THE ENERGY SPECTRUM OF THE X RAYS FROM A 70-MEV. SYNCHROTRON

Abstract

The spectrum of the X rays produced in the forward direction by 70-Mev. electrons striking a very thick target has been measured. The scattering method has been used to determine the energies of about 650 electron pairs produced by the X rays in G-5 emulsions and from this the spectrum has been deduced. The number of photons found below 25 Mev. is considerably less than that expected from the Bethe–Heitler–Schiff theory. No satisfactory explanation of this has been found but the measured spectrum is in agreement with "yield" measurements done iii this laboratory.