“scrubbing” Process of Cu Surfaces Induced by Electron Bombardment

We studied energy distribution of electrons emitted from samples of the real Cu surface used in the Large Hadron Collider (LHC). The spectra have been detected as a function of scrubbing conditions and have been analyzed by dividing the whole energy range into three energy regions, conventionally termed reflected, rediffused and true-secondary electrons. We observe, for fixed electron impact energy, that the true secondary electrons gradually decrease for increasing electron dose, while we don’t observe any variation in the EE and RE components. These results provide useful information on the electron cloud formation in particle accelerators and may shed light on the involved physical mechanisms.