EPAC08 - List of Authors (Sullivan, M. K.)

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Sullivan, M. K.

Paper	Title	Page
TUPP053	Radiolocation of a HOM Source in the PEP-II Rings	1664
	A. Novokhatski, J. Seeman, M. K. Sullivan SLAC, Menlo Park, California
	A signal from the antenna situated in the LER (Low Energy Ring) helped to find a broken shielded bellows in the HER (High Energy Ring) during a single HER bunch operation.
TUPP054	A Model of an Electrical Discharge in the Flange Contacts with Omega Seals at High Currents in PEP-II	1667
	A. Novokhatski, J. Seeman, M. K. Sullivan SLAC, Menlo Park, California
	During operation with high currents at HER (High Energy Ring), high temperature elevation was found at almost every location of the vacuum chamber flange contacts. Omega RF seals were strongly damaged or even evaporated by sparks and electrical discharge. We suggest a physical model, which may explain this effect.
TUPP055	Loss Factor of the PEP-II Rings	1670
	A. Novokhatski, M. K. Sullivan SLAC, Menlo Park, California
	RF power balance method is used to measure the synchrotron radiation losses and the wake field losses. We present the history of the loss factor during the last several runs, which reveals many interesting correlations with vacuum chamber improvement and processing.
WEPP042	An Improved Design for a SuperB Interaction Region	2614
	M. K. Sullivan, J. Seeman, U. Wienands SLAC, Menlo Park, California S. Bettoni CERN, Geneva M. E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma) E. Paoloni University of Pisa and INFN, Pisa
	We present an improved design for a SuperB interaction region. The new design attempts to minimize the bending of the two colliding beams which results from shared magnetic elements near the Interaction Point (IP). The total crossing angle at the IP is increased from 34 mrad to 50 mrad and the distance from the IP to the first quadrupole is increased. Although the two beams still travel through this shared magnet, these changes allow for a new a new magnetic field design with a septum which gives the magnet two magnetic centers. This greatly reduces the beam bending from this shared quadrupole and thereby reduces the radiative bhabha background for the detector as well as any beam emittance growth from the bending. We decribe the new design for the interaction region.
WEPP044	Commissioning the 90° Lattice for the PEP II High Energy Ring	2617
	W. Wittmer, Y. Cai, W. X. Cheng, W. S. Colocho, F.-J. Decker, S. Ecklund, A. S. Fisher, Y. Nosochkov, A. Novokhatski, M. K. Sullivan, U. Wienands, Y. T. Yan, G. Yocky SLAC, Menlo Park, California
	In order to benefit from further reduction of the vertical IP beta function of the PEP-II HER the bunch length should be reduced. This will be achieved by changing the phase advance from 60 deg to 90 deg in the four arcs not adjacent to the IR region, thus reducing momentum compaction by about 30% and reducing bunch length from a present 12 mm down to 8.5 mm at low beam current. In preparation to implement the 90 deg lattice the main HER quadrupole and sextupole strings and their power supplies have been reconfigured. Compared to the 60 deg lattice it was expected that dynamic aperture and injection will be more difficult. The synchrotron tune initially will be lower but can be brought back by raising the rf voltage. Beam emittance is held at 48 nmr by introducing a significant dispersion beat in the arcs. The lattice was successfully commissioned at currents up to 800mA in August 2007. In this paper we will compare the actual machine with the predicted behaviour, explain the correction strategies used and give an overall assessment of the operation and the benefit of the new lattice configuration.
THPC007	Permanent Magnet Skew Quadrupoles for the Low Emittance LER Lattice of PEP-II	2987
	F.-J. Decker, S. D. Anderson, D. Kharakh, M. K. Sullivan SLAC, Menlo Park, California
	The vertical emittance of the low energy ring (LER) in the PEP-II B-Factory was reduced by using skew quadrupoles consisting of permanent magnet material. The advantages over electric quadrupoles or rotating existing normal quadrupoles are discussed. To assure a high field quality a Biot Savart calculation was used to cancel the natural 12-pole component by using different size poles over a few layers. A magnetic measurement confirmed the high quality of the magnets. After installation and adjusting the original 12 skew and 16 normal quadrupoles the emittance contribution from the region close to the interaction point, which was the biggest part in the original design, was considerably reduced.
