LINAC2026 - 33rd Linear Accelerator Conference

650 MHz CW mode RF-grided gun design for SRF linac applications

TUPO021

18 Aug 2026, 16:00

2h

1F Exhibition Hall (Daejeon Convention Center)

Poster Presentation MC1.A02 Electron and ion sources, guns, photo injectors, charge breeders TUPO - Poster Session

Speaker

Yu Du (Institute of Modern Physics, Chinese Academy of Sciences, University of Chinese Academy of Sciences)

Description

To address the growing demand for high-power commercial electron irradiation, the Institute of Modern Physics (IMP) has developed a 100 mA, 4.6 MeV superconducting linac prototype. This compact facility features a conduction-cooled Nb3Sn SRF cavity (650 MHz, 5-cell, βopt=0.82) to drive high-intensity beams. However, the existing conventional DC gridded thermionic gun cannot provide the requisite temporal structure or injection velocity to match the SRF cavity acceptance. This severe longitudinal mismatch induces excessive beam loss and low transmission efficiency, inherently preventing continuous-wave (CW) operation. To overcome this critical bottleneck, IMP is developing a novel RF-modulated gridded thermionic gun designed to generate 650 MHz CW bunches. By superimposing an RF electric field directly onto the cathode surface, the emitted DC beam is effectively pre-modulated and bunched, enabling seamless, lossless transmission through the downstream cavity. This paper details the systematic electromagnetic design and comprehensive beam dynamics simulations of this RF-gridded gun, concluding with an outlook on its upcoming fabrication and integration.