Author: Morita, A.
Paper Title Page
WEPO027 Design Study of Final Focusing Superconducting Magnets for the SuperKEKB 2457
 
  • M. Tawada, N. Higashi, M. Iwasaki, H. Koiso, A. Morita, Y. Ohnishi, N. Ohuchi, K. Oide, T. Oki, K. Tsuchiya, H. Yamaoka, Z.G. Zong
    KEK, Ibaraki, Japan
 
  For SuperKEKB, which is an upgrade project of KEKB, we are studying the design of the final focus quadrupole magnets for the interaction region. The 7 GeV electrons in the high-energy ring and the 4 GeV positrons in the low-energy ring collide at one IP with a finite crossing angle of 83 mrad. For each beam, the final beam focusing system consists of the superconducting quadrupole-doublets. These quadrupole magnets have to meet specifications described below. (1) Because of the small beam separation between two beam lines, the superconducting magnet is designed with thin coils and the conductor size is required to be minimized. (2) Since the beta functions are so large, a large space with a good field quality is required. (3) These magnets must apply the focusing fields on electrons and positrons, independent each other. The quadrupole magnets in the solenoid field of the particle detector are designed without an iron yoke. Consequently, the reduction of the leakage fields from the adjacent beam lines is a critical issue to achieve large dynamic aperture. In this paper we will report the design of final focusing system.  
 
THPZ006 SuperKEKB Interaction Region Modeling 3690
 
  • A. Morita, H. Koiso, Y. Ohnishi, K. Oide, Y. Sugimoto
    KEK, Ibaraki, Japan
 
  In the SuperKEKB interaction region(IR) design, the beam-line intersects solenoid-axis with large angle and the superconducting final focusing quadrupole magnets are installed into each beam-lines without iron-shield. Because of these features, the emittance and dynamic aperture evaluation have to consider the solenoid fringe field and the leakage multipole field of another beam-line magnet, respectively. The IR lattice modeling and the magnetic field handling of both solenoid and multipole field would be reported in this article.  
 
THPZ007 Lattice Design of Low Emittance and Low Beta Function at Collision Point for SuperKEKB 3693
 
  • Y. Ohnishi, H. Koiso, A. Morita, K. Oide, H. Sugimoto
    KEK, Ibaraki, Japan
 
  Extremely low beta function at the interaction point(IP) and low emittance are necessary to achieve the design luminosity of 8x1035 cm-2 s-1 for a SuperKEKB project. The low emittance with a large Piwinski angle makes this possible with longer bunch longitudinally compared with the vertical beta function at IP. We call this Nano-beam scheme. In this scheme, a beam-beam parameter is realized to be less than 0.09 for the design luminosity. The lattice features, chromaticity corrections, and dynamic aperture are discussed in this article.