Author: Ohkuma, H.
Paper Title Page
TUOAB01 Lattice Design of a Very Low-emittance Storage Ring for SPring-8-II 942
 
  • Y. Shimosaki, K.K. Kaneki, T. Nakamura, H. Ohkuma, J. Schimizu, K. Soutome, M. Takao
    JASRI/SPring-8, Hyogo-ken, Japan
 
  The de­sign work for an up­grade pro­ject of the SPring-8, the SPring-8-II, is in progress. Its ul­ti­mate goal is to pro­vide a su­pe­ri­or bril­liance of pho­tons by re­duc­ing emit­tance of elec­trons until a diffrac­tion limit. A mul­ti-bend lat­tice has been adopt­ed for the emit­tance re­duc­tion; a dou­ble-bend lat­tice (nat­u­ral emit­tance of 2000 pmrad at 6 GeV), a triple-bend lat­tice (400 pmrad) and a quadru­ple-bend lat­tice (170 pmrad) were de­signed step by step for study­ing its fea­si­bil­i­ty*. For an ad­di­tion­al emit­tance re­duc­tion, beam dy­nam­ic is­sues for a sex­tu­ple-bend lat­tice have been ex­am­ined for the first can­di­date. In this case, the nat­u­ral emit­tance is about 70 pmrad. The dy­nam­ic aper­ture has been en­larged by study­ing beam dy­nam­ic phe­nom­e­na caused by non­lin­ear dis­per­sion, non­lin­ear chro­matic­i­ty, non­lin­ear res­o­nance, etc., and by op­ti­miz­ing lin­ear and non­lin­ear op­tics. The lat­tice de­sign for the com­ing up­grade of SPring-8 will be pre­sent­ed in de­tail.
* K. Soutome et al., "Design Study of a very Low-emittance Storage Ring for the Future Upgrade Plan of SPring-8", Proc. of IPAC10, WEPEA032, p. 2555 (2010).
 
slides icon Slides TUOAB01 [4.812 MB]  
 
THPC032 Current Status of SPring-8 Upgrade Plan 2981
 
  • T. Watanabe, T. Asaka, H. Dewa, H. Ego, T. Fujita, K. Fukami, M. Masaki, C. Mitsuda, A. Mochihashi, T. Nakamura, H. Ohkuma, Y. Okayasu, Y. Shimosaki, K. Soutome, M. Takao
    JASRI/SPring-8, Hyogo-ken, Japan
  • T. Tanaka
    RIKEN Spring-8 Harima, Hyogo, Japan
 
  The SPring-8 up­grade plan has been dis­cussed. The main goal is to re­place the stor­age ring in the ex­ist­ing tun­nel so that the re­sult­ing emit­tance will get as close to the diffrac­tion limit in hard x-ray re­gion as pos­si­ble. For 10 keV pho­tons, for in­stance, the diffrac­tion limit cor­re­sponds to the emit­tance of as small as 10 pm.​rad. For the chal­leng­ing goal, the new ring fea­tures a mul­ti-bend lat­tice with damp­ing wig­glers, which pre­sum­ably en­ables us to re­duce an emit­tance by two or­ders of mag­ni­tudes or more com­pared with the cur­rent dou­ble-bend lat­tice with­out damp­ing wig­glers. Up to now, a six-bend lat­tice has been main­ly stud­ied, which is sup­posed to gen­er­ate a nat­u­ral emit­tance of 60–70 pm.​rad for 6 GeV. In ad­di­tion, damp­ing wig­glers and cou­pling con­trol should as­sist to re­duce the emit­tance even more for ap­proach­ing the ul­ti­mate goal. The major mod­i­fi­ca­tion re­quires not only an ad­vanced lat­tice de­sign via ma­nip­u­la­tion of non-lin­ear beam dy­nam­ics but also ex­ten­sive tech­no­log­i­cal de­vel­op­ments in al­most every com­po­nent such as mag­nets, mon­i­tors, and RF sys­tems. The over­all re­view of the up­grade plan, in­clud­ing some de­tailed dis­cus­sions on the crit­i­cal is­sues, will be pre­sent­ed.  
 
THPC144 The Construction Status of Beam Transport Line from XFEL-linac to SPring-8 Storage Ring 3224
 
  • C. Mitsuda, N. Azumi, T. Fujita, K. Fukami, H. Kimura, H. Ohkuma, M. Oishi, Y. Okayasu, M. Shoji, K. Tsumaki, T. Watanabe
    JASRI/SPring-8, Hyogo-ken, Japan
  • M. Hasegawa, Y. Maeda, T. Nakanishi, Y. Tukamoto, M. Yamashita
    SES, Hyogo-pref., Japan
  • N. Kumagai, S. Matsui
    RIKEN/SPring-8, Hyogo, Japan
 
  The beam trans­port line from XFEL-linac to SPring-8 stor­age ring is now under con­struc­tion to use the ultra short bunched elec­tron beam at the stor­age ring. The newly con­struct­ed line is about 300 m, which is just a half of the whole path from the XFEL linac to the stor­age ring. The beam ex­tract­ed from XFEL-linac is guid­ed to the beam trans­port tun­nel con­nect­ed to the match­ing sec­tion of boost­er syn­chrotron bend­ing by 55.2 de­grees hor­i­zon­tal­ly and by 10.0 de­grees ver­ti­cal­ly. A dou­ble-bend based lat­tice was adopt­ed to rea­son­ably sup­press emit­tance growth and bunch length­en­ing. Sup­pos­ing a bunch length and hor­i­zon­tal emit­tance at the exit of the XFEL-linac are es­ti­mat­ed about 100 fs and 0.04 nmrad re­spec­tive­ly, it is ex­pect­ed that the cur­rent beam emit­tance in stor­age ring is im­proved to about 0.4 nmrad and al­most same bunch length in­clud­ing co­her­ent syn­chrotron ra­di­a­tion ef­fect. In 2010, the con­struc­tion of ex­tract­ing part from XFEL-linac was com­plet­ed and we fin­ished the in­stal­la­tion and align­ment of main com­po­nents. The con­cep­tu­al de­sign and con­struc­tion sta­tus of trans­port line will be pre­sent­ed with the em­pha­sis on the de­tail mag­net de­sign and the fab­ri­ca­tion.