IPAC2012 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOXBP01	The First Two Years of LHC Operation	luminosity, proton, ion, dipole	1
	S. Myers CERN, Geneva, Switzerland
	The operational performance of the LHC machine both for proton and lead ion operation are reviewed for the period 2010 and up the present. The beam parameter path allowing the very high rate of collider performance is presented and discussed. The accelerator issues encountered and those somewhat surprisingly not encountered are also discussed. The short and longer term plans for the LHC are also briefly presented.
	Slides MOXBP01 [17.468 MB]

MOOAA01	Performance of the Cornell High-Brightness, High-Power Electron Injector	cathode, gun, laser, electron	20
	B.M. Dunham, A.C. Bartnik, I.V. Bazarov, L. Cultrera, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, X. Liu, F. Löhl, P. Quigley, D.H. Rice, E.N. Smith, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao CLASSE, Ithaca, New York, USA S.S. Karkare, H. Li, J.M. Maxson Cornell University, Ithaca, New York, USA
	Funding: NSF DMR-0807731 The last year has seen significant progress in demonstrating the feasibility of a high current, high brightness photoinjector as required for the Energy Recovery Linac driven X-ray source at Cornell University. Both low emittances (0.4 mm-mrad rms normalized for 100% of the beam at 20 pC per bunch and 0.15 mm-mrad rms core emittance with 70% of the beam, and twice these values at 80 pC per bunch) and high average currents with a good lifetime well in excess of 1000 Coulombs at 5 MeV, 20 mA have been demonstrated. If these beams can be accelerated to 5 GeV without diluting the phase space, it would already provide a beam brightness higher than any existing storage ring. Operational experience, results, and the outlook for the future will be presented.
	Slides MOOAA01 [1.424 MB]

MOOAA02	Instrumentation and Diagnostics for High Repetition Rate Linac-driven FELs	linac, FEL, diagnostics, laser	23
	J.M. Byrd, S. De Santis, L.R. Doolittle, D. Filippetto, G. Huang, M. Placidi, A. Ratti LBNL, Berkeley, California, USA
	Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. One of the concepts for the next generation of linac-driven FELs is a cw superconducting linac driving an electron beam with MHz repetition rates. The beam is then switched into an array of independently configurable FELs. The demand for high brightness beams and the high rep-rate presents a number of challenges for the instrumentation and diagnostics. The high rep-rate also presents opportunities for increased beam stability because of the ability for much higher sampling rates for beam-based feedbacks. In this paper, we present our plans for instrumentation and diagnostics for such a machine.
	Slides MOOAA02 [1.710 MB]

MOOAB03	FACET First Beam Commissioning	linac, damping, sextupole, lattice	46
	G. Yocky, C.I. Clarke, W.S. Colocho, F.-J. Decker, M.J. Hogan, N. Lipkowitz, J. Nelson, P.M. Schuh, J.T. Seeman, J. Sheppard, H. Smith, T.J. Smith, M. Stanek, Y. Sun, J.L. Turner, M.-H. Wang, S.P. Weathersby, G.R. White, U. Wienands, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515. The FACET (Facility for Advanced aCcelerator Experimental Tests) facility at SLAC has been under Construction since summer 2010. Its goal is to produce ultrashort and transversely small bunches of very high intensity (20kA peak current) to facilitate advanced acceleration experiments like PWFA and DLA. In June of 2011 the first electron beam was brought into the newly constructed bunch-compression chicane. Commissioning work included restarting the linac and damping ring, verifying hardware, establishing a good beam trajectory, verifying the optics of the chicane, commissioning diagnostic devices for transverse and longitudinal bunch size, and tuning up the beam size and bunch compression. Running a high-intensity beam through the linac without BNS damping and with large energy spread is a significant challenge. Optical aberrations as well as wakefields conspire to increase beam emittance and the bunch compression is quite sensitive to details of the beam energy and orbit, not unlike what will be encountered in a linear-collider final-focusing system. In this paper we outline the steps we took while commissioning as well as the challenges encountered and how they were overcome.
	Slides MOOAB03 [9.167 MB]

MOOBB01	Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam	cavity, electron, simulation, radiation	49
	J.C.T. Thangaraj, H.T. Edwards, A.S. Johnson, A.H. Lumpkin, T.J. Maxwell, J. Ruan, J.K. Santucci, Y.-E. Sun, R.M. Thurman-Keup Fermilab, Batavia, USA
	Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.
	Slides MOOBB01 [2.338 MB]

MOEPPB002	The MICE Experiment	target, solenoid, electron, coupling	76
	A.P. Blondel DPNC, Genève, Switzerland
	Ionization Cooling is the only practical solution to preparing high brilliance muon beams for a neutrino factory or muon collider. The muon ionization cooling experiment (MICE) is under development at the Rutherford Appleton Laboratory (UK) by an international collaboration. The muon beam line has been commissioned and first measurements of emittance with particle physics detectors have been performed. The remaining apparatus is currently under construction. First results with a liquid-hydrogen absorber will be produced in 2013; a couple of years later a full cell of a representative ionization cooling channel, including RF re-acceleration, will be in operation. The design offers opportunities for tests with various absorbers and several optics configurations. Results will be compared with detailed simulations of cooling channel performance to ensure full understanding of the cooling process. on behalf of the MICE collaboration

MOEPPB004	A Compact Ring Design with Tunable Momentum Compaction	damping, dynamic-aperture, dipole, quadrupole	82
	Y. Sun SLAC, Menlo Park, California, USA
	A storage ring with tunable momentum compaction has the advantage in achieving diﬀerent RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre- damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and ﬁne tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

MOEPPB010	Measurement of Satellite Bunches at the LHC	photon, synchrotron, ion, coupling	97
	A. Jeff, M. Andersen, A. Boccardi, S. Bozyigit, E. Bravin, T. Lefèvre, A. Rabiller, F. Roncarolo CERN, Geneva, Switzerland A.S. Fisher SLAC, Menlo Park, California, USA C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Adam Jeff is a DITANET fellow, supported by the EU's Marie Curie actions contract PITN-GA-2008-215080. The RF gymnastics involved in the delivery of proton and lead ion bunches to the LHC can result in satellite bunches of varying intensity occupying the nominally empty RF buckets. Quantification of these satellites is crucial for bunch-by-bunch luminosity normalization as well as for machine protection. We present an overview of the longitudinal density monitor (LDM) which is the principal instrument for the measurement of satellite bunches in the LHC. The LDM uses single photon counting of synchrotron light. The very high energies reached in the LHC, combined with a dedicated undulator for diagnostics, allow synchrotron light measurements to be made with both protons and heavy ions. The arrival times of photons are collected over a few million turns, with the resulting histogram corrected for the effects of the detector’s deadtime and afterpulsing in order to reconstruct the longitudinal profile of the entire LHC ring. The LDM has achieved a dynamic range in excess of 10⁵ and a time resolution of 90 ps. Example results are presented and the measurements are benchmarked against satellite distributions based on collision data from the LHC experiments.

MOEPPB011	The Two Methods for Beam Profile Measurement of BEPCⅡ Storage Ring	synchrotron, monitoring, synchrotron-radiation, coupling	100
	L. Wang, J. Cao IHEP, Beijing, People's Republic of China
	The two method as spatial interferometor and visible light imaging for real time beam profile measurment for BEPCⅡ Storage Ring will be introduced in detail, including optical Magnification measurment, point spread function measurement, image reversion and spatial coherence measurment. the transverse emittance and copouling coefficient was gotten from the result of the beam profile monitor.

MOPPC005	Parameter Space for the LHC Luminosity Upgrade*	luminosity, target, optics, brightness	127
	F. Zimmermann, O.S. Brüning CERN, Geneva, Switzerland
	Funding: Work supported by the European Commission under the FP7 Research Infrastructures projects EuCARD, grant agreement no. 227579, and HiLumi LHC, grant agreement no. 284404. We review the parameter space for the high-luminosity upgrade of the LHC (HL-LHC). Starting from the luminosity targets and the primary limitations, e.g., long-range beam-beam effects, event pile up, electron cloud, turnaround time, intrabeam scattering, we determine the range for compatible beam parameters such as the beam intensity, bunch spacing, transverse and longitudinal emittances, bunch length, and IP beta functions required to meet the HL-LHC goals. A selection of a few possible parameter sets is presented for comparison and discussion.

MOPPC007	Plans for High Beta Optics in the LHC	optics, quadrupole, insertion, scattering	133
	H. Burkhardt, A. Macpherson CERN, Geneva, Switzerland S. Cavalier, P.M. Puzo LAL, Orsay, France
	Based on what has been learned with the first high β^* = 90 m operation in 2011, we describe the potential and practical scenarios for reaching very high β^* in the LHC in 2012 and beyond. Very high β^* optics require dedicated running time and conditions in the LHC. We describe a plan which is optimized to maximize the physics potential in a minimum of dedicated running time.

MOPPC017	Causes and Solutions for Emittance Blow-Up During the LHC Cycle	injection, luminosity, proton, feedback	160
	M. Kuhn Uni HH, Hamburg, Germany G. Arduini, B.J. Holzer, J.M. Jowett, V. Kain, F. Roncarolo, M. Schaumann, R. Versteegen, J. Wenninger CERN, Geneva, Switzerland
	Emittance measurements during the run 2011 indicated a blow-up of 20 % to 30 % from LHC injection to collisions. At the LHC design stage the total allowed emittance increase through the cycle was set to 7 %. One of the goals of the 2012 LHC run is therefore to understand and counteract the blow-up. Emittance growth measurements through the LHC cycle along with correlations with possible sources are presented in this paper. Solutions are proposed where possible. The emittance determination accuracy relies on the knowledge of the beam optics and on the present performance of the transverse profile monitors. Possible improvements of the diagnostics and of the related data analysis are also discussed.

MOPPC022	Off-momentum Dynamic Aperture for Lattices in the RHIC Heavy Ion Runs	lattice, luminosity, ion, heavy-ion	175
	Y. Luo, M. Bai, M. Blaskiewicz, W. Fischer, X. Gu, A. Marusic, T. Roser, S. Tepikian, S.Y. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this article we calculate and compare the off-momentum dynamic aperture for lattices with different phase advances per FODO cell in the RHIC heavy ion runs. A lattice with an increased phase advance was adopted in 2008-2011 to reduce transverse emittance growth rates from intra-beam scattering. However, during these runs, a large beam loss was observed with longitudinal RF re-bucketing which increased the momentum spread. With operational transverse stochastic cooling in the 2011 RHIC heavy ion run, the transverse intra-beam scattering emittance growth was eliminated, and the beam loss during stores was determined by the off-momentum aperture and burn-off from luminosity. We investigate the possibilities to increase the off-momentum dynamic aperture that would lead to an increase in the integrated luminosity.

MOPPC025	RHIC Polarized Proton Operation in Run 12	polarization, luminosity, proton, acceleration	184
	V. Schoefer, L. A. Ahrens, A. Anders, E.C. Aschenauer, G. Atoian, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, A. Dion, K.A. Drees, W. Fischer, C.J. Gardner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, L.T. Hoff, H. Huang, R.L. Hulsart, A. Kirleis, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, F. Severino, D. Smirnov, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, M. Wilinski, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang BNL, Upton, Long Island, New York, USA
	Successful RHIC operation with polarized protons requires meeting demanding and sometimes competing goals for maximizing both luminosity and beam polarization. In Run 12 we sought to fully integrate into operation the many systems that were newly commissioned in Run 11 as well as to enhance collider performance with incremental improvements throughout the acceleration cycle. For luminosity maximization special attention was paid to several possible source of emittance dilution along the injector chain, in particular to optical matching during transfer between accelerators. Possible sources of depolarization in the AGS and RHIC were also investigated including the effects of local coupling and low frequency (10 Hz) oscillations in the vertical equilibrium orbit during the RHIC ramp. The results of a fine storage energy scan made in an effort to improve store polarization lifetime are also reported in this note.

MOPPC028	Coherent Beam-Beam Effects Observation and Mitigation at the RHIC Collider	simulation, damping, coupling, dipole	193
	S.M. White, M. Bai, W. Fischer, Y. Luo, A. Marusic, M.G. Minty BNL, Upton, Long Island, New York, USA
	Funding: Work partially supported by Brookhaven Science Associates, LARP, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

MOPPC034	Use of Helical Transport Channels for Bunch Recombination	simulation, collider, luminosity, focusing	205
	D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA C.M. Ankenbrandt, C. Y. Yoshikawa Muons, Inc, Batavia, USA
	Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed.

MOPPC046	End-to-End G4Beamline Simulation of an Inverse Cyclotron for Muon Cooling	cyclotron, simulation, solenoid, extraction	238
	T.L. Hart, T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA K. Paul Tech-X, Boulder, Colorado, USA
	An inverse cyclotron is a novel, intriguing idea for muon cooling necessary for proposed neutrino factories and muon colliders. We present the latest results of an end-to-end inverse cyclotron simulation that cools muons in the following sequence: single turn injection and initial cooling of 100 MeV kinetic energies to about 5 MeV with lithium hydrogen wedges; further substantial cooling to keV range kinetic energies and trapping with carbon foils and a rising electric field; and re-acceleration of the cooled, trapped muons back to 100 MeV. For neutrino factory and muon collider applications, the time of the entire cooling/trapping/re-acceleration process needs to be comparable to the muon lifetime so that decay losses are tolerable and the acceptance of the inverse cyclotron needs to be sufficiently large (on order 10 mm-rad normalized emittance). The latest progress toward these ends is presented.

MOPPC055	A New Platform for Global Optimization	linac, simulation, TRIUMF, solenoid	256
	C. Gong, Y.-C. Chao TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Funding: Funding is received from Natural Sciences and Engineering Research Council of Canada and National Research Council of Canada for this research. This paper describes a new platform for the multi-objective global optimization of accelerator design. While local optimization is relatively simple, global optimization for accelerator design remains a challenging task. The user often must write many lines of code to combine the output of a large variety of simulation engines, then send the results to the optimization engine. The optimization code also requires significant revision when applied to different problems. This paper presents an alternative method. The TRIUMF optimization platform, based on the genetic algorithm, is an extension of the PISA framework. It uses a flexible XML input format, in which users can easily combine multiple physics engines, such as ASTRA and PARMELA, into the same optimization problem. The TRIUMF platform is also parallel capable, designed to take advantage of computation clusters such as WestGrid. Results of the optimization platform applied to TRIUMF's 50 MeV, 0.5 MW electron linac are shown.

MOPPC064	Simulation of the Behavior of Ionized Residual Gas in the Field of Electrodes	ion, simulation, electron, vacuum	283
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Meseck HZB, Berlin, Germany
	Funding: Work supported by BMBF under contract number 05K10HRC Light sources of the next generation such as ERLs require minimal beam losses as well as a stable beam position and emittance over the time. Instabilities caused by ionized residual gas have to be avoided. In this paper we present simulations of the behavior of ionized residual gas in the field of clearing electrodes and investigate e.g. clearing times. For these simulations we apply MOEVE PIC Tracking developed at Rostock University. We demonstrate numerical results with parameters planed for the ERL BERLinPro.

MOPPC072	Mathematical Model of Charged Particles Dynamics Optimization in RFQ Accelerators	rfq, controls, resonance, focusing	298
	A.D. Ovsyannikov St. Petersburg State University, St. Petersburg, Russia
	Mathematical model of optimization of transverse motion of charged particles in accelerators is suggested. Linear and nonlinear systems are considered when describing the transverse motion. Interaction of the particles is taken into account. Optimization algorithm based on minimax functionals is built. Numerical results for RFQ accelerators are presented.

MOPPC079	Modelling of the EMMA ns-FFAG Ring Using GPT	space-charge, injection, quadrupole, electron	319
	R.T.P. D'Arcy, S. Jolly UCL, London, United Kingdom J.K. Jones, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in the autumn of 2010. The energy recovery linac ALICE will serve as an injector for EMMA, within an energy range of 10 to 20 MeV. The injection line consists of a symmetric 30 degree dogleg to extract the beam from ALICE, a matching section and a tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. The ring is composed of 42 cells, each containing one focusing and one defocusing quadrupole. Acceleration over many turns of the EMMA machine has recently been confirmed. In some cases the bunch will traverse upwards of 100 turns, at which point the effects of space-charge may be significant. It is therefore necessary to model the electron beam transport in the ring using a code capable of both calculating the effect of and compensating for space-charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modeled for comparison with experimental results.

MOPPC080	Modeling Space Charge in an FFAG with Zgoubi	space-charge, lattice, acceleration, synchrotron	322
	S.C. Tygier, R. Appleby, H.L. Owen UMAN, Manchester, United Kingdom R.J. Barlow University of Huddersfield, Huddersfield, United Kingdom
	The Zgoubi particle tracker uses a ray tracing algorithm that can accurately track particles with large offset from any reference momentum and trajectory, making it suitable for FFAGs. In high current FFAGs, for example an ADSR driver, space charge has a significant effect on the beam. A transverse space charge model was added to Zgoubi using the interface pyZgoubi. The magnets are sliced and a space charge kick is applied between each slice. Results are presented for an ADSR driver lattice.

MOPPC086	Accelerator Simulation - Beyond High Performance Computing	lattice, target, simulation, site	340
	S. James, G.M. Jung, B.C. Li, K. Muriki, H. Nishimura, Y. Qin, K. Song, C. Sun LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Accelerator modeling and simulation studies heavily rely on High Performance Computing (HPC). Public Cloud computing has opened a new service horizon for HPC by offering an on-demand, Virtual Private Cloud (VPC). Previously, we investigated using Amazon HPC public Cloud for lattice optimization applications and evaluated performance. In this research, we use the Amazon VPC technology to extend local HPC resources to provide a seamless, hybrid, and secure environment when the demand for computing capacity spikes. C. Sun et al., "HPC Cloud Applied to Lattice Optimization," Proc. PAC2011, New York, WEP151, p. 1767 (2011).

MOPPC091	Parallel 3D Simulations to Support Commissioning of a Solenoid-based LEBT Test Stand	simulation, rfq, solenoid, cyclotron	349
	B.T. Schwartz, D.T. Abell, D.L. Bruhwiler, Y. Choi, S. Mahalingam, P. Stoltz, J. von Stecher Tech-X, Boulder, Colorado, USA B. Han, M.P. Stockli ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844. A solenoid-based low-energy beam transport (LEBT) test stand is under development for the Spallation Neutron Source (SNS). To support commissioning of the test stand, the parallel Vorpal framework is being used for 3D electrostatic particle-in-cell (PIC) simulations of H⁻ beam dynamics in the LEBT, including impact ionization physics and MHz chopping of the partially-neutralized \Hm beam. Here we describe the process of creating a partially-neutralized beam and examine the effects of a single chopping event on the beam's emittance.

MOPPD003	DITANET - An International Network in Beam Diagnostics	diagnostics, instrumentation, simulation, monitoring	370
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by the European Union under contract PITN-GA-2008-215080. DITANET is the largest-ever EU funded research and training network in beam diagnostics. It brings together universities, research centers and industry partners to jointly develop diagnostics methods for a wide range of existing or future particle accelerators. This is achieved through a cohesive approach that allows for the exploitation of synergies, whilst promoting knowledge exchange between partners. In addition to its broad research program, the network organizes a large number of international schools and topical workshops for the beam instrumentation and particle accelerator communities. The project comes to an end in May 2012. This contribution presents some of the network's recent research outcomes and training activities.

MOPPD004	oPAC - Optimizing Accelerators through International Collaboration	simulation, laser, controls, instrumentation	373
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by the European Union under contract PITN-GA-2011-289485. The optimization of the performance of any particle accelerator critically depends on an in-depth understanding of the beam dynamics in the machine and the availability of simulation tools to study and continuously improve all accelerator components. It also requires a complete set of beam diagnostics methods to monitor all important machine and beam parameters with high precision and a powerful control and data acquisition system. Within the oPAC project all these aspects will be closely linked with the aim to optimize the performance of present and future accelerators that lie at the heart of many research infrastructures. The project brings together 22 institutions from around the world. With a project budget of 6 M€, it is one of the largest research and training networks ever funded by the EC. This contribution gives an overview of the network's broad research program and summarizes the training events that will be organized by the consortium within the next 4 years.

MOPPD009	Stochastic Cooling Developments for HESR at FAIR	target, ion, heavy-ion, scattering	388
	H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich, Germany C. Dimopoulou, A. Dolinskii, T. Katayama, Yu.A. Litvinov, M. Steck, T. Stöhlker GSI, Darmstadt, Germany
	The High-Energy Storage Ring (HESR) is part of the upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. The HESR is planned to dedicate to the field of high-energy antiproton physics to explore the research areas of charmonium spectroscopy, hadronic structure, and quark-gluon dynamics with high-quality beams over a broad momentum range from 1.5 to 15 GeV/c. The new facility provides the combination of powerful phase-space cooled antiproton beams and internal Pellet and gas jet targets to achieve the requirements of the experiment PANDA in terms of beam quality and luminosity. Detailed theoretical analyses have been carried out to design the stochastic cooling system for accumulation and stochastic cooling of antiprotons with target operation. Recently it is proposed to utilize the HESR also for the atomic and nuclear physics with highly charged heavy ions such as 132Sn⁵⁰⁺ in the dedicated experiments at high energies 0.74-3 GeV/u. In this contribution the feasibility of stochastic cooling of heavy ions with internal targets is in detail investigated under the constraint of the cooling system hardware as foreseen for anti-proton cooling.

MOPPD037	Investigation of Space Charge Compensation at FETS	space-charge, ion, ion-source, rfq	445
	J.K. Pozimski, S.M.H. Alsari, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom D.C. Faircloth, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The ion source and LEBT are operational with the RFQ under manufacture. In the LEBT a high degree of space charge compensation (~90%) and a rise time of space charge compensation around ~ 50 μs could be concluded indirectly from measurements . As a more detailed knowledge is of interest also for other projects like ESS the FETS LEBT was updated to perform a detailed experimental analysis of space charge compensation. In this paper the results of the experimental work will be presented together with discussion of the findings in respect to beam transport.

MOPPD058	LHC Abort Gap Cleaning Studies during Luminosity Operation	luminosity, kicker, injection, beam-losses	496
	E. Gianfelice-Wendt Fermilab, Batavia, USA W. Bartmann, A. Boccardi, C. Bracco, E. Bravin, B. Goddard, W. Höfle, D. Jacquet, A. Jeff, V. Kain, M. Meddahi, F. Roncarolo, J.A. Uythoven, D. Valuch CERN, Geneva, Switzerland
	The presence of significant intensities of un-bunched beam is a potentially serious issue in the LHC. Procedures using damper kickers for cleaning both Abort Gap (AG) and buckets targeted for injection, are currently in operation at flat bottom. Recent observations of relatively high population of the AG during physics runs brought up the need for AG cleaning during luminosity operation as well. In this paper the results of experimental studies performed in October 2011 are presented.

MOPPD062	Aperture Measurements in the LHC Interaction Regions	injection, luminosity, optics, resonance	508
	S. Redaelli, M.C. Alabau Pons, R.W. Assmann, R. Bruce, M. Giovannozzi, G.J. Müller, M. Pojer, J. Wenninger CERN, Geneva, Switzerland
	The aperture of the LHC interaction regions is crucial for the LHC performance because it determines the smaller β^* that can be achieved. The aperture has been measured at a maximum energy of 3.5 TeV and at different β^* values, following optimized procedure to allow safe measurements at high energy. In this paper, the results of these aperture measurements, which are used as a reference for β^* reach and crossing scheme estimates at the LHC interaction points, are presented.

MOPPP011	Narrow Band Optimization of a Compton Gamma-Ray Source Produced From an X-Band Linac	electron, laser, simulation, linac	592
	F. Albert, S.G. Anderson, C.P.J. Barty, D.J. Gibson, F.V. Hartemann, R.A. Marsh, S.S.Q. Wu LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Nuclear photonics is an emerging field of research that will require high precision gamma-ray (MeV) sources. In particular, nuclear resonance fluorescence applications necessitate a low (< 1%) relative gamma-ray spectral width. Within this context, Compton scattering, where laser photons are scattered off relativistic electron beams to produce tunable, collimated gamma rays, will produce the desired gamma-ray output. This paper will present the spectral narrowband optimization of such a light source currently being built at LLNL. In this case, PARMELA and elegant simulations of the full 250 MeV, high-gradient X-band linac provide the properties of the high brightness electron bunch. The electron beam simulations are then implemented into our newly developed weakly nonlinear Compton scattering code to produce theoretical gamma-ray spectra. The influence that the electron beam, laser beam and interaction geometry parameters have on the produced gamma-ray spectra will be shown with our simulations.

MOPPP018	Construction Status of the Compact ERL	linac, cryomodule, gun, radiation	607
	S. Sakanaka, H. Kawata, Y. Kobayashi, N. Nakamura KEK, Ibaraki, Japan R. Hajima JAEA, Ibaraki-ken, Japan
	Future synchrotron light source based on a 3-GeV energy recovery linac (ERL) is under proposal at KEK, and we are conducting extensive R&D efforts. To demonstrate reliable operations of key components for the ERL project, as well as to demonstrate the generation of ultra-low emittance beams, we are constructing the Compact ERL (cERL). The cERL will also be used to demonstrate the generation of brilliant gamma-rays that is useful for analyzing radioisotopes. Key components, such as a photocathode DC gun, both cryomodules for the injector and the main linac, rf sources, magnets, and beam instrumentations, are under fabrication. Construction of radiation shielding for the cERL started in December, 2011. We report up-to-date status of the cERL.

