A new method for making long-lived carbon foils for heavy ion beam strippers

Abstract

New methods for preparing long-lived carbon foils of approximately 10 μg/cm 2 in thickness for use as strippers in heavy ion linear accelerators have been developed. The carbon foils were made by ion beam sputtering and carbon arc-discharge techniques. Parting agents of KCl and NiCl 2 were used. Carbon was deposited onto glass slides heated to approximately 180°C. Lifetimes of the carbon foils prepared by ion beam sputtering were determined to be 5 to 55 h when irradiated with 3.0 MeV, 1 μA, Ne + ion beams. A stripper-foil changer system with a large foil capacity (more than 360 foils) was designed, fabricated, and successfully operated. In this paper, comparisons between carbon foil preparation processes and foil lifetimes are made, and a description of the foil changer system is included in the appendix.