Mori, S. Satoh, D. Yoshida, M. JACoW Publishing Geneva, Switzerland 2226-0366 978-3-95450-194-6 10.18429/JACoW-LINAC2018-MOPO008 English 54-58 MOPO008 cavity electron cathode emittance gun Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-LINAC2018-MOPO008 http://jacow.org/linac2018/papers/mopo008.pdf We apply the dielectric assist accelerating (DAA) structure to the RF gun, which is a candidate for a high average current and high brightness electron source. The DAA structure consists of ultralow-loss dielectric cylinders and disks which are periodically arranged in a metallic enclosure. Due to the high quality factor and the high shunt impedance of the DAA cavity, the RF gun adopting the DAA cavity can be a high-duty electron beam source at room temperature. We provide design work for RF gun adopting the DAA structure.