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Nakamura, N.

Paper Title Page
TUPD104 Development of an Yb-doped Fiber Laser System for an ERL Photocathode Gun 2141
 
  • I. Ito, N. Nakamura
    ISSP/SRL, Chiba
  • Y. Honda
    KEK, Ibaraki
  • Y. Kobayashi, K. Torizuka, D. Yoshitomi
    AIST, Tsukuba
  
 

We are de­vel­op­ing an Yb fiber laser sys­tem that drives an ERL pho­to­cath­ode gun. An Yb fiber laser is ex­pect­ed to have both high sta­bil­i­ty and high out­put power re­quired for the drive laser of an ERL pho­to­cath­ode gun. First we start­ed to de­vel­op an Yb fiber laser os­cil­la­tor with a high rep­e­ti­tion rate up to 1.3 GHz that is the RF fre­quen­cy of a su­per­con­duct­ing ac­cel­er­at­ing cav­i­ty and then a 30W pream­pli­fi­er using an Yb doped pho­ton­ic crys­tal fiber. We re­port our re­cent progress in this de­vel­op­ment.

  
TUPE083 Effects of Alignment Error of Main Superconducting Cavities on ERLs and their Correction 2314
 
  • N. Nakamura
    ISSP/SRL, Chiba
  • R. Hajima
    JAEA/ERL, Ibaraki
  • K. Harada, Y. Kobayashi, S. Sakanaka, M. Shimada
    KEK, Ibaraki
  
 

In ERLs, su­per­con­duct­ing cav­i­ties ac­cel­er­ate low-emit­tance beams with high-gra­di­ent stand­ing-wave RF fields. If align­ment error of the cav­i­ties is con­sid­er­able, they can harm­ful­ly af­fect the beam tra­jec­to­ry and qual­i­ty be­cause the cav­i­ties have strong trans­verse fo­cus­ing. Achiev­ing high align­ment ac­cu­ra­cy of the cav­i­ties is dif­fi­cult com­pared with the other ERL el­e­ments such as mag­nets be­cause the cav­i­ties are con­tained in cry­omod­ules. There­fore we stud­ied ef­fects of the align­ment error of main su­per­con­duct­ing cav­i­ties with an­a­lyt­i­cal ap­proach­es and sim­u­la­tions, using a one-loop model of the com­pact ERL as an ex­am­ple. In this paper, we pre­sent the ef­fects of align­ment error of main su­per­con­duct­ing cav­i­ties on ERLs and their cor­rec­tion.

  
TUPE084 Tolerance Study on RF Amplitude and Phase of Main Superconducting Cavities and Injection Timing for the Compact ERL 2317
 
  • N. Nakamura
    ISSP/SRL, Chiba
  • R. Hajima
    JAEA/ERL, Ibaraki
  • Y. Kobayashi, T. Miyajima, S. Sakanaka, M. Shimada
    KEK, Ibaraki
  
 

In ERL-based light sources, high­er ac­cu­ra­cy is ex­pect­ed to be re­quired for RF con­trol and tim­ing, be­cause the ERL beam has much short­er bunch length (less than 100 fs at min­i­mum) com­pared with that of the ex­ist­ing SR sources. We stud­ied ef­fects of RF am­pli­tude and phase vari­a­tion of main su­per­con­duct­ing cav­i­ties and ef­fects of tim­ing jit­ter of beam in­jec­tion from an in­jec­tor, using a sim­u­la­tion code 'el­e­gant'. In this paper, we pre­sent the sim­u­la­tion re­sults and dis­cuss tol­er­ances for the RF am­pli­tude and phase and the in­jec­tion tim­ing.

  
TUPE085 Application of the Eigenvector Method with Constraints to Orbit Correction for ERLs 2320
 
  • N. Nakamura
    ISSP/SRL, Chiba
  • K. Harada
    KEK, Ibaraki
  
 

Orbit cor­rec­tion in an ERL is more com­pli­cat­ed than those of an or­di­nary linac and a trans­port line, be­cause the ERL beam pass­es a straight sec­tion con­tain­ing main su­per­con­duct­ing cav­i­ties at least two times with dif­fer­ent en­er­gies. A cor­rec­tor in this sec­tion gives a dif­fer­ent kick angle to the beam in a dif­fer­ent turn. There­fore a so­phis­ti­cat­ed orbit cor­rec­tion method is re­quired for ERLs and ERL-based light sources. The eigen­vec­tor method with con­straints (EVC)* can per­form glob­al orbit cor­rec­tion under con­straint con­di­tions and has been pro­posed and used for unit­ing glob­al and exact local orbit cor­rec­tions main­ly in stor­age-ring based SR sources**. We ap­plied this EVC method to orbit cor­rec­tion in an ERL. In this paper, we pre­sent how to use the EVC method for an ERL and sim­u­la­tion re­sults of orbit cor­rec­tion for the com­pact ERL.


