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...
ASYMMETRICAL SPECTRUM OBSERVED AT THE KEKB HIGH-ENERGY ELECTRON RING (2008)
T. Ieiri, Y. Ohnishi, M. Tobiyama
It was observed that the vertical tune-spectrum of an electron bunch showed an asymmetrical distribution biased to a higher tune in normal colliding operations. The asymmetry depended on the...
DYNAMIC BEAM-BEAM EFFECTS MEASURED AT KEKB (2008)
T. Ieiri, Y. Funakoshi, T. Kawamoto, M. Masuzawa, M. Tobiyama
A series of measurements were carried out to investigate the dynamic beam-beam effects. The beambeam kick and the beam-beam tune-shift were obtained by comparing the beam parameters between a...
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...
OBSERVATION OF VERTICAL BEAM BLOW-UP IN KEKB LOW ENERGY RING (2007)
M. Tejima, M. Tobiyama, T. Tsuboyama, N. Yamamoto, M. Yoshida, S. Yoshimoto, ...
This paper describes an experimental study of the enlargement of the vertical beam size observed in single beam operation at the KEKB LER. 1
Impurity Growth In Single Bunch Operation Of Pf (2007)
Tobiyama Higuchi Mitsuhashi, M. Tobiyama, A. Higuchi, T. Mitsuhashi, T. Kasuga, S. Sakanaka
Growth of the single bunch impurity was observed in the Photon Factory storage ring. The phenomenon caused by recapture of electrons that are thrown out of the main bucket by Touschek effect was...
Study Of Bunch By Bunch Feedback System In Tristan-Ar (2007)
Tobiyama And Kikutani, M. Tobiyama, E. Kikutani
Beam tests of the KEKB bunch by bunch feedback system prototypes have been performed in the TRISTAN-AR on both longitudinal and transverse planes. A two-tap FIR filter system consisting of hardware...
KEKB Beam Instrumentation Systems (2007)
M. Arinaga, J. Flanagan, S. Hiramatsu, T. Ieiri, H. Ikeda, H. Ishii, ...
For the stable high-luminosity operation and luminosity-increase, the electron and positron storage rings of the KEK B-Factory (KEKB) is equipped with various beam instrumentations, which have being...
Abstract PRESENT STATUS OF THE KEKB BUNCH FEEDBACK SYSTEMS (2007)
E. Kikutani, J. Flanagan, T. Ieiri, M. Tobiyama
KEKB is a double-ring energy-asymmetric electronpositron collider, now operating at KEK. In order to achieve a luminosity on the order of10 33 =cm 2 =sor more, a very large number of bunches are...
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...
COMMISSIONING OF KEKB BUNCH FEEDBACK SYSTEMS (2007)
Commissioning of KEKB started at the end of the last year. In the early stages of the commissioning, we observed transverse instabilities in both rings and started tuning of the bunch feedback...
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,...
Kekb Injection Kicker Magnet System (2007)
Mimashi Kikuchi Nakayama, T. Mimashi, M. Kikuchi, H. Nakayama, K. Satoh, M. Tobiyama, ...
The design, construction and operation of the KEKB injection kicker magnets are described. The magnet operates up to 35kV and 2kA with magnetic field rise and fall time of around 1sec each. The...
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...
Beam Diagnostics Using Bunch-By-Bunch Feedback (2007)
Systems In The, M. Tobiyama, E. Kikutani, J. W. Flanagan, S. Hiramatsu
Transverse bunch-by-bunch feedback systems for damping coupled-bunch instabilities in the KEKB rings have been working well since the early stages of the commissioning of the rings. Beam diagnostic...
Measurement Of Xy Coupling Using Turn-By-Turn Bpm (2007)
At Kekb Ohnishi, Y. Ohnishi, Y. Funakoshi, K. Mori, E. Perevedentsev, M. Tanaka, ...
We have measured xy coupling of the interaction point(I.P.) at KEKB. When a normal mode is excited by a shaker with tune frequency, the horizontal or vertical betatron oscillations can be measured by...
Overviewofbeaminstrumentationforhigh-Intensity (2007)
Storagerings Flanagan Arinaga, T. Mimashi, K. Mori, T. Mitsuhashi, H. Mizuno, M. Tejima, ...
This paper will present an overview of beam instrumentation with a view towards relevance for future accelerator projects on the basis of experience at KEKB. The KEKB B-Factory shares with other...
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...
Limitations Of Multibunch Feedback Systems And (2007)
Extrapolation Kikutani Flanagan, E. Kikutani, J. Flanagan, M. Tobiyama
In recent years, multibunch feedback systems which can handle bunches with 10-ns spacing (or shorter) are working at several accelerators around the world. The number of bunches stored in some of...
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...
Bunch By Bunch Feedback Systems For The Kekb Rings (2000)
Tobiyama Kikutani Flanagan, M. Tobiyama, E. Kikutani, J. W. Flanagan, S. Hiramatsu
Transverse bunch-by-bunch feedback systems for damping coupled-bunch instabilities in the KEKB rings have been working since the early stage of the commissioning of the rings. Stabilization of the...
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...
1st Asian Particle Accelerator Conference (1998)
Chin, Y H, Kihara, Motohiro, Kobayashi, Hitoshi, Akasaka, N, Nigorikawa, K, Tobiyama, M
Experimental study of the ion trapping phenomenon in TRISTAN-AR (1998)
Matsumoto, S, Fukuma, H, Ohmi, K, Tobiyama, M, Kikutani, E, Suetake, M, ...
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, ...
Impurity growth in single bunch operation of PF (1996)
Tobiyama, M, Higuchi, A, Mitsuhashi, T, Kasuga, T, Sakanaka, S
Front-end electronics for the bunch feedback systems for KEKB (1994)
Kikutani, E, Obina, T, Kasuga, T, Minagawa, Y, Tobiyama, M, Ma, L
Development of bunch feedback system for KEKB (1994)
Kikutani, E, Kasuga, T, Minagawa, Y, Obina, T, Tobiyama, M, Ma, L
Recent Progress In The Development Of The Bunch Feedback Systems For Kekb
Kikutani Kasuga Minagawa, E. Kikutani, T. Kasuga, Y. Minagawa, T. Obina, M. Tobiyama
In KEKB, which is a B-factory project at KEK, the bunch spacing is very short, only 2 ns, and the number of the bunches comes up to about 5000 per ring. In order to cure the instabilities due to the...