EMISSION OF SECONDARY IONS FROM CONDUCTIVE MATERIALS BOMBARDED WITH HIGH ENERGY HEAVY IONS T. SEKIOKA*, M. TERASAWA*, M. SATAKA#, S. KITAZAWA# and M. NIIBE** *Department of Physics, Himeji Institute of Technology, Himeji, Hyogo, 671-2201 Japan #Japan Atomic Energy Research Institute (JAERI), Tokai-mura, Ibaraki, 319-1195 Japan **Laboratory of Advanced Science and Technology for Industry, Himeji Institute of Technology, Kamigori, Hyogo, 678-1201 Japan We have studied the dependence on the electronic stopping power of secondary ion yield from thin conductive solid targets irradiated by high energy heavy ion beams from the JAERI tandem accelerator. The results show the importance of the electronic excitation effect. It is suggested that Coulomb explosion is the major mechanism of producing the columnar defects along the incident ion path.