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Zhang, C.

Paper Title Page
TUOAG02 Commissioning of BEPCII 959
 
  • J. Q. Wang, L. Ma, C. Zhang
    IHEP Beijing, Beijing
 
  BEPCII is the upgrade project of Beijing Electron Positron Collider (BEPC), serving continuously for both high energy physics experiment and light soure use. As an e+-e- collider, BEPCII will operate in the beam energy region of 1-2.1 GeV with design luminosity of 1*1033cm-2s-1 at 1.89 GeV. The beam commissioning of BEPCII storage rings started out in Nov. 2006. From Nov. 2006 to Aug. 2007, the phase one commissioning was carried out successfully with the so called backup scheme adopting conventional magnets in the IR intead of the superconducting insertion magnets (SIM). After the SIM was intalled into the interaction region, phase two commissioning began in Oct. 2007. The tuning method for high luminosity but low background was extensively studied during phase two, and the beam current has reached more than 1/3 of the design of 0.91 A. The third phase of beam commissioning is planned in May this year after the detector is moved into the on-line position. It is expected that the luminosity would reach to about 30% of its design specification. This paper describes the procedure of beam commissioning of BEPCII and focuses on results of its second phase.  
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WEPC060 Studies on the Beam Current Dependent Phenomena in the BEPC-II Storage Rings 2130
 
  • Q. Qin, N. Huang, W. B. Liu, Y. D. Liu, Y. M. Peng, J. Qiu, D. Wang, J. Q. Wang, N. Wang, X. H. Wang, Y. Wei, X. M. Wen, J. Xing, G. Xu, C. H. Yu, C. Zhang, Y. Zhang, Z. Zhao, D. M. Zhou
    IHEP Beijing, Beijing
 
  The upgrade project of the Beijing Electron Positron Collider (BEPC-II) has been being commissioned since Nov. 2006. Besides the commissioning of the luminosity, which is expected to be 100 times higher than the BEPC, the BEPC-II also provided beam to the synchrotron radiation users as a light source during these two years. Some beam current dependent phenomena, such as bunch lengthening, single beam instabilities, blow-up in collision, etc., in both collision and synchrotron radiation modes are observed in the machine performance. In this paper, some observations and analyses on these phenomena are given.  
WEPC076 Remote Tilt-control System of Injection Bump Magnet in the SPring-8 Storage Ring 2172
 
  • K. Fukami, C. Mitsuda, M. Oishi, M. Shoji, K. Soutome, H. Yonehara, C. Zhang
    JASRI/SPring-8, Hyogo-ken
  • M. Hasegawa, T. Nakanishi
    SES, Hyogo-pref.
  • T. Ohshima
    RIKEN/SPring-8, Hyogo
 
  The SPring-8 storage ring has four pulse-bump magnets to generate bump orbit for beam injection. Rotational error of the bump magnets around a beam-axis (tilt) induces the stored-beam oscillation in vertical direction due to horizontal error field. In the top-up operation, vertical perturbation of the stored-beam during beam injection is mainly produced by the tilt. We evaluated the tilt angle by measuring of the perturbation turn-by-turn using a single-pass BPM system and realigned bump magnets manually inside the accelerator tunnel. It was required to repeat the measurement and realignment processes two or three times for convergence. To correct the tilts smoothly, we developed a remote tilt-control system. The system consists of two fixed and one movable supports in vertical direction under each bump magnets. The movable support is driven by a stepper motor through 1/30 worm gear in the range of ±4 mrad with the accuracy of less than 0.1 mrad. By using this system, we succeeded complete on-beam reduction of the perturbation.  
THPC112 KONUS Dynamics and H-mode DTL Structures for EUROTRANS and IFMIF 3239
 
  • C. Zhang, M. Busch, H. Klein, H. Podlech, U. Ratzinger, R. Tiede
    IAP, Frankfurt am Main
 
  During the last two decades, the combination of the KONUS beam dynamics and H-mode DTL structures has been developed as an efficient solution for accelerating low- and medium-energy proton and ion beams. EUROTRANS is a EUROpean Research Programme for the TRANSmutation of High Level Nuclear Waste in an Accelerator Driven System. IFMIF is a planned International Fusion Material Irradiation Facility to test materials for fusion reactors. For the driver linacs of both projects, two H-DTLs have been proposed to cover the energy ranges of 3–17MeV and 5–40MeV, respectively. The beam dynamics designs as well as the error studies of the H-DTLs are presented in this paper.  
THPP080 A Superconducting CH-Linac for IFMIF 3548
 
  • H. Podlech, A. Bechtold, M. Busch, F. Dziuba, H. Klein, H. Liebermann, U. Ratzinger, R. Tiede, C. Zhang
    IAP, Frankfurt am Main
 
  The IFMIF accelerator which has to provide a 40 MeV 250 mA Deuteron beam requires a duty cycle of 100%. The IAP Frankfurt has proposed 175 MHz H-type drift tube linac consisting of an IH-cavity and a chain of superconducting CH-cavities. A superconducting CH-prototype cavity has been tested very successfully and reached effective gradients of 7 MV/m. Two rf power couplers are necessary to feed one CH-cavity. The maximum rf power per cavity is approximately 500 kW. As amplifiers the originally foreseen 1 MW tubes or 300 kW tubes can be used. The focusing scheme in the CH-linac is based on superconducting solenoids. Beam dynamics simulations have been performed with an error analysis using the LORASR code based on the KONUS dynamics. An updated and improved linac design will be presented. A contribution of IAP for the EVEDA phase could consists of the construction and the test of the room temperature IH-cavity and the first complete CH cryo-module. A study together with industry has been already performed regarding the production process and the system integration of auxiliary equipment like couplers and tuner.  
THPC070 Symmetry Restoration of the SPring-8 Storage Ring by Counter-sextupole Magnets 3149
 
  • K. Soutome, S. Daté, T. Fujita, K. Fukami, C. Mitsuda, A. Mochihashi, H. Ohkuma, M. Oishi, S. Sasaki, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, K. Tsumaki, H. Yonehara, C. Zhang
    JASRI/SPring-8, Hyogo-ken
  • S. Matsui, H. Takebe, H. Tanaka
    RIKEN/SPring-8, Hyogo
 
  In the SPring-8 storage ring there are four magnet-free long straight sections of about 30m. These were realized in 2000 by locally rearranging quadrupole and sextupole magnets. In modifying the optics we took care of the periodicity of cell structure, especially of sextupole field distribution along the ring. To keep the periodicity high and hence the dynamic aperture large, we adopted a scheme in which "betatron phase matching" and "local chromaticity correction" are combined. In this scheme the dynamic aperture for on-momentum electrons is kept by the phase matching and that for off-momentum electrons is enlarged by the local chromaticity correction with weak sextupoles (SL). After modifying the lattice, we tried to recover the symmetry of the ring further and found that a harmful effect of nonlinear kick due to SL can be minimized by additional "counter-sextupole magnets" placed 180 degrees apart in horizontal betatron phase from SL. We installed such counter-sextupoles in every long straight sections and confirmed that the aperture was improved. In the paper we discuss these topics showing experimental data of injection efficiency, momentum acceptance, etc.