• T. Imai, K. Tsukiyama
  Tokyo University of Science, IR FEL Research Center, Chiba
• K. Hisazumi, T. Morotomi
  MELCO SC, Tsukuba
• T. Shidara, M. Yoshida
  KEK, Ibaraki

IR-FEL re­search cen­ter of Tokyo Uni­ver­si­ty of Sci­ence (FEL-TUS) is a fa­cil­i­ty for aim­ing at the de­vel­op­ment of high per­for­mance FEL de­vice and pro­mo­tion of pho­to-sci­ence using it. The main part of FEL-TUS is a mid-in­frared FEL (MIR FEL) which con­sists of an S-band linac and an un­du­la­tor com­bined with an op­ti­cal res­o­nance cav­i­ty. MIR-FEL pro­vides con­tin­u­ous­ly tun­able ra­di­a­tion in the range of 5-14 mi­cron and a va­ri­ety of ex­per­i­ments are by the use of this pho­ton en­er­gy cor­re­spond­ing to the var­i­ous vi­bra­tional modes of molecules are now un­der­way. We also de­vel­op far-in­frared FEL (FIR FEL) in­stalled an RF-gun with Disk-and-Wash­er ac­cel­er­at­ing cav­i­ty for high qual­i­ty elec­tron beam. The cur­rent sta­tus of FEL-TUS will be pre­sent­ed.

• 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.

• M. Akemoto, S. Fukuda, H. Honma, H. Nakajima, T. Shidara
  KEK, Ibaraki

This paper de­scribes a long-pulse 1.3 GHz klystron mod­u­la­tor that was re­cent­ly de­vel­oped for the Su­per­con­duct­ing RF Test Fa­cil­i­ty (STF) at High En­er­gy Ac­cel­er­a­tor Re­search Or­ga­ni­za­tion (KEK). The mod­u­la­tors is a di­rect-switched-type de­sign with a 1:15 step-up trans­former and a bounc­er cir­cuit to com­pen­sate for the out­put pulse droop with­in ±0.5%; it can drive a klystron with up to 10 MW peak power, 1.5 ms rf pulse width, and up to 5 pps rep­e­ti­tion rate. The main fea­tures of this mod­u­la­tor are the use of four 50 kW switch­ing power sup­plies in par­al­lel to charge the stor­age ca­pac­i­tors to 10 kV, self-heal­ing-type ca­pac­i­tor to re­al­ize a com­pact stor­age ca­pac­i­tor bank, and a high­ly re­li­able IGBT switch which en­ables elim­i­na­tion of a crow­bar cir­cuit. De­sign con­sid­er­a­tions and its per­for­mance are pre­sent­ed. An IEGT (In­jec­tion En­hanced Gate Tran­sis­tor) switch, com­posed of six se­ries de­vices with a rat­ing of 4.5 kV and 2100 A-DC, has been also de­vel­oped and test­ed for R&D to re­al­ize a com­pact mod­u­la­tor.

• T. Higo, T. Abe, M. Akemoto, S. Fukuda, N. Higashi, Y. Higashi, N.K. Kudo, S. Matsumoto, T. Shidara, T. Takatomi, K. Ueno, Y. Watanabe, K. Yokoyama, M. Yoshida
  KEK, Ibaraki

Under the CERN-SLAC-KEK col­lab­o­ra­tion, we have been de­vel­op­ing the high gra­di­ent TW ac­cel­er­a­tor struc­tures. One of the main fo­cus­es is the fea­si­bil­i­ty study of CLIC ac­cel­er­a­tor struc­ture at X-band. A high power fa­cil­i­ty, Nex­tef*, was es­tab­lished at KEK in 2007. A few struc­tures have been test­ed, in­clud­ing an un-damped disk-load­ed struc­ture suc­cess­ful­ly test­ed be­yond 100 MV/m, a heav­i­ly damped struc­ture to be test­ed from late 2009 and a struc­ture made in a quad­rant con­fig­u­ra­tion. These struc­tures fol­low the same ac­cel­er­at­ing-mode RF pa­ram­e­ter pro­file, called CLIC-C**, but show dif­fer­ent fea­tures at high gra­di­ent op­er­a­tion. Var­i­ous ob­serv­ables, such as dark cur­rent, vac­u­um ac­tiv­i­ties, light emis­sion, break­down rate, and so on, are mea­sured. We dis­cuss the high gra­di­ent phe­nom­e­na re­lat­ed to these ob­serv­ables and the pos­si­ble im­prove­ment for sta­ble op­er­a­tion at a high­er gra­di­ent.

