PAC07 - List of Authors (Molloy, S.)

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Molloy, S.

Paper	Title	Page
THOAC03	Measurement of the Beam's Trajectory Using the Higher Order Modes it Generates in a Superconducting Accelerating Cavity	2642
	S. Molloy N. Baboi, O. Hensler, R. Paparella, L. M. Petrosyan DESY, Hamburg N. E. Eddy, L. Piccoli, R. Rechenmacher, M. Wendt Fermilab, Batavia, Illinois J. C. Frisch, J. May, D. J. McCormick, M. C. Ross, T. J. Smith SLAC, Menlo Park, California O. Napoly, C. Simon CEA, Gif-sur-Yvette
	Funding: US DOE Contract #DE-AC02-76SF00515 It is well known that an electron beam excites Higher Order Modes (HOMs) as it passes through an accelerating cavity~[panofsky68]. The properties of the excited signal depend not only on the cavity geometry, but on the charge and trajectory of the beam. It is, therefore, possible to use these signals as a monitor of the beam's position. Electronics were installed on all forty cavities present in the FLASH~[flashref] linac in DESY. These electronics filter out a mode known to have a strong dependence on the beam's position, and mix this down to a frequency suitable for digitisation. An analysis technique based on Singular Value Decomposition (SVD) was developed to calculate the beam's trajectory from the output of the electronics. The entire system has been integrated into the FLASH control system.
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THPMS049	Investigations of the Wideband Spectrum of Higher Order Modes Measured on TESLA-style Cavities at the FLASH Linac	3100
	S. Molloy C. Adolphsen, K. L.F. Bane, J. C. Frisch, Z. Li, J. May, D. J. McCormick, T. J. Smith SLAC, Menlo Park, California N. Baboi DESY, Hamburg N. E. Eddy, L. Piccoli, R. Rechenmacher Fermilab, Batavia, Illinois R. M. Jones UMAN, Manchester
	Funding: US DOE Contract #DE-AC02-76SF00515 Higher Order Modes (HOMs) excited by the passage of the beam through an accelerating cavity depend on the properties of both the cavity and the beam. It is possible, therefore, to draw conclusions on the inner geometry of the cavities based on observations of the properties of the HOM spectrum. A data acquisition system based on two 20 GS/s, 6 GHz scopes has been set up at the FLASH facility, DESY, in order to measure a significant fraction of the HOM spectrum predicted to be generated by the TESLA cavities used for the acceleration of its beam. The HOMs from a particular cavity at FLASH were measured under a range of known beam conditions. The dipole modes have been identified in the data. 3D simulations of different manufacturing errors have been made, and it has been shown that these simulations can predict the measured modes.
FRPMS073	Picosecond Bunch Length and Energy-z Correlation Measurements at SLAC's A-Line and End Station A	4201
	S. Molloy V. Blackmore OXFORDphysics, Oxford, Oxon P. Emma, J. C. Frisch, R. H. Iverson, D. J. McCormick, M. Woods SLAC, Menlo Park, California M. C. Ross Fermilab, Batavia, Illinois S. Walston LLNL, Livermore, California
	Funding: US DOE Contract #DE-AC02-76FS00515 We report on measurements of picosecond bunch lengths and the energy-z correlation of the bunch with a high energy electron test beam to the A-line and End Station A (ESA) facilities at SLAC. The bunch length and the energy-z correlation of the bunch are measured at the end of the linac using a synchrotron light monitor diagnostic at a high dispersion point in the A-line and a transverse RF deflecting cavity at the end of the linac. Measurements of the bunch length in ESA were made using high frequency diodes (up to 100 GHz) and pyroelectric detectors at a ceramic gap in the beamline. Modelling of the beam's longitudinal phase space through the linac and A-line to ESA is done using the 2-dimensional tracking program LiTrack, and LiTrack simulation results are compared with data. High frequency diode and pyroelectric detectors are planned to be used as part of a bunch length feedback system for the LCLS FEL at SLAC. The LCLS also plans precise bunch length and energy-z correlation measurements using transverse RF deflecting cavities.