MOPPP028	SRF Photoinjector for Proof-of-principle Experiment of Coherent Electron Cooling at RHIC	electron, SRF, gun, FEL	622
	D. Kayran, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, X. Liang, G.T. McIntyre, I. Pinayev, B. Sheehy, J. Skaritka, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, Q. Wu, T. Xin BNL, Upton, Long Island, New York, USA V. Litvinenko, M. Ruiz-Osés Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and by Stony Brook DOE grant DE-SC0005713. Coherent Electron Cooling (CEC) based on FEL amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

MOPPP033	Diagnostics at PITZ 2.0 Beamline: Status and New Developments	electron, diagnostics, dipole, FEL	634
	M. Otevřel, A. Donat, H.-J. Grabosch, M. Groß, L. Hakobyan, H.M. Henschel, L. Jachmann, M. Khojoyan, G. Klemz, W. Köhler, G. Koss, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, H. Leich, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, J. Meissner, A. Oppelt, M. Penno, B. Petrosyan, M. Pohl, S. Riemann, M. Sachwitz, B. Schöneich, J. Schultze, A. Shapovalov, F. Stephan, F. Tonisch, G. Vashchenko, L.V. Vu, T. Walter, S. Weisse, R.W. Wenndorff, M. Winde DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria N.I. Brusova, L.V. Kravchuk, V.V. Paramonov RAS/INR, Moscow, Russia A. Gonnin, M. Joré, B. Mercier, C. Prevost, A. Variola LAL, Orsay, France I.I. Isaev MEPhI, Moscow, Russia Ye. Ivanisenko IERT, Kharkov, Ukraine D. Richter HZB, Berlin, Germany S. Rimjaem Chiang Mai University, Chiang Mai, Thailand A.A. Zavadtsev, D.A. Zavadtsev Nano, Moscow, Russia
	The main aim of the Photo Injector Test Facility at DESY, Zeuthen (PITZ) site is to develop and test an FEL photo injector system capable of producing high charge short electron bunches of lowest possible transverse emittance to allow optimum FEL performance. The last major beamline upgrade realized in the second half of the year 2011 completed the evolution of the PITZ setup ongoing since 2005. The most recent upgrades include the installation of a new RF deflecting cavity - a prerequisite for longitudinal emittance and high resolution slice emittance measurements and installation of a new dispersive section for longitudinal phase space diagnostics of the high energy electron bunches. The paper will give an overview on electron beam diagnostics at PITZ, including the above mentioned upgrades.

MOPPP034	Simulation of the Longitudinal Phase Space Measurement with Transverse Deflecting Structure at PITZ	cavity, electron, dipole, simulation	637
	D. Malyutin, M. Krasilnikov, M. Otevřel, F. Stephan DESY Zeuthen, Zeuthen, Germany
	The main goal of the Photo Injector Test facility at DESY, Zeuthen site, (PITZ) is the development, optimization and detailed characterization of electron sources for the short wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL. For successful operation of such type of FELs the injector must provide high quality electron bunches, enough short in duration with high charge and small transverse and longitudinal emittance values. Installation of the Transverse Deflecting Structure (TDS) at PITZ will provide the possibility for detailed characterization of bunch temporal profile, bunch transverse slice emittance and longitudinal phase space. The TDS cavity is currently installed at the PITZ beamline, and commissioning of the whole TDS system is expected in the spring 2012. In the first part of the paper the basic principles of the TDS deflector are described. In the next section, simulation of measurements by TDS cavity applied to the PITZ beam parameters is presented. The temporal resolution for different types of measurements is discussed. Systematic limitations are estimated.

MOPPP035	Initial Emittance and Temporal Response Measurement for GaAs Based Photocathodes	electron, cathode, laser, cavity	640
	S. Matsuba Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan Y. Honda, T. Miyajima, T. Uchiyama, M. Yamamoto KEK, Ibaraki, Japan X.G. Jin Institute for Advanced Research, Nagoya, Japan Y. Takeda Nagoya University, Nagoya, Japan
	For future light source based on Energy Recovery Linac (ERL) is planned in KEK. For the ERL, an ultra low emittance and fast temporal response and high current electron source is needed. To achieve these requirements, a high voltage DC gun with a Negative Electron Affinity photo-cathode is under development. In this development, it is important to investigate the performance of photo-cathodes. We have constructed an ERL gun test stand to measure emittance and temporal profile. We use a solenoid scan technique for emittance measurements and a deflecting cavity technique for temporal profile measurements. In this presentation, we introduce KEK ERL gun test stand and beam test results.

MOPPP038	Optics Design and Layout for the Electron Beam Test Facility at Daresbury Laboratory	gun, quadrupole, beam-transport, laser	646
	D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.K. Jones Cockcroft Institute, Warrington, Cheshire, United Kingdom
	An Electron Beam Test Facility (EBTF) is being developed at Daresbury Laboratory to provide the beam for industrial applications and as a front end of future light source facility test under consideration. The RF photoinjector will deliver ~6 MeV beam to industrial users* and will serve as an injector for the future light source facility under consideration at Daresbury*. The Photoinjector design in first phase consists of 2.5 cell RF gun (on loan from Strathclyde) to be driven by Ti:S laser. The photo injector design is aimed to deliver bunches with 10-250 pC bunch charge at low transverse emittances and short bunch lengths. The beam transport optics design described in this paper includes a dedicated diagnostics section capable of measuring ultra short and ultra low emittance bunches and transport to two user areas. P. McIntosh, these proceedings. ** J. Clarke, these proceedings.

MOPPP039	Masked Photocathode for Photoinjectors	electron, cathode, laser, vacuum	649
	J. Qiang LBNL, Berkeley, California, USA
	Funding: This research was supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research used resources of the NERSC. In this paper, we propose using masked photocathode in photoinjector for generating high brightness electron beam. An electrode with small hole is used as a mask to shield a large size photocathode from accelerating vacuum chamber. Using a mask will significantly increase lifetime of a photocathode by rotating unexplored photocathode material behind the electrode into the hole. Furthermore, the mask helps reduce dark current or secondary electron emission from the photocathode material. It also provides a control of initial beam transverse emittances.

MOPPP041	Effect of Roughness on Emittance of Potassium Cesium Antimonide Photocathodes	cathode, laser, electron, extraction	655
	T. Vecchione, J. Feng, H.A. Padmore, W. Wan LBNL, Berkeley, California, USA I. Ben-Zvi, M. Ruiz-Osés, L. Xue Stony Brook University, Stony Brook, USA D. Dowell SLAC, Menlo Park, California, USA T. Rao, J. Smedley BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences of the U. S. Department of Energy, under Contract DE-AC02-05CH11231, KC0407-ALSJNT-I0013, and DE-SC0005713 Here we present first measurements of the effect of roughness on the emittance of K2CsSb photocathodes under high fields. We show that for very thin cathodes the effect is negligible at up to 3 MV/m but for thicker and more efficient cathodes the effect becomes significant. We discuss ways to modify the deposition to circumvent this problem.

MOPPP042	Modeling Multi-bunch X-band Photoinjector Challenges	gun, electron, linac, laser	658
	R.A. Marsh, S.G. Anderson, C.P.J. Barty, D.J. Gibson, F.V. Hartemann LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. The test station will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. Of critical import to the functioning of the LLNL X-band system with multiple electron bunches is the performance of the photoinjector. In depth modeling of the Mark 1 LLNL/SLAC X-band rf photoinjector performance will be presented addressing important challenges that must be addressed in order to fabricate a multi-bunch Mark 2 photoinjector. Emittance performance is evaluated under different nominal electron bunch parameters using electrostatic codes such as PARMELA. Wake potential is analyzed using electromagnetic time domain simulations using the ACE3P code T3P. Beam-loading effects and low level rf compensation schemes are explored as well, using a semi-analytic formalism and computer algorithm. Plans for multi-bunch experiments and implementation of photoinjector advances for the Mark 2 design will also be discussed.

MOPPP046	RF Gun Photocathode Research at SLAC	gun, cathode, laser, electron	664
	E.N. Jongewaard, R. Akre, A. Brachmann, W.J. Corbett, S. Gilevich, K. Grouev, P. Hering, P. Krejcik, J.R. Lewandowski, H. Loos, T. M. Montagne, J. Sheppard, P. Stefan, A.E. Vlieks, S.P. Weathersby, F. Zhou SLAC, Menlo Park, California, USA
	Funding: DOE contract DE-AC02-76SF00515. LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of ~1x10^-4 and projected emittance eNx,y=0.45 μm at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), processed to the design rf gradient of >120 MV/m. As part of a wider photocathode R&D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

MOPPP050	Physics Results of the NSLS-II Linac Front End Test Stand	linac, simulation, gun, electron	673
	R.P. Fliller, F. Gao, J. Rose, T.V. Shaftan, X. Yang BNL, Upton, Long Island, New York, USA G. Blokesch PPT, Dortmund, Germany C. Piel RI Research Instruments GmbH, Bergisch Gladbach, Germany
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The NSLS-II linac is produced by Research Instruments and will be commissioned in the spring of 2012. As part of the procurement, the linac front end consisting of the gun, prebunching cavity, and diagnostics was delivered early to BNL for testing. We designed a short beamline to supplement the Front End diagnostics to characterize the beam. These tests were instrumental in demonstrating the functioning of the gun, pinpointing technical problems at an early project stage and gaining experience with the linac gun by BNL staff prior to commissioning of the full linac. In this report we show the results of the tests, including charge, bunch length, and transverse emittance measurements and compare them with the relevant linac specifications.

MOPPP052	Booster Synchrotron for SIRIUS Light Source	booster, injection, dipole, extraction	679
	F. H. de Sá, L. Liu, A.R.D. Rodrigues LNLS, Campinas, Brazil
	A full energy 3 GeV booster for the new Brazilian Synchrotron Light Laboratory (LNLS) third generation light source, SIRIUS, is proposed. The 144 m circumference magnetic lattice consists of two super-periods of FODO cells with defocusing dipoles and focusing quadrupoles. The optics provides a low emittance beam of 38 nm.rad at 3 GeV, high horizontal betatron and zero dispersion functions at straight sections. The top-up operation requires a cycling energy ramp from 150 MeV to 3 GeV with repetition rate of 1 Hz.

MOPPP054	Study of a New Injection Scheme for the SSRF Storage Ring	injection, kicker, storage-ring, dynamic-aperture	685
	M.Z. Zhang, B.C. Jiang, L. Ouyang, Q.L. Sun, S.Q. Tian SINAP, Shanghai, People's Republic of China
	A low emittance configuration of the SSRF storage ring had been designed and commissioned. Along with reducing the emittance, the dynamic aperture decreases quickly. It doesn’t meet aperture require of the normal injection scheme anymore and the injection efficiency is lower. The pulsed multi-pole magnets give the opportunity to overcome the smaller dynamic aperture. Pulsed quadrupole and sextupole both are study for the injection scheme. With and without the orbit bump kickers are also considered in this study. The injection scheme suggestions are presented in this paper.

MOPPP057	Optimization of the Low-emittance Lattice of the APS Booster Synchrotron	booster, lattice, injection, sextupole	690
	C. Yao, V. Sajaev, N. Sereno, H. Shang ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06- CH11357. The APS booster is a 7GeV electron synchrotron. Three lattices have been originally designed with a nominal beam emittance of 132, 109, and 92 nm, respectively. In the past we have mostly operated the booster with the 132 nm lattice because of its better stability. The lower-emittance lattices are not utilized. In early 2010 we upgraded the booster ramp correction and reduced the 360Hz current ripples of the ramp supplies. Current ramp errors have been significantly reduced. This raises our interest in running the low- emittance lattice to improve APS storage ring injection efficiency and reduce radiation losses. This report presents the optimization methods and measurement results of booster beam performance of the booster 92nm lattice.

MOPPP062	Soleil Emittance Reduction using a Robinson Wiggler	photon, brightness, damping, wiggler	702
	H.B. Abualrob, P. Brunelle, M.-E. Couprie, O. Marcouillé, A. Nadji, L.S. Nadolski, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	For both synchrotron light sources as SOLEIL and colliders, the emittance is one of the key parameters to increase the photon brightness and the beam luminosity. In order to decrease the emittance, the ring optics is built on very focusing lattices leading to large chromaticities and potential reduction of the dynamics aperture and momentum transverse acceptance. Thus, some facilities have installed damping wigglers in zero dispersion straight sections to relax the optics and to reach sub-nanometer horizontal emittances. This solution requires however tens or hundreds meters of insertion devices. For storage ring equipped with zero-gradient bending magnets, an alternative solution can be given by installing a single Robinson wiggler [1] in a dispersive section enabling to divide the emittance by a factor 2. The uniqueness of this wiggler results from the presence of an alternated gradient superimposed the main periodic magnetic field. This paper recalls the concept of the wiggler, presents the expected gain for SOLEIL storage ring with the impact on the linear optics and the brightness. A preliminary magnetic design is also proposed. [1] K.W. Robinson, Phys. Rev, p. 373 (1958).

MOPPP066	Calculated Spectra from Magnetic Field Measurements of 1.5 m Superconducting Undulator Coils	undulator, permanent-magnet, vacuum, storage-ring	711
	S. Casalbuoni, T. Baumbach, S. Gerstl, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany C. Boffo, W. Walter BNG, Würzburg, Germany
	In this contribution we report on the spectra calculated from the field measurements performed in a liquid helium bath of 1.5 m superconducting undulator coils. The coils are foreseen for a superconducting undulator demonstrator with a period length of 15 mm planned to be installed in ANKA middle 2012 and tested at the new beamline NANO for high resolution X-ray diffraction. The spectral performance at ANKA and at low emittance sources is compared with the competing cryogenic permanent magnet technology.

MOPPR002	Overview of the Beam Diagnostics in the MedAustron Accelerator: Design Choices and Test Beam Commissioning	synchrotron, injection, extraction, proton	774
	F. Osmic, M. Feurstein, A. Gyorgy, A. Kerschbaum, M. Repovz, S.M. Schwarz EBG MedAustron, Wr. Neustadt, Austria G. Burtin CERN, Geneva, Switzerland
	The MedAustron center is a synchrotron based accelerator complex for cancer treatment and for clinical and non-clinical research with protons and light ions, currently under construction in Wiener Neustadt, Austria. The accelerator complex is based on the CERN-PIMMS study and its technical implementation by the Italian CNAO foundation in Pavia. The MedAustron beam diagnostics system is based on sixteen different monitor types (153 devices in total) and will allow measuring all relevant beam parameters from the source to the irradiation rooms. The monitors will have to cope with large intensity and energy ranges. Currently, one ion source, the low energy beam transfer line and the RFQ are being commissioned in the Injector Test Stand (ITS) at CERN. This paper gives an overview of all beam monitors foreseen for the MedAustron accelerator, elaborates some of the design choices, and reports the first beam commissioning results from the ITS.

MOPPR010	Simultaneous Measurement of Emittance at the Storage Ring and the External Beamlines of ELSA	quadrupole, synchrotron, extraction, diagnostics	792
	S. Zander, F. Frommberger, W. Hillert, D. Proft ELSA, Bonn, Germany
	Funding: Funded by the DFG within the SFB / TR 16. The Electron Stretcher Facility (ELSA) consists of several accelerator stages, the last one being a storage ring providing a beam of polarized electrons of up to 3.5 GeV. To ensure a high duty cycle, a slow extraction via a third integer resonance is applied at ELSA. The resonance extraction cause a variation of the emittance in the external beamline. A system for simultaneous measurement of emittance in the storage ring and the external beamlines has been installed. First results including a comparison of both emittances will be shown.

MOPPR024	Non-intercepting Emittance Measurements by means of Optical Diffraction Radiation Interference for High Brightness Electron Beam	radiation, quadrupole, electron, target	831
	A. Cianchi Università di Roma II Tor Vergata, Roma, Italy V. Balandin, N. Golubeva, K. Honkavaara, G. Kube DESY, Hamburg, Germany M. Castellano, E. Chiadroni INFN/LNF, Frascati (Roma), Italy L. Catani INFN-Roma II, Roma, Italy
	Conventional intercepting transverse electron beam diagnostics, e.g. based on Optical Transition Radiation (OTR), cannot tolerate high power beams without remarkable mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR) is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitations of this method is the low signal to noise ratio, mainly due to the unavoidable synchrotron radiation background. This problem can be overcome by using ODRI (Optical Diffraction Radiation Interference). In this case the beam goes through two slits opened on metallic foils, placed in a distance shorter than the radiation formation zone. Thanks to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. Here we report the first measurements, carried out at FLASH (DESY, Germany), of the beam emittance using ODRI. Our results demonstrate the unique potential of this technique.

MOPPR025	The BPM DAQ System Upgrade for SuperKEKB Injector Linac	linac, electron, positron, injection	834
	M. Satoh, K. Furukawa, F. Miyahara, T. Suwada KEK, Ibaraki, Japan T. Kudou, S. Kusano MELCO SC, Tsukuba, Japan
	The non-destructive beam position monitor (BPM) is indispensable diagnostic tool for the stable beam operation. In the KEK Linac, approximately nineteen BPMs with the strip-line type electrodes are used for the beam orbit measurement and feedback. In addition, some of them are also used for the beam energy feedback loops. The current DAQ system consists of the fast digital oscilloscopes. A signal from each electrode is analyzed with a predetermined response function up to 50 Hz. The beam position resolution of current system is limited to about 0.5 mm because of ADC resolution. Towards SuperKEKB project, we have a plan to upgrade the BPM DAQ system since the Linac should provide the smaller emittance beam. We will report the system description of the new DAQ system and the results of performance test in detail.

MOPPR040	Design and Measurements of a Test Stand for the SEM-Grid System of the ESS-BILBAO	electron, vacuum, diagnostics, linac	867
	D. Belver, J. Feuchtwanger, P.J. González ESS Bilbao, LEIOA, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain V. Etxebarria, J. Jugo University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	In the framework of the ESS-Bilbao accelerator, a test stand for the development of Secondary Electron EMission grid (SEM-Grid) has been designed and manufactured as a part of the diagnostics system for beam profile measurements. This test stand is a vacuum system based on an EQ 22/35 electron source from SPECS used as a beam injector. This electron source has an energy range from 0 to 5 KeV and a maximum beam current up to 200 μA. Although we have thought in a SEM-Grid of 40 wires (20 wires in each X and Y direction), two prototypes of 16 wires (8x8) of 250 μm diameter and spaced 1 and 2 mm, respectively, have been developed due to its easier implementation and tested in the test stand. In order to develop an electronics readout system for the SEM-Grid, first studies of the prototype signals have been done. The secondary emission current of each wire will be integrated and amplified to provide a significant voltage signal that can be measured by our acquisition system. A description of the SEM-Grid test stand and the measurements developed is given here.

MOPPR044	Optics and Emittance Studies using the ATF2 Multi-OTR System	coupling, quadrupole, target, controls	879
	J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López IFIC, Valencia, Spain J. Cruz, D.J. McCormick, G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Funding Agency: FPA2010-21456-C02-01. Work supported in part by Department of Energy Contract DE-AC02-76SF00515. A multi-OTR system (4 beam ellipse diagnostic devices based on optical transition radiation) was installed in the extraction line of ATF2 and has been fully operational since September 2011. The OTRs have been upgraded with a motorized zoom-control lens system to improve beam finding and accommodate different beam sizes. The system is being used routinely for beam size and emittance measurements as well as coupling correction. In this paper we present measurements performed during the winter run of 2011 and the early 2012 runs. We show the reconstruction of twiss parameters and emittance, discuss the reliability of the OTR system and show comparisons with simulations. We also present new work to calculate all 4 coupling terms and form the “4-D” intrinsic emittance of the beam utilizing all the information available from the 2-D beam profile images. We also show details and experimental results for performing a 1-shot automated coupling correction.

MOPPR048	Beam Instrumentation for the HIE-ISOLDE Linac at CERN	diagnostics, linac, cryomodule, ion	891
	E. Bravin, A.G. Sosa, D. Voulot, F.J.C. Wenander, F. Zocca CERN, Geneva, Switzerland M.A. Fraser UMAN, Manchester, United Kingdom J.H. Galipienzo AVS, Eibar, Gipuzkoa, Spain M. Pasini Instituut voor Kern- en Stralingsfysica, K. U. Leuven, Leuven, Belgium C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	In the framework of the High Intensity and Energy (HIE)-ISOLDE project at CERN, a beam instrumentation R&D program is on-going for the superconducting upgrade of the REX-ISOLDE heavy-ion post-accelerator. An overview of the foreseen beam diagnostics system is presented, focusing on the challenging specifications required by the HIE-ISOLDE linac. Due to the low beam intensities, the diagnostic instrumentation will be based on high-sensitivity intercepting devices. The project includes intensity and transverse profile monitors to be implemented in the very narrow longitudinal space that is available for beam diagnostics in the regions between the superconducting cryomodules. A longitudinal profile monitor is foreseen downstream of the linac to measure the beam energy and arrival time distributions and to allow for a fast phase-tuning of the superconducting cavities. A custom-made emittance meter will provide transverse emittance measurements based on a phase space sampling technique. The design status of the different instruments will be presented as well as the results of some experimental tests.

MOPPR068	Design and Development of the Diagnostic System for 75 MeV Electron Drive Beam for the AWA Upgrade	diagnostics, controls, wakefield, cavity	942
	J.G. Power, S.P. Antipov, M.E. Conde, W. Gai, C.-J. Jing, W. Liu, E.E. Wisniewski, Z.M. Yusof ANL, Argonne, USA
	Funding: Work supported by High Energy Physics, Office of Science, US DOE We report on the development of the diagnostic system for the ongoing upgrade to the Argonne Wakefield Accelerator (AWA) facility where the electron drive beam energy will be increased from 15 to 75 MeV. The facility will produce a wide dynamic range of drive bunch train formats ranging from a single microbunch of 100 pC to bunch trains of up to 32 bunches spaced by 769 ps with up to 100 nC per bunch. In addition to standard diagnostics, this drive bunch train format poses two challenges for the diagnostic system: (i) the close spacing of the drive bunches, 769 ps, makes resolving the individual pulses difficult and (ii) the dynamic range of the bunch charge varies by x1000. A critical parameter of the drive bunch train for the wakefield accelerator is the charge along the train. To measure this, we are planning to use a 15 GHz digital oscilloscope to read either a BPM or Bergoz FCT. To handle the large dynamic range of charge, the imaging system will make use of GigE Vision cameras and a distributed system of motorized lenses, with remote control of focus, zoom, and aperture, which are operated through terminal servers and RS232 controllers.

MOPPR072	Fermilab PXIE Beam Diagnostics Development and Testing at the HINS Beam Facility	diagnostics, laser, linac, rfq	954
	V.E. Scarpine, B.M. Hanna, V.A. Lebedev, L.R. Prost, A.V. Shemyakin, J. Steimel, M. Wendt Fermilab, Batavia, USA
	Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359. Fermilab is planning the construction of a prototype front end of the Project X linac. The Project X Injector Experiment (PXIE) is expected to accelerate 1 mA cw H⁻ beam up to 30 MeV. Some of the major goals of the project are to test a cw RFQ and H⁻ source, a broadband bunch-by-bunch beam chopper and a low-energy superconducting linac. The successful characterization and operation of such an accelerator places stringent requirements on beam line diagnostics. These crucial beam measurements include bunch currents, beam orbit, beam phase, bunch length, transverse profile and emittance, beam halo and tails, as well as the extinction performance of the broadband chopper. This paper presents PXIE beam measurement requirements and instrumentation development plans. Also presented are plans to test many of these instruments at the Fermilab High Intensity Neutrino Source (HINS) beam facility. Since HINS is already an operational accelerator, utilizing HINS for instrumentation testing allows for quicker development of the required PXIE diagnostics.

MOPPR076	Using the BRAN Luminosity Detectors for Beam Emittance Monitoring During LHC Physics Runs	luminosity, monitoring, interaction-region, proton	966
	A. Ratti, H.S. Matis, M. Placidi, W.C. Turner LBNL, Berkeley, California, USA E. Bravin CERN, Geneva, Switzerland T.E. Lahey SLAC, Menlo Park, California, USA E.S.M. McCrory Fermilab, Batavia, USA R. Miyamoto ESS, Lund, Sweden S.M. White BNL, Upton, Long Island, New York, USA
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). The BRAN Ionization Chambers installed at the IP1 and IP5 Interaction Points of the LHC provide a relative measurement of the total and bunch-by-bunch luminosities. This information, combined with the logged bunch charges from a fast BCT monitor, offers the possibility of evaluating the Interaction Area in collision for each of the colliding bunch pairs and monitor its time evolution. A Graphic User Interface (GUI) has been implemented to display the interaction area of the proton bunches interacting in IP1 and IP5 during each of the Physics Runs in the attempt of displaying the contribution to the Luminosity time decay originating from possible emittance blow-up when operating the Accelerator close to the beam-beam limit. Early results confirm the ability to characterize the bunch by bunch emittance behavior during the store and study possible differences among bunches in the same fill.

MOPPR079	Horizontal Beam-size Measurements at CESR-TA Using Synchrotron-light Interferometer	synchrotron, synchrotron-radiation, scattering, lattice	972
	S. Wang, J.V. Conway, D.L. Hartill, M.A. Palmer, D. L. Rubin CLASSE, Ithaca, New York, USA R.F. Campbell, R. Holtzapple CalPoly, San Luis Obispo, California, USA
	Funding: DOE Award DE-FC02-08ER41538 NSF Award (PHY-0734867) NSF Award (PHY-1002467) NSF Award (PHY-1068662). A horizontal beam profile monitor utilizing visible synchrotron radiation from a bending magnet has been designed and installed in CESR. The monitor employs a double-slit interferometer which has been successfully implemented to measure horizontal beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 microns can be measured with a resolution of approximately 5 microns. The method for extracting the horizontal beam size from the interference pattern is presented and its application to intrabeam scattering studies is described. A configuration for measuring the small vertical beam size is also discussed.

MOPPR087	Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center	quadrupole, electron, linac, background	990
	S. Setiniyaz, T.A. Forest ISU, Pocatello, Idaho, USA K. Chouffani, Y. Kim IAC, Pocatello, IDAHO, USA A. Freyberger JLAB, Newport News, Virginia, USA
	A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

MOPPR092	SVD-BASED METHOD FOR MEASUREMENT OF BEAM PARAMETERS AND FLAG RESOLUTION	quadrupole, simulation, booster, focusing	999
	G.M. Wang, R.P. Fliller, I. Pinayev, T.V. Shaftan BNL, Upton, Long Island, New York, USA
	In NSLS II booster to storage ring transport line, the typical beam size in vertical plane is ~60 μm, which requires very high flag resolution to get good beam parameters measurement. This paper describes a new SVD-based method to measure transverse beam parameters and flag resolution simultaneously with double quads scan. Implementation simulations of the proposed method are performed for a dispersion free region in the NSLS-II booster to storage ring transport line. With this method, it breaks the limitation of beam parameters measurement accuracy duo to the flag resolution.

MOPPR094	Preparation for NSLS II Linac to Booster Transport Line Commissioning	linac, controls, booster, status	1002
	G.M. Wang, M.A. Davidsaver, R.P. Fliller, G. Ganetis, H.-C. Hseuh, Y. Hu, D. Padrazo, T.V. Shaftan, G. Shen, O. Singh, Y. Tian, H. Xu, L. Yang BNL, Upton, Long Island, New York, USA
	The National Synchrotron Light Source II (NSLS-II) is a state-of-the-art 3-GeV third generation light source currently under construction at Brookhaven National Laboratory. The first part of the Linac to Booster Transport (LBT) line has been installed for the linac commissioning. This part will be used for the linac acceptance test. In this paper, we describe the preparation of the LBT sub-system integration test and the high level applications.

