Accelerator mass spectrometry of 63Ni using a gas-filled magnet at the Munich Tandem Laboratory

The detection of Ni-63 (T-1/2 = 100.1 yr) by means of accelerator mass spectrometry (AMS) using a gas-filled magnet (GFM) is described. The experimental setup includes a dedicated ion source, a 14 MV MP tandem, a GFM and a multianode ionization chamber. First results indicate a background level of Ni-63/Ni ratios as low as 2 x 10(-14). This sensitivity will allow - for the first time ever - to detect Ni-63 induced by fast neutrons in copper samples from Hiroshima and Nagasaki, even for distances beyond 1500 m from the hypocenters. Thus, it will be possible to reconstruct experimentally the neutron doses of the A-bomb survivors from Hiroshima and Nagasaki. (C) 2000 Elsevier Science B.V. All rights reserved.