THE SOLUTION OF X-RAY ACTIVATION CURVES FOR PHOTONUCLEAR CROSS SECTIONS

Abstract

A method is presented for the computation of photonuclear cross sections from their X-ray activation or yield curves. It is based on the photon differences between successive Schiff representations of bremsstrahlung spectra and assumes that the activation curves have smooth first and second derivatives. Artificially prepared activation curves have been satisfactorily solved by this method, and the published photonuclear activation curves determined in this laboratory have been reanalyzed. The resulting cross section curves are in essential agreement with those originally determined; however the new values are believed to be more reliable. New constants for two proposed relationships between (γ, n) "resonance" peak energies and atomic mass number have been determined. Appended to the paper are tables of the Schiff bremsstrahlung spectra for maximum photon energies between 8 and 28 Mev. and also of special functions for cross section computations between the same energies.