| Paper | Title | Page |
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| TUPME010 | High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB | 1583 |
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| After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 1035 /s.cm2, 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction. | ||
| WEPFI019 | High Power Test of Kanthal-coated L-band Lossy Cavity | 2744 |
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We have been developing a Kanthal (Al-Cr-Fe)-coated collinear load as a possible candidate of the L-band acc. structure of SuperKEKB positron capture system. In order to achieve the higher capture efficiency comparing to that of KEKB, the upgrade of the e+ production and capture section is required. The system consists of a W target with a flux concentrator followed by acc. structures surrounded by solenoids. The increase of the e+ bunch charge and the reduction of satellite bunches are the main issues for this system. The frequency choice of L-band is based on the larger transverse and longitudinal acceptances than those of the S-band one. The load is preferable to compose the system with compact magnets and to minimize the dip in the solenoid field. The design of the load was reported in previous work*. We understand that the Kanthal-coated cell should be confirmed in high power to confirm the feasibility at our design field of 10 MV/m level. We are making a test cavity which consists of 3 cells and one of them is composed of Kanthal-coated disks to lower the intrinsic Q value from 20000 to the order of 1000. The cavity production and the experimental result will be reported.
*Development of L-band accelerating structure with Kanthal-coated collinear load for SuperKEKB, IPAC12, THLR04. |
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| WEPME017 | Development and Application of the Trigger Timing Watchdog System in KEK Electron/Positron Linac | 2962 |
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| The KEK injector linac provides electrons and positrons to several accelerator facilities. A 50 Hz beam-mode switching system has been constructed to realize simultaneous top-up injections for Photon Factory and the KEKB high- and low-energy rings, which require different beam characteristics. An event-based timing and control system was built to change the parameters of various accelerator components within 20 ms. The components are spread over a 600-m-long linac and require changes to a total of 100 timing and control parameters. The system has been operated successfully since the autumn of 2008 and has been improved upon as beam operation experience has been accumulated. The timing watchdog and alert system are indispensable for the stable and high quality beam operation. For this purpose, we developed and utilized several timing watchdog system. We will present the detail of timing signal watchdog system for the KEK injector linac. | ||