Double capture with simultaneous ionization in ${\mathrm{He}}^{2+}$ on Ar collisions

We have investigated double electron capture with simultaneous target ionization in collisions of 25-keV/amu ${}^3{\mathrm{He}}^{2+}$ projectiles on argon. Doubly differential cross sections for electrons emitted in angles $0°,20°,$ $45°,90°,$ $128°,175°,$ in coincidence with the neutralized projectiles were obtained. To establish the relative importance of the double capture channel in the electron emission at the present intermediate impact velocity, differential cross sections for total electron emission were also measured. A narrow symmetric cusp-shaped structure for electrons with velocity close to the ion velocity, associated with the neutral emerging projectile, is observed. Binary encounter electrons, masked by other processes in total emission, are clearly observed for the double capture plus ionization channel.