Diamond electron stripping foils for high energy ion beams

Summary form only given. Performance issues associated with electron stripping foils become critical for the production of accelerator ion beams at extremely high powers and high Z values. Increases in absorbed power lead to decreases in foil lifetime. Diamond stripping foils offer the potential of an improved lifetime as compared to carbon stripping elements based on graphitic carbon. This report describes fabrication, modeling, and preliminary testing observations of polycrystalline diamond electron stripping foils. Two different foil types are described. In the first, the diamond thickness is on the order of a micrometer and the foil is designed to serve as an electron stripper for heavy ions in the National Superconducting Cyclotron. In the second design, the foils are approximately 50 mum thick to absorb the entire beam energy. These foils are used to simulate power absorption levels such as may be expected in the rare isotope accelerator design. The modeling includes thermal calculations based on a beam spot of 3 mm diameter incident on a 10times10 mm foil and considers varying values of thermal conductivity and emissivity. Testing of the thick foils was performed using a ¹³⁶Xe^19- beam with energy of seven MeV/u