Energy-dependent He flux redistribution through the Si〈1 0 0〉 channel

Flux redistribution with formation of channeling peaks were recently observed in transmission experiments done with a variety of ion-crystal combinations. This phenomenon was called a cooling effect and was observed to be function of the ion-target combination, the incident energy and even the crystallographic direction. In the present work we have looked for the same phenomena with a completely different experimental approach. With this aim we have used the Rutherford backscattering technique under channeling conditions and a SIMOX target. By performing He in Si〈1 0 0〉 channeling experiments we were able to determine the electronic stopping powers between +2° and −2° around the 〈1 0 0〉 direction in a 600-2000 keV energy range. With this information and the Lindhard's angular compensation rule, we were able to deduce the characteristics of the He flux as a function of the energy. We found that between 600 and 1500 keV we are in presence of a cooling effect. However, at around 2000 keV, according to the Lindhard's rule, the He flux distribution approaches to a normal behavior.