|
内容記述 |
A newly developed 14-GHz electron cyclotron resonance ion source (ECRIS) has been installed at the Heavy Ion Medical Accelerator in Chiba (HIMAC). The new ECRIS was developed to deliver four ion species, namely, helium, carbon, oxygen, and neon ions and to switch among them quickly for a new treatment method called multi-ion treatment. The ECRIS was designed for use in a next-generation ultra-compact accelerator complex called Quantum Scalpel, which is being constructed at the National Institutes for Quantum Science and Technology (QST) in Chiba, Japan. To realize quick ion switching, we developed a new method for switching among the gases to be ionized. We have performed the first test on ECRIS since its installation in March 2022. In the first test, to enhance the intensity of multiply charged ions such as O6+ and Ne7+, we used two-frequency heating, gas mixing, and a new technique called ‘‘bias-disk boost technique’’, which was developed in the first test project. In this paper, we present the performance of the newly developed multi-ion ECRIS, such as its stability, time required to switch ion species, and intensities of the four ion species. Finally, we discuss future plans to obtain better performance that is essential for practical use in multi-ion therapy. |
