Production of highly charged ions with an ECRIS using high temperature super-conducting coils

摘要

Highly charged ions are widely used in atomic physics, nuclear physics and material science. One requirement to produce highly charged ions for an ECRIS [P. Sortais et al., ECRIS development at GANIL, in: Proceedings of the 12th Int. Conf. on Cyclotrons, Berlin, 1989; P. Sortais et al., in: Proceedings of the Int. Conf. on Ion sources, Berkley 1989, p. 288] is a high resonance frequency, hence a high resonance magnetic field. With electromagnets, we can produce limited magnetic fields, generally, in the range of 2 T. Also, electromagnets require a significant amount of electrical power, powerful DC power supplies and large cooling systems. As a consequence, producing highly charged ions with a source setup, at ground, is rather difficult and becomes a serious technical and financial challenge if the source is on a high voltage terminal. The use of low temperature superconducting coils 'LTC' has a real advantage when it comes to electrical power. A reduction factor of 10-20 in the total AC power is obtained. However, the handling of cryogenic liquids generates difficulties and extra costs. An elegant solution consists in using high temperature superconducting wire 'HTS' [Y.L. Tang et al., Super Cond. Sci. Technol. 15 (2002); L. Masure et al., 2002, in: ISS2002 Conf. Proc. (Yokohama, Japan, November 2002) in press]. Indeed, the superconductivity of the HTS wire starts at 77 K. Cryogenic generators with sufficient cooling power at 20 K are commercially available and need only few kW of AC power. In addition to that, the coils are very compact and easy to handle. The following paper presents PKDELIS [ECR HTS source using superconducting coils, French Patent No. FR98 06579]. The first ECRIS in the world using HTS wires, jointly designed and constructed by PANTECHNIK and NSC New Delhi, India.