Author: Miyamoto, A.
Paper Title Page
MOPRO079 Design of Ultra-low Emittance Ring with Multi-bend Lattice on a Torus-knot 271
 
  • A. Miyamoto, S. Sasaki
    HSRC, Higashi-Hiroshima, Japan
 
  We proposed a torus knot type synchrotron radiation ring in that the beam orbit does not close in one turn but closes after multiple turns around the ring. Currently, we are designing a new ring based on the shape of a (11, 3) torus knot for our future plan ‘HiSOR-II.’ This ring is mid-low energy light source ring with a beam energy of 700 MeV. Recently some light source rings are achieving very low emittance that reaches a diffraction limited light by adopting a multi-bend scheme to the arc section of the ring. It is not difficult for low-mid energy VUV-SX light source ring because the electron beam less than 10 nmrad can provide the diffraction limited light in the energy less than 10eV. However the multi-bend lattice has many families of the magnets, therefore it is not easy to decide the parameters of the lattice. Especially, it is difficult for the torus knot type SR ring because there is a lot of geometric limitation around the cross points of orbits. We present the details of the designing procedure and the specifications of the ultra-low emittance light source ring having innovatively odd shape.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO079  
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WEPRO038 Possibility for Quasi-periodic Knot-APPLE Undulator 2026
 
  • S. Sasaki, A. Miyamoto
    HSRC, Higashi-Hiroshima, Japan
  • N. Kawata, T. Mitsuyasu
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
  • S. Qiao
    SIMIT, Shanghai, People's Republic of China
 
  An intense on-axis radiation power from an undulator is a serious problem especially for a low-photon-energy beamline in a facility with high or medium energy storage ring. This problem may be solved by using a Figure-8, a Pera, or a Knot undulator configuration*,**. However, these schemes are useless for variably polarizing undulators such as an APPLE undulator and other similar variations since such devices are not capable for reducing on-axis power density in the linear mode. In these circumstances, we have completed a conceptual magnet design of Knot-APPLE udulator which is capable to generate elliptically polarized radiation as well as linearly polarized radiation. This pure permanent magnet device is equipped with a motion mechanism of APPLE undulator. In this paper, we present detailed magnet design feature, magnetic field distributions, and radiation properties including variations of polarization in comparisons with other exotic devices. In addition, a possibility to introduce a quasi-periodicity in this type of undulator is considered in order to achieve further reduction of second and third harmonic radiation intensities.
*S. Sasaki, "Undulators, wigglers and their applications," p.237-243 (Ed. by H. Onuki and P. Elleaume, Taylor & Francis Inc, New York, 2003).
**S. Qiao, et. al, Rev. Sci. Instrum., 80, 085108 (2009).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO038  
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