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Sawamura, Masaru; Hajima, Ryoichi; Nagai, Ryoji; Nishimori, Nobuyuki
Proceedings of 16th International Conference on RF Superconductivity (SRF 2013) (Internet), p.1081 - 1084, 2014/02
It is important to damp higher-order modes (HOMs) of superconducting accelerators especially for energy-recovery linacs of high current operation. Though various types of HOM couplers, beam line HOM dampers and waveguide HOM couplers have been developed, there are some problems such as inner conductor heating of output connector for HOM couplers and low packing factor for beam line HOM dampers. We propose new design of HOM coupler. This coupler consists of a coaxial line coupled with a cavity or a beam pipe and a rounded waveguide which cuts off the accelerating mode. The rounded waveguide is similar to a coaxial line and the inner conductor and outer conductor are connected with a plate which corresponds to waveguide side wall. This enables the inner connector cooled down efficiently through the outer conductor. The calculation results of MW-STUDIO will be presented.
Sakai, Hiroshi*; Enami, Kazuhiro*; Furuya, Takaaki*; Sato, Masato*; Shinoe, Kenji*; Umemori, Kensei*; Sawamura, Masaru; Cenni, E.*
Proceedings of 16th International Conference on RF Superconductivity (SRF 2013) (Internet), p.855 - 859, 2014/02
A main linac cryomodule have been constructed for Compact ERL project. It contains two 9-cell cavities, mounted with HOM absorbers and input couplers. After cavity string assembly, they were installed into the vacuum vessel of the cryomodule. It was placed inside radiation shield of cERL and connected to a refrigerator system. The cryomodule was successfully cooled down to 2K and low power and high power measurements were carried out.
Sakai, Hiroshi*; Aoto, Tomohiro*; Enami, Kazuhiro*; Furuya, Takaaki*; Sato, Masato*; Shinoe, Kenji*; Umemori, Kensei*; Sawamura, Masaru; Cenni, E.*; Hayashi, Kyohei*; et al.
Proceedings of 16th International Conference on RF Superconductivity (SRF 2013) (Internet), p.291 - 296, 2014/02
Alignment of superconducting cavities is one of the important issues for linear collider and/or future light source like ERL and X-FEL. To measure the cavity displacement under cooling to liquid He temperature more precisely, we newly developed the position monitor by using white light interferometer. This monitor is based on the measurement of the interference of light between the measurement target and the reference point. It can measure the position from the outside of the cryomodule. We applied this monitor to the main linac cryomodule of Compact ERL (cERL) and successfully measured the displacement during 2 K cooling with the resolution of 10 
m.
Cenni, E.*; Enami, Kazuhiro*; Furuya, Takaaki*; Sakai, Hiroshi*; Sato, Masato*; Shinoe, Kenji*; Umemori, Kensei*; Sawamura, Masaru
Proceedings of 16th International Conference on RF Superconductivity (SRF 2013) (Internet), p.678 - 682, 2014/02
A compact Energy Recovery Linac (cERL) is under construction at KEK in order to test the performance of the key components required for the future ERL project. The main linac L-band cavities were assembled and tested in the cryomodule under high power operation. During the test, information concerning field emission were gathered by means of PIN diodes rings and NaI scintillator located at the cavities ends. The data were analyzed by means of simulations.
