A. Khadjavi

• IBM Watson Laboratory, New York, New York

W. Happer, Jr.^*

• Columbia Radiation Laboratory, Columbia University, New York, New York

A. Lurio

• IBM Watson Laboratory, New York, New York

• ^*This work was supported in part by the Joint Services Electronics Program (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract No. DA-28-043 AMC-00099(E) and in part by the National Aeronautics and Space Administration under Grant No. NsG-360.