[1] LUND INST TECHNOL,DEPT NUCL PHYS,S-22362 LUND,SWEDEN
[2] UNIV UPPSALA,DEPT INORGAN CHEM,S-75122 UPPSALA,SWEDEN
[3] ROYAL INST TECHNOL,DEPT ELECTR,S-16440 KISTA,SWEDEN
[4] AUSTRALIAN NUCL SCI & TECHNOL ORG,PMB 1,MENAI,NSW 2234,AUSTRALIA
[5] ROYAL MELBOURNE INST TECHNOL,DEPT APPL PHYS,MELBOURNE,VIC 3001,AUSTRALIA