Development of 800 kV/30 mA Cockcroft-Walton Electron Accelerator for Radiation Application

The development of an 800 kV/30 mA DC electron accelerator based on a symmetrical Cockcroft-Walton cascade circuit driven by line frequency with two gas insulated step-up transformers was introduced. In such an arrangement, the transformers, instead of oil insulated ones, can be directly housed in the same SF6 pressure vessel as the cascade circuit, which yields an accelerator footprint as small and electric feedthrough as simple as possible. Four special-design isolation transformers were connected in series between the ground and HV to power the electron gun. In the tests after improvements, the machine can be conditioned to 860 kV with non-load, 700 kV/30 mA stable operations have been demonstrated several times, and an electrical efficiency of around 90% appears very promising for it to be developed as a good alternative for industrial electron accelerators below 1 MV.