EPAC 2006 - List of Authors

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Cai, Y.

Paper	Title	Page
MOPLS045	Achieving a Luminosity of 10³⁴/cm²/s in the PEP-II B-factory	643
	J. Seeman, J. Browne, Y. Cai, W.S. Colocho, F.-J. Decker, M.H. Donald, S. Ecklund, R.A. Erickson, A.S. Fisher, J.D. Fox, S.A. Heifets, R.H. Iverson, A. Kulikov, A. Novokhatski, V. Pacak, M.T.F. Pivi, C.H. Rivetta, M.C. Ross, P. Schuh, K.G. Sonnad, M. Stanek, M.K. Sullivan, P. Tenenbaum, D. Teytelman, J.L. Turner, D. Van Winkle, M. Weaver, U. Wienands, W. Wittmer, M. Woodley, Y.T. Yan, G. Yocky SLAC, Menlo Park, California M.E. Biagini INFN/LNF, Frascati (Roma) W. Kozanecki CEA, Gif-sur-Yvette
	For the PEP-II Operation Staff: PEP-II is an asymmetric e⁺e^- collider operating at the Upsilon 4S and has recently set several performance records. The luminosity has exceeded 1x10³⁴/cm²/s and has delivered an integrated luminosity of 728/pb in one day. PEP-II operates in continuous injection mode for both beams, boosting the integrated luminosity. The peak positron current has reached 2.94 A and 1.74 A of electrons in 1732 bunches. The total integrated luminosity since turn on in 1999 has reached over 333/fb. This paper reviews the present performance issues of PEP-II and also the planned increase of luminosity in the near future to over 2 x 10³⁴/cm²/s. Upgrade details and plans are discussed.
MOPLS047	Design of an Asymmetric Super-B Factory	646
	J. Seeman, Y. Cai, A. Novokhatski, A. Seryi, M.K. Sullivan, U. Wienands SLAC, Menlo Park, California M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma)
	Submitted for the High Luminosity Study Group for an Asymmetric Single-pass Super-B Factory: Parameters are being studied for a high luminosity e⁺e^- collider operating at the Upsilon 4S that would deliver a luminosity of over 10³⁶/cm²/s. This collider would use a novel combination of linear collider and storage ring techniques. In this scheme an electron beam and a positron beam are first stored in fast-damping and low-emittance damping rings, then extracted, accelerated, compressed and focused to the interaction point. After collision the two beams are decelerated and re-injected in the damping rings to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Design parameters for very flat beams and round beams have been studied.
MOPLS048	Doubling the PEP-II Luminosity in Simulations	649
	Y. Cai, J. Seeman, K.G. Sonnad, U. Wienands SLAC, Menlo Park, California
	The PEP-II luminosity reached 1x10³⁴cm-2s-1 in October 2005. The question of how to increase the luminosity using modest improvements in the PEP-II accelerator in the coming years is the subject of this paper. We found that the parasitic collisions significantly degrade the simulated luminosity as the beam currents are increased from 3A and 1.7A to 4A and 2.2A in the low and high energy rings, respectively. Using the beam-beam code BBI, we systematically optimized the luminosity and showed that a luminosity of over 2x10³⁴cm-2s-1 is achievable within the limits of machine parameters.
MOPLS049	Anomalous High Radiation Beam Aborts in the PEP-II B-factory	652
	M.K. Sullivan, Y. Cai, S. DeBarger, F.-J. Decker, S. Ecklund, A.S. Fisher, S.M. Gierman, S.A. Heifets, R.H. Iverson, A. Kulikov, N. Kurita, S.J. Metcalfe, A. Novokhatski, J. Seeman, K.G. Sonnad, D. Teytelman, J.L. Turner, U. Wienands, D. Wright, Y.T. Yan, G. Yocky SLAC, Menlo Park, California
	The PEP-II B-factory at SLAC has recently experienced unexpected beam losses due to anomalously high radiation levels at the BaBar detector. The problem was finally traced to the occurrence of very high pressure (>100 nTorr) spikes that have a very short duration (few seconds). We describe the events and show analysis predicting where in the vacuum system the events originated and describe what was discovered in the vacuum system.
