Triple differential cross sections for the electron-impact ionization of argon and neon

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