TUXA03	Increasing the AGS Beam Polarization with 80 Tune Jumps	resonance, polarization, quadrupole, closed-orbit	1015
	V. Schoefer, L. A. Ahrens, M. Bai, E.D. Courant, W. Fu, C.J. Gardner, J.W. Glenn, H. Huang, F. Lin, A.U. Luccio, J.-L. Mi, J. Morris, P.J. Rosas, T. Roser, P. Thieberger, N. Tsoupas, A. Zelenski, K. Zeno BNL, Upton, Long Island, New York, USA
	Vertical depolarizing resonances in the AGS are removed by partial Siberian snakes. These magnets move the stable spin direction and lead to horizontal depolarizing resonances. The tune jump quadrupole system increases the crossing rate for horizontal resonances by a factor of six. This presentation will review the fundamental mechanism of depolarizing resonances, the partial Siberian snake solution and describe recent experimental evidence at the AGS demonstrating improvements to beam polarization and the beam dynamics challenges posed by the tune jump.
	Slides TUXA03 [5.199 MB]

TUYA01	Research and Development of Future Muon Collider	cavity, collider, plasma, proton	1020
	K. Yonehara Fermilab, Batavia, USA
	A muon collider would provide a unique facility for future elementary-particle physics research, and present unique challenges for accelerator physics and technology. An R&D effort is underway to address major challenges in the design of a future muon collider. This talk should provide an opportunity to discuss the muon collider's challenges, present recent R&D results, and describe future prospects.

TUXB01	Progress Towards Ultimate Storage Ring Light Sources	brightness, electron, dipole, wiggler	1035
	M. Borland ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Developments such as the low emittance NSLS-II storage ring, followed by the even lower emittance MAX-IV ring, demonstrate that the technology of storage ring light sources has not reached full maturity. Indeed, these new sources are paving the way toward realizing diffraction-limited angstrom-wavelength storage ring light sources in the not-too-distant future. Our discussion begins with a review of recent trends and developments in storage ring design. We then survey on-going work around the world to develop concepts and designs for so-called "ultimate" storage ring light sources.
	Slides TUXB01 [3.442 MB]

TUXB02	Review of ERL Projects at KEK and Around the World	linac, gun, FEL, electron	1040
	N. Nakamura KEK, Ibaraki, Japan
	Future synchrotron light sources based on energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The Japanese collaboration team is making efforts for realizing an ERL-based VUV and X-ray source with R&D efforts on super-conducting cavities and the electron gun at KEK and elsewhere. This presentation will describe the developments of the compact ERL project and the outline of the 3-GeV ERL light source project at KEK and also review ERL projects around the world, including potential applications to colliders.
	Slides TUXB02 [25.328 MB]

TUOAA03	Tests of Low Emittance Tuning Techniques at SLS and DAΦNE	quadrupole, coupling, alignment, collider	1065
	S.M. Liuzzo, M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma), Italy M. Aiba Paul Scherrer Institut, Villigen, Switzerland M. Böge PSI, Villigen, Switzerland
	The SuperB collider design is based on extremely low emittances, comparable to those of synchrotron light sources. A Low Emittance Tuning (LET) algorithm was developed for SuperB and has been tested last year at DIAMOND. This paper will report on the results of the application of LET to SLS (PSI) and DAΦNE (LNF) in order to compare and confirm the previous results. In this tests, the correction of orbit, dispersion and coupling is applied simultaneously to the detection of Beam Position Monitors tilts. The effect of beam based alignment at DAΦNE is also presented, together with an evaluation of the effects of other possible sources of emittance growth.
	Slides TUOAA03 [4.313 MB]

TUOBA01	Summary of Fermilab’s Recycler Electron Cooler Operation and Studies	electron, antiproton, ion, extraction	1068
	L.R. Prost, A.V. Shemyakin Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Fermilab’s Recycler ring was used as a storage ring for accumulation and subsequent manipulations of 8 GeV antiprotons destined for the Tevatron collider. To satisfy these missions, a unique electron cooling system was designed, developed and successfully implemented. The most important features that distinguish the Recycler cooler from other existing electron coolers are its relativistic energy (it employs a 4.3 MeV, 0.1 A DC electron beam), a weak continuous longitudinal magnetic field in the cooling section (~100 G), and lumped focusing elsewhere. With the termination of the collider operation at Fermilab, the cooler operation was also terminated. In this article, we will summarize the experience of commissioning, optimizing and running this unique machine over the 6 years of its existence.
	Slides TUOBA01 [2.503 MB]

TUOBB01	A European Proposal for the Compton Gamma-ray Source of ELI-NP	laser, photon, electron, scattering	1086
	L. Serafini, I. Boscolo, F. Broggi, V. Petrillo Istituto Nazionale di Fisica Nucleare, Milano, Italy O. Adriani, G. Graziani, G. Passaleva INFN-FI, Sesto Fiorentino, Italy S. Albergo, A. Tricomi INFN-CT, Catania, Italy D. Alesini, M.P. Anania, A. Bacci, R. Bedogni, M. Bellaveglia, C. Biscari, R. Boni, M. Boscolo, M. Castellano, E. Chiadroni, A. Clozza, E. Di Pasquale, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, F. Marcellini, C. Maroli, G. Mazzitelli, E. Pace, L. Pellegrino, R. Ricci, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, P. Tomassini, C. Vaccarezza, S. Vescovi, F. Villa INFN/LNF, Frascati (Roma), Italy D. Angal-Kalinin, J.A. Clarke, B.D. Fell, A.R. Goulden, J.D. Herbert, S.P. Jamison, P.A. McIntosh, R.J. Smith, S.L. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P. Antici, M. Coppola, L. Lancia, A. Mostacci, L. Palumbo URLS, Rome, Italy N. Bliss, B.G. Martlew STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom P. Cardarelli, M. Gambaccini INFN-Ferrara, Ferrara, Italy L. Catani, A. Cianchi INFN-Roma II, Roma, Italy I. Chaikovska, O. Dadoun, A. Stocchi, A. Variola, Z.F. Zomer LAL, Orsay, France C. De Martinis INFN/LASA, Segrate (MI), Italy F. Druon, P. Fichot ILE, Palaiseau Cedex, France E. Iarocci University of Rome "La Sapienza", Rome, Italy M. Migliorati Rome University La Sapienza, Roma, Italy A.-S. Müller IN2P3, Paris, France V. Nardone Università di Roma I La Sapienza, Roma, Italy C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy M. Veltri Uniurb, Urbino (PU), Italy
	A European proposal is under preparation for the Compton gamma-ray Source of ELI-NP. In the Romanian pillar of ELI (the European Extreme Light Infrastructure) an advanced gamma-ray beam is foreseen, coupled to two 10 PW laser systems. The photons will be generated by Compton back-scattering in the collision between a high quality electron beam and a high power laser. A European collaboration formed by INFN, Univ. of Roma La Sapienza, Orsay-LAL of IN2P3, Univ. de Paris Sud XI and ASTeC at Daresbury, is preparing a TDR exploring the feasibility of a machine expected to achieve the Gamma-ray beam specifications: energy tunable between 1 and 20 MeV, narrow bandwidth (0.3%) and high spectral density, 10⁴ photons/sec/eV. We will describe the lay-out of the 720 MeV RF Linac and the collision laser with the associated optical cavity, as well as the optimized beam dynamics to achieve maximum phase space density at the collision, taking into account beam loading and beam break-up due to the acceleration of long bunch trains. The predicted gamma-ray spectra will be evaluated as the gamma photons collimators background. An option for electron bunches recirculation will also be illustrated.
	Slides TUOBB01 [5.099 MB]

TUOBC01	Experimental Verification of the CLIC Two-beam Scheme, Status and Outlook	linac, acceleration, target, gun	1101
	R. Corsini CERN, Geneva, Switzerland
	The feasibility of the CLIC novel scheme of two-beam acceleration was extensively tested in the CTF3 facility over the last few years. In particular, efficient full beam loading acceleration, isochronous ring operation, beam recombination by transverse RF deflectors have been fully proven. 12 GHz RF power production by high-current drive beam is now part of CTF3 routine operation, and two-beam acceleration up to 150 MV/m has been achieved. Drive beam deceleration tests were carried out as well. In this paper we summarize the main results obtained, including the more recent ones. We also outline and discuss the future experimental program, both in CTF3 and in other beam facilities, as well as the path to a possible facility needed in the initial stage of the CLIC project, CLIC0.
	Slides TUOBC01 [9.921 MB]

TUEPPB006	Direct Numerical Modeling of E-Cloud Driven Instability of Three Consecutive Batches in the CERN SPS	electron, simulation, feedback, betatron	1125
	J.-L. Vay, M.A. Furman, M. Venturini LBNL, Berkeley, California, USA
	Funding: Supported by the US-DOE under Contract DE-AC02-05CH11231, the SciDAC program ComPASS and the US-LHC Accelerator Research Program (LARP). Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. The simulation package WARP-POSINST was recently upgraded for handling multiple bunches and modeling concurrently the electron cloud buildup and its effect on the beam, allowing for direct self-consistent simulation of bunch trains generating, and interacting with, electron clouds. We have used the WARP-POSINST package on massively parallel supercomputers to study the buildup and interaction of electron clouds with a proton bunch train in the CERN SPS accelerator. Results suggest that a positive feedback mechanism exists between the electron buildup and the e-cloud driven transverse instability, leading to a net increase in predicted electron density. Used resources of NERSC.

TUPPC003	Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors	coupling, quadrupole, sextupole, betatron	1152
	A. Chancé, J. Payet CEA/DSM/IRFU, France B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC004	Study of a Lattice with a Lower Emittance at SOLEIL	dipole, lattice, optics, betatron	1155
	R. Nagaoka, P. Brunelle, A. Nadji, L.S. Nadolski SOLEIL, Gif-sur-Yvette, France
	The paper introduces the first preliminary feasibility study made at SOLEIL towards a possible future upgrade of the lattice in furthermore reducing the horizontal emittance, so to raise the storage ring performance. The approach taken is to employ whatever emittance reduction methods available, by respecting the given constraints on the lattice structure and the optics, particularly the circumference, insertion device straights, the required optics behavior as well as its tunability. Specifically, the possibility of introducing superbends into the double bend lattice is pursued, which are beneficial to hard X-ray users and could simultaneously help reducing the emittance thanks to its longitudinally varying field profile. Although the present study shall mainly focus on the linear properties of the optical solutions found, optimization of nonlinear optics is also discussed in view of the large dependence of the latter on the former.

TUPPC008	Twiss Parameters of Coupled Particle Beams with Equal Eigenemittances	beam-transport	1167
	V. Balandin, R. Brinkmann, W. Decking, N. Golubeva DESY, Hamburg, Germany
	The parametrization of coupled beam motion has been studied intensively over the past decades. Nevertheless, there is still no representation of general coupled motion that would be as elegant and as complete as the one dimensional Courant-Snyder theory. In this context the consideration of different partial cases plays an important highlighting role, and in this paper we study the parametrization of coupled particle beams with equal eigenemittances. We show that such beams allow description which in many aspects resembles the one dimensional Courant-Snyder theory.

TUPPC010	Study of Effects of Failure of Beamline Elements and its Compensation in CW Superconducting Linac	linac, cavity, beam-losses, focusing	1173
	A. Saini, K. Ranjan University of Delhi, Delhi, India C.S. Mishra, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	Project-X is the proposed high intensity proton facility to be built at Fermilab in United States. First stage of the Project-X consists of H^- superconducting linac (SC) which will be operated in continuous wave (CW) mode to accelerate the beam from kinetic energy of 2.1 MeV to 3 GeV. The operation in CW mode puts stringent tolerances on the beam line components, particularly at low energy section. The failure of beam line elements result in mismatch of the beam with the following sections due to different beam parameters than designed parameters. It makes the beam unstable which causes emittance dilution, and ultimately results in beam losses. In worst case, it can affect the reliability of the machine and may lead to the shutdown of the linac to replace the failed elements. Thus, it is important to study impacts of these effects and their compensation to restore linac performance to avoid beam interruption. This paper presents the studies performed for the failure of accelerating cavity and focusing magnets at the critical locations in the Project-X CW superconducting linac

TUPPC013	Optimization of Lower Emittance Optics for the SPring-8 Storage Ring	optics, photon, lattice, brilliance	1182
	Y. Shimosaki, K.K. Kaneki, M. Masaki, T. Nakamura, H. Ohkuma, J. Schimizu, K. Soutome, S. Takano, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	A design work of the present SPring-8 storage ring is in progress to improve its performance. The linear optics has been changed to reduce the natural emittance below the nominal of 3.4 nmrad at 8 GeV, and the nonlinear optics has been optimized with a genetic algorithm to suppress the amplitude-dependent tune shifts and to enlarge the dynamic aperture. As a preliminary study, the optics with the natural emittance of 2.4 nmrad at 8 GeV has been examined, theoretically and experimentally. In this optics, 1.5 times higher brilliance for 10 keV photons than the present can theoretically be expected for the standard undulator beamline. The improved optics design and its beam performance will be presented in detail. In this presentation, a optics for a future upgrade of the SPring-8 (SPring-8 II) will not be discussed, which is a full-scale major lattice modification, while the method we used in optimizing the nonlinear optics can also be adopted to the SPring-8 II. Y. Shimosaki et al., "Design Study of Nonlinear Optics for a Very Low-emittance Lattice of the SPring-8 II," these proceedings.

TUPPC014	Design Study of Nonlinear Optics for a Very Low-emittance Lattice of the SPring-8 II	lattice, sextupole, resonance, optics	1185
	Y. Shimosaki, K.K. Kaneki, T. Nakamura, H. Ohkuma, J. Schimizu, K. Soutome, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	A feasibility of a very low-emittance storage ring has been studied for an upgrade project, SPring-8 II. Its ultimate goal is to provide a superior brilliance for 0.5 ~ 100 keV photons. A sextupole bend lattice with the natural emittance of 70 pmrad at 6 GeV has been examined as the first candidate. The nonlinear optics has been optimized to enlarge the dynamic aperture by correcting nonlinear resonances based on an isolated resonance Hamiltonian with thick lens approximation, and by non-interleaved sextupole method. A genetic algorithm, which has been examined to improve the performance of the present SPring-8, will be adopted for detailed optimization of the tunes and sextupole strength to adjust the non-interleaved scheme and to correct higher order resonances. The correction scheme of nonlinear optics and its results will be presented in detail. Y. Shimosaki et al., IPAC’11, TUOAB01, p. 942 (2011). **Y. Shimosaki et al., "Optimization of Lower Emittance Optics for the SPring-8 Storage Ring", these proceedings.

TUPPC017	Orbit and Optics Correction to Realize Designed Machine Performance	optics, lattice, target, closed-orbit	1194
	Y. Seimiya, S. Kamada, A. Morita, K. Ohmi, K. Oide KEK, Ibaraki, Japan
	It is difficult for actual accelerators to achieve the designed machine performance without appropriate correction or adjustment of magnet errors. By correction as magnets are aligned to design orbit, we aim to be realized the designed machine performance. However, it is not easy to estimate the design orbit in real accelerators. In KEKB and PF, beam position monitor(BPM) can be calibrated to the center of quadrupole magnet(QM). BPM and QM misalignments (except rotation misalignment) referring to design orbit can be estimated using assumption that these misalignments are coincident. This is, design orbit at BPM and QM can be derived.

TUPPC018	Estimation of Orbit and Optics Distortion of SuperKEKB by Tunnel Deformation	quadrupole, optics, coupling, luminosity	1197
	A. Morita, H. Koiso, Y. Ohnishi, K. Oide, H. Sugimoto KEK, Ibaraki, Japan
	The tunnel which was used for the KEKB B-factory is reused for the accelerator tunnel of the SuperKEKB. The total vertical displacement of the tunnel subsidence reached almost 30mm during 10 years KEKB operation. In order to operate the SuperKEKB which might be more delicate machine than the previous KEKB B-factory, we are evaluating the optics distortion by the tunnel deformation and studying the machine performance after the orbit and optics correction. We report the estimation of the machine performance degradation by the tunnel subsidence and the requirement of the correction.

TUPPC021	Design Study on KEK Injector Linac Upgrade for High-current and Low-emittance Beams	linac, simulation, wakefield, acceleration	1206
	H. Sugimoto, M. Satoh, M. Yoshida KEK, Ibaraki, Japan
	Injector linac at KEK is now under upgrading to produce high current (5nC for e-, 4nC for e+) and low emittance (20 mm mrad for e-, 6 mm mrad for e+) electron and positron beams to a SuperB collider called SuperKEKB. Emittance growth resulted from both wakefield at the acceleration structure and dispersive effects at the focusing structure are troublesome in keeping the beam quality during the beam propagation. In this study, a possible solution to mitigate these effects in the KEK injector linac is explored by considering bunch compression in an existing bending section, orbit correction to suppress the wakefield excitation, and beam optics design.

TUPPC022	Straight Scaling FFAG Experiment	linac, vacuum, closed-orbit, instrumentation	1209
	J.-B. Lagrange, Y. Ishi, Y. Kuriyama, Y. Mori, R. Nakano, B. Qin, T. Uesugi, E. Yamakawa Kyoto University, Research Reactor Institute, Osaka, Japan Y. Niwa, K. Okabe, I. Sakai University of Fukui, Faculty of Engineering, Fukui, Japan
	Straight scaling FFAG experiment has been done at Kyoto University research reactor institute. Details and results are presented here.

TUPPC024	R&D of an Ultrafast Probe Apparatus Based on MeV Electron Diffraction at Tsinghua University	electron, solenoid, simulation, cathode	1215
	X.H. Lu, Y.-C. Du, W.-H. Huang, H.J. Qian, C.-X. Tang TUB, Beijing, People's Republic of China
	Funding: This work is supported by National Natural Science Foundation of China and National Basic Research Program of China (973 Program). An ultrafast probe apparatus based on MeV ultrafast electron diffraction is developed at Tsinghua University. It aims at generating 1.5 to 3 MeV pulse with sub-pC charge and sub-ps pulse length for pump-probe experiments. It consists of an S-band 1.6-cell radiofrequency photocathode gun, a solenoid, a sample chamber, a deflecting cavity, a detection system and other diagnostics tools. Simulations show the position of solenoid coil affects the spot size on detection screen and the charge of collimated bunch significantly. The collimator is found to be helpful to stabilize the charge of collimated bunch and reduce its normalized emittance. The construction of the apparatus is almost finished and the commissioning test will start soon.

TUPPC027	Multi Objective Genetic Optimization for Linac Lattice of PAL XFEL	linac, lattice, electron, quadrupole	1224
	C.H. Yi, M.-H. Cho, S.H. Kim, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea H.-S. Kang PAL, Pohang, Kyungbuk, Republic of Korea K.-J. Kim ANL, Argonne, USA
	Funding: Work supported by MEST and POSTECH Physics BK21 Program. There are a large number of variables and objectives in design of XFEL linac lattices. Recently, most of accelerator physics field, are applying the multi-objective genetic algorithm (MOGA) for these kinds of problems. MOGA was applied to the PAL XFEL linac lattice design. Longitudinal position of all components was fixed before applying MOGA. RF parameters of RF cavities and bending angles of bunch compressors are selected as variables. Various beam parameters computed by ELEGANT were used as objectives. By using MOGA, new linac lattice designs with 2 and 3 bunch compressors was generated and their beam properties are presented in this paper.

TUPPC033	Random Walk Optimization in Accelerators: Vertical Emittance Tuning at SLS	target, quadrupole, luminosity, controls	1230
	M. Aiba, M. Böge, N. Milas, A. Streun Paul Scherrer Institut, Villigen, Switzerland
	The operation of a high performance accelerator is realized only when several beam based corrections are implemented. These corrections are, however, limited by measurement errors as the correction approaches the ideal value. To overcome this limitation, we investigate the application of a random walk (RW) optimization specifically to minimize the vertical emittance at the SLS. A systematic minimization is performed by measuring linear coupling and spurious vertical dispersion and correcting them using 36 skew quadrupole correctors. On the other hand, the minimization can be performed by simply applying a multi-variable optimization from the mathematics point of view, where the best combination of skew corrections is to be found. The measured vertical beam size is available as a stable target function of the minimization even at very low vertical emittance. Although RW and other algorithms are implemented into various accelerator computer codes, it is interesting to apply this concept to the real machine, where measurement errors are unavoidable and may prohibit systematic minimization based on a machine model. Possible applications of the technique in general are also discussed.

TUPPC034	Preparation of SLS for IBS Measurements	diagnostics, optics, impedance, radiation	1233
	N. Milas, M. Böge, A. Streun PSI, Villigen, Switzerland M. Aiba, A. Lüdeke, A. Saa Hernandez Paul Scherrer Institut, Villigen, Switzerland F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland
	It is planned to use the SLS for testing damping ring issues related to linear colliders. One aspect is the study of Intra-Beam Scattering (IBS) effects, which are a limiting factor for ultra-low emittance rings. In this paper we present the setup and characterization of a new mode of operation in which the SLS runs at lower energy (1.57 GeV) with a natural emittance of 2.4 nm rad. This is much smaller than that at the nominal energy (2.41 GeV) and should make IBS effects more easily visible. In order to be able to observe IBS a careful setup is required: Optics measurement and correction as well as measurements of the bunch natural energy spread and the onset of turbulent bunch lengthening. Also, a detailed discussion on the available diagnostics and their limitations are shown and finally some preliminary results of beam emittance measurements, in all three planes, as a function of single bunch current are presented.

TUPPC041	A 3 TeV Muon Collider Lattice Design	quadrupole, lattice, dipole, collider	1254
	Y. Alexahin, E. Gianfelice-Wendt Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy A new lattice for 3 TeV c.o.m. energy with β^=5mm was developed which follows the basic concept of the earlier 1.5 TeV design but uses quad triplets for the final focus in order to keep the maximum magnet strength and aperture about the same as in 1.5 TeV case. Another difference is employment of combined-function magnets with the goal to lower heat deposition in magnet cold mass and to eliminate regions without bending field which produce “hot spots” of neutrino radiation that can be an issue at higher energy. The proposed lattice is shown to satisfy the requirements on luminosity, dynamic aperture and momentum acceptance. * Y.Alexahin, E.Gianfelice-Wendt, A.Netepenko, Proc. IPAC10, Kyoto, May 2010, p. 1563

TUPPC044	Emittance and Phase Space Tomography for the Fermilab Linac	linac, focusing, optics, quadrupole	1263
	C. Johnstone, F.G.G. Garcia, T. Kobilarcik, G.M. Koizumi, C.D. Moore, D.L. Newhart Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy. The Fermilab Linac delivers a variable intensity, 400-MeV beam to the The MuCool Test Area experimental hall via a beam line specifically designed to facilitate measurements of the Linac beam emittance and properties. A 10 m, dispersion-free and magnet-free straight utilizes an upstream quadrupole focusing triplet in combination with the necessary in-straight beam diagnostics to fully characterize the transverse beam properties. Since the Linac does not produce a strictly elliptical phase space, tomography must be performed on the profile data to retrieve the actual particle distribution in phase space. This is achieved by rotating the phase space distribution using different waist focusing conditions of the upstream triplet and performing a de-convolution of the profile data. Preliminary measurements using this diagnostic section are reported here.

TUPPC049	A Tapered-foil Emittance-exchange Experiment at LANSCE	proton, simulation, scattering, collimation	1278
	R.C. McCrady LANL, Los Alamos, New Mexico, USA
	We are planning an experiment at the Los Alamos Neutron Science Center (LANSCE) to demonstrate a technique for reducing the transverse emittance of the proton beam by passing the beam through a wedge-shaped energy degrader to produce a non-symplectic correlation between transverse position and energy, then removing this correlation with a bending magnet. This technique was proposed by Peterson* in 1983. We present a specific beamline layout that is expected to mitigate several complications associated with fielding an experiment to demonstrate the technique with a low-emittance proton beam. We present simulated results and expected outcomes of this demonstration. * J. M. Peterson, Proc. of PAC 1983, pP. 2403-2405 (1984).

TUPPC055	Development of an Automatic MATLAB based Emittance Measurement Tool for the IAC Accelerators	quadrupole, EPICS, background, controls	1296
	C.F. Eckman, A. Andrews, Y. Kim, S. Setiniyaz, D.P. Wells IAC, Pocatello, IDAHO, USA A.W. Hunt ISU, Pocatello, Idaho, USA
	At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating fifteen low energy accelerators. To optimize those accelerators properly, we have to measure the transverse beam emittance. To measure the transverse beam emittance of an S-band linear accelerator with the quadrupole scan technique, we installed an Optical Transition Radiation (OTR) screen and a digital CCD camera in the bealime of the accelerator. From the images of the digital CCD camera, the transverse beam profile on the OTR screen can be acquired. To extract the transverse beam size and to estimate the transverse emittance, we have developed a MATLAB program. This paper describe the details of the MATLAB program and performance of our MATLAB based emittance measurement tool.

TUPPC065	High Intensity Beam Analysis for the Superconducting Radio-frequency Linac (SRF-Linac) of the IFMIF-EVEDA Accelerators	resonance, linac, SRF, space-charge	1323
	W. Simeoni CEA/IRFU, Gif-sur-Yvette, France N. Chauvin, P.A.P. Nghiem, D. Uriot CEA/DSM/IRFU, France
	In this proceeding we analyze space charge effects on the beam dynamics of IFMIF accelerators. The objective is to be able to characterize and understand the crucial issues like halo formation, emittance growth and sudden particle losses in the SRF-Linac. We use the Hofmann stability charts to identify modes of collective space charge density oscillations that are responsible for the transfer and growth of the emittance. With identification of modes we are able to treat the parametric resonance between the modes and the nonlinear motion of an individual ion the amplitude of which is greater than the core radius. The resulting phase space consists of an inner separatrix containing the core and an outer separatrix that becomes the locus near which the halo particles enter and cluster.

TUPPC073	Frequency Map Analysis for SuperB	resonance, lattice, dynamic-aperture, sextupole	1341
	S.M. Liuzzo, M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma), Italy T. Demma LAL, Orsay, France Y. Papaphilippou CERN, Geneva, Switzerland
	The frequency map analysis is applied to the SuperB HER and LER lattices including the Final Focus, in order to understand the dynamic aperture limitation and provide insight for a working point optimization. In this respect, frequency and diffusion maps are evaluated applying random magnet misalignments and tilts, before and after correction of orbit, dispersion and coupling using Low Emittance Tuning techniques. The same analysis is performed for on and off momentum particles. The lattice properties are further investigated using working point scans and the correction of non linear resonance driving terms and amplitude detuning.

