EXAMINATION OF THE SURFACE OF COPPER AFTER PROLONGED EXPOSURE TO A PROTON FLUX IN AN ACCELERATOR.

We have examined the surface of copper used in accelerators of various types after prolonged exposure to proton fluxes at energies from 30 to 100 MeV. The action of the proton flux on a copper electrode produced clusters of two types at the surface as well as sputtering during the five years of operation. An internal copper lining that had been exposed to a proton flux for 16 years in an accelerator shows the deposition of copper in the amorphous state and a cluster structure of the second type. The surface and subsurface layers of copper in both cases show extensive impregnation with carbon.