Technology development for recirculating heavy-ion accelerators

Summary

The «recirculator», a recirculating heavy-ion accelerator, has been identified as a promising approach for an inertial-fusion driver. System studies have been conducted to evaluate the recirculator on the basis of feasibility and cost. The recirculator has been shown to have significant cost advantages over other potential driver schemes, but some of the performance requirements exceed the capabilities of present technology. The system studies identified the high-leverage areas where advances in technology will significantly impact the cost and performance of a recirculator. One of the high-leverage areas is the modulator system which generates the acceleration potentials in the induction cells. The modulator system must be capable of generating the acceleration potentials at peak repetition rates in excess of 100kHz with variable pulse widths. LLNL is developing a modulator technology capable of driving induction cells using the latest in solid-state MOSFET technology. A small-scale modulator has been built and tested to prove the concept and the next version is presently being designed. Our objective is to demonstrate a modulator operating at 5 kV, 1 kA, with 0.2–1 pulse widths while driving an induction cell at >100 khz within the next year. This paper describes the recirculator, the technology requirements necessary to implement it and the modulator system development that is being pursued to meet these requirements.