• M. Tawada, Y. Funakoshi, M. Iwasaki, H. Koiso, A. Morita, Y. Ohnishi, N. Ohuchi, K. Oide, K. Tsuchiya, Z.G. Zong
  KEK, Ibaraki

KEK is study­ing the de­sign of the in­ter­ac­tion re­gion quadrupoles for the Su­perKEKB of which the two beams of 4GeV/7GeV for LER/HER have a cross­ing angle of 83 mrad. For each beam, the final beam fo­cus­ing sys­tem con­sist­ing of su­per­con­duct­ing and per­ma­nent mag­nets is stud­ied. The su­per­con­duct­ing quadrupoles close to the in­ter­ac­tion point for each beam are lo­cat­ed in the com­pen­sa­tion su­per­con­duct­ing solenoid which can­cels the solenoid field by the par­ti­cle de­tec­tor, Belle. These mag­net pa­ram­e­ters are op­ti­mized to ob­tain high­er lu­mi­nos­i­ty. In this paper, the de­sign progress of final fo­cus­ing sys­tem and mag­nets will be re­port­ed.

• Z.G. Zong, N. Higashi, N. Ohuchi, M. Tawada, K. Tsuchiya
  KEK, Ibaraki

To sup­ply the elec­tri­cal power for the su­per­con­duct­ing cor­rec­tors in the in­ter­ac­tion re­gion of the pro­posed Su­perKEKB, a kind of vapor cooled cur­rent leads is de­signed, which con­sists of 8 brass leads and can trans­port cur­rents to 4 cor­rec­tors si­mul­ta­ne­ous­ly. The de­sign cur­rent of the leads is about 50 A. The ther­mal and elec­tri­cal be­hav­iors have stud­ied by the fi­nite el­e­ments method and the cryo­genic ex­per­i­ment is also planed to val­i­date the per­for­mance. In this paper the de­sign will be pre­sent­ed and the fi­nite el­e­ment model will be com­pared with the ex­per­i­men­tal data.

• R. Kato, K. Furuhashi, G. Isoyama, S. Kashiwagi, M. Morio, S. Suemine, N. Sugimoto, Y. Terasawa
  ISIR, Osaka
• K. Tsuchiya, S. Yamamoto
  KEK, Ibaraki

We have been de­vel­op­ing a Ter­a­hertz free elec­tron laser (FEL) based on the 40 MeV, 1.3 GHz L-band elec­tron linac at the In­sti­tute of Sci­en­tif­ic and In­dus­tri­al Re­search (ISIR), Osaka Uni­ver­si­ty. After the FEL las­ing at the wave­length of 70 um (4.3 THz)*, next tar­gets of the FEL de­vel­op­ment are to ex­tend the avail­able laser wave­length, to in­crease the FEL power, and to eval­u­ate char­ac­ter­is­tics of FEL. Since the low­est en­er­gy of the linac was re­strict­ed by a fixed-ra­tio power di­vider be­tween the ac­cel­er­a­tion tube and the bunch­er, we have pre­pared the new one with a dif­fer­ent ratio to ex­tend the wave­length longer side. As a re­sult, the wave­length re­gion is able to be ex­tend­ed to 25 - 147 um (12.5 - 2 THz). The max­i­mum out­put en­er­gy of the FEL macropulse so far ob­tained is 3.6 mJ at 66 um. The peak macropulse power avail­able to user ex­per­i­ments is es­ti­mat­ed to be 1 kW or less, given that the pulse du­ra­tion is 3 us. Three users groups have begun ex­per­i­ments using the FEL. We will re­port these re­cent ac­tiv­i­ties on the Ter­a­hertz FEL.

* G. Isoyama, R. Kato, S. Kashiwagi, T. Igo, Y. Morio, Infrared Physics & Technology 51 (2008) 371-374.

• 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.

