are scattered into the solid angle of the detector. An approximation of the energy spectrum of the primary beam may be obtained by calculating the primary photon energies from the measured scattered photon energy spectrum. This method differs from that of Unsworth and Greening by considering Compton and Rayleigh scattering separately.