TRIPLE DIFFERENTIAL CROSS-SECTIONS FOR THE ELECTRON-IMPACT IONIZATIONOF ARGON AND NEON

Cross sections have been measured for the electron-impact ionization o f argon and neon in a coplanar symmetric geometry. Results are present ed for impact energies of 115.8, 85.8 and 50 eV for argon and 50 eV fo r neon. A comparison is made with distorted-wave Born approximation ca lculations which include initial channel polarization and final channe l post-collisional interactions. The lowest-energy argon data appear t o indicate that polarization effects are very significant, and, in ord er to explore this, additional measurements have been performed in the coplanar constant theta(ab) geometry.