PAC07 - List of Authors (Ohmi, K.)

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Ohmi, K.

Paper	Title	Page
TUPAN047	Beam-beam Effects in Crab Crossing and Crab Waist Schemes	1493
	K. Ohmi M. E. Biagini, P. Raimondi, M. Zobov INFN/LNF, Frascati (Roma) Y. Funakoshi KEK, Ibaraki
	To boost up the luminosity performance in B factories, crab crossing and crab waist schemes are proposed. The crab crossing scheme compensates crossing angle, while the crab waist scheme compensates nonlinear tems induced by crossing angle with sextupole magnets. We discuss which nonlinear terms in the beam-beam map are enhanced by the crossing angle and which terms are compensated by the crab waist sextupole.
TUPAN048	Beam-beam Effects With an External Noise in LHC	1496
	K. Ohmi R. Calaga BNL, Upton, Long Island, New York W. Hofle, R. Tomas, F. Zimmermann CERN, Geneva
	Proton beam do not have any damping mechanism for an incoherent betatron motion. A noise, which kicks beam particles in the transverse plane, gives a coherent betatron amplitude. Nonlinear force due to the beam-beam interactions causes a decoherence for the betatron motion with keeping an amplitude of each beam particle, with the result that an emittance growth arises. We focus fast transverse turn by turn noises caused by a bunch by bunch feedback system and a cavity phase zitter in crab collision.
THPAN040	Study of Halo Formation in JPARC-MR	3318
	K. Ohmi S. Igarashi, H. Koiso, T. Koseki, K. Oide KEK, Ibaraki
	JPARC is a high intensity proton facility which is constructing as a joint project JAERI-KEK in Japan. JPARC equips two proton ring accelerators, Rapid Cycle Synchrotron (RCS) and Main Ring (MR). We discuss the space charge effect of MR in this paper. The proton beam with the population of 4.15·10¹³ x 8 bunches is accelerated from 3 GeV to 50 GeV and extracted with 0.5 Hz in MR. Beam loss during the acceleration is caused by an incoherent emittance growth due to the space charge force. We discuss the emittance growth and halo formation using a computer simulation based on the particle in cell method.
MOZAKI01	Compensation of the Crossing Angle with Crab Cavities at KEKB	27
	K. Oide T. Abe, K. Akai, M. Akemoto, A. Akiyama, A. Arinaga, K. Ebihara, K. Egawa, A. Enomoto, J. W. Flanagan, S. Fukuda, H. Fukuma, Y. Funakoshi, K. Furukawa, T. Furuya, K. Hara, T. Higo, S. Hiramatsu, H. Hisamatsu, H. Honma, K. Hosoyama, T. Ieiri, N. Iida, H. Ikeda, M. Ikeda, S. Isagawa, H. Ishii, A. Kabe, E. Kadokura, T. Kageyama, K. Kakihara, E. Kako, S. Kamada, T. Kamitani, K.-I. Kanazawa, H. Katagiri, S. Kato, T. Kawamoto, S. Kazakov, M. Kikuchi, E. Kikutani, K. Kitagawa, H. Koiso, Y. Kojima, K. Komada, T. Kubo, K. Kudo, N. K. Kudo, K. Marutsuka, M. Masuzawa, S. Matsumoto, T. Matsumoto, S. Michizono, K. Mikawa, T. Mimashi, S. Mitsunobu, K. Mori, A. Morita, Y. Morita, H. Nakai, H. Nakajima, T. T. Nakamura, H. Nakanishi, K. Nakao, S. Ninomiya, Y. Ogawa, K. Ohmi, Y. Ohnishi, S. Ohsawa, Y. Ohsawa, N. Ohuchi, M. Ono, T. Ozaki, K. Saito, H. Sakai, Y. Sakamoto, M. Sato, M. Satoh, K. Shibata, T. Shidara, M. Shirai, A. Shirakawa, T. Sueno, M. Suetake, Y. Suetsugu, R. Sugahara, T. Sugimura, T. Suwada, O. Tajima, S. Takano, S. Takasaki, T. Takenaka, Y. Takeuchi, M. Tawada, M. Tejima, M. Tobiyama, N. Tokuda, S. Uehara, S. Uno, Y. Yamamoto, Y. Yano, K. Yokoyama, Ma. Yoshida, M. Yoshida, S. I. Yoshimoto, K. Yoshino KEK, Ibaraki E. Perevedentsev, D. N. Shatilov BINP SB RAS, Novosibirsk
	The crab cavities are presently being installed in the KEKB rings to compensate the crossing angle at collision and thus increase luminosity. This will be the first experience with such cavities in colliders. Results on the beam operation of the new cavities, both for single and colliding beams, will be presented including the luminosity performance and limitations. Work presented on behalf of the KEKB Accelerator Group.