FRPMS074	Measurements of the Transverse Collimator Wakefields due to Varying Collimator Characteristics	4207
	S. Molloy C. D. Beard, J.-L. Fernandez-Hernando STFC/DL/ASTeC, Daresbury, Warrington, Cheshire A. Bungau UMAN, Manchester S. Seletskiy, M. Woods SLAC, Menlo Park, California J. D.A. Smith Cockcroft Institute, Warrington, Cheshire A. Sopczak Lancaster University, Lancaster N. K. Watson STFC/RAL/ASTeC, Chilton, Didcot, Oxon
	Funding: EUROtev Contract #011899RIDS US DOE Contract DEAC02-76SF00515 We report on measurements of the transverse wakefields induced by collimators of differing characteristics. An apparatus allowing the insertion of different collimator jaws into the path of a beam was installed in End Station A (ESA) in SLAC. Eight comparable collimator geometries were designed, including one that would allow easy comparison with previous results, and were installed in this apparatus. Measurements of the beam kick due to the collimator wakefields were made with a beam energy of 28.5 GeV, and beam dimensions of ~100 microns vertically and a range of 0.5 to 1.5 mm longitudinally. The trajectory of the beam upstream and downstream of the collimator test apparatus was determined from the outputs of ten BPMs (four upstream and six downstream), thus allowing a measurement of the angular kick imparted to the beam by the collimator under test. The transverse wakefield was inferred from the measured kick. The different aperture designs, data collection and analysis, and initial comparison to theoretical and analytic predictions are presented here. * "An Apparatus for the Direct Measurement of Collimator Transverse Wakefields", P. Tenenbaum, PAC '99** "Direct Measurement of the Resistive Wakefield in Tapered Collimators", P Tenenbaum, PAC '04
MOPAN108	The FONT4 ILC Intra-train Beam-based Digital Feedback System Prototype	416
	P. Burrows G. B. Christian, C. I. Clarke, B. Constance, A. F. Hartin, H. D. Khah, C. Perry, C. Swinson, G. R. White JAI, Oxford A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire S. Molloy SLAC, Menlo Park, California
	We present the design of the FONT4 intra-train beam-based digital position feedback system prototype. The system incorporates a fast analogue beam position monitor front-end signal processor, a digital feedback board, and a fast kicker-driver amplifier. The system latency goal is less than 150ns. We report preliminary results of beam tests at the Accelerator Test Facility (ATF) at KEK using electron bunches separated by c. 150ns.
WEOBAB01	Electromagnetic Background Tests for the ILC Interaction Point Feedback System	1970
	P. Burrows R. Arnold, S. Molloy, S. Smith, G. R. White, M. Woods SLAC, Menlo Park, California G. B. Christian, C. I. Clarke, B. Constance, A. F. Hartin, H. D. Khah, C. Perry, C. Swinson, G. R. White JAI, Oxford A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	We present results obtained with the T-488 experiment at SLAC Endstation A (ESA). A material model of the ILC extraction-line design was assembled and installed in ESA. The module includes materials representing the mask, beamline calorimeter, and first extraction quadrupole, encompassing a stripline interaction-point feedback system beam position monitor (BPM). The SLAC high-energy electron beam was used to irradiate the module in order to mimic the electromagnetic (EM) backgrounds expected in the ILC interaction region. The impact upon the performance of the feedback BPM was measured, and compared with detailed simulations of its expected response.