TUPPC077	Numerical Study of Beam Trapping in Stable Islands for Simple 2D Models of Betatronic Motion	simulation, resonance, extraction, octupole	1350
	M. Giovannozzi, C. Hernalsteens CERN, Geneva, Switzerland
	An essential ingredient for the proposed Multi-Turn Extraction (MTE) at the CERN PS is the beam trapping in stable islands. The control of the trapping process is essential for the quality of the final beam in terms of intensity sharing and emittance. In this paper, the splitting process is studied quantitatively by means of numerical simulations performed on 2D model representing the horizontal non-linear betatronic motion. The results are reviewed and discussed in details.

TUPPC078	Proposal of an Inverse Logarithm Scaling Law for the Luminosity Evolution	luminosity, collider, dynamic-aperture, hadron	1353
	M. Giovannozzi CERN, Geneva, Switzerland C.H. Yu IHEP, Beijing, People's Republic of China
	A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. It was showed that dynamic aperture has a logarithmic dependence on time, which would be suggested by some fundamental theorems of the theory of dynamical systems. Such a scaling law was recently extended also to the intensity evolution in a storage ring. In this paper, inspired by these results, and inverse logarithm scaling law for the luminosity in a circular collider is proposed. The law is then tested against the data from the LHC physics runs and also with some examples from other machines. The results are presented and discussed in details.

TUPPC086	Conceptual Design of the CLIC damping rings	wiggler, damping, positron, vacuum	1368
	Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann CERN, Geneva, Switzerland C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain A. Bernhard KIT, Karlsruhe, Germany M.J. Boland ASCo, Clayton, Victoria, Australia A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev BINP SB RAS, Novosibirsk, Russia M. Korostelev Cockcroft Institute, Warrington, Cheshire, United Kingdom E. Koukovini EPFL, Lausanne, Switzerland M.A. Palmer CLASSE, Ithaca, New York, USA M.T.F. Pivi, S.R. Smith SLAC, Menlo Park, California, USA R.P. Rassool, K.P. Wootton The University of Melbourne, Melbourne, Australia L. Rinolfi JUAS, Archamps, France A. Vivoli Fermilab, Batavia, USA
	The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.

TUPPC091	Simulation of Colliding Beams with Feedback in LHC	simulation, feedback, luminosity, kicker	1374
	S. Paret, J. Qiang LBNL, Berkeley, California, USA
	Funding: This work supported partially by the US LHC Accelerator Research Program (LARP) of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Beam-beam effects impose restrictions on beam and beam optical parameters as they may degrade the luminosity and the emittance or cause coherent instabilities and particle loss. In the planned High Luminosity Large Hadron Collider (HL-LHC), beam-beam effects will significantly affect the beams because of unprecedented beam parameters and new features like crab cavities or elliptical beam cross sections at the interaction points. Noise from various sources can further worsen the situation. Therefore investigations are required to identify limitations of possible HL-LHC layouts. The impact of beam-beam effects on the beam dynamics is investigated by virtue of particle tracking simulations. Using the code BeamBeam3D and the strong-strong collision model, simulations including perturbations by noise and LHC's feedback system, an important means to mitigate transverse emittance growth due to coherent beam excitation, were carried out. The impact of numerical noise on the emittance in simulations and the state of the feedback modeling are presented.

TUPPC096	Optimization of the Dynamic Aperture for SPEAR3 Low-emittance Upgrade	sextupole, resonance, dynamic-aperture, optics	1380
	L. Wang, X. Huang, Y. Nosochkov, J.A. Safranek SLAC, Menlo Park, California, USA M. Borland ANL, Argonne, USA
	A low emittance upgrade is planned for SPEAR3. As the first phase, the emittance is reduced from 10nm to 7nm without addition magnets. A further upgrade with even lower emittance will require a damping wiggler. There is a smaller dynamic aperture for the lower emittance optics due to the stronger nonlinearity. A Multi-Objective Genetic Optimization (MOGA) code is used to maximize the dynamic aperture. Both the dynamic aperture and beam lifetime are optimized simultaneously. Various configurations of the sextupole magnets have been studied in order to find the best configuration. The betatron tune also can be optimized to minimize resonance effects. The optimized dynamic aperture increases 15% from the normal case and the life time increases from 15 hours to 17 hours. It is important that the increase of the dynamic aperture is mainly in the beam injection direction. Therefore the injection efficiency will benefit from this improvement.

TUPPC097	Computational Modeling of Electron Cloud For MEIC	electron, simulation, collider, ion	1383
	S. Ahmed, J.D. Dolph, G.A. Krafft, T. Satogata, B.C. Yunn JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. This work is the continuation of our earlier studies on electron cloud (EC) simulations reported in IPAC'11 for the medium energy electron-ion collider (MEIC) envisioned at JLab beyond the 12 GeV upgrade of CEBAF. In this paper, we will study the EC saturation density in various MEIC operations scenarios to calculate details of the EC-induced wakefield to establish more stringent bounds on instability thresholds and determine whether EC mitigation, such as NEG coatings or solenoid fields, should be considered in the MEIC design.

TUPPD003	Optimisation of Cooling Lattice Based on Bucked Coils for the Neutrino Factory	lattice, factory, simulation, cavity	1407
	A. Alekou, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The ionisation cooling technique will be used at the Neutrino Factory to reduce the transverse phase space of the muon beam. For efficient cooling, high average RF gradient and strong focusing are required to be applied in the cooling channel. However, high magnetic field at the position of the RF cavities induces electric field breakdown and therefore, a novel configuration, the Bucked Coils lattice, has been proposed to mitigate this problem. The Bucked Coils lattice has significantly lower magnetic field in the RF cavities by using coils of different radius and opposite polarity. This paper presents the optimisation of this lattice, its cooling performance, together with the preliminary conceptual engineering design.

TUPPD007	Multiple Scattering Measurements in the MICE Experiment	scattering, simulation, solenoid, factory	1419
	T. Carlisle, J.H. Cobb JAI, Oxford, United Kingdom D.V. Neuffer Fermilab, Batavia, USA
	The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test and characterize a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with a relative accuracy of 1% by measuring muons individually. Muon detectors include two scintillating fibre trackers embedded within 4 T solenoid fields, TOF counters and a muon ranger. Step IV of MICE will begin in 2012, producing the experiment's first precise emittance-reduction measurements. Multiple scattering in candidate Step IV absorber materials was studied in G4MICE, based on GEANT4. Equilibrium emittances for low-Z materials from hydrogen to aluminium can be studied experimentally in Step IV of MICE, and compared with simulations.

TUPPD011	Studies of the Twin Helix Parametric-resonance Ionization Cooling Channel with COSY INFINITY	simulation, resonance, quadrupole, collider	1428
	J.A. Maloney, K.B. Beard, R.P. Johnson Muons, Inc, Batavia, USA A. Afanasev GWU, Washington, USA S.A. Bogacz, Y.S. Derbenev, V.S. Morozov JLAB, Newport News, Virginia, USA B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA
	Funding: Supported in part by SBIR Grant DE-SC00005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A primary technical challenge to the design of a high luminosity muon collider is an effective beam cooling system. An epicyclic twin-helix channel utilizing parametric-resonance ionization cooling has been proposed for the final 6D cooling stage. A proposed design of this twin-helix channel is presented that utilizes correlated optics between the horizontal and vertical betatron periods to simultaneously focus transverse motion of the beam in both planes. Parametric resonance is induced in both planes via a system of helical quadrupole harmonics. Ionization cooling is achieved via periodically placed wedges of absorbing material, with intermittent rf cavities restoring longitudinal momentum necessary to maintain stable orbit of the beam. COSY INFINITY is utilized to simulate the theory at first order. The motion of particles around a hyperbolic fixed point is tracked. Comparison is made between the EPIC cooling channel and standard ionization cooling effects. Cooling effects are measured, after including stochastic effects, for both a single particle and a distribution of particles.

TUPPD012	Complete Muon Cooling Channel Design and Simulations	dipole, simulation, solenoid, collider	1431
	C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson Muons, Inc, Batavia, USA Y.S. Derbenev, V.S. Morozov JLAB, Newport News, Virginia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD013	Bunch Coalescing in a Helical Channel	collider, acceleration, simulation, factory	1434
	C. Y. Yoshikawa, C.M. Ankenbrandt Muons, Inc, Batavia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Funding: Supported in part by SBIR Grant 4725 · 09SC02739. A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV.

TUPPD014	To the Ionization Cooling in a RF Cavity with Absorber	cavity, scattering, focusing, radiation	1437
	A.A. Mikhailichenko CLASSE, Ithaca, New York, USA
	We are considering a RF cavity with Beryllium disk installed in the middle of the cavity as a ionization cooling element for the muon beam. Specially arranged shape of disk together with nonzero dispersion allows 6D cooling of muon beam. Technical aspects of this system and conceptual design are discussed in this paper also. This type of cooler demonstrates advantages if compared with the RF cavity filled with pressurized gas or with the helical cooler.

TUPPD019	New Injector for the EMMA ns-FFAG Ring	booster, cavity, gun, linac	1449
	B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	EMMA is the world’s first non-scaling FFAG which has recently demonstrated acceleration in the serpentine channel. At present, the electron beam is injected into EMMA from the ALICE accelerator. However, funding will be re-directed to an Electron Beam Test Facility (EBTF) in the near future, therefore, in order to continue the broad portfolio of planned experiments required to characterize non-scaling FFAGs, it essential to consider an alternative injection scheme. In this paper, we propose re-utilizing a thermionic gun and a 12 MeV linac from the SRS (Synchrotron Radiation Source) at Daresbury Laboratory. The paper looks at how the required EMMA beam properties can be matched with this new set-up and the advantages and disadvantages involved.

TUPPD026	Study of the RFQ Beam Cooler for SPES project	ion, rfq, quadrupole, extraction	1467
	M.M. Maggiore, A.M. Porcellato, S. Stark INFN/LNL, Legnaro (PD), Italy
	The SPES project is the new Radioactive Ion Beam facility under construction at Laboratori Nazionali of Legnaro, Italy. In this framework in order to improve the beam quality in terms of emittance and energy spread, a study of a new RFQ beam cooler device is accomplishing. The electromagnetic design of the RFQ section and the electrostatic layout of the injection and extraction regions have been done. The study about the beam dynamic is going on by means of dedicated codes which allow to take into account the interaction of the ions with the buffer gas needed to cool the beams. The status of the project and the results will be shown in this report.

TUPPD035	SuperKEKB Injector Upgrade for High Charge and Low Emittance Electron Beam	gun, alignment, wakefield, cathode	1482
	M. Yoshida, N. Iida, Y. Ogawa, M. Sato, L. Zang KEK, Ibaraki, Japan
	The design strategy of SuperKEKB is based on the nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, new photocathode RF-Gun with the focusing electric field was installed. Further the emittance growth in the linac is an important issue for the low emittance injection. We will report the machine study of the RF-Gun and the emittance growth through the linac.

TUPPD039	Simulation Study of Space Charge Effects for a 100-keV, 150-mA Class Deuteron Source	extraction, simulation, plasma, focusing	1491
	M. Ichikawa, H. Suzuki Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan S. Maebara JAEA, Ibaraki-ken, Japan
	Ion sources providing high current beam with low emittance are required for accelerators to expand to apply them to fusion material science. A 100-keV, 150-mA class deuteron source with low emittance is required for an accelerator-based neutron irradiation facility to develop fusion materials, and the study for space charge effects in the range of a 20- to 150-mA deuteron beam is indispensable to extract the low beam emittance. For this purpose, each ion source to extract the beam current of 20, 50, 100, and 150 mA was designed by the Igun code, under the condition to extract a beam radius of 4 mm, a beam energy of 100 keV, and a normalized emittance of 0.2 PI mm mrad. In this article, these simulation results from the viewpoint of space charge effects will be presented in detail.

TUPPD047	Injection Sequence for High-power Isochronous Cyclotrons for ADS Fission	cyclotron, ion, rfq, ion-source	1509
	S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, P.M. McIntyre, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: This work is supported by grants from the State of Texas (ASE) and the Mitchell Family Foundation. A high-current injector sequence is being developed for use in a flux-coupled stack of high-current cyclotrons for accelerator-driven subcritical (ADS) fission. The design includes an ECR ion source, LEBT, RF quadrupole, and multi-stage chopper. A first cyclotron then accelerates the beams to 100 MeV for injection to the sector isochronous cyclotron. Provisions for control of emittance and bunch tails are described.

TUPPD051	Operational Experience with the Nb/Pb SRF Photoelectron Gun	cathode, solenoid, laser, cavity	1518
	T. Kamps, W. Anders, R. Barday, A. Jankowiak, J. Knobloch, O. Kugeler, A.N. Matveenko, A. Neumann, T. Quast, J. Rudolph, S.G. Schubert, J. Völker HZB, Berlin, Germany P. Kneisel JLAB, Newport News, Virginia, USA R. Nietubyć The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland J.K. Sekutowicz DESY, Hamburg, Germany J. Smedley BNL, Upton, Long Island, New York, USA J. Teichert HZDR, Dresden, Germany V. Volkov BINP SB RAS, Novosibirsk, Russia I. Will MBI, Berlin, Germany
	SRF photoelectron guns offer the promise of high brightness, high average current beam production for the next generation of accelerator driven light sources such as free electron lasers, THz radiation sources or energy-recovery linac driven synchrotron radiation sources. In a first step a fully superconducting RF (SRF) photoelectron gun is under development by a collaboration between HZB, DESY, JLAB, BNL and NCBJ. The aim of the experiment is to understand and improve the performance of a Nb SRF gun cavity coated with a small metallic Pb cathode film on the cavity backplane. This paper describes the highlights from the commissioning and beam parameter measurements. The main focus is on lessons learned from operation of the SRF gun.

TUPPD057	High Charge Low Emittance RF Gun for SuperKEKB	gun, cathode, injection, laser	1533
	T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou KEK, Ibaraki, Japan
	We are developing a new RF gun for SuperKEKB. We are upgrading KEKB to SuperKEKB now. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun. Now, we are testing a Disk and Washer (DAW) type RF gun. Its photo cathode material is LaB6. Normally, LaB6 is used as a thermionic cathode, but it is suitable for　long-life photo cathode operation. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. We will obtain 3.2 MeV beam energy with the gun. The design of RF gun and experimental results will be shown.

TUPPD061	High-Power RF Test of an RF-Gun for PAL-XFEL	gun, laser, electron, injection	1539
	J.H. Hong, J.H. Han, H.-S. Kang, C. Kim, S.H. Kim, C.-K. Min, S.S. Park, S.J. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea M.S. Chae, I.S. Ko, Y.W. Parc POSTECH, Pohang, Kyungbuk, Republic of Korea
	A photocathode RF-gun for the X-ray free electron laser (XFEL) at the Pohang Accelerator Laboratory (PAL) has been fabricated and tested at PAL. This RF-gun is based on a 1.6-cell cavity with dual-feed waveguide ports and two pumping ports. The RF gun was designed by PAL and POSTECH. The RF-gun has been successfully tested with a cathode electric field gradient up to 126MV/m at a repetition rate of 30 Hz. This paper reports the recent results on the beam test of the RF-gun with high power RF at the gun test facility. We present and discuss the measurements of the basic beam parameters such as charge, energy, energy spread, and transverse emittance.

TUPPD062	The Source of Emittance Dilution and photoemission tunneling effect in Photocathode RF Guns	cathode, laser, cavity, simulation	1542
	V. Volkov BINP SB RAS, Novosibirsk, Russia R. Barday, T. Kamps, J. Knobloch, A.N. Matveenko, S.G. Schubert, J. Völker HZB, Berlin, Germany J.K. Sekutowicz DESY, Hamburg, Germany
	Funding: Work supported by Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association VH-NG-636 and HRJRG-214. Experimental data on HoBiCaT SRF photoinjector give an emittance which is much larger than the predicted thermal emittance. Modeling of photocathode RF gun beams with the different imperfections of experimental setup (alignment errors, inhomogeneity of quantum efficiency and laser power distributions on the cathode) is given. The main reason for the beam emittance dilution is photocathode field imperfections induced by field emitters that change the local electric field. Some field models of such photocathodes are tested in the simulations. The dependence of photocathode beam currents on the surface electric field was measured with the HoBiCaT SRF Photoinjector. The dependence can be explained by the tunneling effect described by Fowler-Nordheim like equation and is difficult to explain by usually applying Schottky effect.

TUPPD075	Simulated Performance of the Wisconsin Superconducting Electron Gun	solenoid, simulation, quadrupole, focusing	1572
	R.A. Bosch, K.J. Kleman UW-Madison/SRC, Madison, Wisconsin, USA R.A. Legg JLAB, Newport News, Virginia, USA
	The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an emittance of about one mm-mrad can be produced for a free-electron laser.

TUPPD078	A Novel Design of a High Brightness Superconducting RF Photoinjector Gun Cavity	gun, cavity, SRF, cathode	1581
	F. Marhauser, R. Rodriguez MuPlus, Inc., Newport News, USA Z. Li SLAC, Menlo Park, California, USA
	Funding: Work supported under U.S. DOE Grant Application Number 98802B12-I Next generation electron accelerators for research, medical, defense or industrial use are in need of electron sources operating at high repetition rates of 1 MHz and beyond, with normalized emittance of 1 mm-mrad or less and bunch charges as much as one nC or more. A conceptual layout of a novel superconducting RF photoinjector gun cavity (SRF gun) is proposed, which can provide unprecedented flexibility to vary beam pulse patterns in the MHz regime and beyond at average currents around 1 mA. It does not require an opening in the center of the back wall and avoids the complex cathode exchange system, but still allows an exchange or refurbishment of the cathode. The demountable back plate has the major benefit to clean the cavity cells independently from the back wall carrying a superconductive photocathode. This mitigates risks of cavity contamination and eases fabrication and chemical post-processing to achieve high accelerating fields, a key parameter to guarantee high brightness beams.

TUPPD079	Design of an L-Band RF Photoinjector for the Idaho Accelerator Center 44 MeV Linac	linac, gun, laser, solenoid	1584
	M. Titberidze, A.W. Hunt, D.P. Wells IAC, Pocatello, IDAHO, USA Y. Kim ISU, Pocatello, Idaho, USA
	At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating a 44 MeV L-band RF (1300 MHz) linear accelerator (LINAC) for various user applications such as medical isotope production, Laser Compton Scattering (LCS), positron annihilation energy spectroscopy, and photo fission. But the LINAC is not optimized properly to supply high quality electron beam for those experiments due to limitations of an existing 85 kV thermionic DC gun. In the near future, we are planning to use the L-band LINAC for new user applications such as Accelerator Driven subcritical nuclear reactor System (ADS), photon tagging facility, Ultrafast Electron Diffraction (UED) facility, and high power coherent Terahertz light source facility. Therefore, recently, we have been studying a future upgrade of the L-band LINAC with an RF photoinjector using ASTRA code. In this paper, we describe ASTRA simulation results and a new layout of the L-band LINAC, which is based on an L-band 1.5 cell RF photoinjector. Then, we describe its expected performance for two different single bunch charges (1 nC and 5 nC).

TUPPP002	GLASS Study of the Canadian Light Source Storage Ring Lattice	dynamic-aperture, lattice, quadrupole, sextupole	1602
	W.A. Wurtz, L.O. Dallin CLS, Saskatoon, Saskatchewan, Canada
	GLASS is a technique for finding all potential operating points of a storage ring lattice by examining all possible configurations of the linear lattice. The Canadian Light Source (CLS) storage ring uses three quadrupole families, making it computationally efficient to use GLASS to study the lattice with unbroken symmetry. CLS does not employ harmonic sextupoles and has only two families of chromatic sextupoles. We can exhaust the sextupole degrees of freedom by requiring the horizontal and vertical chromaticities to be both zero. With no remaining free parameters in our lattice, it is possible to calculate dynamic aperture and momentum acceptance for select regions of interest uncovered by the GLASS scan. We find two regions with reasonable dynamic aperture and momentum acceptance: the region where we presently operate and a region that can be accessed by reversing the polarity of one quadrupole family.

TUPPP005	LUNEX5: A French FEL Test Facility Light Source Proposal	FEL, laser, electron, undulator	1611
	A. Loulergue, C. Benabderrahmane, M. Bessière, P. Betinelli-Deck, F. Bouvet, A. Buteau, L. Cassinari, M.-E. Couprie, J. Daillant, J.-C. Denard, P. Eymard, B. Gagey, C. Herbeaux, M. Labat, A. Lestrade, P. Marchand, J.L. Marlats, C. Miron, P. Morin, A. Nadji, F. Polack, J.B. Pruvost, F. Ribeiro, J.P. Ricaud, P. Roy SOLEIL, Gif-sur-Yvette, France S. Bielawski, C. Evain, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France B. Carré CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France G. Devanz, M. Luong CEA/DSM/IRFU, France L. Farvacque, G. Lebec ESRF, Grenoble, France G. Lambert, A. Lifschitz, V. Malka, A. Rousse LOA, Palaiseau, France M. Le Parquier CERLA, Villeneuve d'Ascq, France J. Lüning CCPMR, Paris, France R. Roux LAL, Orsay, France
	LUNEX5 is a new synchrotron FEL source project aiming at delivering short and coherent X-ray pulses to probe ultrafast phenomena at the femto-second scale, to investigate extremely low density samples as well as to image individual nm scale objects. The proposed machine layout is based on a 400 MeV super-conducting Conventional Linear Accelerator (CLA) mainly composed of 2 XFEL type cryo-modules together with a normal-conducting high brightness photo RF gun. This present mature and reliable technology is able to deliver high quality electron bunches up to few kHz suitable for user experiments. Further more, the last decade improvement in synchronization and stability offer a fertile land to explore the different and innovative seeded FEL operations aiming at producing higher coherence and energetic X-rays for the pilot user full benefits. In parallel of the CLA branch, the very promising and highly innovative Laser Wake-Field Accelerator (LWFA) able to produce very short electron bunches in the range of the femto-second and high peak current up to few GeV is foreseen as a FEL bench test using the same undulator lines.

TUPPP014	HiSOR-II, Compact Light Source with a Torus-knot Type Accumulator Ring	lattice, quadrupole, insertion, insertion-device	1635
	A. Miyamoto, S. Sasaki HSRC, Higashi-Hiroshima, Japan
	Funding: This work is partially supported by Cooperative and Supporting Program for Researches and Educations in University sponsored by KEK. We proposed a torus knot type synchrotron radiation ring where the beam orbit is not closed with one turn but return to the starting position after multiple turns around the ring. This ring is capable of having many straight sections and it is advantageous for installation of insertion devices. We named this architecture AMATELAS. We are designing a new ring based on the shape of a (11, 3) torus knot for our future plan HiSOR-II. This ring has eleven 3.6-m-long straight sections though the ring diameter is as compact as 15 m. The achieved emittance is 17.4 nmrad with the lattice having bending magnets with combined function. This level of emittance is as low as the conventional 3rd generation light source. On the other hand, there is a potential problem caused by that the radius of the orbit and focusing force are not constant in the bending magnets. However, we confirmed that it does not make serious influence to the beam by calculating with dividing the bending into several sections. We will compare the parameters of this new ring with the conventional ring which we have designed as the future plan of our facility and evaluate performance as the compact synchrotron light source.

TUPPP015	Status and Recent Progress of SPring-8	coupling, lattice, storage-ring, optics	1638
	H. Ohkuma JASRI/SPring-8, Hyogo-ken, Japan
	The SPring-8 is an 8 GeV synchrotron radiation facility that has been in operation since 1997. The SPring-8 has been operated well and total user time has reached more than 53,700 hours, 75% of the total operation time. The average user time per year is about 4,000 hours. The average availability is about 98% in the past 15 years. The operational status and recent progress overview of SPring-8 is presented: the local lattice modification of 30-m long straight section for installing small gap (min. gap is 5.2 mm) in-vacuum undulators, the emittance coupling correction for the vertical beam size reduction, the test operation of low energy operation for the energy saving, and the study of lower emittance optics for the present SPring-8 storage ring. An outline of a future upgrade with a full-scale major lattice modification is also presented. We also present a little about recent progress of SPring-8 injecting accelerators.

TUPPP017	Lattice Design of the SSRF Storage Ring with Superbend	lattice, photon, dipole, optics	1644
	S.Q. Tian, B.C. Jiang, H.H. Li, M.Z. Zhang, W.Z. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	The SSRF storage ring is being investigated by upgrading with normal conducting superbend of 3 T. The bending magnets are shortened, and thus some additional straight sections with the length of about 2 m are created in the center of the arc cell. They can be used to install more insertion devices. The lattice adjustment and the optics design are presented in this paper, where much efforts are made to maintain the effective emittance along the ring with respect to the nominal optics.

TUPPP018	Design and Commissioning of the Very Low Emittance Optics in the SSRF Storage Ring	optics, injection, storage-ring, lattice	1647
	S.Q. Tian, J. Chen, B.C. Jiang, Y.B. Leng, H.H. Li, L.Y. Yu, M.Z. Zhang, W.Z. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	In synchrotron radiation light sources, there are continuous efforts to lower the storage ring emittance and thus increase its photon beam brightness. The lowest effective emittance of SSRF is found by a systematic method. Results of design and commissioning of this kind of optics are presented, of which the beam emittance is smaller than the nominal one by 1 nm.rad. The measured beam parameters agree well with the design ones.

TUPPP022	Beam Optics Measurements during ALBA Commissioning	quadrupole, lattice, optics, storage-ring	1656
	M. Muñoz, G. Benedetti, J. Campmany, D. Einfeld, Z. Martí CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The synchrotron light source ALBA is in the final stage of the Storage Ring commissioning, with the beamline commissioning well under way. This paper reviews the results of the modeling of the lattice and the agreement with the LOCO measurement of the machine; the performance of the beta beating correction (critical in the ALBA case due to the large gradient in the bending magnet and the low number of quadrupole families), including effect of insertion devices; the lifetime measurement; tune scans; tune shift with horizontal amplitude; and the general agreement of the machine to the model using during the design. A brief summary of the modeling of the injector chain is included.