• T. Honda, T. Aoto, S. Asaoka, K. Ebihara, K. Furukawa, K. Haga, K. Harada, Y. Honda, T. Ieiri, N. Iida, M. Izawa, T. Kageyama, M. Kikuchi, Y. Kobayashi, K. Marutsuka, A. Mishina, T. Miyajima, H. Miyauchi, S. Nagahashi, T.T. Nakamura, T. Nogami, T. Obina, K. Oide, M. Ono, T. Ozaki, C.O. Pak, H. Sakai, H. Sakai, Y. Sakamoto, S. Sakanaka, H. Sasaki, Y. Sato, K. Satoh, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, S. Takasaki, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto, Ma. Yoshida, S.I. Yoshimoto
  KEK, Ibaraki

KEK man­ages two syn­chrotron ra­di­a­tion sources, Pho­ton Fac­to­ry stor­age ring (PF-ring) of 2.5 GeV and Pho­ton Fac­to­ry ad­vanced ring (PF-AR) of 6.5 GeV. These rings share an in­jec­tor linac with the two main rings of KEK B-fac­to­ry, 8-GeV HER and 3.5-GeV LER. Re­cent­ly, the linac has suc­ceed­ed in a pulse by pulse mul­ti-en­er­gy ac­cel­er­a­tion. A top-up op­er­a­tion of PF-ring has been re­al­ized as the si­mul­ta­ne­ous con­tin­u­ous in­jec­tion to the 3 rings, PF-ring, HER and LER. De­vel­op­ment of new in­jec­tion scheme using a pulsed sex­tupole mag­net con­tin­ues aim­ing at prac­ti­cal use in the top-up op­er­a­tion. A rapid-po­lar­iza­tion-switch­ing de­vice con­sist­ing of tan­dem two AP­PLE-II type un­du­la­tors has been de­vel­oped at PF-ring. The first un­du­la­tor was in­stalled in 2008, and the sec­ond one will be in­stalled in 2010 sum­mer. PF-AR, op­er­at­ed in a sin­gle-bunch mode at all times, has been suf­fered from sud­den life­time drop phe­nom­e­na at­tribut­ed to dust trap­ping for many years. Using the mov­able elec­trodes in­stalled for ex­per­i­ment, we con­firmed that the dis­charge cre­at­ed by the elec­trode was fol­lowed by the dust trap­ping, and suc­ceed­ed in a vi­su­al ob­ser­va­tion of lu­mi­nous dust streak­ing in front of CCD cam­eras.

• K. Tsuchiya, T. Aoto
  KEK, Ibaraki

We have been de­vel­op­ing a rapid-po­lar­iza­tion-switch­ing source at the B15-16 straight sec­tion in the PF 2.5GeV ring. The source con­sists of tan­dem two AP­PLE-II type el­lip­ti­cal­ly po­lar­iz­ing un­du­la­tors (EPU), name­ly U#16-1 and U#16-2, and a fast kick­er sys­tem. These two un­du­la­tors are de­signed to ob­tain the soft x-ray at the en­er­gy re­gion from 200eV to 1keV with var­i­ous po­lar­iza­tion states. We have con­struct­ed U#16-1 and in­stalled in the PF ring in March 2008. The op­er­a­tion of U#16-1 for the user ex­per­i­ments has been start­ed suc­cess­ful­ly since April 2008. The con­struc­tion of the sec­ond un­du­la­tor U#16-2 is un­der­way. U#16-2 will be in­stalled in the PF ring at this sum­mer. We re­port the re­sult of the mag­net­ic field ad­just­ment of the U#16-2.

