STUDY OF STRONG FINAL STATE CORRELATION FOR 
              ELECTRON IMPACT IONIZATION OF ARGON
                                
                                
        D. B. Chitwood, J. L. Peacher, and D. H. Madison
                                
                                
      University of Missouri - Rolla, Rolla, Missouri, USA
                                
                                
     The final state interaction between two ejected electrons is strongest
when the two electrons leave
     the collision with a small angular separation and nearly equivalent
energies.  In a recent (e,2e)
     experiment with an argon target to measure the ionization cross section
a pronounced minimum was
     found when both electrons were ejected near 45 degrees.  We have
performed a distorted wave Born
     calculation for this process, and do not find the pronounced minimum.