MOPLS050	Combined Phase Space Characterization at the PEP-II IP using Single-beam and Luminous-region Measurements	655
	A.J. Bevan Queen Mary University of London, London Y. Cai, A.S. Fisher, C. O'Grady, J.M. Thompson, M. Weaver SLAC, Menlo Park, California W. Kozanecki CEA, Gif-sur-Yvette B.F. Viaud Montreal University, Montreal, Quebec
	We present a novel method to characterize the e ± phase space at the IP of the SLAC B-factory, that combines single-beam measurements with a detailed mapping of luminous-region observables. Transverse spot sizes are determined in the two rings with synchrotron-light monitors & extrapolated to the IP using measured lattice functions. The 3-D luminosity distribution, as well as the spatial dependence of the transverse-boost distribution of the colliding beams, are measured using e⁺ e^- –> mu+ mu- events reconstructed in the BaBar tracking detectors; they provide information on the luminous spot size, the e^- angular divergence & the vertical emittance. The specific luminosity, which is proportional to the inverse product of the overlap IP beam sizes, is continuously monitored using Bhabha-scattering events. The combination of these measurements provide constraints on the horizontal & vertical spot sizes, angular divergences, emittances & beta functions of both beams at the IP during routine high-luminosity operation. Preliminary results of this combined-spot size analysis are confronted with measurements of IP beta-functions & overlap IP beam sizes at low beam current.
MOPLS052	Luminosity Improvement at PEP-II Based on Optics Model and Beam-beam Simulation	661
	Y. Cai, W.S. Colocho, F.-J. Decker, Y. Nosochkov, P. Raimondi, J. Seeman, K.G. Sonnad, M.K. Sullivan, J.L. Turner, M. Weaver, U. Wienands, W. Wittmer, M. Woodley, Y.T. Yan, G. Yocky SLAC, Menlo Park, California
	The model independent analysis (MIA) has been successfully used at PEP-II to understand machine optics and improve the luminosity. However, the rate of success was limited because the improvement of optics does not necessarily lead to increase of luminosity. Recently, we were able to reconstruct MIA model in a full optics code, LEGO, and used it to calculate complete lattice and beam parameters. These parameters were fed to the beam-beam code, BBI, to understand the luminosity histories at PEP-II over the past year. Using these tools, we optimized the luminosity by varying the beam parameters such as emittance. Finally, we implemented an optimized solution with a set of asymmetric horizontal orbit bumps into the machines during a delivery shift with a few percentage gain in luminosity. The solution was retained at PEP-II machines along with the luminosity. Later, these asymmetric bumps also played a vital role in reaching 1x10³⁴cm-2s-1 as the beam currents increased.
WEPCH062	Precision Measurement and Improvement of Optics for e+, e^- Storage Rings	2065
	Y.T. Yan, Y. Cai, W.S. Colocho, F.-J. Decker, J. Seeman, M.K. Sullivan, J.L. Turner, U. Wienands, M. Woodley, G. Yocky SLAC, Menlo Park, California
	Through horizontal and vertical excitations, we have been able to make a precision measurement of linear geometric optics parameters with a Model-Independent Analysis (MIA). We have also been able to build up a computer model that matches the real accelerator in linear geometric optics with an SVD-enhanced Least-square fitting process. Recently, with the addition of longitudinal excitation, we are able to build up a computer virtual machine that matches the real accelerators in linear optics including dispersion without additional fitting variables. With this optics-matched virtual machine, we are able to find solutions that make changes of many normal and skew quadrupoles for machine optics improvement. It has made major contributions to improve PEP-II optics and luminosity. Examples from application to PEP-II machines will be presented.
WEPCH141	Accelerator Physics Code Web Repository	2254
	F. Zimmermann, R. Basset, E. Benedetto, U. Dorda, M. Giovannozzi, Y. Papaphilippou, T. Pieloni, F. Ruggiero, G. Rumolo, F. Schmidt, E. Todesco CERN, Geneva D.T. Abell Tech-X, Boulder, Colorado R. Bartolini Diamond, Oxfordshire O. Boine-Frankenheim, G. Franchetti, I. Hofmann GSI, Darmstadt Y. Cai, M.T.F. Pivi SLAC, Menlo Park, California Y.H. Chin, K. Ohmi, K. Oide KEK, Ibaraki S.M. Cousineau, V.V. Danilov, J.A. Holmes, A.P. Shishlo ORNL, Oak Ridge, Tennessee L. Farvacque ESRF, Grenoble A. Friedman LLNL, Livermore, California M.A. Furman, D.P. Grote, J. Qiang, G.L. Sabbi, P.A. Seidl, J.-L. Vay LBNL, Berkeley, California D. Kaltchev TRIUMF, Vancouver T.C. Katsouleas USC, Los Angeles, California E.-S. Kim PAL, Pohang, Kyungbuk S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon J. Payet CEA, Gif-sur-Yvette T. Sen Fermilab, Batavia, Illinois J. Wei BNL, Upton, Long Island, New York B. Zotter Honorary CERN Staff Member, Grand-Saconnex
	In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans.