KEK, Ibaraki
SLAC, Menlo Park, California
Fermilab, Batavia
INFN/LASA, Segrate (MI)
DESY, Hamburg
In an attempt at demonstrating an average field gradient of 31.5 MV/m as per the design accelerating gradient for ILC, a program called S1-Global is in progress as an international research collaboration among KEK, INFN, FNAL, DESY and SLAC. The design of the S1-G cryomodule began at May 2008 by INFN and KEK. The S1-Global cryomodule was designed to contain eight superconducting cavities from FNAL, DESY and KEK, and to be constructed by joining two half-size cryomodules, each 6 m in length. The module containing four cavities from FNAL and DESY was constructed by INFN. Four KEK cavities have been assembled in the 6 m module which KEK fabricated. All major components were transported to KEK from INFN, FNAL and DESY in December 2009. The assembly of the two 6-m cryomodules started from January 2010 in a collaborative work of FNAL, DESY, INFN and KEK. The construction of the S1-G cryomodule will complete in May, and the cool-down of the S1-G cryomodule is scheduled from June 2010 at the KEK-STF. In this paper, the construction and the cold tests of the S1-Global cryomodule in the worldwide research collaboration will be presented.
KEK, Ibaraki
Development of the superconducting injector Linac for compact ERL has been continuing at KEK. The cryomodule including three two-cell SC cavities was designed. Two prot-type two-cell cavities were fabricated, and the vertival test were carried out after the standard surface preparation at STF. The high power tests of the input couplers were also carried out at the test stand with 300 kW cw klystron. The status of the cERL injector cryomodue will be reported.
KEK, Ibaraki
MHI#10 and #11 cavities are measured in KEK-STF as the s0 plan for ILC. After these vertical tests, they will be sent to J-Lab and tested at least once there. Moreover, two new cavities without HOM coupler are fabricated and measured in STF, which are made by two new vendors (HITACHI and TOSHIBA). As the international collaboration, one cavity from IHEP in Beijing will be sent to KEK, optical inspected, high pressure rinsed and vertical tested. Although MHI#8 cavity for S1-Global reached 38MV/m, it could not achieve ILC specification (35MV/m, 0.8x109) due to the heavy field emission. To overcome this problem, the various tests were done in the stage of the surface treatment. For example, the EP parameters and the rinsing procedure were changed. In this report, the recent results of the vertical tests including the surface treatment in KEK-STF will be presented in detail.
Kyoto ICR, Uji, Kyoto
KEK, Ibaraki
Optical inspections on superconducting cavities seem to become familiar to those who are involved in the cavity fabrications. Further improvements on the Kyoto Camera have been carried out these years together with further investigation technique developments, such as high density T-map or eddy current scan. Improvements on Kyoto Camera includes change of EL sheets to LEDs, which raised the brightness 10 times and the lifetime very long as known well. The resolution was also increased. The high density T-map will help to locate a hot spot during the vertical tests and the eddy current scan will be useful for screening of bare Nb sheets with possible defects. These progresses will be reported.
KEK, Ibaraki
Cryomodule tests of four Tesla-like superconducting cavities is under preparation in the S1-Global project at KEK. Assembly of the cryomodule was started in January 2010, and the installtion in the STF tunnel was completed in April. First cool-down tests are scheduled in June. The low rf power tests of the Tesla-like cavities will be carried out in July. The high rf power tests are scheduled between September and December, 2010.
IHEP Beijing, Beijing
KEK, Ibaraki
IHEP Beiing, Beijing
The combination of the low-loss shape and large grain niobium material is expected to be the possible way to achieve higher gradient and lower cost for ILC 9-cell cavities. As the key component of the 'IHEP 1.3 GHz SRF Accelerating Unit and Horizontal Test Stand Project', a low-loss shape 9-cell cavity using Ningxia large grain niobium (IHEP-01) was fabricated and surface treated (CBP, CP, annealing, pre-tuning) at IHEP. Then the cavity was shipped to KEK STF for ultrasonic cleaning, high pressure rinsing, baking and vertical test. The cavity reached 20 MV/m in the first vertical test on July 1st 2010. The quench location has been found by T-mapping and optical inspection. The strong field emission and equator defects will be removed by further treatment. The fabrication procedure, surface treatment recipes and the first test results are summarized in this paper.