Plutonium isotope measurements from across continental Australia

The Pu-240/Pu-239 ratio of the global plutonium fallout from atmospheric nuclear weapons testing is typically in the range 0.17-0.19. However, the influence of regional nuclear installations or nearby weapons test sites can lead to local values outside this range. We report Pu-240/Pu-239 ratios at 14 representative sites across the Australian continent, and find that the weapons tests carried out in Australia appear to have made a significant contribution to the total fallout in the center of the continent, despite their relatively small explosive yield. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.