TUPPP023	Operation Status of ALBA Synchrotron Light Source	storage-ring, feedback, vacuum, kicker	1659
	M. Pont CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a 3.0 GeV third generation synchrotron light source which has been commissioned during 2011. From October 2011 up to 7 beamlines are delivering beam for beamline commissioning, 6 from insertion devices and 1 from a bending magnet. Since April 2012 the facility is open to external users. Beam current has been continuously increased and the present stored beam current for users is 200 mA in a multi-bunch filling pattern. Orbit stability is kept at ±1 micron with a slow orbit feedback. The paper will review the operation and performance status of the different subsystems and review also the main objectives for 2012: target current of 400 mA, delivery of 3000 hours of beam to beamlines, testing of a fast orbit feedback system as well as preparations for top-up operation.

Paper

Title

Other Keywords

Page

MOXBP01

The First Two Years of LHC Operation

luminosity, proton, ion, dipole

1

S. Myers
CERN, Geneva, Switzerland

The operational performance of the LHC machine both for proton and lead ion operation are reviewed for the period 2010 and up the present. The beam parameter path allowing the very high rate of collider performance is presented and discussed. The accelerator issues encountered and those somewhat surprisingly not encountered are also discussed. The short and longer term plans for the LHC are also briefly presented.

Slides MOXBP01 [17.468 MB]

MOOAA01

Performance of the Cornell High-Brightness, High-Power Electron Injector

cathode, gun, laser, electron

20

B.M. Dunham, A.C. Bartnik, I.V. Bazarov, L. Cultrera, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, X. Liu, F. Löhl, P. Quigley, D.H. Rice, E.N. Smith, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao
CLASSE, Ithaca, New York, USA
S.S. Karkare, H. Li, J.M. Maxson
Cornell University, Ithaca, New York, USA

Funding: NSF DMR-0807731
The last year has seen significant progress in demonstrating the feasibility of a high current, high brightness photoinjector as required for the Energy Recovery Linac driven X-ray source at Cornell University. Both low emittances (0.4 mm-mrad rms normalized for 100% of the beam at 20 pC per bunch and 0.15 mm-mrad rms core emittance with 70% of the beam, and twice these values at 80 pC per bunch) and high average currents with a good lifetime well in excess of 1000 Coulombs at 5 MeV, 20 mA have been demonstrated. If these beams can be accelerated to 5 GeV without diluting the phase space, it would already provide a beam brightness higher than any existing storage ring. Operational experience, results, and the outlook for the future will be presented.

Slides MOOAA01 [1.424 MB]

MOOAA02

Instrumentation and Diagnostics for High Repetition Rate Linac-driven FELs

linac, FEL, diagnostics, laser

23

J.M. Byrd, S. De Santis, L.R. Doolittle, D. Filippetto, G. Huang, M. Placidi, A. Ratti
LBNL, Berkeley, California, USA

Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
One of the concepts for the next generation of linac-driven FELs is a cw superconducting linac driving an electron beam with MHz repetition rates. The beam is then switched into an array of independently configurable FELs. The demand for high brightness beams and the high rep-rate presents a number of challenges for the instrumentation and diagnostics. The high rep-rate also presents opportunities for increased beam stability because of the ability for much higher sampling rates for beam-based feedbacks. In this paper, we present our plans for instrumentation and diagnostics for such a machine.

Slides MOOAA02 [1.710 MB]

MOOAB03

FACET First Beam Commissioning

linac, damping, sextupole, lattice

46

G. Yocky, C.I. Clarke, W.S. Colocho, F.-J. Decker, M.J. Hogan, N. Lipkowitz, J. Nelson, P.M. Schuh, J.T. Seeman, J. Sheppard, H. Smith, T.J. Smith, M. Stanek, Y. Sun, J.L. Turner, M.-H. Wang, S.P. Weathersby, G.R. White, U. Wienands, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515.
The FACET (Facility for Advanced aCcelerator Experimental Tests) facility at SLAC has been under Construction since summer 2010. Its goal is to produce ultrashort and transversely small bunches of very high intensity (20kA peak current) to facilitate advanced acceleration experiments like PWFA and DLA. In June of 2011 the first electron beam was brought into the newly constructed bunch-compression chicane. Commissioning work included restarting the linac and damping ring, verifying hardware, establishing a good beam trajectory, verifying the optics of the chicane, commissioning diagnostic devices for transverse and longitudinal bunch size, and tuning up the beam size and bunch compression. Running a high-intensity beam through the linac without BNS damping and with large energy spread is a significant challenge. Optical aberrations as well as wakefields conspire to increase beam emittance and the bunch compression is quite sensitive to details of the beam energy and orbit, not unlike what will be encountered in a linear-collider final-focusing system. In this paper we outline the steps we took while commissioning as well as the challenges encountered and how they were overcome.

Slides MOOAB03 [9.167 MB]

MOOBB01

Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam

cavity, electron, simulation, radiation

49

J.C.T. Thangaraj, H.T. Edwards, A.S. Johnson, A.H. Lumpkin, T.J. Maxwell, J. Ruan, J.K. Santucci, Y.-E. Sun, R.M. Thurman-Keup
Fermilab, Batavia, USA

Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.

Slides MOOBB01 [2.338 MB]

MOEPPB002

The MICE Experiment

target, solenoid, electron, coupling

76

A.P. Blondel
DPNC, Genève, Switzerland

Ionization Cooling is the only practical solution to preparing high brilliance muon beams for a neutrino factory or muon collider. The muon ionization cooling experiment (MICE) is under development at the Rutherford Appleton Laboratory (UK) by an international collaboration. The muon beam line has been commissioned and first measurements of emittance with particle physics detectors have been performed. The remaining apparatus is currently under construction. First results with a liquid-hydrogen absorber will be produced in 2013; a couple of years later a full cell of a representative ionization cooling channel, including RF re-acceleration, will be in operation. The design offers opportunities for tests with various absorbers and several optics configurations. Results will be compared with detailed simulations of cooling channel performance to ensure full understanding of the cooling process.
on behalf of the MICE collaboration

MOEPPB004

A Compact Ring Design with Tunable Momentum Compaction

damping, dynamic-aperture, dipole, quadrupole

82

Y. Sun
SLAC, Menlo Park, California, USA

A storage ring with tunable momentum compaction has the advantage in achieving diﬀerent RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre- damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and ﬁne tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

MOEPPB010

Measurement of Satellite Bunches at the LHC

photon, synchrotron, ion, coupling

97

A. Jeff, M. Andersen, A. Boccardi, S. Bozyigit, E. Bravin, T. Lefèvre, A. Rabiller, F. Roncarolo
CERN, Geneva, Switzerland
A.S. Fisher
SLAC, Menlo Park, California, USA
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Adam Jeff is a DITANET fellow, supported by the EU's Marie Curie actions contract PITN-GA-2008-215080.
The RF gymnastics involved in the delivery of proton and lead ion bunches to the LHC can result in satellite bunches of varying intensity occupying the nominally empty RF buckets. Quantification of these satellites is crucial for bunch-by-bunch luminosity normalization as well as for machine protection. We present an overview of the longitudinal density monitor (LDM) which is the principal instrument for the measurement of satellite bunches in the LHC. The LDM uses single photon counting of synchrotron light. The very high energies reached in the LHC, combined with a dedicated undulator for diagnostics, allow synchrotron light measurements to be made with both protons and heavy ions. The arrival times of photons are collected over a few million turns, with the resulting histogram corrected for the effects of the detector’s deadtime and afterpulsing in order to reconstruct the longitudinal profile of the entire LHC ring. The LDM has achieved a dynamic range in excess of 10⁵ and a time resolution of 90 ps. Example results are presented and the measurements are benchmarked against satellite distributions based on collision data from the LHC experiments.

MOEPPB011

The Two Methods for Beam Profile Measurement of BEPCⅡ Storage Ring

synchrotron, monitoring, synchrotron-radiation, coupling

100

L. Wang, J. Cao
IHEP, Beijing, People's Republic of China

The two method as spatial interferometor and visible light imaging for real time beam profile measurment for BEPCⅡ Storage Ring will be introduced in detail, including optical Magnification measurment, point spread function measurement, image reversion and spatial coherence measurment. the transverse emittance and copouling coefficient was gotten from the result of the beam profile monitor.

MOPPC005

Parameter Space for the LHC Luminosity Upgrade*

luminosity, target, optics, brightness

127

F. Zimmermann, O.S. Brüning
CERN, Geneva, Switzerland

Funding: Work supported by the European Commission under the FP7 Research Infrastructures projects EuCARD, grant agreement no. 227579, and HiLumi LHC, grant agreement no. 284404.
We review the parameter space for the high-luminosity upgrade of the LHC (HL-LHC). Starting from the luminosity targets and the primary limitations, e.g., long-range beam-beam effects, event pile up, electron cloud, turnaround time, intrabeam scattering, we determine the range for compatible beam parameters such as the beam intensity, bunch spacing, transverse and longitudinal emittances, bunch length, and IP beta functions required to meet the HL-LHC goals. A selection of a few possible parameter sets is presented for comparison and discussion.

MOPPC007

Plans for High Beta Optics in the LHC

optics, quadrupole, insertion, scattering

133

H. Burkhardt, A. Macpherson
CERN, Geneva, Switzerland
S. Cavalier, P.M. Puzo
LAL, Orsay, France

Based on what has been learned with the first high β^* = 90 m operation in 2011, we describe the potential and practical scenarios for reaching very high β^* in the LHC in 2012 and beyond. Very high β^* optics require dedicated running time and conditions in the LHC. We describe a plan which is optimized to maximize the physics potential in a minimum of dedicated running time.

MOPPC017

Causes and Solutions for Emittance Blow-Up During the LHC Cycle

injection, luminosity, proton, feedback

160

M. Kuhn
Uni HH, Hamburg, Germany
G. Arduini, B.J. Holzer, J.M. Jowett, V. Kain, F. Roncarolo, M. Schaumann, R. Versteegen, J. Wenninger
CERN, Geneva, Switzerland

Emittance measurements during the run 2011 indicated a blow-up of 20 % to 30 % from LHC injection to collisions. At the LHC design stage the total allowed emittance increase through the cycle was set to 7 %. One of the goals of the 2012 LHC run is therefore to understand and counteract the blow-up. Emittance growth measurements through the LHC cycle along with correlations with possible sources are presented in this paper. Solutions are proposed where possible. The emittance determination accuracy relies on the knowledge of the beam optics and on the present performance of the transverse profile monitors. Possible improvements of the diagnostics and of the related data analysis are also discussed.

MOPPC022

Off-momentum Dynamic Aperture for Lattices in the RHIC Heavy Ion Runs

lattice, luminosity, ion, heavy-ion

175

Y. Luo, M. Bai, M. Blaskiewicz, W. Fischer, X. Gu, A. Marusic, T. Roser, S. Tepikian, S.Y. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this article we calculate and compare the off-momentum dynamic aperture for lattices with different phase advances per FODO cell in the RHIC heavy ion runs. A lattice with an increased phase advance was adopted in 2008-2011 to reduce transverse emittance growth rates from intra-beam scattering. However, during these runs, a large beam loss was observed with longitudinal RF re-bucketing which increased the momentum spread. With operational transverse stochastic cooling in the 2011 RHIC heavy ion run, the transverse intra-beam scattering emittance growth was eliminated, and the beam loss during stores was determined by the off-momentum aperture and burn-off from luminosity. We investigate the possibilities to increase the off-momentum dynamic aperture that would lead to an increase in the integrated luminosity.

MOPPC025

RHIC Polarized Proton Operation in Run 12

polarization, luminosity, proton, acceleration

184

V. Schoefer, L. A. Ahrens, A. Anders, E.C. Aschenauer, G. Atoian, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, A. Dion, K.A. Drees, W. Fischer, C.J. Gardner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, L.T. Hoff, H. Huang, R.L. Hulsart, A. Kirleis, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, F. Severino, D. Smirnov, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, M. Wilinski, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA

Successful RHIC operation with polarized protons requires meeting demanding and sometimes competing goals for maximizing both luminosity and beam polarization. In Run 12 we sought to fully integrate into operation the many systems that were newly commissioned in Run 11 as well as to enhance collider performance with incremental improvements throughout the acceleration cycle. For luminosity maximization special attention was paid to several possible source of emittance dilution along the injector chain, in particular to optical matching during transfer between accelerators. Possible sources of depolarization in the AGS and RHIC were also investigated including the effects of local coupling and low frequency (10 Hz) oscillations in the vertical equilibrium orbit during the RHIC ramp. The results of a fine storage energy scan made in an effort to improve store polarization lifetime are also reported in this note.

MOPPC028

Coherent Beam-Beam Effects Observation and Mitigation at the RHIC Collider

simulation, damping, coupling, dipole

193

S.M. White, M. Bai, W. Fischer, Y. Luo, A. Marusic, M.G. Minty
BNL, Upton, Long Island, New York, USA

Funding: Work partially supported by Brookhaven Science Associates, LARP, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

MOPPC034

Use of Helical Transport Channels for Bunch Recombination

simulation, collider, luminosity, focusing

205

D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA
C.M. Ankenbrandt, C. Y. Yoshikawa
Muons, Inc, Batavia, USA

Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed.

MOPPC046

End-to-End G4Beamline Simulation of an Inverse Cyclotron for Muon Cooling

cyclotron, simulation, solenoid, extraction

238

T.L. Hart, T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA
K. Paul
Tech-X, Boulder, Colorado, USA

An inverse cyclotron is a novel, intriguing idea for muon cooling necessary for proposed neutrino factories and muon colliders. We present the latest results of an end-to-end inverse cyclotron simulation that cools muons in the following sequence: single turn injection and initial cooling of 100 MeV kinetic energies to about 5 MeV with lithium hydrogen wedges; further substantial cooling to keV range kinetic energies and trapping with carbon foils and a rising electric field; and re-acceleration of the cooled, trapped muons back to 100 MeV. For neutrino factory and muon collider applications, the time of the entire cooling/trapping/re-acceleration process needs to be comparable to the muon lifetime so that decay losses are tolerable and the acceptance of the inverse cyclotron needs to be sufficiently large (on order 10 mm-rad normalized emittance). The latest progress toward these ends is presented.

MOPPC055

A New Platform for Global Optimization

linac, simulation, TRIUMF, solenoid

256

C. Gong, Y.-C. Chao
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Funding: Funding is received from Natural Sciences and Engineering Research Council of Canada and National Research Council of Canada for this research.
This paper describes a new platform for the multi-objective global optimization of accelerator design. While local optimization is relatively simple, global optimization for accelerator design remains a challenging task. The user often must write many lines of code to combine the output of a large variety of simulation engines, then send the results to the optimization engine. The optimization code also requires significant revision when applied to different problems. This paper presents an alternative method. The TRIUMF optimization platform, based on the genetic algorithm, is an extension of the PISA framework. It uses a flexible XML input format, in which users can easily combine multiple physics engines, such as ASTRA and PARMELA, into the same optimization problem. The TRIUMF platform is also parallel capable, designed to take advantage of computation clusters such as WestGrid. Results of the optimization platform applied to TRIUMF's 50 MeV, 0.5 MW electron linac are shown.

MOPPC064

Simulation of the Behavior of Ionized Residual Gas in the Field of Electrodes

ion, simulation, electron, vacuum

283

G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
A. Meseck
HZB, Berlin, Germany

Funding: Work supported by BMBF under contract number 05K10HRC
Light sources of the next generation such as ERLs require minimal beam losses as well as a stable beam position and emittance over the time. Instabilities caused by ionized residual gas have to be avoided. In this paper we present simulations of the behavior of ionized residual gas in the field of clearing electrodes and investigate e.g. clearing times. For these simulations we apply MOEVE PIC Tracking developed at Rostock University. We demonstrate numerical results with parameters planed for the ERL BERLinPro.

MOPPC072

Mathematical Model of Charged Particles Dynamics Optimization in RFQ Accelerators

rfq, controls, resonance, focusing

298

A.D. Ovsyannikov
St. Petersburg State University, St. Petersburg, Russia

Mathematical model of optimization of transverse motion of charged particles in accelerators is suggested. Linear and nonlinear systems are considered when describing the transverse motion. Interaction of the particles is taken into account. Optimization algorithm based on minimax functionals is built. Numerical results for RFQ accelerators are presented.

MOPPC079

Modelling of the EMMA ns-FFAG Ring Using GPT

space-charge, injection, quadrupole, electron

319

R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
J.K. Jones, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in the autumn of 2010. The energy recovery linac ALICE will serve as an injector for EMMA, within an energy range of 10 to 20 MeV. The injection line consists of a symmetric 30 degree dogleg to extract the beam from ALICE, a matching section and a tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. The ring is composed of 42 cells, each containing one focusing and one defocusing quadrupole. Acceleration over many turns of the EMMA machine has recently been confirmed. In some cases the bunch will traverse upwards of 100 turns, at which point the effects of space-charge may be significant. It is therefore necessary to model the electron beam transport in the ring using a code capable of both calculating the effect of and compensating for space-charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modeled for comparison with experimental results.

MOPPC080

Modeling Space Charge in an FFAG with Zgoubi

space-charge, lattice, acceleration, synchrotron

322

S.C. Tygier, R. Appleby, H.L. Owen
UMAN, Manchester, United Kingdom
R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom

The Zgoubi particle tracker uses a ray tracing algorithm that can accurately track particles with large offset from any reference momentum and trajectory, making it suitable for FFAGs. In high current FFAGs, for example an ADSR driver, space charge has a significant effect on the beam. A transverse space charge model was added to Zgoubi using the interface pyZgoubi. The magnets are sliced and a space charge kick is applied between each slice. Results are presented for an ADSR driver lattice.

MOPPC086

Accelerator Simulation - Beyond High Performance Computing

lattice, target, simulation, site

340

S. James, G.M. Jung, B.C. Li, K. Muriki, H. Nishimura, Y. Qin, K. Song, C. Sun
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Accelerator modeling and simulation studies heavily rely on High Performance Computing (HPC). Public Cloud computing has opened a new service horizon for HPC by offering an on-demand, Virtual Private Cloud (VPC). Previously, we investigated using Amazon HPC public Cloud for lattice optimization applications and evaluated performance*. In this research, we use the Amazon VPC technology to extend local HPC resources to provide a seamless, hybrid, and secure environment when the demand for computing capacity spikes.
* C. Sun et al., "HPC Cloud Applied to Lattice Optimization," Proc. PAC2011, New York, WEP151, p. 1767 (2011).

MOPPC091

Parallel 3D Simulations to Support Commissioning of a Solenoid-based LEBT Test Stand

simulation, rfq, solenoid, cyclotron

349

B.T. Schwartz, D.T. Abell, D.L. Bruhwiler, Y. Choi, S. Mahalingam, P. Stoltz, J. von Stecher
Tech-X, Boulder, Colorado, USA
B. Han, M.P. Stockli
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844.
A solenoid-based low-energy beam transport (LEBT) test stand is under development for the Spallation Neutron Source (SNS). To support commissioning of the test stand, the parallel Vorpal framework is being used for 3D electrostatic particle-in-cell (PIC) simulations of H⁻ beam dynamics in the LEBT, including impact ionization physics and MHz chopping of the partially-neutralized \Hm beam. Here we describe the process of creating a partially-neutralized beam and examine the effects of a single chopping event on the beam's emittance.

MOPPD003

DITANET - An International Network in Beam Diagnostics

diagnostics, instrumentation, simulation, monitoring

370

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the European Union under contract PITN-GA-2008-215080.
DITANET is the largest-ever EU funded research and training network in beam diagnostics. It brings together universities, research centers and industry partners to jointly develop diagnostics methods for a wide range of existing or future particle accelerators. This is achieved through a cohesive approach that allows for the exploitation of synergies, whilst promoting knowledge exchange between partners. In addition to its broad research program, the network organizes a large number of international schools and topical workshops for the beam instrumentation and particle accelerator communities. The project comes to an end in May 2012. This contribution presents some of the network's recent research outcomes and training activities.

MOPPD004

oPAC - Optimizing Accelerators through International Collaboration

simulation, laser, controls, instrumentation

373

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the European Union under contract PITN-GA-2011-289485.
The optimization of the performance of any particle accelerator critically depends on an in-depth understanding of the beam dynamics in the machine and the availability of simulation tools to study and continuously improve all accelerator components. It also requires a complete set of beam diagnostics methods to monitor all important machine and beam parameters with high precision and a powerful control and data acquisition system. Within the oPAC project all these aspects will be closely linked with the aim to optimize the performance of present and future accelerators that lie at the heart of many research infrastructures. The project brings together 22 institutions from around the world. With a project budget of 6 M€, it is one of the largest research and training networks ever funded by the EC. This contribution gives an overview of the network's broad research program and summarizes the training events that will be organized by the consortium within the next 4 years.

MOPPD009

Stochastic Cooling Developments for HESR at FAIR

target, ion, heavy-ion, scattering

388

H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen
FZJ, Jülich, Germany
C. Dimopoulou, A. Dolinskii, T. Katayama, Yu.A. Litvinov, M. Steck, T. Stöhlker
GSI, Darmstadt, Germany

The High-Energy Storage Ring (HESR) is part of the upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. The HESR is planned to dedicate to the field of high-energy antiproton physics to explore the research areas of charmonium spectroscopy, hadronic structure, and quark-gluon dynamics with high-quality beams over a broad momentum range from 1.5 to 15 GeV/c. The new facility provides the combination of powerful phase-space cooled antiproton beams and internal Pellet and gas jet targets to achieve the requirements of the experiment PANDA in terms of beam quality and luminosity. Detailed theoretical analyses have been carried out to design the stochastic cooling system for accumulation and stochastic cooling of antiprotons with target operation. Recently it is proposed to utilize the HESR also for the atomic and nuclear physics with highly charged heavy ions such as 132Sn⁵⁰⁺ in the dedicated experiments at high energies 0.74-3 GeV/u. In this contribution the feasibility of stochastic cooling of heavy ions with internal targets is in detail investigated under the constraint of the cooling system hardware as foreseen for anti-proton cooling.

MOPPD037

Investigation of Space Charge Compensation at FETS

space-charge, ion, ion-source, rfq

445

J.K. Pozimski, S.M.H. Alsari, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
D.C. Faircloth, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The ion source and LEBT are operational with the RFQ under manufacture. In the LEBT a high degree of space charge compensation (~90%) and a rise time of space charge compensation around ~ 50 μs could be concluded indirectly from measurements . As a more detailed knowledge is of interest also for other projects like ESS the FETS LEBT was updated to perform a detailed experimental analysis of space charge compensation. In this paper the results of the experimental work will be presented together with discussion of the findings in respect to beam transport.

MOPPD058

LHC Abort Gap Cleaning Studies during Luminosity Operation

luminosity, kicker, injection, beam-losses

496

E. Gianfelice-Wendt
Fermilab, Batavia, USA
W. Bartmann, A. Boccardi, C. Bracco, E. Bravin, B. Goddard, W. Höfle, D. Jacquet, A. Jeff, V. Kain, M. Meddahi, F. Roncarolo, J.A. Uythoven, D. Valuch
CERN, Geneva, Switzerland

The presence of significant intensities of un-bunched beam is a potentially serious issue in the LHC. Procedures using damper kickers for cleaning both Abort Gap (AG) and buckets targeted for injection, are currently in operation at flat bottom. Recent observations of relatively high population of the AG during physics runs brought up the need for AG cleaning during luminosity operation as well. In this paper the results of experimental studies performed in October 2011 are presented.

MOPPD062

Aperture Measurements in the LHC Interaction Regions

injection, luminosity, optics, resonance

508

S. Redaelli, M.C. Alabau Pons, R.W. Assmann, R. Bruce, M. Giovannozzi, G.J. Müller, M. Pojer, J. Wenninger
CERN, Geneva, Switzerland

The aperture of the LHC interaction regions is crucial for the LHC performance because it determines the smaller β^* that can be achieved. The aperture has been measured at a maximum energy of 3.5 TeV and at different β^* values, following optimized procedure to allow safe measurements at high energy. In this paper, the results of these aperture measurements, which are used as a reference for β^* reach and crossing scheme estimates at the LHC interaction points, are presented.

MOPPP011

Narrow Band Optimization of a Compton Gamma-Ray Source Produced From an X-Band Linac

electron, laser, simulation, linac

592

F. Albert, S.G. Anderson, C.P.J. Barty, D.J. Gibson, F.V. Hartemann, R.A. Marsh, S.S.Q. Wu
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Nuclear photonics is an emerging field of research that will require high precision gamma-ray (MeV) sources. In particular, nuclear resonance fluorescence applications necessitate a low (< 1%) relative gamma-ray spectral width. Within this context, Compton scattering, where laser photons are scattered off relativistic electron beams to produce tunable, collimated gamma rays, will produce the desired gamma-ray output. This paper will present the spectral narrowband optimization of such a light source currently being built at LLNL. In this case, PARMELA and elegant simulations of the full 250 MeV, high-gradient X-band linac provide the properties of the high brightness electron bunch. The electron beam simulations are then implemented into our newly developed weakly nonlinear Compton scattering code to produce theoretical gamma-ray spectra. The influence that the electron beam, laser beam and interaction geometry parameters have on the produced gamma-ray spectra will be shown with our simulations.

MOPPP018

Construction Status of the Compact ERL

linac, cryomodule, gun, radiation

607

S. Sakanaka, H. Kawata, Y. Kobayashi, N. Nakamura
KEK, Ibaraki, Japan
R. Hajima
JAEA, Ibaraki-ken, Japan

Future synchrotron light source based on a 3-GeV energy recovery linac (ERL) is under proposal at KEK, and we are conducting extensive R&D efforts. To demonstrate reliable operations of key components for the ERL project, as well as to demonstrate the generation of ultra-low emittance beams, we are constructing the Compact ERL (cERL). The cERL will also be used to demonstrate the generation of brilliant gamma-rays that is useful for analyzing radioisotopes. Key components, such as a photocathode DC gun, both cryomodules for the injector and the main linac, rf sources, magnets, and beam instrumentations, are under fabrication. Construction of radiation shielding for the cERL started in December, 2011. We report up-to-date status of the cERL.

