Triple differential cross section of rare gas atoms in different low energy kinematics

Triple differential cross sections have been measured for the electron-impact ionization of rare gases in two coplanar geometries. Results are presented for 20 eV excess energy with respect to ionization threshold for ionization of helium, neon and argon. These enable us to investigate the target dependence of triple differential cross section angular-distributions. For ionization of helium, we compare our absolute measurements with the convergent close coupling calculations whereas, for ionization of neon and argon, the comparison is made with the distorted wave Born approximation calculations. Additional measurements carried out on argon near threshold are also presented