COINCIDENT DETECTION OF ELECTRONS EJECTED AT LARGE ANGLES AND TARGET RECOIL IONS PRODUCED IN MULTIPLY IONIZING COLLISIONS FOR THE 1-MEV U O-Q++AR COLLISION SYSTEM/

The angular distributions of energetic electrons ejected at angles bet ween 45-degrees and 135-degrees with respect to the incident-beam dire ction have been measured in coincidence with the charge states of the target recoil ions produced in multiply ionizing collisions for the I- MeV/u O(q)+ (q=4,7)+Ar collision systems. These measurements have been made for approximately 179-, approximately 345-, and approximately 50 5-eV electrons. Additionally, the energy distributions of electrons ej ected into specific angular regions have been measured. Ar LMM satelli te Auger electrons appear as a peak in the energy spectrum of electron s ejected at all large angles. The center of this peak is found at an electron energy of approximately 179 eV. Electrons with approximately 179 eV energy, ejected at large angles, are preferentially produced in coincidence with recoil ions of charge state 4+. Electrons with appro ximately 345 eV energy and approximately 505 eV energy ejected at larg e angles are preferentially produced in coincidence with recoil ions o f charge state 3+. The angular distributions for these electrons are s trongly peaked in the forward direction; essentially no electrons are observed at angles larger than 90-degrees. These results are consisten t with the dominant production mechanism for energetic electrons eject ed at large angles being a binary-encounter process. Differential cros s sections have been calculated from these angular distributions. They are on the order of 10(-21) cm2/(eV sr).