Preparation of radioactive targets for tandem accelerator experiments by high vacuum evaporation-condensation

摘要

Radioactive thin film targets have been prepared by high vacuum evaporation-condensation in the hot-lab facility of the University of Munich. Targets made by this technique are of high density and excellent smoothness, being well suited for experiments aimed at the production and spectroscopy of fission fragments. Cold crucible electron beam heating is the preferred method for evaporation of actinide isotopic material of sufficient abundance, for instance Th-230, Th-232, U-233, U-235, U-238 and Pu-239. Exotic isotopes, which are available only in submilligram quantities, are processed in a micro-evaporator module consisting of a chimney-type crucible heated by low-tension electron bombardment. This set-up is characterised by a high collection efficiency and was used for the production of Pu-244 and Be-10 targets. (C) 2001 Published by Elsevier Science B.V. References: 7