Multi-beam RFQ linac structure for heavy ion fusion

Both the RF linear accelerator (linac) and the linear induction accelerator have been considered as injectors in a driver system for heavy ion fusion (HIF). In order to relax beam defocusing by space charge effect in the low-energy region, the accelerating beams that were merged and had their beam currents increased by the funnel tree system are injected into storage rings. A multi-beam linac that accelerates multiple beams in an accelerator cavity has the advantages of cost reduction and downsizing of the system. We modeled the multi-beam Interdigital-H type radio frequency quadruple (IH-RFQ) cavities with the different beam numbers and evaluated the electromagnetic characteristics by simulation. As a result, the reasonable ranges of their configuration were indicated for a practical use.