BETATRON SIDEBANDS DUE TO ELECTRON CLOUDS UNDER COLLIDING BEAM CONDITIONS (2008)
J. W. Flanagan, K. Ohmi, H. Fukuma, Y. Funakoshi, S. Hiramatsu, H. Ikeda, ...
Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee Recently, we have observed vertical betatron sidebands in the transverse beam spectra of positron bunches at the KEKB LER...
COUPLED BUNCH INSTABILITY CAUSED BY ELECTRON CLOUD (2008)
M. Tobiyama, J. W. Flanagan, H. Fukuma, S. Kurokawa, K. Ohmi, S. S. Win
Coupled bunch instability caused by electron cloud has been observed in the KEKB-LER. Time evolution of the instabilities just after the turning-off the transverse bunch feedback have been recorded...
MOVEMENT OF BPMS DUE TO THERMAL STRESS IN KEKB (2008)
M. Tejima, M. Arinaga, T. Ieiri, H. Ishii, H. Fukuma, M. Tobiyama, ...
Movements of Beam Position Monitors due to thermal stress in high beam current operation were observed in KEKB. For high luminosity operation of KEKB, the beam current as high as 1.7 A is accumulated...
SIMULATION ANALYSIS OF HEAD-TAIL MOTION CAUSED BY ELECTRON CLOUD (2008)
K. Ohmi, J. W. Flanagan, H. Fukuma, S. Hiramatsu, H. Ikeda, M. Tobiyama
Synchro-beta side band signal caused by electron cloud instability has been observed at KEK-B factory. The sideband appears above the threshold of beam size blow-up and disappears by exciting...
J. W. Flanagan, N. Akasaka, H. Fukuma, S. Hiramatsu, T. Mitsuhashi
In order to investigate the single-beam vertical beam-size blow-up observed[1] in the KEKB 3.5 GeV positron ring (LER), we performed beam-size observations using a highspeed gated camera capable of...
F. Zimmermann, H. Fukuma, K. Ohmi
We report recent electron-cloud studies for the Low Energy Ring (LER) of KEKB, continuing earlier investigations [1, 2]. Here we simulate the build up and decay time of the cloud for various solenoid...
FIRST BEAM COLLISION IN THE KEKB (2007)
Y. Funakoshi, K. Akai, N. Akasaka, A. Enomoto, J. Flanagan, H. Fukuma, ...
following expression. The first beam collision study was done in the KEKB double ring collider. Beam collision conditions were found by searching beam-beam deflection curves in a trial-and-error...
K. Akai, N. Akasaka, A. Enomoto, J. Flanagan, H. Fukuma, Y. Funakoshi, ...
The commissioning of the KEKB B–Factory storage rings started on Dec. 1, 1998. The two rings both achieved a stored current of over 0.5 A after operating for four months. The two beams were...
RECENT STUDIES ON BEAM-PHOTOELECTRON INSTABILITY IN BEPC (2007)
Y. H. Chin, H. Fukuma, S. Hiramatsu, M. Izawa, T. Kasuga, E. Kikutani, ...
An experiment investigating the photoelectron instability has been performed in BEPC at IHEP, China. The betatron oscillation of each bunch was observed and recorded by a single pass beam position...
LATTICE DIAGNOSTICS USING SINGLE KICK CLOSED ORBIT AT KEKB (2007)
Y. Ohnishi, K. Akai, N. Akasaka, A. Enomoto, J. Flanagan, H. Fukuma, ...
We have measured beta functions using single kick closed orbit at KEKB. The measured beta functions were compared with the model lattice and gradient errors were extracted from the result in a beta...
Beam-Beam Effect Observed In The Kekb (2007)
Funakoshi Akai Ebihara, Y. Funakoshi, K. Akai, K. Ebihara, K. Egawa, A. Enomoto, ...
This report summarizes observed phenomena related to the beam-beam effects in the KEKB collider. A general performance of the beam-beam effect is described. An emphasis is put on the reduction of the...
Measurement Of Beam-Beam Tune-Shift Parameter At Kekb (2007)
Ieiri Flanagan Fukuma, T. Ieiri, J. Flanagan, H. Fukuma, E. Kikutani, M. Tobiyama
We have measured the coherent beam-beam tune shift at KEKB, an asymmetric double-ring electron/positron collider. The relationship between the tune shift and the beam-beam parameter is nonlinear,...
Beam Diagnostics By Gating A Single Bunch At Kekb (2007)
Akai Fukuma Ieiri, K. Akai, H. Fukuma, T. Ieiri, T. Kawamoto, E. Kikutani, ...
A fast gate module has been developed at KEKB, which can pick up a signal of one bunch along a bunch train.Thegatemodulewasattachedtoatune measurement system and to a turn-by-turn beam-position...
Current Ma Current, Y. Funakoshi, K. Akai, N. Akasaka, K. Bane, A. Enomoto, ...
This report summarizes a recent progress of the KEKB whose commissioning started on December 1st 1998. Since the commissioning of earlier period was described in other papers [1][2], this report...
Study Of Fast Ion Instability At Kekb Electron Ring (2007)
Ohnishi Fukuma Kikutani, Y. Ohnishi, H. Fukuma, E. Kikutani, K. Oide, M. Tobiyama
We have studied fast ion instability (FII) in the electron ring (HER) at KEKB. We introduce an application of Singular Value Decomposition (SVD) to study multi-bunch beam oscillations. The SVD...
