High-current injector for heavy-ion fusion

Summary

A 2 MV, 800 mA, K⁺ injector for heavy-ion fusion studies is under construction. This new injector is a one-beam version of the proposed 4-beam ILSE injector. A new 36-module MARX is being built to achieve a 5 μs flat top. The high-voltage generator is stiff (<5 kω) to minimize effects of beam-induced transients. A large (≈7" diameters) curved hot alumino-silicate source emits a 1 μs long beam pulse through a gridless extraction electrode, and the ions are accelerated to 1 MV in a diode configuration. Acceleration to 2 MV takes place in a set of electrostatic quadrupole (ESQ) units, arranged to simultaneously focus and accelerate the ion beam. Heavy shields and other protection devices have been built in to minimize risks of high-voltage breakdown. Beam aberration effects through the ESQ have been studied extensively with theory, simulations, and scaled experiments. The design, simulations, experiments, and engineering of the ESQ injector will be presented.