MOPP031	Challenges and Concepts for Design of an Interaction Region with Push-pull Arrangement of Detectors - an Interface Document	616
	A. Seryi, T. W. Markiewicz, M. Oriunno, M. K. Sullivan SLAC, Menlo Park, California D. Angal-Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire B. Ashmanskas, V. R. Kuchler, N. V. Mokhov Fermilab, Batavia, Illinois K. Buesser DESY, Hamburg P. Burrows OXFORDphysics, Oxford, Oxon A. Enomoto, Y. Sugimoto, T. Tauchi, K. Tsuchiya KEK, Ibaraki A. Herve, J. A. Osborne CERN, Geneva A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York B. Parker BNL, Upton, Long Island, New York T. Sanuki Tohoku University, School of Scinece, Sendai J. Weisend NSF, Arlington H. Y. Yamamoto Tohoku University, Sendai
	Two experimental detectors working in a push-pull mode has been considered for the Interaction Region of the International Linear Collider [1]. The push-pull mode of operation sets specific requirements and challenges for many systems of detector and machine, in particular for the IR magnets, for the cryogenics system, for alignment system, for beamline shielding, for detector design and overall integration, and so on. These challenges and the identified conceptual solutions discussed in the paper intend to form a draft of the Interface Document which will be developed further in the nearest future. The authors of the present paper include the organizers and conveners of working groups of the workshop on engineering design of interaction region IRENG07 [2], the leaders of the IR Integration within Global Design Effort Beam Delivery System, and the representatives from each detector concept submitting the Letters Of Intent.
WEPP039	Design of a 10³⁶ cm^-2 s^-1 Super-B Factory	2605
	J. Seeman, K. J. Bertsche, A. Novokhatski, M. K. Sullivan, U. Wienands, W. Wittmer SLAC, Menlo Park, California S. Bettoni CERN, Geneva M. E. Biagini, R. Boni, M. Boscolo, T. Demma, A. Drago, S. Guiducci, P. Raimondi, S. Tomassini, M. Zobov INFN/LNF, Frascati (Roma) A. Bogomyagkov, I. Koop, E. B. Levichev, S. A. Nikitin, P. A. Piminov, D. N. Shatilov BINP SB RAS, Novosibirsk G. Marchiori INFN-Pisa, Pisa E. Paoloni University of Pisa and INFN, Pisa
	Submitted for the High Luminosity Study Group for an Asymmetric 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 1 to 2 x 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 stored in low-emittance damping rings similar to those designed for a Linear Collider (LC) or the next generation light source. A LC style interaction region is included in the ring to produce sub-millimeter vertical beta functions at the collision point. A large crossing angle (±25 mrad) is used at the collision point to allow beam separation. A crab-waist scheme is used to reduce the hourglass effect and restore peak luminosity. Beam currents of about 1.8 A in 1400 bunches can produce a luminosity of 10³⁶/cm²/s with upgrade possibilities. Design parameters and beam dynamics effects are discussed.
WEPP040	New Low Emittance Lattices for the SuperB Accelerator Project	2608
	M. E. Biagini, M. Boscolo, P. Raimondi, S. Tomassini, M. Zobov INFN/LNF, Frascati (Roma) S. Bettoni CERN, Geneva A. Bogomyagkov, I. Koop, E. B. Levichev, S. A. Nikitin, P. A. Piminov, D. N. Shatilov BINP SB RAS, Novosibirsk E. Paoloni University of Pisa and INFN, Pisa J. Seeman, M. K. Sullivan, U. Wienands, W. Wittmer SLAC, Menlo Park, California
	New low emittance lattices (1.6 nm at 7 GeV, 2.8 nm at 4 GeV) have been designed for the asymmetric SuperB accelerator aiming at a luminosity of 10³⁶ cm^-2 s^-1. Main optics features are two alternating arc cells with different horizontal phase advance, in order to decrease beam emittance and allow at the same time for easy chromaticity correction in the arcs. Emittance can be further reduced by a factor of two for luminosity upgrade. New beam parameters have been chosen to fulfill the transparency conditions for 4x7 GeV beams, different from the asymmetric currents used in operating B-Factories. Beam polarization schemes have been studied and will be implemented in the lattice.
WEPP041	High-current Effects in the PEP-II Storage Rings	2611
	U. Wienands, W. X. Cheng, W. S. Colocho, S. DeBarger, F.-J. Decker, S. Ecklund, A. S. Fisher, D. Kharakh, A. Krasnykh, A. Novokhatski, M. K. Sullivan SLAC, Menlo Park, California
	High beam currents, 2A(HER) & 3A(LER), in PEP-II has been a challenge for the vacuum system. For the ~1 cm long bunches peak currents reach 50 A. Thus modest impedances can give rise to voltage spikes and discharges. A weakness was uncovered during Run 6: rf seals at the "flex flanges" that join the HER arc dipole and quadrupole chambers became a source of an increasing number of HER beam aborts. Vacuum activity was seen and thermal sensors on these flanges saw temperature spikes. Inspection of the seals found arcing and melting, prompting us to replace all of these seals with an improved design using Inconel instead of GlidCop fingers. We believe the GlidCop fingers do not maintain elasticity and hence can not follow chamber motion due to thermal effects. The Run 7 startup confirmed the success of this repair. However, high bunch current in the LER caused breakdown in a LER kicker. This limited the LER bunch current to about 1 mA. Inspection revealed damage to one of the recently added Macor pins that help support the electrodes. Failure analysis revealed heating of the pin & post-facto modeling shows high fields coming from a combination of HOM impedance and high peak currents.