• S. Kashiwagi, G. Isoyama, R. Kato
  ISIR, Osaka
• K. Tsuchiya, S. Yamamoto
  KEK, Ibaraki

The edge-fo­cus­ing (EF) wig­gler has been fab­ri­cat­ed to eval­u­ate its per­for­mance rig­or­ous­ly with the mag­net­ic field mea­sure­ment. It is a 5-pe­ri­od pla­nar wig­gler with an edge angle of 2° and a pe­ri­od length of 60 mm. The mag­net­ic field is mea­sured using Hall probes at four dif­fer­ent wig­gler gaps. It is ex­per­i­men­tal­ly con­firmed that a high field gra­di­ent of 1.0 T/m is re­al­ized, as de­signed, along the beam axis. The mag­net­ic field gra­di­ent of the EF wig­gler is de­rived as a func­tion of the mag­net­ic gap. The field gra­di­ent de­creas­es with in­creas­ing mag­net gap more slow­ly than the peak mag­net­ic field does for the pre­sent ex­per­i­men­tal model. An an­a­lyt­ic for­mu­la for the field gra­di­ent of the EF wig­gler is de­rived and it is shown that the slope of the field gra­di­ent with the mag­net gap can be changed by vary­ing the mag­net width of the EF wig­gler. We an­a­lyzed the re­la­tion be­tween the ori­en­ta­tion er­rors of the mea­sure­ment sys­tem and the mea­sured mag­net­ic field or field gra­di­ent using a model mag­net­ic field of the EF wig­gle. We cor­rect­ed the mea­sure­ment mag­net­ic field based on this anal­y­sis and eval­u­at­ed the per­for­mance of the EF wig­gler.

• 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.

• B. Parker, M. Anerella, J. Escallier, P. He, A.K. Jain, A. Marone, P. Wanderer, K.-C. Wu
  BNL, Upton, Long Island, New York
• P. Bambade
  LAL, Orsay
• B. Bolzon, A. Jeremie
  IN2P3-LAPP, Annecy-le-Vieux
• P.A. Coe, D. Urner
  OXFORDphysics, Oxford, Oxon
• C. Hauviller, E. Marin, R. Tomás, F. Zimmermann
  CERN, Geneva
• N. Kimura, K. Kubo, T. Kume, S. Kuroda, T. Okugi, T. Tauchi, N. Terunuma, T. Tomaru, K. Tsuchiya, J. Urakawa, A. Yamamoto
  KEK, Ibaraki
• A. Seryi, C.M. Spencer, G.R. White
  SLAC, Menlo Park, California

The KEK ATF2 fa­cil­i­ty, with a well in­stru­ment­ed beam line and Final Focus (FF), is a prov­ing ground for lin­ear col­lid­er (LC) tech­nol­o­gy to demon­strate the ex­treme beam de­mag­ni­fi­ca­tion and spot sta­bil­i­ty need­ed for a LC FF*. ATF2 uses water cooled mag­nets but the base­line ILC calls for a su­per­con­duct­ing FF**. Thus we plan to re­place some ATF2 FF mag­nets with su­per­con­duct­ing ones made via di­rect wind con­struc­tion as planned for the ILC. With no cryo­genic sup­ply at ATF2, we look to cool mag­nets and cur­rent leads with a few cry­ocool­ers. ATF2 FF coil wind­ing is un­der­way at BNL and pro­duc­tion warm mag­net­ic mea­sure­ments in­di­cate good field qual­i­ty. Hav­ing FF mag­nets with larg­er aper­ture and bet­ter field qual­i­ty than pre­sent FF might allow re­duc­ing the beta func­tion at the FF for study of fo­cus­ing regimes rel­e­vant to CLIC. Our ATF2 mag­net cryo­stat will have laser view ports for cold mass move­ment mea­sure­ment and FF sup­port and sta­bi­liza­tion re­quire­ments under study. We plan to make sta­bil­i­ty mea­sure­ments at BNL and KEK to re­late ATF2 FF mag­net per­for­mance to that of a full length ILC R&D pro­to­type at BNL. We want to be able to pre­dict LC FF per­for­mance with con­fi­dence.

* ATF2 proposal, volumes 1 and 2 at http://lcdev.kek.jp/ILC-AsiaWG/WG4notes/atf2/proposal/index.html
** International Linear Collider Reference Design Report, ILC-REPORT-2007-001, August 2007.