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.