Design of a 14 GHz min-B Electron Cyclotron Resonace Ion Source for Heavy Ion Accelerator in Korea Cancer Center Hospital

Abstract

A 14 GHz min-B ECR ion source with movable iron plug and bias electrode has been designed. This will be used as an ion source for heavy ion accelerator, applications in atomic physics research, and for further physical understanding of electron cyclotron resonance (ECR) plasmas. To comply with requests for various beam characteristics and to optimize the system the source is designed to operate with flexibilities in magnetic structure and extraction system. The designed magnetic field is min-B structure generated by the two main yoked coils and 12 segmented permanent magnets. Mirror ratio can be adjusted from 2.5 to 4. By using both the movable iron plug and the center coil at mid-length of chamber the maximum B field and the central field can be changed respectively. The waveguide for rf injection is inserted directly to the source to make its radial position lie along the resonance surfaces so that it can ensure the maximum power coupling as well as the accessibility of the auxiliary system such as gas feeding and biased disk. The extraction system is also has been designed so that the ion beam with the desired mass and charge state can be optimized by varying the extraction gap. The more detail features of the source will be described.