* N. Nakamura et al., Nucl. Instr. Meth. A 556 (2006) 421-432.
** K. Harada et al., Nucl. Instr. Meth. A 604 (2009) 481-488.

  
WEPEC029 Power Coupler Development for ERL Main LINAC in Japan 2953
 
  • H. Sakai, T. Furuya, S. Sakanaka, T. Takahashi, K. Umemori
    KEK, Ibaraki
  • A. Ishii, N. Nakamura, K. Shinoe
    ISSP/SRL, Chiba
  • M. Sawamura
    JAEA/ERL, Ibaraki
  
 

We start­ed to de­vel­op an input power cou­pler for a 1.3GHz ERL su­per­con­duct­ing cav­i­ty for ERL main linac. Re­quired input power is about 20kW for the cav­i­ty ac­cel­er­a­tion field of 20MV/m and the beam cur­rent of 100mA in en­er­gy re­cov­ery op­er­a­tion. The input cou­pler is de­signed based on the STF-BL input cou­pler, es­pe­cial­ly choke-mode type ce­ram­ic win­dow was ap­plied. After that some mod­i­fi­ca­tions are ap­plied for the CW 20kW power op­er­a­tion. We fab­ri­cat­ed input cou­pler com­po­nents such as ce­ram­ic win­dows and bel­lows and car­ried out the high-pow­er test of the com­po­nents by using a 30kW IOT power source and a test stand con­struct­ed.

  
TUPE091 Recent Progress in the Energy Recovery Linac Project in Japan 2338
 
  • S. Sakanaka, M. Akemoto, T. Aoto, D.A. Arakawa, S. Asaoka, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, M. Isawa, E. Kako, T. Kasuga, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, T. Matsumoto, H. Matsushita, S. Michizono, T.M. Mitsuhashi, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, E. Nakamura, K. Nakanishi, K. Nakao, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, S. Ohsawa, T. Ozaki, C.O. Pak, H. Sakai, H. Sasaki, Y. Sato, K. Satoh, M. Satoh, T. Shidara, M. Shimada, T. Shioya, T. Shishido, T. Suwada, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, S. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
    KEK, Ibaraki
  • M. Adachi, M. Katoh, H. Zen
    UVSOR, Okazaki
  • R. Hajima, R. Nagai, N. Nishimori, M. Sawamura
    JAEA/ERL, Ibaraki
  • H. Hanaki
    JASRI/SPring-8, Hyogo-ken
  • H. Iijima, M. Kuriki
    HU/AdSM, Higashi-Hiroshima
  • I. Ito, H. Kudoh, N. Nakamura, S. Shibuya, K. Shinoe, H. Takaki
    ISSP/SRL, Chiba
  • H. Kurisu
    Yamaguchi University, Ube-Shi
  • M. Kuwahara, T. Nakanishi, S. Okumi
    Nagoya University, Nagoya
  • S. Matsuba
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
  • T. Muto
    Tohoku University, School of Scinece, Sendai
  • K. Torizuka, D. Yoshitomi
    AIST, Tsukuba
  
 

Fu­ture syn­chrotron light source using a 5-GeV-class en­er­gy re­cov­ery linac (ERL) is under pro­pos­al by our Japanese col­lab­o­ra­tion team, and we are con­duct­ing ac­tive R&D ef­forts for that. We are de­vel­op­ing su­per-bril­liant DC pho­to­cath­ode guns, two types of cry­omod­ules for both in­jec­tor and main su­per­con­duct­ing linacs, 1.3 GHz high CW-pow­er rf sources, and other im­por­tant com­po­nents. We are also con­struct­ing a com­pact ERL for demon­strat­ing the re­cir­cu­la­tion of low-emit­tance, high-cur­rent beams using those key com­po­nents. We pre­sent our re­cent progress in this pro­ject.