RELATIVE DIFFERENTIAL CROSS SECTIONS FOR ELASTIC SCATTERING OF ELECTRONS FROM Ar${}^{7+}$ IONS BY USING A TOROIDAL ANALYZER J. Matsumoto, Z. Wang, A. Danjo,${}^{1}$ M. Yoshino,${}^{2}$ H. Tanuma and N. Kobayashi Department of Physics, Tokyo Metropolitan University, ${}^{1}$Department of Environmental science, Niigata University, ${}^{2}$Shibaura Institute of Technology The angular distribution of the elastically scattered electrons from Ar${}^{7+}$ ions has been measured by using a toroidal analyzer. The relative differential cross sections are presented in the scattering angles from $40^{\circ}$ to $80^{\circ}$ at a collision energy of 100~eV.