HYDROGEN IONS EMISSION UNDER FAST CHARGED PARTICLES : THE BEGINNING OF THE DESORPTION PROCESS E.F. DA SILVEIRA, M.G. BLAIN et E.A. SCHWEIKERT J. Phys. Colloques, 50 C2 (1989) C2-79-C2-84 DOI: 10.1051/jphyscol:1989215