MOPPP028

SRF Photoinjector for Proof-of-principle Experiment of Coherent Electron Cooling at RHIC

electron, SRF, gun, FEL

622

D. Kayran, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, X. Liang, G.T. McIntyre, I. Pinayev, B. Sheehy, J. Skaritka, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, Q. Wu, T. Xin
BNL, Upton, Long Island, New York, USA
V. Litvinenko, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and by Stony Brook DOE grant DE-SC0005713.
Coherent Electron Cooling (CEC) based on FEL amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

MOPPP033

Diagnostics at PITZ 2.0 Beamline: Status and New Developments

electron, diagnostics, dipole, FEL

634

M. Otevřel, A. Donat, H.-J. Grabosch, M. Groß, L. Hakobyan, H.M. Henschel, L. Jachmann, M. Khojoyan, G. Klemz, W. Köhler, G. Koss, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, H. Leich, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, J. Meissner, A. Oppelt, M. Penno, B. Petrosyan, M. Pohl, S. Riemann, M. Sachwitz, B. Schöneich, J. Schultze, A. Shapovalov, F. Stephan, F. Tonisch, G. Vashchenko, L.V. Vu, T. Walter, S. Weisse, R.W. Wenndorff, M. Winde
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
N.I. Brusova, L.V. Kravchuk, V.V. Paramonov
RAS/INR, Moscow, Russia
A. Gonnin, M. Joré, B. Mercier, C. Prevost, A. Variola
LAL, Orsay, France
I.I. Isaev
MEPhI, Moscow, Russia
Ye. Ivanisenko
IERT, Kharkov, Ukraine
D. Richter
HZB, Berlin, Germany
S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand
A.A. Zavadtsev, D.A. Zavadtsev
Nano, Moscow, Russia

The main aim of the Photo Injector Test Facility at DESY, Zeuthen (PITZ) site is to develop and test an FEL photo injector system capable of producing high charge short electron bunches of lowest possible transverse emittance to allow optimum FEL performance. The last major beamline upgrade realized in the second half of the year 2011 completed the evolution of the PITZ setup ongoing since 2005. The most recent upgrades include the installation of a new RF deflecting cavity - a prerequisite for longitudinal emittance and high resolution slice emittance measurements and installation of a new dispersive section for longitudinal phase space diagnostics of the high energy electron bunches. The paper will give an overview on electron beam diagnostics at PITZ, including the above mentioned upgrades.

MOPPP034

Simulation of the Longitudinal Phase Space Measurement with Transverse Deflecting Structure at PITZ

cavity, electron, dipole, simulation

637

D. Malyutin, M. Krasilnikov, M. Otevřel, F. Stephan
DESY Zeuthen, Zeuthen, Germany

The main goal of the Photo Injector Test facility at DESY, Zeuthen site, (PITZ) is the development, optimization and detailed characterization of electron sources for the short wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL. For successful operation of such type of FELs the injector must provide high quality electron bunches, enough short in duration with high charge and small transverse and longitudinal emittance values. Installation of the Transverse Deflecting Structure (TDS) at PITZ will provide the possibility for detailed characterization of bunch temporal profile, bunch transverse slice emittance and longitudinal phase space. The TDS cavity is currently installed at the PITZ beamline, and commissioning of the whole TDS system is expected in the spring 2012. In the first part of the paper the basic principles of the TDS deflector are described. In the next section, simulation of measurements by TDS cavity applied to the PITZ beam parameters is presented. The temporal resolution for different types of measurements is discussed. Systematic limitations are estimated.

MOPPP035

Initial Emittance and Temporal Response Measurement for GaAs Based Photocathodes

electron, cathode, laser, cavity

640

S. Matsuba
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
Y. Honda, T. Miyajima, T. Uchiyama, M. Yamamoto
KEK, Ibaraki, Japan
X.G. Jin
Institute for Advanced Research, Nagoya, Japan
Y. Takeda
Nagoya University, Nagoya, Japan

For future light source based on Energy Recovery Linac (ERL) is planned in KEK. For the ERL, an ultra low emittance and fast temporal response and high current electron source is needed. To achieve these requirements, a high voltage DC gun with a Negative Electron Affinity photo-cathode is under development. In this development, it is important to investigate the performance of photo-cathodes. We have constructed an ERL gun test stand to measure emittance and temporal profile. We use a solenoid scan technique for emittance measurements and a deflecting cavity technique for temporal profile measurements. In this presentation, we introduce KEK ERL gun test stand and beam test results.

MOPPP038

Optics Design and Layout for the Electron Beam Test Facility at Daresbury Laboratory

gun, quadrupole, beam-transport, laser

646

D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.K. Jones
Cockcroft Institute, Warrington, Cheshire, United Kingdom

An Electron Beam Test Facility (EBTF) is being developed at Daresbury Laboratory to provide the beam for industrial applications and as a front end of future light source facility test under consideration. The RF photoinjector will deliver ~6 MeV beam to industrial users* and will serve as an injector for the future light source facility under consideration at Daresbury**. The Photoinjector design in first phase consists of 2.5 cell RF gun (on loan from Strathclyde) to be driven by Ti:S laser. The photo injector design is aimed to deliver bunches with 10-250 pC bunch charge at low transverse emittances and short bunch lengths. The beam transport optics design described in this paper includes a dedicated diagnostics section capable of measuring ultra short and ultra low emittance bunches and transport to two user areas.
* P. McIntosh, these proceedings.
** J. Clarke, these proceedings.

MOPPP039

Masked Photocathode for Photoinjectors

electron, cathode, laser, vacuum

649

J. Qiang
LBNL, Berkeley, California, USA

Funding: This research was supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research used resources of the NERSC.
In this paper, we propose using masked photocathode in photoinjector for generating high brightness electron beam. An electrode with small hole is used as a mask to shield a large size photocathode from accelerating vacuum chamber. Using a mask will significantly increase lifetime of a photocathode by rotating unexplored photocathode material behind the electrode into the hole. Furthermore, the mask helps reduce dark current or secondary electron emission from the photocathode material. It also provides a control of initial beam transverse emittances.

MOPPP041

Effect of Roughness on Emittance of Potassium Cesium Antimonide Photocathodes

cathode, laser, electron, extraction

655

T. Vecchione, J. Feng, H.A. Padmore, W. Wan
LBNL, Berkeley, California, USA
I. Ben-Zvi, M. Ruiz-Osés, L. Xue
Stony Brook University, Stony Brook, USA
D. Dowell
SLAC, Menlo Park, California, USA
T. Rao, J. Smedley
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences of the U. S. Department of Energy, under Contract DE-AC02-05CH11231, KC0407-ALSJNT-I0013, and DE-SC0005713
Here we present first measurements of the effect of roughness on the emittance of K2CsSb photocathodes under high fields. We show that for very thin cathodes the effect is negligible at up to 3 MV/m but for thicker and more efficient cathodes the effect becomes significant. We discuss ways to modify the deposition to circumvent this problem.

MOPPP042

Modeling Multi-bunch X-band Photoinjector Challenges

gun, electron, linac, laser

658

R.A. Marsh, S.G. Anderson, C.P.J. Barty, D.J. Gibson, F.V. Hartemann
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. The test station will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. Of critical import to the functioning of the LLNL X-band system with multiple electron bunches is the performance of the photoinjector. In depth modeling of the Mark 1 LLNL/SLAC X-band rf photoinjector performance will be presented addressing important challenges that must be addressed in order to fabricate a multi-bunch Mark 2 photoinjector. Emittance performance is evaluated under different nominal electron bunch parameters using electrostatic codes such as PARMELA. Wake potential is analyzed using electromagnetic time domain simulations using the ACE3P code T3P. Beam-loading effects and low level rf compensation schemes are explored as well, using a semi-analytic formalism and computer algorithm. Plans for multi-bunch experiments and implementation of photoinjector advances for the Mark 2 design will also be discussed.

MOPPP046

RF Gun Photocathode Research at SLAC

gun, cathode, laser, electron

664

E.N. Jongewaard, R. Akre, A. Brachmann, W.J. Corbett, S. Gilevich, K. Grouev, P. Hering, P. Krejcik, J.R. Lewandowski, H. Loos, T. M. Montagne, J. Sheppard, P. Stefan, A.E. Vlieks, S.P. Weathersby, F. Zhou
SLAC, Menlo Park, California, USA

Funding: DOE contract DE-AC02-76SF00515.
LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of ~1x10^-4 and projected emittance eNx,y=0.45 μm at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), processed to the design rf gradient of >120 MV/m. As part of a wider photocathode R&D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

MOPPP050

Physics Results of the NSLS-II Linac Front End Test Stand

linac, simulation, gun, electron

673

R.P. Fliller, F. Gao, J. Rose, T.V. Shaftan, X. Yang
BNL, Upton, Long Island, New York, USA
G. Blokesch
PPT, Dortmund, Germany
C. Piel
RI Research Instruments GmbH, Bergisch Gladbach, Germany

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The NSLS-II linac is produced by Research Instruments and will be commissioned in the spring of 2012. As part of the procurement, the linac front end consisting of the gun, prebunching cavity, and diagnostics was delivered early to BNL for testing. We designed a short beamline to supplement the Front End diagnostics to characterize the beam. These tests were instrumental in demonstrating the functioning of the gun, pinpointing technical problems at an early project stage and gaining experience with the linac gun by BNL staff prior to commissioning of the full linac. In this report we show the results of the tests, including charge, bunch length, and transverse emittance measurements and compare them with the relevant linac specifications.

MOPPP052

Booster Synchrotron for SIRIUS Light Source

booster, injection, dipole, extraction

679

F. H. de Sá, L. Liu, A.R.D. Rodrigues
LNLS, Campinas, Brazil

A full energy 3 GeV booster for the new Brazilian Synchrotron Light Laboratory (LNLS) third generation light source, SIRIUS, is proposed. The 144 m circumference magnetic lattice consists of two super-periods of FODO cells with defocusing dipoles and focusing quadrupoles. The optics provides a low emittance beam of 38 nm.rad at 3 GeV, high horizontal betatron and zero dispersion functions at straight sections. The top-up operation requires a cycling energy ramp from 150 MeV to 3 GeV with repetition rate of 1 Hz.

MOPPP054

Study of a New Injection Scheme for the SSRF Storage Ring

injection, kicker, storage-ring, dynamic-aperture

685

M.Z. Zhang, B.C. Jiang, L. Ouyang, Q.L. Sun, S.Q. Tian
SINAP, Shanghai, People's Republic of China

A low emittance configuration of the SSRF storage ring had been designed and commissioned. Along with reducing the emittance, the dynamic aperture decreases quickly. It doesn’t meet aperture require of the normal injection scheme anymore and the injection efficiency is lower. The pulsed multi-pole magnets give the opportunity to overcome the smaller dynamic aperture. Pulsed quadrupole and sextupole both are study for the injection scheme. With and without the orbit bump kickers are also considered in this study. The injection scheme suggestions are presented in this paper.

MOPPP057

Optimization of the Low-emittance Lattice of the APS Booster Synchrotron

booster, lattice, injection, sextupole

690

C. Yao, V. Sajaev, N. Sereno, H. Shang
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06- CH11357.
The APS booster is a 7GeV electron synchrotron. Three lattices have been originally designed with a nominal beam emittance of 132, 109, and 92 nm, respectively. In the past we have mostly operated the booster with the 132 nm lattice because of its better stability. The lower-emittance lattices are not utilized. In early 2010 we upgraded the booster ramp correction and reduced the 360Hz current ripples of the ramp supplies. Current ramp errors have been significantly reduced. This raises our interest in running the low- emittance lattice to improve APS storage ring injection efficiency and reduce radiation losses. This report presents the optimization methods and measurement results of booster beam performance of the booster 92nm lattice.

MOPPP062

Soleil Emittance Reduction using a Robinson Wiggler

photon, brightness, damping, wiggler

702

H.B. Abualrob, P. Brunelle, M.-E. Couprie, O. Marcouillé, A. Nadji, L.S. Nadolski, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

For both synchrotron light sources as SOLEIL and colliders, the emittance is one of the key parameters to increase the photon brightness and the beam luminosity. In order to decrease the emittance, the ring optics is built on very focusing lattices leading to large chromaticities and potential reduction of the dynamics aperture and momentum transverse acceptance. Thus, some facilities have installed damping wigglers in zero dispersion straight sections to relax the optics and to reach sub-nanometer horizontal emittances. This solution requires however tens or hundreds meters of insertion devices. For storage ring equipped with zero-gradient bending magnets, an alternative solution can be given by installing a single Robinson wiggler [1] in a dispersive section enabling to divide the emittance by a factor 2. The uniqueness of this wiggler results from the presence of an alternated gradient superimposed the main periodic magnetic field. This paper recalls the concept of the wiggler, presents the expected gain for SOLEIL storage ring with the impact on the linear optics and the brightness. A preliminary magnetic design is also proposed. [1] K.W. Robinson, Phys. Rev, p. 373 (1958).

MOPPP066

Calculated Spectra from Magnetic Field Measurements of 1.5 m Superconducting Undulator Coils

undulator, permanent-magnet, vacuum, storage-ring

711

S. Casalbuoni, T. Baumbach, S. Gerstl, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
C. Boffo, W. Walter
BNG, Würzburg, Germany

In this contribution we report on the spectra calculated from the field measurements performed in a liquid helium bath of 1.5 m superconducting undulator coils. The coils are foreseen for a superconducting undulator demonstrator with a period length of 15 mm planned to be installed in ANKA middle 2012 and tested at the new beamline NANO for high resolution X-ray diffraction. The spectral performance at ANKA and at low emittance sources is compared with the competing cryogenic permanent magnet technology.

MOPPR002

Overview of the Beam Diagnostics in the MedAustron Accelerator: Design Choices and Test Beam Commissioning

synchrotron, injection, extraction, proton

774

F. Osmic, M. Feurstein, A. Gyorgy, A. Kerschbaum, M. Repovz, S.M. Schwarz
EBG MedAustron, Wr. Neustadt, Austria
G. Burtin
CERN, Geneva, Switzerland

The MedAustron center is a synchrotron based accelerator complex for cancer treatment and for clinical and non-clinical research with protons and light ions, currently under construction in Wiener Neustadt, Austria. The accelerator complex is based on the CERN-PIMMS study and its technical implementation by the Italian CNAO foundation in Pavia. The MedAustron beam diagnostics system is based on sixteen different monitor types (153 devices in total) and will allow measuring all relevant beam parameters from the source to the irradiation rooms. The monitors will have to cope with large intensity and energy ranges. Currently, one ion source, the low energy beam transfer line and the RFQ are being commissioned in the Injector Test Stand (ITS) at CERN. This paper gives an overview of all beam monitors foreseen for the MedAustron accelerator, elaborates some of the design choices, and reports the first beam commissioning results from the ITS.

MOPPR010

Simultaneous Measurement of Emittance at the Storage Ring and the External Beamlines of ELSA

quadrupole, synchrotron, extraction, diagnostics

792

S. Zander, F. Frommberger, W. Hillert, D. Proft
ELSA, Bonn, Germany

Funding: Funded by the DFG within the SFB / TR 16.
The Electron Stretcher Facility (ELSA) consists of several accelerator stages, the last one being a storage ring providing a beam of polarized electrons of up to 3.5 GeV. To ensure a high duty cycle, a slow extraction via a third integer resonance is applied at ELSA. The resonance extraction cause a variation of the emittance in the external beamline. A system for simultaneous measurement of emittance in the storage ring and the external beamlines has been installed. First results including a comparison of both emittances will be shown.

MOPPR024

Non-intercepting Emittance Measurements by means of Optical Diffraction Radiation Interference for High Brightness Electron Beam

radiation, quadrupole, electron, target

831

A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
V. Balandin, N. Golubeva, K. Honkavaara, G. Kube
DESY, Hamburg, Germany
M. Castellano, E. Chiadroni
INFN/LNF, Frascati (Roma), Italy
L. Catani
INFN-Roma II, Roma, Italy

Conventional intercepting transverse electron beam diagnostics, e.g. based on Optical Transition Radiation (OTR), cannot tolerate high power beams without remarkable mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR) is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitations of this method is the low signal to noise ratio, mainly due to the unavoidable synchrotron radiation background. This problem can be overcome by using ODRI (Optical Diffraction Radiation Interference). In this case the beam goes through two slits opened on metallic foils, placed in a distance shorter than the radiation formation zone. Thanks to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. Here we report the first measurements, carried out at FLASH (DESY, Germany), of the beam emittance using ODRI. Our results demonstrate the unique potential of this technique.

MOPPR025

The BPM DAQ System Upgrade for SuperKEKB Injector Linac

linac, electron, positron, injection

834

M. Satoh, K. Furukawa, F. Miyahara, T. Suwada
KEK, Ibaraki, Japan
T. Kudou, S. Kusano
MELCO SC, Tsukuba, Japan

The non-destructive beam position monitor (BPM) is indispensable diagnostic tool for the stable beam operation. In the KEK Linac, approximately nineteen BPMs with the strip-line type electrodes are used for the beam orbit measurement and feedback. In addition, some of them are also used for the beam energy feedback loops. The current DAQ system consists of the fast digital oscilloscopes. A signal from each electrode is analyzed with a predetermined response function up to 50 Hz. The beam position resolution of current system is limited to about 0.5 mm because of ADC resolution. Towards SuperKEKB project, we have a plan to upgrade the BPM DAQ system since the Linac should provide the smaller emittance beam. We will report the system description of the new DAQ system and the results of performance test in detail.

MOPPR040

Design and Measurements of a Test Stand for the SEM-Grid System of the ESS-BILBAO

electron, vacuum, diagnostics, linac

867

D. Belver, J. Feuchtwanger, P.J. González
ESS Bilbao, LEIOA, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
V. Etxebarria, J. Jugo
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain

In the framework of the ESS-Bilbao accelerator, a test stand for the development of Secondary Electron EMission grid (SEM-Grid) has been designed and manufactured as a part of the diagnostics system for beam profile measurements. This test stand is a vacuum system based on an EQ 22/35 electron source from SPECS used as a beam injector. This electron source has an energy range from 0 to 5 KeV and a maximum beam current up to 200 μA. Although we have thought in a SEM-Grid of 40 wires (20 wires in each X and Y direction), two prototypes of 16 wires (8x8) of 250 μm diameter and spaced 1 and 2 mm, respectively, have been developed due to its easier implementation and tested in the test stand. In order to develop an electronics readout system for the SEM-Grid, first studies of the prototype signals have been done. The secondary emission current of each wire will be integrated and amplified to provide a significant voltage signal that can be measured by our acquisition system. A description of the SEM-Grid test stand and the measurements developed is given here.

MOPPR044

Optics and Emittance Studies using the ATF2 Multi-OTR System

coupling, quadrupole, target, controls

879

J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López
IFIC, Valencia, Spain
J. Cruz, D.J. McCormick, G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Funding Agency: FPA2010-21456-C02-01. Work supported in part by Department of Energy Contract DE-AC02-76SF00515.
A multi-OTR system (4 beam ellipse diagnostic devices based on optical transition radiation) was installed in the extraction line of ATF2 and has been fully operational since September 2011. The OTRs have been upgraded with a motorized zoom-control lens system to improve beam finding and accommodate different beam sizes. The system is being used routinely for beam size and emittance measurements as well as coupling correction. In this paper we present measurements performed during the winter run of 2011 and the early 2012 runs. We show the reconstruction of twiss parameters and emittance, discuss the reliability of the OTR system and show comparisons with simulations. We also present new work to calculate all 4 coupling terms and form the “4-D” intrinsic emittance of the beam utilizing all the information available from the 2-D beam profile images. We also show details and experimental results for performing a 1-shot automated coupling correction.

MOPPR048

Beam Instrumentation for the HIE-ISOLDE Linac at CERN

diagnostics, linac, cryomodule, ion

891

E. Bravin, A.G. Sosa, D. Voulot, F.J.C. Wenander, F. Zocca
CERN, Geneva, Switzerland
M.A. Fraser
UMAN, Manchester, United Kingdom
J.H. Galipienzo
AVS, Eibar, Gipuzkoa, Spain
M. Pasini
Instituut voor Kern- en Stralingsfysica, K. U. Leuven, Leuven, Belgium
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

In the framework of the High Intensity and Energy (HIE)-ISOLDE project at CERN, a beam instrumentation R&D program is on-going for the superconducting upgrade of the REX-ISOLDE heavy-ion post-accelerator. An overview of the foreseen beam diagnostics system is presented, focusing on the challenging specifications required by the HIE-ISOLDE linac. Due to the low beam intensities, the diagnostic instrumentation will be based on high-sensitivity intercepting devices. The project includes intensity and transverse profile monitors to be implemented in the very narrow longitudinal space that is available for beam diagnostics in the regions between the superconducting cryomodules. A longitudinal profile monitor is foreseen downstream of the linac to measure the beam energy and arrival time distributions and to allow for a fast phase-tuning of the superconducting cavities. A custom-made emittance meter will provide transverse emittance measurements based on a phase space sampling technique. The design status of the different instruments will be presented as well as the results of some experimental tests.

MOPPR068

Design and Development of the Diagnostic System for 75 MeV Electron Drive Beam for the AWA Upgrade

diagnostics, controls, wakefield, cavity

942

J.G. Power, S.P. Antipov, M.E. Conde, W. Gai, C.-J. Jing, W. Liu, E.E. Wisniewski, Z.M. Yusof
ANL, Argonne, USA

Funding: Work supported by High Energy Physics, Office of Science, US DOE
We report on the development of the diagnostic system for the ongoing upgrade to the Argonne Wakefield Accelerator (AWA) facility where the electron drive beam energy will be increased from 15 to 75 MeV. The facility will produce a wide dynamic range of drive bunch train formats ranging from a single microbunch of 100 pC to bunch trains of up to 32 bunches spaced by 769 ps with up to 100 nC per bunch. In addition to standard diagnostics, this drive bunch train format poses two challenges for the diagnostic system: (i) the close spacing of the drive bunches, 769 ps, makes resolving the individual pulses difficult and (ii) the dynamic range of the bunch charge varies by x1000. A critical parameter of the drive bunch train for the wakefield accelerator is the charge along the train. To measure this, we are planning to use a 15 GHz digital oscilloscope to read either a BPM or Bergoz FCT. To handle the large dynamic range of charge, the imaging system will make use of GigE Vision cameras and a distributed system of motorized lenses, with remote control of focus, zoom, and aperture, which are operated through terminal servers and RS232 controllers.

MOPPR072

Fermilab PXIE Beam Diagnostics Development and Testing at the HINS Beam Facility

diagnostics, laser, linac, rfq

954

V.E. Scarpine, B.M. Hanna, V.A. Lebedev, L.R. Prost, A.V. Shemyakin, J. Steimel, M. Wendt
Fermilab, Batavia, USA

Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359.
Fermilab is planning the construction of a prototype front end of the Project X linac. The Project X Injector Experiment (PXIE) is expected to accelerate 1 mA cw H⁻ beam up to 30 MeV. Some of the major goals of the project are to test a cw RFQ and H⁻ source, a broadband bunch-by-bunch beam chopper and a low-energy superconducting linac. The successful characterization and operation of such an accelerator places stringent requirements on beam line diagnostics. These crucial beam measurements include bunch currents, beam orbit, beam phase, bunch length, transverse profile and emittance, beam halo and tails, as well as the extinction performance of the broadband chopper. This paper presents PXIE beam measurement requirements and instrumentation development plans. Also presented are plans to test many of these instruments at the Fermilab High Intensity Neutrino Source (HINS) beam facility. Since HINS is already an operational accelerator, utilizing HINS for instrumentation testing allows for quicker development of the required PXIE diagnostics.

MOPPR076

Using the BRAN Luminosity Detectors for Beam Emittance Monitoring During LHC Physics Runs

luminosity, monitoring, interaction-region, proton

966

A. Ratti, H.S. Matis, M. Placidi, W.C. Turner
LBNL, Berkeley, California, USA
E. Bravin
CERN, Geneva, Switzerland
T.E. Lahey
SLAC, Menlo Park, California, USA
E.S.M. McCrory
Fermilab, Batavia, USA
R. Miyamoto
ESS, Lund, Sweden
S.M. White
BNL, Upton, Long Island, New York, USA

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
The BRAN Ionization Chambers installed at the IP1 and IP5 Interaction Points of the LHC provide a relative measurement of the total and bunch-by-bunch luminosities. This information, combined with the logged bunch charges from a fast BCT monitor, offers the possibility of evaluating the Interaction Area in collision for each of the colliding bunch pairs and monitor its time evolution. A Graphic User Interface (GUI) has been implemented to display the interaction area of the proton bunches interacting in IP1 and IP5 during each of the Physics Runs in the attempt of displaying the contribution to the Luminosity time decay originating from possible emittance blow-up when operating the Accelerator close to the beam-beam limit. Early results confirm the ability to characterize the bunch by bunch emittance behavior during the store and study possible differences among bunches in the same fill.

MOPPR079

Horizontal Beam-size Measurements at CESR-TA Using Synchrotron-light Interferometer

synchrotron, synchrotron-radiation, scattering, lattice

972

S. Wang, J.V. Conway, D.L. Hartill, M.A. Palmer, D. L. Rubin
CLASSE, Ithaca, New York, USA
R.F. Campbell, R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: DOE Award DE-FC02-08ER41538 NSF Award (PHY-0734867) NSF Award (PHY-1002467) NSF Award (PHY-1068662).
A horizontal beam profile monitor utilizing visible synchrotron radiation from a bending magnet has been designed and installed in CESR. The monitor employs a double-slit interferometer which has been successfully implemented to measure horizontal beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 microns can be measured with a resolution of approximately 5 microns. The method for extracting the horizontal beam size from the interference pattern is presented and its application to intrabeam scattering studies is described. A configuration for measuring the small vertical beam size is also discussed.

MOPPR087

Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center

quadrupole, electron, linac, background

990

S. Setiniyaz, T.A. Forest
ISU, Pocatello, Idaho, USA
K. Chouffani, Y. Kim
IAC, Pocatello, IDAHO, USA
A. Freyberger
JLAB, Newport News, Virginia, USA

A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

MOPPR092

SVD-BASED METHOD FOR MEASUREMENT OF BEAM PARAMETERS AND FLAG RESOLUTION

quadrupole, simulation, booster, focusing

999

G.M. Wang, R.P. Fliller, I. Pinayev, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

In NSLS II booster to storage ring transport line, the typical beam size in vertical plane is ~60 μm, which requires very high flag resolution to get good beam parameters measurement. This paper describes a new SVD-based method to measure transverse beam parameters and flag resolution simultaneously with double quads scan. Implementation simulations of the proposed method are performed for a dispersion free region in the NSLS-II booster to storage ring transport line. With this method, it breaks the limitation of beam parameters measurement accuracy duo to the flag resolution.

