1. Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233, Takasaki, Watanuki, Gunma, 370-1292, Japan, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki, 319-1195, Japan, and Valence Corp., 2200 N. Rodney Parham, Suite 210, Little Rock, Arkansas 72212