@misc{oai:repo.qst.go.jp:00077731,
 author = {Obina, Takashi and Arakawa, Dai and Egi, Masato and Furuya, Takaaki and Haga, Kaiichi and Harada, Kentaro and Honda, Tohru and Honda, Yosuke and Honma, Teruya and Kako, Eiji and Kato, Ryukou and Kawata, Hiroshi and Kobayashi, Yukinori and Kojima, Yuuji and Konomi, Taro and Matsumura, Hiroshi and Miura, Takako and Miyajima, Tsukasa and Nagahashi, Shinya and Nakai, Hirotaka and Nakamura, Norio and Nakanishi, Kota and Nigorikawa, Kazuyuki and Nogami, Takashi and Qiu, Feng and Sagehashi, Hidenori and Sakai, Hiroshi and Sakanaka, Shogo and Shimada, Miho and Tadano, Mikito and Takahashi, Takeshi and Takai, Ryota and Alexandrovna Tanaka, Olga and Tanimoto, Yasunori and Uchiyama, Takashi and Umemori, Kensei and Yamamoto, Masahiro and 西森, 信行 and 羽島, 良一 and 永井, 良治 and 沢村, 勝 and Hotei, Takahiro and Nishimori, Nobuyuki and Hajima, Ryoichi and Nagai, Ryoji and Sawamura, Masaru},
 month = {May},
 note = {A compact energy-recovery linac (cERL) have been operating since 2013 at KEK to develop critical components for ERL facility. Details of design, construction and the result of initial commissioning are already reported*. This paper will describe the details of further improvements and researches to achieve higher averaged beam current of 1 mA with continuous-wave (CW) beam pattern. At first, to keep the small beam emittance produced by 500 kV DC-photocathode gun, tuning of low-energy beam transport is essential. Also, we found some components degrades the beam quality, i.e., a non-metallic mirror which disturbed the beam orbit. Other important aspects are the measurement and mitigation of the beam losses. Combination of beam collimator and tuning of the beam optics can improve the beam halo enough to operate with 1 mA stably. The cERL has been operated with beam energy at 20 MeV or 17.5 MeV and with beam rep-rate of 1300 MHz or 162.5 MHz depending on the purpose of experiments. In each operation, the efficiency of the energy recovery was confirmed to be better than 99.9 %., 10th International Particle Accelerator Conference},
 title = {1 mA Stable Energy Recovery Beam Operation with Small Beam Emittance},
 year = {2019}
}