Concept design of the megawatt power level gyrotron stabilized by a low-power signal for DEMO project

The specific features of the main components of the new powerful 230GHz/80kV/40A gyrotron aimed to use in the future control fusion facility DEMO are described. The gyrotron design provides a stable output power generation of more than 1 MW using a superconducting magnet with a moderate size warm bore. Furthermore, the new original quasi-optical converter providing the gyrotron operation in three possible regimes  two free oscillation regimes with co-rotating TE33,13 or counter-rotating TE33,-13 mode, and the regime with frequency locking by the stable input signal  is suggested and optimized. The Gaussian content in the output wave-beam in all above-mentioned regimes is about 98%.

Beam dynamics design of HIAF RFQ

The high-intensity heavy ion accelerator facility is a next-generation advanced heavy-ion accelerator facility built by the Institute of Modern Physics, Chinese Academy of Sciences. The RFQ is designed to provide a continuous wave beam and 2[Formula: see text]mA pulse beam with high-quality longitudinal beam distribution for the injection linear accelerator. Two different designs of aiming to suppress the longitudinal emittance were studied, and the optimized scheme which composed of a three-harmonic pre-buncher and an RFQ accelerator with small longitudinal acceptance was chosen. More emphasis is put on the section between pre-buncher and RFQ, where the space charge effect becomes severe with bunched beam. The optimal design and the analysis are presented in this paper.