	Slides
MOOBKI02	DAΦ NE Phi-Factory Upgrade for Siddharta Run	66
	M. E. Biagini D. Alesini, D. Babusci, R. Boni, M. Boscolo, F. Bossi, B. Buonomo, A. Clozza, G. O. Delle Monache, T. Demma, G. Di Pirro, A. Drago, A. Gallo, S. Guiducci, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, F. Murtas, L. Pellegrino, M. A. Preger, L. Quintieri, P. Raimondi, R. Ricci, U. Rotundo, C. Sanelli, G. Sensolini, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, S. Tomassini, C. Vaccarezza, M. Zobov INFN/LNF, Frascati (Roma) S. Bettoni CERN, Geneva I. Koop, E. Levichev, P. A. Piminov, D. N. Shatilov, V. V. Smaluk BINP SB RAS, Novosibirsk K. Ohmi KEK, Ibaraki
	An upgrade of the DAΦNE Phi-Factory at LNF is foreseen in view of the installation of the Siddharta detector in 2007. A new Interaction Region suitable to test the large crossing angle and crabbed waist collision schemes* will be installed. Other machine improvements, such as wigglers modifications, new injection kickers and chambers coating will be realized with the goal of reaching luminosity of the order of 10³³/cm²/s. The principle of operation of the new scheme, together with hardware designs and simulation studies, will be presented. *DAPHNE Upgrade Team, "DAPHNE Upgrade for Siddharta run", DAPHNE Tech. Note G-68, LNF-INFN, Dec. 2006
	Slides
TUPAS089	Small Angle Crab Compensation for LHC IR Upgrade	1853
	R. Calaga K. Akai, K. Ohmi, K. Oide KEK, Ibaraki U. Dorda, R. Tomas, F. Zimmermann CERN, Geneva
	Funding: This work is partially supported by the U. S. DOE A small angle (< 1mrad) crab scheme is an attractive option for the LHC luminosity upgrade to recover the geometric luminosity loss from the finite crossing angle, which steeply increases to unacceptable levels as the IP beta function is reduced below its nominal value. The crab compensation in the LHC can be accomplished using only two sets of deflecting rf cavities, placed in collision-free straight sections of LHC to nullify the crossing angles at IP1 & IP5. We present IR optics configurations with low-angle crab crossing, study the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, lattice errors, crab RF noise sources. We also explore a 400MHz superconducting cavity design and discuss the pertinent RF challenges.
