Experimental test of the bremsstrahlung cross section

The bremsstrahlung cross section has been studied by measuring the activity induced in $^{63}\mathrm{Cu}$ by electrodisintegration and when thin radiators of Cu, Mo, Ta, and Th were placed in the electron beam just ahead of the target. The electron energies were varied from 13.5 to 60 MeV for the electrodisintegration and from 20 to 60 MeV for the radiator-in measurements; the ($\ensuremath{\gamma}$,n) cross section for $^{63}\mathrm{Cu}$ was determined using virtual photon theory; the radiator data were fitted using various bremsstrahlung cross sections. The best fit is obtained using the synthesized spectrum of Seltzer which differs from the Davies-Bethe-Maximon cross section as given by equation (3CS) of Koch and Motz.