• J. Yamazaki, A. Enomoto, Y. Kamiya
  KEK, Ibaraki

One of the most im­por­tant is­sues for ERL in­jec­tors is to gen­er­ate elec­tron beams with ul­tra-low emit­tance and to ac­cel­er­ate the beams through the in­jec­tor with­out emit­tance growth. For this pur­pose, we have de­vel­oped an ef­fi­cient sim­u­la­tion code to in­ves­ti­gate the mech­a­nism of emit­tance growth due to space charge ef­fect and to ex­ploit its sup­pres­sion method. In this code, the lon­gi­tu­di­nal mo­tion is treat­ed by the one-di­men­sion­al dif­fer­ence equa­tions for macro-par­ti­cles, while the ra­di­al mo­tion is solved by the en­ve­lope equa­tions for the pieces of sliced bunch. We find that the total emit­tance takes a min­i­mum when all el­lipses of sliced en­ve­lope have the same di­rec­tion on the a-a' plane, where a is the am­pli­tude of sliced en­ve­lope and a' its deriva­tive along the lon­gi­tu­di­nal di­rec­tion. The pa­ram­e­ters of a 5 MeV in­jec­tor were op­ti­mized by this code, as­sum­ing that the volt­age of the DC elec­tron gun is 330 kV and the ini­tial par­ti­cle dis­tri­bu­tion at the exit of the gun has a uni­form el­lipse. Even for such a low volt­age gun, we ob­tained a min­i­mum value of the rms nor­mal­ized emit­tance, 0.10 mm, and the rms bunch length, 0.83 mm, the val­ues of which were cal­cu­lat­ed by using PARMELA.

• 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.

• Y. Funakoshi, T. Abe, K. Akai, Y. Cai, K. Ebihara, K. Egawa, A. Enomoto, J.W. Flanagan, H. Fukuma, K. Furukawa, T. Furuya, J. Haba, T. Ieiri, N. Iida, H. Ikeda, T. Ishibashi, M. Iwasaki, T. Kageyama, S. Kamada, T. Kamitani, S. Kato, M. Kikuchi, E. Kikutani, H. Koiso, M. Masuzawa, T. Mimashi, T. Miura, A. Morita, T.T. Nakamura, K. Nakanishi, M. Nishiwaki, Y. Ogawa, K. Ohmi, Y. Ohnishi, N. Ohuchi, K. Oide, T. Oki, M. Ono, M. Satoh, Y. Seimiya, K. Shibata, M. Suetake, Y. Suetsugu, T. Sugimura, Y. Susaki, T. Suwada, M. Tawada, M. Tejima, M. Tobiyama, N. Tokuda, S. Uehara, S. Uno, Y. Yamamoto, Y. Yano, K. Yokoyama, M. Yoshida, S.I. Yoshimoto, D.M. Zhou, Z.G. Zong
  KEK, Ibaraki

KEKB is an e-/e⁺ col­lid­er for the study of B physics and is also used for ma­chine stud­ies for fu­ture ma­chines. The peak lu­mi­nos­i­ty of KEKB, which is the world-high­est value, has been still in­creas­ing. This re­port sum­ma­rizes re­cent progress at KEKB.

Slides

• 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.