KEK, Ibaraki
Status of KEKB Superconducting Cavities and Study for Future SKEKB Y.Morita, S.Mitsunobu, T.Furuya, S.Takano, M.Nishiwaki, A.Kabe, T.Tanaka and K.Akai KEK With superconducting crab cavity, 8 superconducting accelerating cavities were stably operated last two years and KEKB luminosity reached the world records of 2.1x1034. For future Super KEK B-Factory(SKEKB) we study a high power input coupler of 600kW, HOM dampers of more than 30 kW and a cavity operation with reversed phase position for high power loading with very low voltage in case of a normal phase condition. The reversed phase experiment at 150 mA of a beam current in KEKB shows potential for the low voltage and high power application.
KEK, Ibaraki
NIMS, Tsukuba, Ibaraki
Superconducting Thin Films on Metals by Pulse Laser deposition at KEK S.Mitsunobu, S.Inagaki, M.Yoshida, K.Saito, H.Nakanishi and M.Wake KEK At KEK, the test of MgB2 thin films on Cu, Ti and Nb by Pulse Laser Deposition(PLD) method based on a fabrication method developed by NIMS have been studied and RF surface resistances have been measured. The direct deposition of MgB2 film on Nb showed two step decrease of the surface resistance. For a TM010 cavity, formed MgB2 films showed no superconductivity at this time due to different heat treatment conditions from disk samples, so we cutting cavity quadruple and one of them used as target. And heat treated as usual. This quadruple shows superconducting transition.
KEK, Ibaraki
Horizontal High Pressure Water Rinsing for KEKB Superconducting Cavity S.Takano, S.Mitsunobu, Y.Morita, M.Nishiwaki and A.Kabe KEK Usually, high pressure water rinsing of superconducting cavities are done at vertical position to vent water and dusts smoothly. The cavities are set horizontally afterward. KEKB cavities have some possibility dust contamination at online tunnel. Horizontal high pressure water rinsing (HHPR) has possibility to clean the cavities at on line. We have been tested HHPR using KEKB proto type SC cavity with 60 bar ultra pure water and aspirator pumping system. Even without any baking, a performance of the cavity cleaned with HHPR measured by a vertical test achieved to 10 MV/m similar to one of before HHPR.