Study on Technology of Preparing Self-supporting Isotopic Target by Vacuum Evaporation of Ultra-short Source-substrate Distance Substrate Rotating

The technology of preparing self-supporting isotopic target by the vacuum evaporation of ultra-short source-substrate distance substrate rotating was studied. The thickness distributions of targets were calculated with different geometric parameters. The material utilization and nonuniformity of targets were also calculated. The optimum source-shaft distances and source-substrate distances were determined. The influences of evaporation boat, evaporation distance and time on forming film were studied. The experiments indicate that in the preparation of a ø10 mm target, the appropriate source-substrate distances are 13, 15, 20 and 25 mm for the materials with melting points of 100-600, 700-1200, 1300-1600 and 1600-1900 ℃, respectively. And the corresponding source-shaft distances are 12.5, 13.0, 14.5 and 16.0 mm, respectively.