TUPAN045	Beam Operation with Crab Cavities at KEKB	1487
	H. Koiso T. Abe, T. A. Agoh, K. Akai, M. Akemoto, A. Akiyama, A. Arinaga, K. Ebihara, K. Egawa, A. Enomoto, J. W. Flanagan, S. Fukuda, H. Fukuma, Y. Funakoshi, K. Furukawa, T. Furuya, K. Hara, T. Higo, S. Hiramatsu, H. Hisamatsu, H. Honma, T. Honma, K. Hosoyama, T. Ieiri, N. Iida, H. Ikeda, M. Ikeda, S. Inagaki, S. Isagawa, H. Ishii, A. Kabe, E. Kadokura, T. Kageyama, K. Kakihara, E. Kako, S. Kamada, T. Kamitani, K.-I. Kanazawa, H. Katagiri, S. Kato, T. Kawamoto, S. Kazakov, M. Kikuchi, E. Kikutani, K. Kitagawa, Y. Kojima, I. Komada, T. Kubo, K. Kudo, N. K. Kudo, K. Marutsuka, M. Masuzawa, S. Matsumoto, T. Matsumoto, S. Michizono, K. Mikawa, T. Mimashi, S. Mitsunobu, K. Mori, A. Morita, Y. Morita, H. Nakai, H. Nakajima, T. T. Nakamura, H. Nakanishi, K. Nakao, S. Ninomiya, Y. Ogawa, K. Ohmi, Y. Ohnishi, S. Ohsawa, Y. Ohsawa, N. Ohuchi, K. Oide, M. Ono, T. Ozaki, K. Saito, H. Sakai, Y. Sakamoto, M. Sato, M. Satoh, K. Shibata, T. Shidara, M. Shirai, A. Shirakawa, T. Sueno, M. Suetake, Y. Suetsugu, R. Sugahara, T. Sugimura, T. Suwada, O. Tajima, S. Takano, S. Takasaki, T. Takenaka, Y. Takeuchi, M. Tawada, M. Tejima, M. Tobiyama, N. Tokuda, S. Uehara, S. Uno, Y. Yamamoto, Y. Yano, K. Yokoyama, Ma. Yoshida, M. Yoshida, S. I. Yoshimoto, K. Yoshino KEK, Ibaraki E. Perevedentsev BINP SB RAS, Novosibirsk
	Beam operation with crab cavities is planned in early 2007 at KEKB. The crab crossing scheme is expected to increase the vertical beam-beam tune-shift parameter significantly. One crab cavity will be installed in each ring where conditions for beam optics are matched to compensate the beam crossing angle of 22 mrad. Operation results on collision tuning with the crab cavities will be presented. For the KEKB Accelerator Group.
THPAN037	Beam-Beam Effects Observed at KEKB	3309
	Y. Funakoshi K. Ohmi, K. Oide, M. Tawada KEK, Ibaraki
	KEKB is an e⁺ e^- collider with a world-highest luminosity of 1.7 x 10³⁴ /cm²/s. It has a half-crossing angle of 11 mrad. We are installing crab cavities for the purpose of eliminating effects of crossing angle in the begining of 2007. Another feature of KEKB is that its operating points are very close to the half interger in the horizontal direction. This report summarizes beam-beam effects observed at KEKB.
THPAN075	Modeling Incoherent Electron Cloud Effects	3393
	F. Zimmermann E. Benedetto, G. Rumolo, D. Schulte, R. Tomas CERN, Geneva W. Fischer BNL, Upton, Long Island, New York G. Franchetti GSI, Darmstadt K. Ohmi KEK, Ibaraki M. T.F. Pivi, T. O. Raubenheimer SLAC, Menlo Park, California K. G. Sonnad, J.-L. Vay LBNL, Berkeley, California
	Incoherent effects driven by an electron cloud could seriously limit the beam lifetime in proton storage rings or blow up the vertical emittance in positron ones. Different approaches to modeling these effects each have their own merits and drawbacks. We compare the simulation results and computing time requirements from a number of dedicated codes under development over the last years, and describe the respective approximations for the beam-electron cloud interaction, the accelerator structure, and the optical lattice, made in each of these codes. Examples considered include the LHC, CERN SPS, RHIC, and the ILC damping ring. Tentative conclusions are drawn and a strategy for further codes development is outlined.
FRPMN037	Ion Instability in the ILC Damping Ring	4030
	E.-S. Kim K. Ohmi KEK, Ibaraki
	Ions created by electron beam trapped in a bunch oscillate with a certain frequency, with the result that the beam oscillate with the same frequency. Recent high intensity and low emittance rings, the growth rate of this ion instability is very rapid. Super B factory and ILC damping ring, which are similar design parameter, are extremely low emittance. We discuss the ion instability for these rings.
FRPMN038	Simulation of Synchro-betatron Sideband Instability caused by Electron Clouds at KEKB	4033
	J. W. Flanagan E. Benedetto CERN, Geneva J. Hyunchang POSTECH, Pohang, Kyungbuk K. Ohmi KEK, Ibaraki
	Electron cloud causes a fast head-tail instability above a threshold density. Experiments at KEKB showed synchro-betatron sideband, which indicates the head-tail instability. The sideband appears near ν_y+kν_s, where 1<k<2, that differs from ordinary instability seen near ν_y-ν_s. We investigate the origin of the sideband using a computer simulation.