IONIZATION OF GALLIUM IONS BY ELECTRON IMPACT M. Steidl, K. Aichele, U. Hartenfeller, D. Hathiramani, F. Scheuermann, M. Westermann and E. Salzborn Institut f\"ur Kernphysik, Justus--Liebig--Universit\"at Giessen, D-35392 Giessen, Germany Electron impact ionization cross sections for Ga$^{q+}$ ions have been measured using the crossed beams technique for different charge states $q$ for single ($q=1-9$), double ($q=1-6$) and triple ($q=1-4$) ionization. The cross sections for single ionization of ions in the charge state $q=1-5$ show contributions in excited, long--lived metastable states. Excitation-autoionization processes vary predictably with the ionization stage for single and multiple ionization of gallium.