Compensation of the Crossing Angle with Crab Cavities at KEKB (2007)
Abe, T., Akai, K., Akemoto, M., Akiyama, A., Arinaga, M., Ebihara, K., ...
Crab cavities have been installed in the KEKB B--Factory rings to compensate the crossing angle at the collision point and thus increase luminosity. The beam operation with crab crossing has been...
Observation of Vertical Betatron Sideband due to Electron Clouds in the KEKB LER (2004)
Flanagan, J. W., Ohmi, K., Fukuma, H., Hiramatsu, S., Tobiyama, M., Perevedentsev, E.
The effects of electron clouds on positively-charged beams have been an active area of research in recent years at particle accelerators around the world. Transverse beam-size blow-up due to electron...
Negative Momentum Compaction at KEKB (2004)
Ikeda, H., Flanagan, J. W., Fukuma, H., Hiramatsu, S., Ieiri, T., Koiso, H., ...
KEKB is a high luminosity e+e- collider for studying B mesons and has achieved the design luminosity of 1034cm-2s-1 in 2003. In order to get higher luminosity, we tested negative momentum compaction...
Zimmermann, Frank, Fukuma, H, Ohmi, K, Ohnishi, Y, Win, S S
We simulate the interaction of a bunch train with either an external wake field, (semi-)trapped ions in a field-free region or in a dipole field, or an electron cloud, on successive turns, using a...
Electron cloud studies for KEKB (2001)
Rumolo, Giovanni, Zimmermann, Frank, Fukuma, H, Ohmi, K
Electron-cloud build up, incoherent tune spread and electron-induced beam instability are likely to be responsible for the vertical beam-size increase observed at the KEKB Low Energy Ring (LER). We...
Electron cloud studies for KEKB (2001)
Rumolo, Giovanni, Zimmermann, Frank, Fukuma, H, Ohmi, K
Electron-cloud build up, incoherent tune spread and electron-induced beam instability are likely to be responsible for the vertical beam-size increase observed at the KEKB Low Energy Ring (LER). We...
Beam optics matching in the KEKB injector linac (2000)
Kamitani, T, Koiso, H, Akasaka, N, Enomoto, A, Flanagan, J, Fukuma, H, ...
Impedance Measurements In The Kekb (2000)
Ieiri Ohmi Tobiyama, T. Ieiri, K. Ohmi, M. Tobiyama, H. Fukuma, K. Bane
In the KEKB storage rings, we have measured the current dependence of the betatron tunes and the damping rate to evaluate the broad-band transverse impedance. The measured impedances were...
Commissioning of the KEKB linac (1998)
Ogawa, Y, Akasaka, N, Enomoto, A, Flanagan, J, Fukuma, H, Funakoshi, Y, ...
Experimental study of the ion trapping phenomenon in TRISTAN-AR (1998)
Matsumoto, S, Fukuma, H, Ohmi, K, Tobiyama, M, Kikutani, E, Suetake, M, ...
Beam-based measurement of strength errors in quadrupole magnets with orbit bumps (1996)
Koiso, H, Fukuma, H, Funakoshi, Y, Kamada, S, Matsumoto, S, Oide, K, ...
The proposed experimental study on beam-photoelectron interactions in BEPC (1996)
Guo, Z Y, Liu, D K, Ma, L, Wang, J Q, Wang, S H, Zhang, C, ...
Maeda, G, Yokoyama, R, Ohtomo, K, Takayama, J, Beppu, Y, Fukuma, H, ...
FUS/TLS-CHOP chimeric transcripts in liposarcoma tissues (1995)
Yang, X, Nagasaki, K, Egawa, S, Maruyama, K, Futami, H, Tsukada, T, ...
LOW CARBON AND SILICON STEEL QUADRUPOLE MAGNETS (1984)
Fukuma, H., Kumagai, N., Takeuchi, Y., Endo, K., Komatsubara, M.
The low carbon steel developped for the magnet core material is compared with the silicon steel in regard to the performance of the quadrupole magnet.
PERFORMANCE OF THE TRISTAN-AR MAGNET (1984)
Egawa, K., Fukuma, H., Kubo, Ta., Kumagai, N., Takeuchi, Y., Endo, K.
A magnet system of the storage accelerator, TRISTAN-AR, is described with respect to the fabrication, performances and beam properties expected from the field data.
LOW CARBON AND SILICON STEEL QUADRUPOLE MAGNETS (1984)
Fukuma, H., Kumagai, N., Takeuchi, Y., Endo, K., Komatsubara, M.
The low carbon steel developped for the magnet core material is compared with the silicon steel in regard to the performance of the quadrupole magnet.
PERFORMANCE OF THE TRISTAN-AR MAGNET (1984)
Egawa, K., Fukuma, H., Kubo, Ta., Kumagai, N., Takeuchi, Y., Endo, K.
A magnet system of the storage accelerator, TRISTAN-AR, is described with respect to the fabrication, performances and beam properties expected from the field data.
LOW CARBON AND SILICON STEEL QUADRUPOLE MAGNETS (1984)
Fukuma, H., Kumagai, N., Takeuchi, Y., Endo, K., Komatsubara, M.
The low carbon steel developped for the magnet core material is compared with the silicon steel in regard to the performance of the quadrupole magnet.
PERFORMANCE OF THE TRISTAN-AR MAGNET (1984)
Egawa, K., Fukuma, H., Kubo, Ta., Kumagai, N., Takeuchi, Y., Endo, K.
A magnet system of the storage accelerator, TRISTAN-AR, is described with respect to the fabrication, performances and beam properties expected from the field data.