Supported 242Cm in the marine environment

A search was made for evidence for sup(242m)Am in the environment using samples collected in December 1974 from the vicinity of the fuel processing plant at UKAEA Windscale. The method of chemical separation is described, and the separated source comprising Am and Cm was first measured in July 1975 by α-spectrometry, then being remeasured at intervals over 500 days to follow the decay of 242Cm. Results are shown tabulated. Applying the method of least squares to the data produced a derived half-life value of 166.0 +- 2.1 days, which is very close to the accepted value of 163 days for 242Cm. It is assumed that the apparently longer half-life was due to a small constant amount of 242Cm supported by a precursor with very long half-life. The results indicated, however, that little, if any, supported 242Cm had been detected, but further work is in hand to check the preliminary data. (U.K.)