IPAC2018 - List of Authors (Soutome, K.)

Paper	Title	Page
THPMF059	Simulation Studies of Beam Commissioning and Expected Performance of the SPring-8-II Storage Ring	4203
	Y. Shimosaki JASRI, Hyogo, Japan K. Soutome, M. Takao JASRI/SPring-8, Hyogo-ken, Japan H. Tanaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	In the SPring-8 upgrade project, the 5-bend achromat lattice is adopted for achieving a very low emittance of 157 pm.rad at 6 GeV. Since the dynamic aperture (DA) and the beam performance become sensitive against errors due to the strong quadrupoles and sextupoles, we carried out tracking simulations to evaluate the tolerance of machine imperfections such as the misalignment, magnetic field errors, the BPM offset, etc. It is found that the first-turn-steering (FTS) with the use of single-pass BPM's is indispensable because even under strict (but attainable) tolerances the beam cannot be stored without steering kicks. We then confirmed that after the FTS a sufficiently large DA can be obtained for accumulating the beam by the off-axis injection. By performing the orbit and optics corrections for the stored beam, we can finally achieve an emittance value of 160 ~ 180 pm.rad, being close to the design value. We also found that a naive application of the SVD algorithm to orbit corrections yields unwanted local bumps between BPM's and this deteriorates the vertical emittance. A possible scheme to avoid such local bumps by effectively interpolating the measured orbit will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF059
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THPMF060	Touschek Beam Loss Simulation for Light Source Storage Rings	4206
	M. Takao, K. Soutome JASRI/SPring-8, Hyogo-ken, Japan Y. Shimosaki JASRI, Hyogo, Japan K. Soutome, H. Tanaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	In light source storage rings, it is important to know the distribution of lost electrons due to the Touschek scattering for protecting insertion devices (IDs) from radiation damage. This will become crucial especially in future light sources where narrow gap in-vacuum IDs are normally used. While the Touschek scattered electron begins to oscillate in the horizontal direction with the amplitude proportional to the dispersion at the scattering point and to the momentum deviation after scattering, the motion is converted into the vertical direction due to the betatron coupling and some of the scattered electrons are lost at the narrow gaps of in-vacuum IDs. The momentum deviation by the Touschek scattering reaches 5% more, and according to which the vertical oscillation is more excited. Hence electrons even scattered at small horizontal dispersion are also lost at narrow gap IDs. We carried out computer simulations by taking the present SPring-8 storage ring and a planned 3GeV low-emittance ring as examples. The results and possible measures for ID protection will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF060
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Simulation Studies of Beam Commissioning and Expected Performance of the SPring-8-II Storage Ring

4203

Y. Shimosaki
JASRI, Hyogo, Japan
K. Soutome, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan
H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

In the SPring-8 upgrade project, the 5-bend achromat lattice is adopted for achieving a very low emittance of 157 pm.rad at 6 GeV. Since the dynamic aperture (DA) and the beam performance become sensitive against errors due to the strong quadrupoles and sextupoles, we carried out tracking simulations to evaluate the tolerance of machine imperfections such as the misalignment, magnetic field errors, the BPM offset, etc. It is found that the first-turn-steering (FTS) with the use of single-pass BPM's is indispensable because even under strict (but attainable) tolerances the beam cannot be stored without steering kicks. We then confirmed that after the FTS a sufficiently large DA can be obtained for accumulating the beam by the off-axis injection. By performing the orbit and optics corrections for the stored beam, we can finally achieve an emittance value of 160 ~ 180 pm.rad, being close to the design value. We also found that a naive application of the SVD algorithm to orbit corrections yields unwanted local bumps between BPM's and this deteriorates the vertical emittance. A possible scheme to avoid such local bumps by effectively interpolating the measured orbit will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMF060

Touschek Beam Loss Simulation for Light Source Storage Rings

4206

M. Takao, K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan
Y. Shimosaki
JASRI, Hyogo, Japan
K. Soutome, H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

In light source storage rings, it is important to know the distribution of lost electrons due to the Touschek scattering for protecting insertion devices (IDs) from radiation damage. This will become crucial especially in future light sources where narrow gap in-vacuum IDs are normally used. While the Touschek scattered electron begins to oscillate in the horizontal direction with the amplitude proportional to the dispersion at the scattering point and to the momentum deviation after scattering, the motion is converted into the vertical direction due to the betatron coupling and some of the scattered electrons are lost at the narrow gaps of in-vacuum IDs. The momentum deviation by the Touschek scattering reaches 5% more, and according to which the vertical oscillation is more excited. Hence electrons even scattered at small horizontal dispersion are also lost at narrow gap IDs. We carried out computer simulations by taking the present SPring-8 storage ring and a planned 3GeV low-emittance ring as examples. The results and possible measures for ID protection will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)