Miniature Electron-Cyclotron Resonance (ECR) Ion Source for Industrial Applications and Research

The electron-cyclotron resonance (ECR) source is rapidly becoming the de facto standard source for accelerator applications where a reliable, robust, and low maintenance source of positive ions is needed for a particular application. As a result, a wide variety of ECR sources have been developed for specific accelerator applications ranging from isotope production to proton therapy to ion implantation and industrial processing. Note however that even the simplest of these sources is relatively large and requires hundreds of kilowatts of RF power. Electron-cyclotron resonance (ECR) sources used for industrial processing, such as ion implantation, are larger still. A small, lightweight, and reliable high-current source of singly ionized atoms could have a revolutionary impact on accelerator systems and industrial processing. The design of a miniature ECR (miniECR) ion source, developed under a Phase I grant, is considerably smaller and more compact than those available today. This source makes judicious use of dielectric materials to shrink the dimensions of the ion source to values significantly smaller than the free-space wavelength (~12 cm). An additional benefit of this small size is a reduction in RF power required to energize the source from hundreds of Watts to less than 100 Watts. The design of the miniECR source was completed in Phase I and two sources were fabricated for testing. The proposed Phase II program characterizes miniECR sources under a variety of conditions specific to different missions. In particular, beams of protons produced by a miniECR source will be characterized to optimize the source for proton-beam accelerators (isotope production, proton therapy, etc.). Operation of a miniECR source with deuterium ions will be characterized to optimize source parameters for neutron sources. Finally, characterization of a miniECR source operating with heavy ions optimizes the source for production of ions suitable for ion implantation and as a source of ions for tuning charge-breeder injection lines. The small size of the miniECR source, coupled with the inherent ruggedness and reliability of ECR sources, simplifies considerably the ion injector of proton accelerators and neutron sources. The small size also enables large ion implantation sources to be replaced with an array of miniECR sources. Additionally a linear array of miniECR sources enables wafer processing by sweeping a line source of ions across the wafer. This approach is not possible with existing ion implantation systems and enables a new paradigm in ion implantation processing that is more compatible with the large-aperture bending magnets used to isolate a particular ion species for implanting in the wafer.