MOPPR094

Preparation for NSLS II Linac to Booster Transport Line Commissioning

linac, controls, booster, status

1002

G.M. Wang, M.A. Davidsaver, R.P. Fliller, G. Ganetis, H.-C. Hseuh, Y. Hu, D. Padrazo, T.V. Shaftan, G. Shen, O. Singh, Y. Tian, H. Xu, L. Yang
BNL, Upton, Long Island, New York, USA

The National Synchrotron Light Source II (NSLS-II) is a state-of-the-art 3-GeV third generation light source currently under construction at Brookhaven National Laboratory. The first part of the Linac to Booster Transport (LBT) line has been installed for the linac commissioning. This part will be used for the linac acceptance test. In this paper, we describe the preparation of the LBT sub-system integration test and the high level applications.

TUXA03

Increasing the AGS Beam Polarization with 80 Tune Jumps

resonance, polarization, quadrupole, closed-orbit

1015

V. Schoefer, L. A. Ahrens, M. Bai, E.D. Courant, W. Fu, C.J. Gardner, J.W. Glenn, H. Huang, F. Lin, A.U. Luccio, J.-L. Mi, J. Morris, P.J. Rosas, T. Roser, P. Thieberger, N. Tsoupas, A. Zelenski, K. Zeno
BNL, Upton, Long Island, New York, USA

Vertical depolarizing resonances in the AGS are removed by partial Siberian snakes. These magnets move the stable spin direction and lead to horizontal depolarizing resonances. The tune jump quadrupole system increases the crossing rate for horizontal resonances by a factor of six. This presentation will review the fundamental mechanism of depolarizing resonances, the partial Siberian snake solution and describe recent experimental evidence at the AGS demonstrating improvements to beam polarization and the beam dynamics challenges posed by the tune jump.

Slides TUXA03 [5.199 MB]

TUYA01

Research and Development of Future Muon Collider

cavity, collider, plasma, proton

1020

K. Yonehara
Fermilab, Batavia, USA

A muon collider would provide a unique facility for future elementary-particle physics research, and present unique challenges for accelerator physics and technology. An R&D effort is underway to address major challenges in the design of a future muon collider. This talk should provide an opportunity to discuss the muon collider's challenges, present recent R&D results, and describe future prospects.

TUXB01

Progress Towards Ultimate Storage Ring Light Sources

brightness, electron, dipole, wiggler

1035

M. Borland
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Developments such as the low emittance NSLS-II storage ring, followed by the even lower emittance MAX-IV ring, demonstrate that the technology of storage ring light sources has not reached full maturity. Indeed, these new sources are paving the way toward realizing diffraction-limited angstrom-wavelength storage ring light sources in the not-too-distant future. Our discussion begins with a review of recent trends and developments in storage ring design. We then survey on-going work around the world to develop concepts and designs for so-called "ultimate" storage ring light sources.

Slides TUXB01 [3.442 MB]

TUXB02

Review of ERL Projects at KEK and Around the World

linac, gun, FEL, electron

1040

N. Nakamura
KEK, Ibaraki, Japan

Future synchrotron light sources based on energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The Japanese collaboration team is making efforts for realizing an ERL-based VUV and X-ray source with R&D efforts on super-conducting cavities and the electron gun at KEK and elsewhere. This presentation will describe the developments of the compact ERL project and the outline of the 3-GeV ERL light source project at KEK and also review ERL projects around the world, including potential applications to colliders.

Slides TUXB02 [25.328 MB]

TUOAA03

Tests of Low Emittance Tuning Techniques at SLS and DAΦNE

quadrupole, coupling, alignment, collider

1065

S.M. Liuzzo, M.E. Biagini, P. Raimondi
INFN/LNF, Frascati (Roma), Italy
M. Aiba
Paul Scherrer Institut, Villigen, Switzerland
M. Böge
PSI, Villigen, Switzerland

The SuperB collider design is based on extremely low emittances, comparable to those of synchrotron light sources. A Low Emittance Tuning (LET) algorithm was developed for SuperB and has been tested last year at DIAMOND. This paper will report on the results of the application of LET to SLS (PSI) and DAΦNE (LNF) in order to compare and confirm the previous results. In this tests, the correction of orbit, dispersion and coupling is applied simultaneously to the detection of Beam Position Monitors tilts. The effect of beam based alignment at DAΦNE is also presented, together with an evaluation of the effects of other possible sources of emittance growth.

Slides TUOAA03 [4.313 MB]

TUOBA01

Summary of Fermilab’s Recycler Electron Cooler Operation and Studies

electron, antiproton, ion, extraction

1068

L.R. Prost, A.V. Shemyakin
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Fermilab’s Recycler ring was used as a storage ring for accumulation and subsequent manipulations of 8 GeV antiprotons destined for the Tevatron collider. To satisfy these missions, a unique electron cooling system was designed, developed and successfully implemented. The most important features that distinguish the Recycler cooler from other existing electron coolers are its relativistic energy (it employs a 4.3 MeV, 0.1 A DC electron beam), a weak continuous longitudinal magnetic field in the cooling section (~100 G), and lumped focusing elsewhere. With the termination of the collider operation at Fermilab, the cooler operation was also terminated. In this article, we will summarize the experience of commissioning, optimizing and running this unique machine over the 6 years of its existence.

Slides TUOBA01 [2.503 MB]

TUOBB01

A European Proposal for the Compton Gamma-ray Source of ELI-NP

laser, photon, electron, scattering

1086

L. Serafini, I. Boscolo, F. Broggi, V. Petrillo
Istituto Nazionale di Fisica Nucleare, Milano, Italy
O. Adriani, G. Graziani, G. Passaleva
INFN-FI, Sesto Fiorentino, Italy
S. Albergo, A. Tricomi
INFN-CT, Catania, Italy
D. Alesini, M.P. Anania, A. Bacci, R. Bedogni, M. Bellaveglia, C. Biscari, R. Boni, M. Boscolo, M. Castellano, E. Chiadroni, A. Clozza, E. Di Pasquale, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, F. Marcellini, C. Maroli, G. Mazzitelli, E. Pace, L. Pellegrino, R. Ricci, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, P. Tomassini, C. Vaccarezza, S. Vescovi, F. Villa
INFN/LNF, Frascati (Roma), Italy
D. Angal-Kalinin, J.A. Clarke, B.D. Fell, A.R. Goulden, J.D. Herbert, S.P. Jamison, P.A. McIntosh, R.J. Smith, S.L. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P. Antici, M. Coppola, L. Lancia, A. Mostacci, L. Palumbo
URLS, Rome, Italy
N. Bliss, B.G. Martlew
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
P. Cardarelli, M. Gambaccini
INFN-Ferrara, Ferrara, Italy
L. Catani, A. Cianchi
INFN-Roma II, Roma, Italy
I. Chaikovska, O. Dadoun, A. Stocchi, A. Variola, Z.F. Zomer
LAL, Orsay, France
C. De Martinis
INFN/LASA, Segrate (MI), Italy
F. Druon, P. Fichot
ILE, Palaiseau Cedex, France
E. Iarocci
University of Rome "La Sapienza", Rome, Italy
M. Migliorati
Rome University La Sapienza, Roma, Italy
A.-S. Müller
IN2P3, Paris, France
V. Nardone
Università di Roma I La Sapienza, Roma, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy
M. Veltri
Uniurb, Urbino (PU), Italy

A European proposal is under preparation for the Compton gamma-ray Source of ELI-NP. In the Romanian pillar of ELI (the European Extreme Light Infrastructure) an advanced gamma-ray beam is foreseen, coupled to two 10 PW laser systems. The photons will be generated by Compton back-scattering in the collision between a high quality electron beam and a high power laser. A European collaboration formed by INFN, Univ. of Roma La Sapienza, Orsay-LAL of IN2P3, Univ. de Paris Sud XI and ASTeC at Daresbury, is preparing a TDR exploring the feasibility of a machine expected to achieve the Gamma-ray beam specifications: energy tunable between 1 and 20 MeV, narrow bandwidth (0.3%) and high spectral density, 10⁴ photons/sec/eV. We will describe the lay-out of the 720 MeV RF Linac and the collision laser with the associated optical cavity, as well as the optimized beam dynamics to achieve maximum phase space density at the collision, taking into account beam loading and beam break-up due to the acceleration of long bunch trains. The predicted gamma-ray spectra will be evaluated as the gamma photons collimators background. An option for electron bunches recirculation will also be illustrated.

Slides TUOBB01 [5.099 MB]

TUOBC01

Experimental Verification of the CLIC Two-beam Scheme, Status and Outlook

linac, acceleration, target, gun

1101

R. Corsini
CERN, Geneva, Switzerland

The feasibility of the CLIC novel scheme of two-beam acceleration was extensively tested in the CTF3 facility over the last few years. In particular, efficient full beam loading acceleration, isochronous ring operation, beam recombination by transverse RF deflectors have been fully proven. 12 GHz RF power production by high-current drive beam is now part of CTF3 routine operation, and two-beam acceleration up to 150 MV/m has been achieved. Drive beam deceleration tests were carried out as well. In this paper we summarize the main results obtained, including the more recent ones. We also outline and discuss the future experimental program, both in CTF3 and in other beam facilities, as well as the path to a possible facility needed in the initial stage of the CLIC project, CLIC0.

Slides TUOBC01 [9.921 MB]

TUEPPB006

Direct Numerical Modeling of E-Cloud Driven Instability of Three Consecutive Batches in the CERN SPS

electron, simulation, feedback, betatron

1125

J.-L. Vay, M.A. Furman, M. Venturini
LBNL, Berkeley, California, USA

Funding: Supported by the US-DOE under Contract DE-AC02-05CH11231, the SciDAC program ComPASS and the US-LHC Accelerator Research Program (LARP).
Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. The simulation package WARP-POSINST was recently upgraded for handling multiple bunches and modeling concurrently the electron cloud buildup and its effect on the beam, allowing for direct self-consistent simulation of bunch trains generating, and interacting with, electron clouds. We have used the WARP-POSINST package on massively parallel supercomputers to study the buildup and interaction of electron clouds with a proton bunch train in the CERN SPS accelerator. Results suggest that a positive feedback mechanism exists between the electron buildup and the e-cloud driven transverse instability, leading to a net increase in predicted electron density.
Used resources of NERSC.

TUPPC003

Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors

coupling, quadrupole, sextupole, betatron

1152

A. Chancé, J. Payet
CEA/DSM/IRFU, France
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC004

Study of a Lattice with a Lower Emittance at SOLEIL

dipole, lattice, optics, betatron

1155

R. Nagaoka, P. Brunelle, A. Nadji, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

The paper introduces the first preliminary feasibility study made at SOLEIL towards a possible future upgrade of the lattice in furthermore reducing the horizontal emittance, so to raise the storage ring performance. The approach taken is to employ whatever emittance reduction methods available, by respecting the given constraints on the lattice structure and the optics, particularly the circumference, insertion device straights, the required optics behavior as well as its tunability. Specifically, the possibility of introducing superbends into the double bend lattice is pursued, which are beneficial to hard X-ray users and could simultaneously help reducing the emittance thanks to its longitudinally varying field profile. Although the present study shall mainly focus on the linear properties of the optical solutions found, optimization of nonlinear optics is also discussed in view of the large dependence of the latter on the former.

TUPPC008

Twiss Parameters of Coupled Particle Beams with Equal Eigenemittances

beam-transport

1167

V. Balandin, R. Brinkmann, W. Decking, N. Golubeva
DESY, Hamburg, Germany

The parametrization of coupled beam motion has been studied intensively over the past decades. Nevertheless, there is still no representation of general coupled motion that would be as elegant and as complete as the one dimensional Courant-Snyder theory. In this context the consideration of different partial cases plays an important highlighting role, and in this paper we study the parametrization of coupled particle beams with equal eigenemittances. We show that such beams allow description which in many aspects resembles the one dimensional Courant-Snyder theory.

TUPPC010

Study of Effects of Failure of Beamline Elements and its Compensation in CW Superconducting Linac

linac, cavity, beam-losses, focusing

1173

A. Saini, K. Ranjan
University of Delhi, Delhi, India
C.S. Mishra, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Project-X is the proposed high intensity proton facility to be built at Fermilab in United States. First stage of the Project-X consists of H^- superconducting linac (SC) which will be operated in continuous wave (CW) mode to accelerate the beam from kinetic energy of 2.1 MeV to 3 GeV. The operation in CW mode puts stringent tolerances on the beam line components, particularly at low energy section. The failure of beam line elements result in mismatch of the beam with the following sections due to different beam parameters than designed parameters. It makes the beam unstable which causes emittance dilution, and ultimately results in beam losses. In worst case, it can affect the reliability of the machine and may lead to the shutdown of the linac to replace the failed elements. Thus, it is important to study impacts of these effects and their compensation to restore linac performance to avoid beam interruption. This paper presents the studies performed for the failure of accelerating cavity and focusing magnets at the critical locations in the Project-X CW superconducting linac

TUPPC013

Optimization of Lower Emittance Optics for the SPring-8 Storage Ring

optics, photon, lattice, brilliance

1182

Y. Shimosaki, K.K. Kaneki, M. Masaki, T. Nakamura, H. Ohkuma, J. Schimizu, K. Soutome, S. Takano, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

A design work of the present SPring-8 storage ring is in progress to improve its performance. The linear optics has been changed to reduce the natural emittance below the nominal of 3.4 nmrad at 8 GeV, and the nonlinear optics has been optimized with a genetic algorithm to suppress the amplitude-dependent tune shifts and to enlarge the dynamic aperture. As a preliminary study, the optics with the natural emittance of 2.4 nmrad at 8 GeV has been examined, theoretically and experimentally. In this optics, 1.5 times higher brilliance for 10 keV photons than the present can theoretically be expected for the standard undulator beamline. The improved optics design and its beam performance will be presented in detail. In this presentation, a optics for a future upgrade of the SPring-8 (SPring-8 II) will not be discussed, which is a full-scale major lattice modification, while the method we used in optimizing the nonlinear optics can also be adopted to the SPring-8 II*.
* Y. Shimosaki et al., "Design Study of Nonlinear Optics for a Very Low-emittance Lattice of the SPring-8 II," these proceedings.

TUPPC014

Design Study of Nonlinear Optics for a Very Low-emittance Lattice of the SPring-8 II

lattice, sextupole, resonance, optics

1185

Y. Shimosaki, K.K. Kaneki, T. Nakamura, H. Ohkuma, J. Schimizu, K. Soutome, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

A feasibility of a very low-emittance storage ring has been studied for an upgrade project, SPring-8 II. Its ultimate goal is to provide a superior brilliance for 0.5 ~ 100 keV photons. A sextupole bend lattice with the natural emittance of 70 pmrad at 6 GeV has been examined as the first candidate*. The nonlinear optics has been optimized to enlarge the dynamic aperture by correcting nonlinear resonances based on an isolated resonance Hamiltonian with thick lens approximation, and by non-interleaved sextupole method. A genetic algorithm, which has been examined to improve the performance of the present SPring-8**, will be adopted for detailed optimization of the tunes and sextupole strength to adjust the non-interleaved scheme and to correct higher order resonances. The correction scheme of nonlinear optics and its results will be presented in detail.
*Y. Shimosaki et al., IPAC’11, TUOAB01, p. 942 (2011).
**Y. Shimosaki et al., "Optimization of Lower Emittance Optics for the SPring-8 Storage Ring", these proceedings.

TUPPC017

Orbit and Optics Correction to Realize Designed Machine Performance

optics, lattice, target, closed-orbit

1194

Y. Seimiya, S. Kamada, A. Morita, K. Ohmi, K. Oide
KEK, Ibaraki, Japan

It is difficult for actual accelerators to achieve the designed machine performance without appropriate correction or adjustment of magnet errors. By correction as magnets are aligned to design orbit, we aim to be realized the designed machine performance. However, it is not easy to estimate the design orbit in real accelerators. In KEKB and PF, beam position monitor(BPM) can be calibrated to the center of quadrupole magnet(QM). BPM and QM misalignments (except rotation misalignment) referring to design orbit can be estimated using assumption that these misalignments are coincident. This is, design orbit at BPM and QM can be derived.

TUPPC018

Estimation of Orbit and Optics Distortion of SuperKEKB by Tunnel Deformation

quadrupole, optics, coupling, luminosity

1197

A. Morita, H. Koiso, Y. Ohnishi, K. Oide, H. Sugimoto
KEK, Ibaraki, Japan

The tunnel which was used for the KEKB B-factory is reused for the accelerator tunnel of the SuperKEKB. The total vertical displacement of the tunnel subsidence reached almost 30mm during 10 years KEKB operation. In order to operate the SuperKEKB which might be more delicate machine than the previous KEKB B-factory, we are evaluating the optics distortion by the tunnel deformation and studying the machine performance after the orbit and optics correction. We report the estimation of the machine performance degradation by the tunnel subsidence and the requirement of the correction.

TUPPC021

Design Study on KEK Injector Linac Upgrade for High-current and Low-emittance Beams

linac, simulation, wakefield, acceleration

1206

H. Sugimoto, M. Satoh, M. Yoshida
KEK, Ibaraki, Japan

Injector linac at KEK is now under upgrading to produce high current (5nC for e-, 4nC for e+) and low emittance (20 mm mrad for e-, 6 mm mrad for e+) electron and positron beams to a SuperB collider called SuperKEKB. Emittance growth resulted from both wakefield at the acceleration structure and dispersive effects at the focusing structure are troublesome in keeping the beam quality during the beam propagation. In this study, a possible solution to mitigate these effects in the KEK injector linac is explored by considering bunch compression in an existing bending section, orbit correction to suppress the wakefield excitation, and beam optics design.

TUPPC022

Straight Scaling FFAG Experiment

linac, vacuum, closed-orbit, instrumentation

1209

J.-B. Lagrange, Y. Ishi, Y. Kuriyama, Y. Mori, R. Nakano, B. Qin, T. Uesugi, E. Yamakawa
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Niwa, K. Okabe, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan

Straight scaling FFAG experiment has been done at Kyoto University research reactor institute. Details and results are presented here.

TUPPC024

R&D of an Ultrafast Probe Apparatus Based on MeV Electron Diffraction at Tsinghua University

electron, solenoid, simulation, cathode

1215

X.H. Lu, Y.-C. Du, W.-H. Huang, H.J. Qian, C.-X. Tang
TUB, Beijing, People's Republic of China

Funding: This work is supported by National Natural Science Foundation of China and National Basic Research Program of China (973 Program).
An ultrafast probe apparatus based on MeV ultrafast electron diffraction is developed at Tsinghua University. It aims at generating 1.5 to 3 MeV pulse with sub-pC charge and sub-ps pulse length for pump-probe experiments. It consists of an S-band 1.6-cell radiofrequency photocathode gun, a solenoid, a sample chamber, a deflecting cavity, a detection system and other diagnostics tools. Simulations show the position of solenoid coil affects the spot size on detection screen and the charge of collimated bunch significantly. The collimator is found to be helpful to stabilize the charge of collimated bunch and reduce its normalized emittance. The construction of the apparatus is almost finished and the commissioning test will start soon.

TUPPC027

Multi Objective Genetic Optimization for Linac Lattice of PAL XFEL

linac, lattice, electron, quadrupole

1224

C.H. Yi, M.-H. Cho, S.H. Kim, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea
K.-J. Kim
ANL, Argonne, USA

Funding: Work supported by MEST and POSTECH Physics BK21 Program.
There are a large number of variables and objectives in design of XFEL linac lattices. Recently, most of accelerator physics field, are applying the multi-objective genetic algorithm (MOGA) for these kinds of problems. MOGA was applied to the PAL XFEL linac lattice design. Longitudinal position of all components was fixed before applying MOGA. RF parameters of RF cavities and bending angles of bunch compressors are selected as variables. Various beam parameters computed by ELEGANT were used as objectives. By using MOGA, new linac lattice designs with 2 and 3 bunch compressors was generated and their beam properties are presented in this paper.

TUPPC033

Random Walk Optimization in Accelerators: Vertical Emittance Tuning at SLS

target, quadrupole, luminosity, controls

1230

M. Aiba, M. Böge, N. Milas, A. Streun
Paul Scherrer Institut, Villigen, Switzerland

The operation of a high performance accelerator is realized only when several beam based corrections are implemented. These corrections are, however, limited by measurement errors as the correction approaches the ideal value. To overcome this limitation, we investigate the application of a random walk (RW) optimization specifically to minimize the vertical emittance at the SLS. A systematic minimization is performed by measuring linear coupling and spurious vertical dispersion and correcting them using 36 skew quadrupole correctors. On the other hand, the minimization can be performed by simply applying a multi-variable optimization from the mathematics point of view, where the best combination of skew corrections is to be found. The measured vertical beam size is available as a stable target function of the minimization even at very low vertical emittance. Although RW and other algorithms are implemented into various accelerator computer codes, it is interesting to apply this concept to the real machine, where measurement errors are unavoidable and may prohibit systematic minimization based on a machine model. Possible applications of the technique in general are also discussed.

TUPPC034

Preparation of SLS for IBS Measurements

diagnostics, optics, impedance, radiation

1233

N. Milas, M. Böge, A. Streun
PSI, Villigen, Switzerland
M. Aiba, A. Lüdeke, A. Saa Hernandez
Paul Scherrer Institut, Villigen, Switzerland
F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

It is planned to use the SLS for testing damping ring issues related to linear colliders. One aspect is the study of Intra-Beam Scattering (IBS) effects, which are a limiting factor for ultra-low emittance rings. In this paper we present the setup and characterization of a new mode of operation in which the SLS runs at lower energy (1.57 GeV) with a natural emittance of 2.4 nm rad. This is much smaller than that at the nominal energy (2.41 GeV) and should make IBS effects more easily visible. In order to be able to observe IBS a careful setup is required: Optics measurement and correction as well as measurements of the bunch natural energy spread and the onset of turbulent bunch lengthening. Also, a detailed discussion on the available diagnostics and their limitations are shown and finally some preliminary results of beam emittance measurements, in all three planes, as a function of single bunch current are presented.

TUPPC041

A 3 TeV Muon Collider Lattice Design

quadrupole, lattice, dipole, collider

1254

Y. Alexahin, E. Gianfelice-Wendt
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
A new lattice for 3 TeV c.o.m. energy with β^*=5mm was developed which follows the basic concept of the earlier 1.5 TeV design* but uses quad triplets for the final focus in order to keep the maximum magnet strength and aperture about the same as in 1.5 TeV case. Another difference is employment of combined-function magnets with the goal to lower heat deposition in magnet cold mass and to eliminate regions without bending field which produce “hot spots” of neutrino radiation that can be an issue at higher energy. The proposed lattice is shown to satisfy the requirements on luminosity, dynamic aperture and momentum acceptance.
* Y.Alexahin, E.Gianfelice-Wendt, A.Netepenko, Proc. IPAC10, Kyoto, May 2010, p. 1563

TUPPC044

Emittance and Phase Space Tomography for the Fermilab Linac

linac, focusing, optics, quadrupole

1263

C. Johnstone, F.G.G. Garcia, T. Kobilarcik, G.M. Koizumi, C.D. Moore, D.L. Newhart
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy.
The Fermilab Linac delivers a variable intensity, 400-MeV beam to the The MuCool Test Area experimental hall via a beam line specifically designed to facilitate measurements of the Linac beam emittance and properties. A 10 m, dispersion-free and magnet-free straight utilizes an upstream quadrupole focusing triplet in combination with the necessary in-straight beam diagnostics to fully characterize the transverse beam properties. Since the Linac does not produce a strictly elliptical phase space, tomography must be performed on the profile data to retrieve the actual particle distribution in phase space. This is achieved by rotating the phase space distribution using different waist focusing conditions of the upstream triplet and performing a de-convolution of the profile data. Preliminary measurements using this diagnostic section are reported here.

TUPPC049

A Tapered-foil Emittance-exchange Experiment at LANSCE

proton, simulation, scattering, collimation

1278

R.C. McCrady
LANL, Los Alamos, New Mexico, USA

We are planning an experiment at the Los Alamos Neutron Science Center (LANSCE) to demonstrate a technique for reducing the transverse emittance of the proton beam by passing the beam through a wedge-shaped energy degrader to produce a non-symplectic correlation between transverse position and energy, then removing this correlation with a bending magnet. This technique was proposed by Peterson* in 1983. We present a specific beamline layout that is expected to mitigate several complications associated with fielding an experiment to demonstrate the technique with a low-emittance proton beam. We present simulated results and expected outcomes of this demonstration.
* J. M. Peterson, Proc. of PAC 1983, pP. 2403-2405 (1984).

TUPPC055

Development of an Automatic MATLAB based Emittance Measurement Tool for the IAC Accelerators

quadrupole, EPICS, background, controls

1296

C.F. Eckman, A. Andrews, Y. Kim, S. Setiniyaz, D.P. Wells
IAC, Pocatello, IDAHO, USA
A.W. Hunt
ISU, Pocatello, Idaho, USA

At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating fifteen low energy accelerators. To optimize those accelerators properly, we have to measure the transverse beam emittance. To measure the transverse beam emittance of an S-band linear accelerator with the quadrupole scan technique, we installed an Optical Transition Radiation (OTR) screen and a digital CCD camera in the bealime of the accelerator. From the images of the digital CCD camera, the transverse beam profile on the OTR screen can be acquired. To extract the transverse beam size and to estimate the transverse emittance, we have developed a MATLAB program. This paper describe the details of the MATLAB program and performance of our MATLAB based emittance measurement tool.

TUPPC065

High Intensity Beam Analysis for the Superconducting Radio-frequency Linac (SRF-Linac) of the IFMIF-EVEDA Accelerators

resonance, linac, SRF, space-charge

1323

W. Simeoni
CEA/IRFU, Gif-sur-Yvette, France
N. Chauvin, P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France

In this proceeding we analyze space charge effects on the beam dynamics of IFMIF accelerators. The objective is to be able to characterize and understand the crucial issues like halo formation, emittance growth and sudden particle losses in the SRF-Linac. We use the Hofmann stability charts to identify modes of collective space charge density oscillations that are responsible for the transfer and growth of the emittance. With identification of modes we are able to treat the parametric resonance between the modes and the nonlinear motion of an individual ion the amplitude of which is greater than the core radius. The resulting phase space consists of an inner separatrix containing the core and an outer separatrix that becomes the locus near which the halo particles enter and cluster.

TUPPC073

Frequency Map Analysis for SuperB

resonance, lattice, dynamic-aperture, sextupole

1341

S.M. Liuzzo, M.E. Biagini, P. Raimondi
INFN/LNF, Frascati (Roma), Italy
T. Demma
LAL, Orsay, France
Y. Papaphilippou
CERN, Geneva, Switzerland

The frequency map analysis is applied to the SuperB HER and LER lattices including the Final Focus, in order to understand the dynamic aperture limitation and provide insight for a working point optimization. In this respect, frequency and diffusion maps are evaluated applying random magnet misalignments and tilts, before and after correction of orbit, dispersion and coupling using Low Emittance Tuning techniques. The same analysis is performed for on and off momentum particles. The lattice properties are further investigated using working point scans and the correction of non linear resonance driving terms and amplitude detuning.

