Numerical Study of a High Current Thermionic Electron Gun for a Superconducting Radio Frequency Linac

抄録

Electron linacs based on superconducting radio frequency (SRF) technology are gaining attention as a highly efficient and high-power electron beam (EB) source for variety of applications. We also intend to apply the SRF technology for wastewater purification and radioactive isotope production that requires high-power EBs. Development of an electron source with high average current suitable for the SRF electron linac has been started. The objective of this work is to generate a pulsed EB with a high repetition rate, same as either the SRF accelerating frequency (1.3 GHz) or its subharmonic frequency. As even a small beam loss can quench SRF cavities, the EB produced by an electron gun should be of small emittance and sufficiently short pulses. Using simulation codes, the current dependence of the beam properties has numerically investigated based on the electron gun configuration at Research Center for Electron Photon Science (ELPH). At present, we are conducting studies to optimize and improve the electron gun including the grid pulser with design and development of the SRF linac. In addition, an electron gun test stand is currently under construction to experimentally evaluate the EB produced by the electron gun system. In this paper, we will present the results of numerical studies for the electron gun system.