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THPMN079	Simulation of ILC Feedback BPM Signals in an Intense Background Environment	2889
	A. F. Hartin R. Arnold, S. Molloy, S. Smith, M. Woods SLAC, Menlo Park, California P. Burrows, G. B. Christian, C. I. Clarke, B. Constance, H. D. Khah, C. Perry, C. Swinson, G. R. White JAI, Oxford A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	Funding: This work is supported in part by the Commission of the European Communities under the 6th Framework Programme "Structuring the European Research Area", contract number RIDS-011899. Experiment T-488 at SLAC, End Station A recorded distorted BPM voltage signals and an accurate simulation of these signals was performed. Geant simulations provided the energy and momentum spectrum of the incident spray and secondary emissions, and a method via image charges was used to convert particle momenta and number density into BPM stripline currents. Good agreement was achieved between simulated and measured signals. Further simulation of experiment T-488 with incident beam on axis and impinging on a thin radiator predicted minimal impact due to secondary emission. By extension to worst case conditions expected at the ILC, simulations showed that background hits on BPM striplines would have a negligible impact on the accuracy of beam position measurements and hence the operation of the FONT feedback system
WEOCAB01	Design of the Beam Delivery System for the International Linear Collider	1985
	A. Seryi I. V. Agapov, G. A. Blair, S. T. Boogert, J. Carter Royal Holloway, University of London, Surrey M. Alabau, P. Bambade, J. Brossard, O. Dadoun LAL, Orsay J. A. Amann, R. Arnold, F. Asiri, K. L.F. Bane, P. Bellomo, E. Doyle, A. F. Fasso, L. Keller, J. Kim, K. Ko, Z. Li, T. W. Markiewicz, T. V.M. Maruyama, K. C. Moffeit, S. Molloy, Y. Nosochkov, N. Phinney, T. O. Raubenheimer, S. Seletskiy, S. Smith, C. M. Spencer, P. Tenenbaum, D. R. Walz, G. R. White, M. Woodley, M. Woods, L. Xiao SLAC, Menlo Park, California M. Anerella, A. K. Jain, A. Marone, B. Parker BNL, Upton, Long Island, New York D. A.-K. Angal-Kalinin, C. D. Beard, J.-L. Fernandez-Hernando, P. Goudket, F. Jackson, J. K. Jones, A. Kalinin, P. A. McIntosh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire R. Appleby UMAN, Manchester J. L. Baldy, D. Schulte CERN, Geneva L. Bellantoni, A. I. Drozhdin, V. S. Kashikhin, V. Kuchler, T. Lackowski, N. V. Mokhov, N. Nakao, T. Peterson, M. C. Ross, S. I. Striganov, J. C. Tompkins, M. Wendt, X. Yang Fermilab, Batavia, Illinois K. Buesser DESY, Hamburg P. Burrows, G. B. Christian, C. I. Clarke, A. F. Hartin OXFORDphysics, Oxford, Oxon G. Burt, A. C. Dexter Cockcroft Institute, Warrington, Cheshire J. Carwardine, C. W. Saunders ANL, Argonne, Illinois B. Constance, H. Dabiri Khah, C. Perry, C. Swinson JAI, Oxford O. Delferriere, O. Napoly, J. Payet, D. Uriot CEA, Gif-sur-Yvette C. J. Densham, R. J.S. Greenhalgh STFC/RAL, Chilton, Didcot, Oxon A. Enomoto, S. Kuroda, T. Okugi, T. Sanami, Y. Suetsugu, T. Tauchi KEK, Ibaraki A. Ferrari UU/ISV, Uppsala J. Gronberg LLNL, Livermore, California Y. Iwashita Kyoto ICR, Uji, Kyoto W. Lohmann DESY Zeuthen, Zeuthen L. Ma STFC/DL, Daresbury, Warrington, Cheshire T. M. Mattison UBC, Vancouver, B. C. T. S. Sanuki University of Tokyo, Tokyo V. I. Telnov BINP SB RAS, Novosibirsk E. T. Torrence University of Oregon, Eugene, Oregon D. Warner Colorado University at Boulder, Boulder, Colorado N. K. Watson Birmingham University, Birmingham H. Y. Yamamoto Tohoku University, Sendai
	The beam delivery system for the linear collider focuses beams to nanometer sizes at the interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the physics goals. The beam delivery system of the International Linear Collider has undergone several configuration changes recently. This paper describes the design details and status of the baseline configuration considered for the reference design.
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