PAC 2005 - 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

Fox, J.D.

Paper	Title	Page
MPPP007	Operating Performance of the Low Group Delay Woofer Channel in PEP-II	1069
	D. Teytelman, J.D. Fox, D. Van Winkle SLAC, Menlo Park, California
	Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515. In PEP-II collider a dedicated low group-delay processing channel has been developed in order to provide high damping rates necessary to control the fast-growing longitudinal eigenmodes driven by the fundamental impedances of the RF cavities. A description of the digital processing channel operating at 9.81 MHz and capable of supporting finite impulse response (FIR) controllers with up to 32 taps will be presented. A prototype system has been successfully commissioned in the High-Energy Ring (HER) in May 2004. Operating experiences with the prototype and the newly determined limits on achievable longitudinal damping will be discussed and illustrated with experimental data.
TPPP034	Parameters of a Super-B-Factory Design	2333
	J. Seeman, Y. Cai, S. Ecklund, J.D. Fox, S.A. Heifets, N. Li, P.A. McIntosh, A. Novokhatski, M.K. Sullivan, D. Teytelman, U. Wienands SLAC, Menlo Park, California M.E. Biagini INFN/LNF, Frascati (Roma)
	Funding: Work supported by DOE contract DE-AC02-76SF00515. Submitted for the High Luminosity Study Group: Parameters are being studied for a high luminosity e⁺e^- collider operating at the Upsilon 4S that would deliver a luminosity in the range of 7 to 10 x 10³⁵/cm²/s. Particle physics studies dictate that a much higher luminosity collider is needed to answer new key physics questions. A Super-B-Factory with 20 to 100 times the performance of the present PEP-II accelerator would incorporate a higher frequency RF system, lower impedance vacuum chambers, higher power synchrotron radiation absorbers, and stronger bunch-by-bunch feedback systems. Parameter optimizations are discussed.
WPAT041	Klystron Linearizer for Use with 1.2 MW 476 MHz Klystrons in PEP-II RF Systems	2660
	J.D. Fox, T. Mastorides, D. Teytelman, D. Van Winkle, Y.-B. Zhou SLAC, Menlo Park, California A. Gallo INFN/LNF, Frascati (Roma)
	Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515. The direct and comb loop feedback around the RF cavities in PEP-II is critical in reducing longitudinal instabilities driven by the cavity impedance, and the non-linear 1 MW klystron is in the signal path for these feedback loops. As a result, the effective small-signal gain of the klystron at 85% saturation reduces the impedance control by factors of 5 to 20 as compared to a linear power amplifier. A klystron linearizer circuit has been developed which operates in series with the power amplifier and acts to equalize the small and large signal gains through the combination. The technique must implement a 1 MHz linear control bandwidth over roughly 15 dB of RF signal level variation. The dynamics of this system is operating point dependent, and the channel must have dynamic gain compensation to keep the linearity compensation loop stable over changes in operating point. The design of this non-linear signal processing channel (incorporating RF and DSP techniques) and measured results from full-power klystron testing are presented.
WPAT074	In Depth Diagnostics for RF System Operation in the PEP-II B Factory	3931
	D. Van Winkle, J.D. Fox, D. Teytelman SLAC, Menlo Park, California
	Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515. The PEP-II RF systems incorporate numerous feedback loops in the low-level processing for impedance control and operating point regulation. The interaction of the multiple loops with the beam is complicated, and the systems incorporate online diagnostic tools to configure the feedback loops as well as to record fault files in the case of an RF abort. Rapid and consistent analysis of the RF-related beam aborts and other failures is critical to the reliable operation of the B-Factory, especially at the recently achieved high beam currents. Procedures and algorithms used to extract diagnostic information from time domain fault files are presented and illustrated via example interpretations of PEP-II fault file data. Example faults presented will highlight the subtle interpretation required to determine to root cause. Some such examples are: abort kicker firing asynchronously, klystron and cavity arcs, beam loss leading to longitudinal instability, tuner read back jumps and poorly configured low-level RF feedback loop.
TPPP035	Performance of the PEP-II B-Factory Collider at SLAC	2369
	J. Seeman, J. Browne, Y. Cai, 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, N. Li, A. Novokhatski, M.C. Ross, P. Schuh, T.J. Smith, K.G. Sonnad, M. Stanek, M.K. Sullivan, P. Tenenbaum, D. Teytelman, J.L. Turner, D. Van Winkle, M. Weaver, U. Wienands, M. Woodley, Y.T. Yan, G. Yocky SLAC, Menlo Park, California M.E. Biagini INFN/LNF, Frascati (Roma) W. Kozanecki CEA/DSM/DAPNIA, Gif-sur-Yvette C. Steier, A. Wolski LBNL, Berkeley, California G. Wormser IPN, Orsay
	Funding: Work supported by DOE contract DE-AC02-76SF00515. 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 reached 9.2 x 10³³/cm²/s. PEP-II has delivered an integrated luminosity of 710/pb in one day. It operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.55 A in 1588 bunches. The total integrated luminosity since turn on in 1999 has reached 256/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.
ROAA001	DAFNE Operation and Plans for DAFNE2	112
	M. Zobov, D. Alesini, G. Benedetti, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, A. Clozza, G.O. Delle Monache, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, C. Vaccarezza, M. Vescovi INFN/LNF, Frascati (Roma) J.D. Fox, D. Teytelman SLAC, Menlo Park, California E. Levichev, P.A. Piminov, D.N. Shatilov BINP SB RAS, Novosibirsk
	The e⁺e^- collider DAFNE, a 1.02 Gev c.m. Phi-factory, has exceeded 1.2 1032 cm-2s-1 peak luminosity with 7.5 pb-1 maximum daily integrated luminosity. At the present performance the physics program of the three main experiments DEAR, FINUDA and KLOE will be completed by mid 2007. In this paper we describe the steps which have led to the luminosity improvement and present proposals for the upgrade of the collider towards higher energy and/or luminosity. The main accelerator issues on which we are planning to rely for this purpose, such as lattices with negative momentum compaction, strong RF focusing, design of high field magnets and Linac upgrade, are discussed in detail.
ROAA003	Proposal of an Experiment on Bunch Length Modulation in DAFNE	336
	C. Biscari, D. Alesini, G. Benedetti, M.E. Biagini, R. Boni, M. Boscolo, A. Clozza, G.O. Delle Monache, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, C. Vaccarezza, M. Vescovi, M. Zobov INFN/LNF, Frascati (Roma) J.M. Byrd, F. Sannibale LBNL, Berkeley, California J.D. Fox, D. Teytelman SLAC, Menlo Park, California E. Levichev, P.A. Piminov, D.N. Shatilov BINP SB RAS, Novosibirsk C. Pagani INFN/LASA, Segrate (MI)
	Obtaining very short bunches is a challenge for colliders and Coherent Synchrotron Radiation sources as well. The modulation of the bunch length in a strong RF focusing regime has been proposed, corresponding to a large value of the synchrotron tune. A ring structure where the dependence of the longitudinal position of a particle on its energy (R56) along the ring oscillates between large positive and negative values can produce a bunch length modulation. The synchrotron frequency can be tuned both by means of the rf voltage and by the integral of R56, down to the limit of zero value corresponding to the isochronicity condition. We present here the proposal of bunch length modulation along the DAFNE rings. Its lattice can be tuned to positive or negative momentum compaction, or to structures in which the two arcs are alternately set to positive/negative integrals of R56. With the proposed installation of an extra RF system at 1.3 GHz, experiments on bunch length modulation both in the high and low synchrotron tune regimes can be realized.