Vertical test results for ERL 9-cell cavities for compact ERL project

Umemori, Kensei*; Furuya, Takaaki*; Sakai, Hiroshi*; Sato, Masato*; Shinoe, Kenji*; Sawamura, Masaru; Cenni, E.*

The Compact ERL project, which is a test facility of ERL, is ongoing in Japan. At the first step of this project, main linac cavities accelerate electron beams by 30 MV. Two 9-cell cavities were fabricated for main linac cryomodule. A series of surface treatments were applied for the cavities. For the final EP, current density was selected to be relatively low. Vertical tests were performed for both cavities. Their field successfully reached to 25 MV/m, without any field limitation. The Q-values were more than 110, even at 20 MV/m. Field emission on-sets were to be 14 and 22 MV/m, for each cavity. Both cavities satisfied requirements for ERL main linac cavity. Details of vertical tests, with X-ray and temperature mapping data, are shown, in this paper.