Kim, C. Kim, E.-S. Park, C.S. JACoW Publishing Geneva, Switzerland 2673-5490 978-3-95450-227-1 10.18429/JACoW-IPAC2022-MOPOTK022 English 485-488 Contribution to a conference proceedings 2022 2022-07 https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK022 https://jacow.org/ipac2022/papers/mopotk022.pdf This work presents a design study of a 200 MeV electron linear accelerator consisting of an electron gun, bunchers, and accelerator structures. We aimed to design the linac with low emittance and low energy spread. A coasting beam from a thermionic electron gun is bunched using a series of buncher cavities: sub-harmonic buncher (SHB), a pre-buncher (PB), and a Buncher. The bunched beam is then accelerated up to 200 MeV with 4 cascaded accelerating structures. The SHB was designed with one-cell standing wave structure for improving the bunching efficiency. The two types of the 500 MHz SHB were considered: elliptical and coupled-cavity linac types. We also investigated constant-gradient and constant-impedance types of 3 GHz multi-cell traveling wave resonators for following buncher cavities and accelerating structures. Depending on the type, geometries of each traveling wave structure (TWS) cavity were determined, and then the electromagnetic fields were calculated. RF powers and phases of each cavity along this linac system were optimized using beam dynamics simulation. Furthermore, the beam distributions in the transverse direction are adjusted using solenoid magnets in the lowenergy section as well as quad triplets in the high-energy section.