Study of new accelerator system using multi-beam type RFQ-IH linac with direct plasma injection scheme (DPIS) for Heavy Ion Inertial Fusion (HIF) basic experiments

In order to verify direct plasma injection scheme (DPIS), an acceleration test was carried out using TiTech RFQ heavy ion linear accelerator and CO2 laser heavy-ion source in 2001. The accelerated carbon beam was obtained current 10 mA of C4+. To confirm the capability of the DPIS, we designed and fabricated a new RFQ to accommodate 100 mA. We succeeded to accelerate 60 mA carbon ions with the DPIS in 2004. We have studied a multi-beam type RFQ with Interdigital-H (IH) cavity that is power-efficient structure in low energy. We designed and manufactured a two-beam type RFQ-IH linac as a prototype of the multi-beam type. It had successfully to accelerate from 5keV/u to 60keV/u and 108 mA (2x54 mA/channel). We believe that acceleration techniques of DPIS and the multi-beam type RFQ-IH linac are break through of 21 century for Heavy-ion Inertial confinement Fusion (HIF). Conceptual design of RF linac with these techniques for HIF is studied. New accelerator-system using these techniques for HIF basic experiment is designing to accelerate 400 mA using 4 beams from an RFQ-IH type linac with DPIS. A model of 4 beams acceleration cavity was designed and manufactured for proof of principle accelerator. (author)