Theoretical and experimental study of the correlation between forward and backward electron emissions induced by H-0 or H+ projectiles incident on carbon foils

The emission statistics of secondary electrons emitted from solid targets u nder ion impact has been recently the object of much interest from a theore tical as well as experimental point of view since it provides very useful i nformation about the electron excitation process in the solid. In the case of very thin targets, it is possible to measure simultaneously the number o f electrons emitted from both sides of the target and the exit charge state of the projectile. The resulting two variable (number of electrons emitted in the backward and in the forward directions) statistical distribution sh ows in some cases a clear correlation between the numbers of electrons emit ted from both sides of the target. This correlation between backward and fo rward emission has been studied from Monte Carlo simulations and from exper iments for H-0 and H+ projectiles incident on thin carbon fc,ils in the MeV energy range. It is shown that the charge exchange processes of the incide nt projectiles in the target play an important role in the interpretation o f the backward-forward correlation of the secondary electron emission. (C) 1999 Elsevier Science B.V. All rights reserved.