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Sakanaka, S.

Paper Title Page
WEPCH130 Analysis of Symmetry in Accelerating Structures with Group Theory 2227
 
  • S. Sakanaka
    KEK, Ibaraki
  
  Many rf cavities for modern accelerators have a variety of symmetry. There is a question as to what is the connection between the symmetry of a cavity and of its eigenmodes. This can be clarified* using the representation theory of groups. The geometric symmetry of a cavity can be expressed by a group of symmetry operations. The structure of this group can be represented by a set of matrices called representation. The group is associated with several irreducible representations which can express possible patterns of transformations under the symmetry operations. The irreducible representations are very suitable to express the symmetry of each eigenmode. This method can be used to improve the understanding of non-axially symmetric structures. In this paper, this method is first explained, and then, it is extended to the application of symmetric periodic structures.

*S. Sakanaka, Phys. Rev. ST Accel. Beams 8, 072002 (2005).

 
THPLS036 Results of the Straight-sections Upgrade of the Photon Factory Storage Ring 3365
 
  • T. Honda, S. Asaoka, W.X. Cheng, K. Haga, K. Harada, Y. Hori, M. Izawa, T. Kasuga, Y. Kobayashi, H. Maezawa, A. Mishina, T. Mitsuhashi, T. Miyajima, H. Miyauchi, S. Nagahashi, T. Nogami, T. Obina, C.O. Pak, S. Sakanaka, H. Sasaki, Y. Sato, T. Shioya, M. Tadano, T. Takahashi, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, S. Yamamoto
    KEK, Ibaraki
  
  At the 2.5-GeV ring of the Photon Factory (PF), a large reconstruction of the lattice around the straight sections* has been accomplished in 2005. As a result, four short straight sections of 1.5 m have been newly created, and the lengths of the existing straight sections have been much improved. For example, the length of the longest straight section has been extended to 9 m from 5 m. The optics has been optimized for installing short-period narrow-gap (in-vacuum) undulators at the new straight sections. The reconstruction work on the ring was held from March to September 2005. In the range over two-thirds of the storage ring, all the quadrupole magnets and all the beam ducts have been renewed and rearranged. Commissioning of the storage ring was started from the end of September 2005 and continued for one month. The operation for the user experiment was resumed from the end of October on schedule. Though we made no in-situ baking after the installation for the beam ducts, the vacuum scrubbing by the synchrotron radiation is running very well. The product of the beam lifetime and the beam current exceeded 700 A min for the operation current 450 mA at the end of December 2005.

*S. Asaoka et al. "New Upgrade Project for the Photon Factory Storage Ring", AIP Conf. Proc. 705, p161 (2004).