Metallic Uranium Targets

In 2004 we reported on a new evaporation set up for uranium-compound targets, basically UF4, for heavy-ion experiments [1]. Since for most experiments in nuclear physics and chemistry targets from metallic uranium would be preferred because side reactions are minimized, we upgraded our high-vacuum coater TF 600 from BOC Edwards© with a magnetron sputtering equipment which is suitable for deposition of metallic uranium as well as for uranium oxide or carbide as a possible alternative. In Fig. 1 the interior of the vacuum chamber is shown with the magnetron source and the shutter and the rotating target wheel sitting above. On the left side the gas inlet is situated. The purchase of a sputter target from metallic uranium with the required properties proved to be very difficult. After more than a year of world wide search we finally were successful to get suitable material with a content of U less than 0.2 %, which was a requirement of the GSIsafety department, from Material Manufacturing Sciences Corporation, Oak Ridge, TN, USA. The starting material was processed in high vacuum and the oxygen content remaining in the metal was specified to be less than 25 ppm. The sputtering source was a disk of 1 inch in diameter with a thickness of 3 mm, which corresponds to about 30 g of uranium.