Secondary electron emission from entrance and exit surfaces of thin clean foils bombarded with H+, C+, and O+

Abstract We have measured secondary electron emission from thin, clean foils of C, Al, Ti, Ni, and Cu bombarded with H+, C+, and O+, at energies between 0.3 and 1.2 MeV/amu for protons and 20 to 80 keV/amu for the heavy projectiles. We observe in some but not all cases a proportionality between the secondary electron yield and the stopping power, but such a proportionality seems to break down at the lower projectile energies used by us. The yields emitted in forward direction are generally somewhat larger than those emitted backwards. The results are discussed in the frame of an extended Sternglass model.