* T. Higo et al., THP038, LINAC06,2006.
**A. Grudiev, http://indico.cern.ch/conferenceDisplay.py?confId=30911

• N. Ohuchi, H. Hayano, N. Higashi, E. Kako, Y. Kondou, H. Nakai, S. Noguchi, T. Saeki, M. Satoh, M. Sawabe, T. Shidara, T. Shishido, A. Terashima, K. Tsuchiya, K. Watanabe, A. Yamamoto, Y. Yamamoto, K. Yokoya
  KEK, Ibaraki
• T.T. Arkan, S. Barbanotti, H. Carter, M.S. Champion, R.D. Kephart, J.S. Kerby, D.V. Mitchell, Y. Orlov, T.J. Peterson, M.C. Ross
  Fermilab, Batavia
• A. Bosotti, C. Pagani, R. Paparella, P. Pierini
  INFN/LASA, Segrate (MI)
• D. Kostin, L. Lilje, A. Matheisen, W.-D. Möller, H. Weise
  DESY, Hamburg

In an at­tempt at demon­strat­ing an av­er­age field gra­di­ent of 31.5 MV/m as per the de­sign ac­cel­er­at­ing gra­di­ent for ILC, a pro­gram called S1-Glob­al is in progress as an in­ter­na­tion­al re­search col­lab­o­ra­tion among KEK, INFN, FNAL, DESY and SLAC. The S1-Glob­al cry­omod­ule will con­tain eight su­per­con­duct­ing cav­i­ties from FNAL, DESY and KEK. The cry­omod­ule will be con­struct­ed by join­ing two half-size cry­omod­ules, each 6 m in length. The mod­ule con­tain­ing four cav­i­ties from FNAL and DESY has been con­struct­ed by INFN. The mod­ule for four KEK cav­i­ties is being mod­i­fied at pre­sent. The as­sem­bly of the cry­omod­ules is sched­uled from Jan­uary 2010, and the op­er­a­tion of the sys­tem is sched­uled from June 2010 at the KEK-STF. In this paper, the con­struc­tion of the S1-Glob­al cry­omod­ule will be pre­sent­ed.

• S. Fukuda, M. Akemoto, D.A. Arakawa, H. Honma, H. Katagiri, S. Matsumoto, T. Matsumoto, S. Michizono, T. Miura, H. Nakajima, K. Nakao, S. Sakanaka, T. Shidara, T. Takahashi, Y. Yano, M. Yoshida
  KEK, Ibaraki

ERL (En­er­gy Re­cov­ery Linac) of 5GeV en­er­gy is a fu­ture plan in KEK and in order to study the tech­ni­cal fea­si­bil­i­ty, con­struc­tion of a com­pact ERL ma­chine (cERL) is con­sid­ered. Beam en­er­gy and cur­rent of cERL are 245MeV and 100mA, re­spec­tive­ly. As 1.3 GHz fre­quen­cy and super con­duct­ing cav­i­ty are cho­sen for the RF sys­tem, sim­i­lar tech­nol­o­gy with KEK STF is em­ployed. From 2008, KEK start­ed the prepa­ra­tion of cERL and one RF unit of in­jec­tor linac is in­tro­duced in this fis­cal 2009. A new cw klystron of 300kW out put power, 150kW Y-type cir­cu­la­tor and high power water load were de­vel­oped in FY2009. DC power sup­ply was under man­u­fac­tur­ing. Pre­lim­i­nary test of HLRF and the high power cou­plers are sched­uled in the Pho­ton Fac­to­ry site by mak­ing use of the old DC power sup­ply. For main ac­cel­er­a­tor, we also in­tro­duced a 30kW IOT and a 35kW klystron and a DC power sup­ply. At the same time, cERL is de­ter­mined to be con­struct­ed in the East Counter Hall in KEK and the de­sign lay­out is pre­ced­ed. In this paper, the re­cent RF source de­vel­op­ment of cERL is de­scribed. Lay­out of the east counter hall, where cERL is con­struct­ed, is pro­gressed and shown in this re­port.

• T. Sugimura, M. Akemoto, D.A. Arakawa, A. Enomoto, S. Fukuda, K. Furukawa, T. Higo, H. Honma, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, H. Nakajima, K. Nakao, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, T. Suwada, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida
  KEK, Ibaraki

The next gen­er­a­tion B-fac­to­ry 'Su­perKEKB' pro­ject whose tar­get lu­mi­nos­i­ty is 8 ×10³⁵ cm^-2s^-1 is under con­sid­er­a­tion. A 'nano-beam scheme' is in­tro­duced to the Su­perKEKB. In the scheme, an elec­tron beam (En­er­gy = 7 GeV, Charge = 3-4 nC/bunch, Ver­ti­cal emit­tance =2.8 x 10^-5 m) and a positron beam (En­er­gy = 4 GeV, Charge = 4 nC/bunch, Ver­ti­cal emit­tance = 1.6 x 10^-5 m), are re­quired at the end of in­jec­tor linac. They are quite chal­leng­ing tar­gets for the pre­sent linac. In order to meet the re­quire­ments, we will in­tro­duce some new com­po­nents to the linac. They are a pho­to-cath­ode RF gun for an elec­tron beam, a positron cap­ture sec­tion using new L-band cav­i­ties, a newly de­signed positron-gen­er­a­tion tar­get sys­tem and a damp­ing ring for a positron beam. This pre­sen­ta­tion shows a strat­e­gy of our in­jec­tor up­grade.