1. Ion Beam Modification and Analysis Laboratory of the University of North Texas, 1155 Union Circle, Denton, Texas 76203, USA
2. Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4026 Debrecen Bem tér 18/c, P.O. Box 51, H-4001 Debrecen, Hungary
3. Louisiana Accelerator Center, University of Louisiana at Lafayette, 104 E University Ave., Lafayette, Louisiana 70503, USA