TUPPC077

Numerical Study of Beam Trapping in Stable Islands for Simple 2D Models of Betatronic Motion

simulation, resonance, extraction, octupole

1350

M. Giovannozzi, C. Hernalsteens
CERN, Geneva, Switzerland

An essential ingredient for the proposed Multi-Turn Extraction (MTE) at the CERN PS is the beam trapping in stable islands. The control of the trapping process is essential for the quality of the final beam in terms of intensity sharing and emittance. In this paper, the splitting process is studied quantitatively by means of numerical simulations performed on 2D model representing the horizontal non-linear betatronic motion. The results are reviewed and discussed in details.

TUPPC078

Proposal of an Inverse Logarithm Scaling Law for the Luminosity Evolution

luminosity, collider, dynamic-aperture, hadron

1353

M. Giovannozzi
CERN, Geneva, Switzerland
C.H. Yu
IHEP, Beijing, People's Republic of China

A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. It was showed that dynamic aperture has a logarithmic dependence on time, which would be suggested by some fundamental theorems of the theory of dynamical systems. Such a scaling law was recently extended also to the intensity evolution in a storage ring. In this paper, inspired by these results, and inverse logarithm scaling law for the luminosity in a circular collider is proposed. The law is then tested against the data from the LHC physics runs and also with some examples from other machines. The results are presented and discussed in details.

TUPPC086

Conceptual Design of the CLIC damping rings

wiggler, damping, positron, vacuum

1368

Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann
CERN, Geneva, Switzerland
C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
A. Bernhard
KIT, Karlsruhe, Germany
M.J. Boland
ASCo, Clayton, Victoria, Australia
A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev
BINP SB RAS, Novosibirsk, Russia
M. Korostelev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
E. Koukovini
EPFL, Lausanne, Switzerland
M.A. Palmer
CLASSE, Ithaca, New York, USA
M.T.F. Pivi, S.R. Smith
SLAC, Menlo Park, California, USA
R.P. Rassool, K.P. Wootton
The University of Melbourne, Melbourne, Australia
L. Rinolfi
JUAS, Archamps, France
A. Vivoli
Fermilab, Batavia, USA

The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.

TUPPC091

Simulation of Colliding Beams with Feedback in LHC

simulation, feedback, luminosity, kicker

1374

S. Paret, J. Qiang
LBNL, Berkeley, California, USA

Funding: This work supported partially by the US LHC Accelerator Research Program (LARP) of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Beam-beam effects impose restrictions on beam and beam optical parameters as they may degrade the luminosity and the emittance or cause coherent instabilities and particle loss. In the planned High Luminosity Large Hadron Collider (HL-LHC), beam-beam effects will significantly affect the beams because of unprecedented beam parameters and new features like crab cavities or elliptical beam cross sections at the interaction points. Noise from various sources can further worsen the situation. Therefore investigations are required to identify limitations of possible HL-LHC layouts. The impact of beam-beam effects on the beam dynamics is investigated by virtue of particle tracking simulations. Using the code BeamBeam3D and the strong-strong collision model, simulations including perturbations by noise and LHC's feedback system, an important means to mitigate transverse emittance growth due to coherent beam excitation, were carried out. The impact of numerical noise on the emittance in simulations and the state of the feedback modeling are presented.

TUPPC096

Optimization of the Dynamic Aperture for SPEAR3 Low-emittance Upgrade

sextupole, resonance, dynamic-aperture, optics

1380

L. Wang, X. Huang, Y. Nosochkov, J.A. Safranek
SLAC, Menlo Park, California, USA
M. Borland
ANL, Argonne, USA

A low emittance upgrade is planned for SPEAR3. As the first phase, the emittance is reduced from 10nm to 7nm without addition magnets. A further upgrade with even lower emittance will require a damping wiggler. There is a smaller dynamic aperture for the lower emittance optics due to the stronger nonlinearity. A Multi-Objective Genetic Optimization (MOGA) code is used to maximize the dynamic aperture. Both the dynamic aperture and beam lifetime are optimized simultaneously. Various configurations of the sextupole magnets have been studied in order to find the best configuration. The betatron tune also can be optimized to minimize resonance effects. The optimized dynamic aperture increases 15% from the normal case and the life time increases from 15 hours to 17 hours. It is important that the increase of the dynamic aperture is mainly in the beam injection direction. Therefore the injection efficiency will benefit from this improvement.

TUPPC097

Computational Modeling of Electron Cloud For MEIC

electron, simulation, collider, ion

1383

S. Ahmed, J.D. Dolph, G.A. Krafft, T. Satogata, B.C. Yunn
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
This work is the continuation of our earlier studies on electron cloud (EC) simulations reported in IPAC'11 for the medium energy electron-ion collider (MEIC) envisioned at JLab beyond the 12 GeV upgrade of CEBAF. In this paper, we will study the EC saturation density in various MEIC operations scenarios to calculate details of the EC-induced wakefield to establish more stringent bounds on instability thresholds and determine whether EC mitigation, such as NEG coatings or solenoid fields, should be considered in the MEIC design.

TUPPD003

Optimisation of Cooling Lattice Based on Bucked Coils for the Neutrino Factory

lattice, factory, simulation, cavity

1407

A. Alekou, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The ionisation cooling technique will be used at the Neutrino Factory to reduce the transverse phase space of the muon beam. For efficient cooling, high average RF gradient and strong focusing are required to be applied in the cooling channel. However, high magnetic field at the position of the RF cavities induces electric field breakdown and therefore, a novel configuration, the Bucked Coils lattice, has been proposed to mitigate this problem. The Bucked Coils lattice has significantly lower magnetic field in the RF cavities by using coils of different radius and opposite polarity. This paper presents the optimisation of this lattice, its cooling performance, together with the preliminary conceptual engineering design.

TUPPD007

Multiple Scattering Measurements in the MICE Experiment

scattering, simulation, solenoid, factory

1419

T. Carlisle, J.H. Cobb
JAI, Oxford, United Kingdom
D.V. Neuffer
Fermilab, Batavia, USA

The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test and characterize a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with a relative accuracy of 1% by measuring muons individually. Muon detectors include two scintillating fibre trackers embedded within 4 T solenoid fields, TOF counters and a muon ranger. Step IV of MICE will begin in 2012, producing the experiment's first precise emittance-reduction measurements. Multiple scattering in candidate Step IV absorber materials was studied in G4MICE, based on GEANT4. Equilibrium emittances for low-Z materials from hydrogen to aluminium can be studied experimentally in Step IV of MICE, and compared with simulations.

TUPPD011

Studies of the Twin Helix Parametric-resonance Ionization Cooling Channel with COSY INFINITY

simulation, resonance, quadrupole, collider

1428

J.A. Maloney, K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, USA
A. Afanasev
GWU, Washington, USA
S.A. Bogacz, Y.S. Derbenev, V.S. Morozov
JLAB, Newport News, Virginia, USA
B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA

Funding: Supported in part by SBIR Grant DE-SC00005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A primary technical challenge to the design of a high luminosity muon collider is an effective beam cooling system. An epicyclic twin-helix channel utilizing parametric-resonance ionization cooling has been proposed for the final 6D cooling stage. A proposed design of this twin-helix channel is presented that utilizes correlated optics between the horizontal and vertical betatron periods to simultaneously focus transverse motion of the beam in both planes. Parametric resonance is induced in both planes via a system of helical quadrupole harmonics. Ionization cooling is achieved via periodically placed wedges of absorbing material, with intermittent rf cavities restoring longitudinal momentum necessary to maintain stable orbit of the beam. COSY INFINITY is utilized to simulate the theory at first order. The motion of particles around a hyperbolic fixed point is tracked. Comparison is made between the EPIC cooling channel and standard ionization cooling effects. Cooling effects are measured, after including stochastic effects, for both a single particle and a distribution of particles.

TUPPD012

Complete Muon Cooling Channel Design and Simulations

dipole, simulation, solenoid, collider

1431

C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson
Muons, Inc, Batavia, USA
Y.S. Derbenev, V.S. Morozov
JLAB, Newport News, Virginia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD013

Bunch Coalescing in a Helical Channel

collider, acceleration, simulation, factory

1434

C. Y. Yoshikawa, C.M. Ankenbrandt
Muons, Inc, Batavia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Funding: Supported in part by SBIR Grant 4725 · 09SC02739.
A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV.

TUPPD014

To the Ionization Cooling in a RF Cavity with Absorber

cavity, scattering, focusing, radiation

1437

A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA

We are considering a RF cavity with Beryllium disk installed in the middle of the cavity as a ionization cooling element for the muon beam. Specially arranged shape of disk together with nonzero dispersion allows 6D cooling of muon beam. Technical aspects of this system and conceptual design are discussed in this paper also. This type of cooler demonstrates advantages if compared with the RF cavity filled with pressurized gas or with the helical cooler.

TUPPD019

New Injector for the EMMA ns-FFAG Ring

booster, cavity, gun, linac

1449

B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

EMMA is the world’s first non-scaling FFAG which has recently demonstrated acceleration in the serpentine channel. At present, the electron beam is injected into EMMA from the ALICE accelerator. However, funding will be re-directed to an Electron Beam Test Facility (EBTF) in the near future, therefore, in order to continue the broad portfolio of planned experiments required to characterize non-scaling FFAGs, it essential to consider an alternative injection scheme. In this paper, we propose re-utilizing a thermionic gun and a 12 MeV linac from the SRS (Synchrotron Radiation Source) at Daresbury Laboratory. The paper looks at how the required EMMA beam properties can be matched with this new set-up and the advantages and disadvantages involved.

TUPPD026

Study of the RFQ Beam Cooler for SPES project

ion, rfq, quadrupole, extraction

1467

M.M. Maggiore, A.M. Porcellato, S. Stark
INFN/LNL, Legnaro (PD), Italy

The SPES project is the new Radioactive Ion Beam facility under construction at Laboratori Nazionali of Legnaro, Italy. In this framework in order to improve the beam quality in terms of emittance and energy spread, a study of a new RFQ beam cooler device is accomplishing. The electromagnetic design of the RFQ section and the electrostatic layout of the injection and extraction regions have been done. The study about the beam dynamic is going on by means of dedicated codes which allow to take into account the interaction of the ions with the buffer gas needed to cool the beams. The status of the project and the results will be shown in this report.

TUPPD035

SuperKEKB Injector Upgrade for High Charge and Low Emittance Electron Beam

gun, alignment, wakefield, cathode

1482

M. Yoshida, N. Iida, Y. Ogawa, M. Sato, L. Zang
KEK, Ibaraki, Japan

The design strategy of SuperKEKB is based on the nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, new photocathode RF-Gun with the focusing electric field was installed. Further the emittance growth in the linac is an important issue for the low emittance injection. We will report the machine study of the RF-Gun and the emittance growth through the linac.

TUPPD039

Simulation Study of Space Charge Effects for a 100-keV, 150-mA Class Deuteron Source

extraction, simulation, plasma, focusing

1491

M. Ichikawa, H. Suzuki
Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
S. Maebara
JAEA, Ibaraki-ken, Japan

Ion sources providing high current beam with low emittance are required for accelerators to expand to apply them to fusion material science. A 100-keV, 150-mA class deuteron source with low emittance is required for an accelerator-based neutron irradiation facility to develop fusion materials, and the study for space charge effects in the range of a 20- to 150-mA deuteron beam is indispensable to extract the low beam emittance. For this purpose, each ion source to extract the beam current of 20, 50, 100, and 150 mA was designed by the Igun code, under the condition to extract a beam radius of 4 mm, a beam energy of 100 keV, and a normalized emittance of 0.2 PI mm mrad. In this article, these simulation results from the viewpoint of space charge effects will be presented in detail.

TUPPD047

Injection Sequence for High-power Isochronous Cyclotrons for ADS Fission

cyclotron, ion, rfq, ion-source

1509

S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, P.M. McIntyre, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: This work is supported by grants from the State of Texas (ASE) and the Mitchell Family Foundation.
A high-current injector sequence is being developed for use in a flux-coupled stack of high-current cyclotrons for accelerator-driven subcritical (ADS) fission. The design includes an ECR ion source, LEBT, RF quadrupole, and multi-stage chopper. A first cyclotron then accelerates the beams to 100 MeV for injection to the sector isochronous cyclotron. Provisions for control of emittance and bunch tails are described.

TUPPD051

Operational Experience with the Nb/Pb SRF Photoelectron Gun

cathode, solenoid, laser, cavity

1518

T. Kamps, W. Anders, R. Barday, A. Jankowiak, J. Knobloch, O. Kugeler, A.N. Matveenko, A. Neumann, T. Quast, J. Rudolph, S.G. Schubert, J. Völker
HZB, Berlin, Germany
P. Kneisel
JLAB, Newport News, Virginia, USA
R. Nietubyć
The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland
J.K. Sekutowicz
DESY, Hamburg, Germany
J. Smedley
BNL, Upton, Long Island, New York, USA
J. Teichert
HZDR, Dresden, Germany
V. Volkov
BINP SB RAS, Novosibirsk, Russia
I. Will
MBI, Berlin, Germany

SRF photoelectron guns offer the promise of high brightness, high average current beam production for the next generation of accelerator driven light sources such as free electron lasers, THz radiation sources or energy-recovery linac driven synchrotron radiation sources. In a first step a fully superconducting RF (SRF) photoelectron gun is under development by a collaboration between HZB, DESY, JLAB, BNL and NCBJ. The aim of the experiment is to understand and improve the performance of a Nb SRF gun cavity coated with a small metallic Pb cathode film on the cavity backplane. This paper describes the highlights from the commissioning and beam parameter measurements. The main focus is on lessons learned from operation of the SRF gun.

TUPPD057

High Charge Low Emittance RF Gun for SuperKEKB

gun, cathode, injection, laser

1533

T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou
KEK, Ibaraki, Japan

We are developing a new RF gun for SuperKEKB. We are upgrading KEKB to SuperKEKB now. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun. Now, we are testing a Disk and Washer (DAW) type RF gun. Its photo cathode material is LaB6. Normally, LaB6 is used as a thermionic cathode, but it is suitable for　long-life photo cathode operation. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. We will obtain 3.2 MeV beam energy with the gun. The design of RF gun and experimental results will be shown.

TUPPD061

High-Power RF Test of an RF-Gun for PAL-XFEL

gun, laser, electron, injection

1539

J.H. Hong, J.H. Han, H.-S. Kang, C. Kim, S.H. Kim, C.-K. Min, S.S. Park, S.J. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Chae, I.S. Ko, Y.W. Parc
POSTECH, Pohang, Kyungbuk, Republic of Korea

A photocathode RF-gun for the X-ray free electron laser (XFEL) at the Pohang Accelerator Laboratory (PAL) has been fabricated and tested at PAL. This RF-gun is based on a 1.6-cell cavity with dual-feed waveguide ports and two pumping ports. The RF gun was designed by PAL and POSTECH. The RF-gun has been successfully tested with a cathode electric field gradient up to 126MV/m at a repetition rate of 30 Hz. This paper reports the recent results on the beam test of the RF-gun with high power RF at the gun test facility. We present and discuss the measurements of the basic beam parameters such as charge, energy, energy spread, and transverse emittance.

TUPPD062

The Source of Emittance Dilution and photoemission tunneling effect in Photocathode RF Guns

cathode, laser, cavity, simulation

1542

V. Volkov
BINP SB RAS, Novosibirsk, Russia
R. Barday, T. Kamps, J. Knobloch, A.N. Matveenko, S.G. Schubert, J. Völker
HZB, Berlin, Germany
J.K. Sekutowicz
DESY, Hamburg, Germany

Funding: Work supported by Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association VH-NG-636 and HRJRG-214.
Experimental data on HoBiCaT SRF photoinjector give an emittance which is much larger than the predicted thermal emittance. Modeling of photocathode RF gun beams with the different imperfections of experimental setup (alignment errors, inhomogeneity of quantum efficiency and laser power distributions on the cathode) is given. The main reason for the beam emittance dilution is photocathode field imperfections induced by field emitters that change the local electric field. Some field models of such photocathodes are tested in the simulations. The dependence of photocathode beam currents on the surface electric field was measured with the HoBiCaT SRF Photoinjector. The dependence can be explained by the tunneling effect described by Fowler-Nordheim like equation and is difficult to explain by usually applying Schottky effect.

TUPPD075

Simulated Performance of the Wisconsin Superconducting Electron Gun

solenoid, simulation, quadrupole, focusing

1572

R.A. Bosch, K.J. Kleman
UW-Madison/SRC, Madison, Wisconsin, USA
R.A. Legg
JLAB, Newport News, Virginia, USA

The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an emittance of about one mm-mrad can be produced for a free-electron laser.

TUPPD078

A Novel Design of a High Brightness Superconducting RF Photoinjector Gun Cavity

gun, cavity, SRF, cathode

1581

F. Marhauser, R. Rodriguez
MuPlus, Inc., Newport News, USA
Z. Li
SLAC, Menlo Park, California, USA

Funding: Work supported under U.S. DOE Grant Application Number 98802B12-I
Next generation electron accelerators for research, medical, defense or industrial use are in need of electron sources operating at high repetition rates of 1 MHz and beyond, with normalized emittance of 1 mm-mrad or less and bunch charges as much as one nC or more. A conceptual layout of a novel superconducting RF photoinjector gun cavity (SRF gun) is proposed, which can provide unprecedented flexibility to vary beam pulse patterns in the MHz regime and beyond at average currents around 1 mA. It does not require an opening in the center of the back wall and avoids the complex cathode exchange system, but still allows an exchange or refurbishment of the cathode. The demountable back plate has the major benefit to clean the cavity cells independently from the back wall carrying a superconductive photocathode. This mitigates risks of cavity contamination and eases fabrication and chemical post-processing to achieve high accelerating fields, a key parameter to guarantee high brightness beams.

TUPPD079

Design of an L-Band RF Photoinjector for the Idaho Accelerator Center 44 MeV Linac

linac, gun, laser, solenoid

1584

M. Titberidze, A.W. Hunt, D.P. Wells
IAC, Pocatello, IDAHO, USA
Y. Kim
ISU, Pocatello, Idaho, USA

At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating a 44 MeV L-band RF (1300 MHz) linear accelerator (LINAC) for various user applications such as medical isotope production, Laser Compton Scattering (LCS), positron annihilation energy spectroscopy, and photo fission. But the LINAC is not optimized properly to supply high quality electron beam for those experiments due to limitations of an existing 85 kV thermionic DC gun. In the near future, we are planning to use the L-band LINAC for new user applications such as Accelerator Driven subcritical nuclear reactor System (ADS), photon tagging facility, Ultrafast Electron Diffraction (UED) facility, and high power coherent Terahertz light source facility. Therefore, recently, we have been studying a future upgrade of the L-band LINAC with an RF photoinjector using ASTRA code. In this paper, we describe ASTRA simulation results and a new layout of the L-band LINAC, which is based on an L-band 1.5 cell RF photoinjector. Then, we describe its expected performance for two different single bunch charges (1 nC and 5 nC).

TUPPP002

GLASS Study of the Canadian Light Source Storage Ring Lattice

dynamic-aperture, lattice, quadrupole, sextupole

1602

W.A. Wurtz, L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada

GLASS is a technique for finding all potential operating points of a storage ring lattice by examining all possible configurations of the linear lattice. The Canadian Light Source (CLS) storage ring uses three quadrupole families, making it computationally efficient to use GLASS to study the lattice with unbroken symmetry. CLS does not employ harmonic sextupoles and has only two families of chromatic sextupoles. We can exhaust the sextupole degrees of freedom by requiring the horizontal and vertical chromaticities to be both zero. With no remaining free parameters in our lattice, it is possible to calculate dynamic aperture and momentum acceptance for select regions of interest uncovered by the GLASS scan. We find two regions with reasonable dynamic aperture and momentum acceptance: the region where we presently operate and a region that can be accessed by reversing the polarity of one quadrupole family.

TUPPP005

LUNEX5: A French FEL Test Facility Light Source Proposal

FEL, laser, electron, undulator

1611

A. Loulergue, C. Benabderrahmane, M. Bessière, P. Betinelli-Deck, F. Bouvet, A. Buteau, L. Cassinari, M.-E. Couprie, J. Daillant, J.-C. Denard, P. Eymard, B. Gagey, C. Herbeaux, M. Labat, A. Lestrade, P. Marchand, J.L. Marlats, C. Miron, P. Morin, A. Nadji, F. Polack, J.B. Pruvost, F. Ribeiro, J.P. Ricaud, P. Roy
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, C. Evain, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Carré
CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
G. Devanz, M. Luong
CEA/DSM/IRFU, France
L. Farvacque, G. Lebec
ESRF, Grenoble, France
G. Lambert, A. Lifschitz, V. Malka, A. Rousse
LOA, Palaiseau, France
M. Le Parquier
CERLA, Villeneuve d'Ascq, France
J. Lüning
CCPMR, Paris, France
R. Roux
LAL, Orsay, France

LUNEX5 is a new synchrotron FEL source project aiming at delivering short and coherent X-ray pulses to probe ultrafast phenomena at the femto-second scale, to investigate extremely low density samples as well as to image individual nm scale objects. The proposed machine layout is based on a 400 MeV super-conducting Conventional Linear Accelerator (CLA) mainly composed of 2 XFEL type cryo-modules together with a normal-conducting high brightness photo RF gun. This present mature and reliable technology is able to deliver high quality electron bunches up to few kHz suitable for user experiments. Further more, the last decade improvement in synchronization and stability offer a fertile land to explore the different and innovative seeded FEL operations aiming at producing higher coherence and energetic X-rays for the pilot user full benefits. In parallel of the CLA branch, the very promising and highly innovative Laser Wake-Field Accelerator (LWFA) able to produce very short electron bunches in the range of the femto-second and high peak current up to few GeV is foreseen as a FEL bench test using the same undulator lines.

TUPPP014

HiSOR-II, Compact Light Source with a Torus-knot Type Accumulator Ring

lattice, quadrupole, insertion, insertion-device

1635

A. Miyamoto, S. Sasaki
HSRC, Higashi-Hiroshima, Japan

Funding: This work is partially supported by Cooperative and Supporting Program for Researches and Educations in University sponsored by KEK.
We proposed a torus knot type synchrotron radiation ring where the beam orbit is not closed with one turn but return to the starting position after multiple turns around the ring. This ring is capable of having many straight sections and it is advantageous for installation of insertion devices. We named this architecture AMATELAS. We are designing a new ring based on the shape of a (11, 3) torus knot for our future plan HiSOR-II. This ring has eleven 3.6-m-long straight sections though the ring diameter is as compact as 15 m. The achieved emittance is 17.4 nmrad with the lattice having bending magnets with combined function. This level of emittance is as low as the conventional 3rd generation light source. On the other hand, there is a potential problem caused by that the radius of the orbit and focusing force are not constant in the bending magnets. However, we confirmed that it does not make serious influence to the beam by calculating with dividing the bending into several sections. We will compare the parameters of this new ring with the conventional ring which we have designed as the future plan of our facility and evaluate performance as the compact synchrotron light source.

TUPPP015

Status and Recent Progress of SPring-8

coupling, lattice, storage-ring, optics

1638

H. Ohkuma
JASRI/SPring-8, Hyogo-ken, Japan

The SPring-8 is an 8 GeV synchrotron radiation facility that has been in operation since 1997. The SPring-8 has been operated well and total user time has reached more than 53,700 hours, 75% of the total operation time. The average user time per year is about 4,000 hours. The average availability is about 98% in the past 15 years. The operational status and recent progress overview of SPring-8 is presented: the local lattice modification of 30-m long straight section for installing small gap (min. gap is 5.2 mm) in-vacuum undulators, the emittance coupling correction for the vertical beam size reduction, the test operation of low energy operation for the energy saving, and the study of lower emittance optics for the present SPring-8 storage ring. An outline of a future upgrade with a full-scale major lattice modification is also presented. We also present a little about recent progress of SPring-8 injecting accelerators.

TUPPP017

Lattice Design of the SSRF Storage Ring with Superbend

lattice, photon, dipole, optics

1644

S.Q. Tian, B.C. Jiang, H.H. Li, M.Z. Zhang, W.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

The SSRF storage ring is being investigated by upgrading with normal conducting superbend of 3 T. The bending magnets are shortened, and thus some additional straight sections with the length of about 2 m are created in the center of the arc cell. They can be used to install more insertion devices. The lattice adjustment and the optics design are presented in this paper, where much efforts are made to maintain the effective emittance along the ring with respect to the nominal optics.

TUPPP018

Design and Commissioning of the Very Low Emittance Optics in the SSRF Storage Ring

optics, injection, storage-ring, lattice

1647

S.Q. Tian, J. Chen, B.C. Jiang, Y.B. Leng, H.H. Li, L.Y. Yu, M.Z. Zhang, W.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

In synchrotron radiation light sources, there are continuous efforts to lower the storage ring emittance and thus increase its photon beam brightness. The lowest effective emittance of SSRF is found by a systematic method. Results of design and commissioning of this kind of optics are presented, of which the beam emittance is smaller than the nominal one by 1 nm.rad. The measured beam parameters agree well with the design ones.

TUPPP022

Beam Optics Measurements during ALBA Commissioning

quadrupole, lattice, optics, storage-ring

1656

M. Muñoz, G. Benedetti, J. Campmany, D. Einfeld, Z. Martí
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The synchrotron light source ALBA is in the final stage of the Storage Ring commissioning, with the beamline commissioning well under way. This paper reviews the results of the modeling of the lattice and the agreement with the LOCO measurement of the machine; the performance of the beta beating correction (critical in the ALBA case due to the large gradient in the bending magnet and the low number of quadrupole families), including effect of insertion devices; the lifetime measurement; tune scans; tune shift with horizontal amplitude; and the general agreement of the machine to the model using during the design. A brief summary of the modeling of the injector chain is included.

TUPPP023

Operation Status of ALBA Synchrotron Light Source

storage-ring, feedback, vacuum, kicker

1659

M. Pont
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

ALBA is a 3.0 GeV third generation synchrotron light source which has been commissioned during 2011. From October 2011 up to 7 beamlines are delivering beam for beamline commissioning, 6 from insertion devices and 1 from a bending magnet. Since April 2012 the facility is open to external users. Beam current has been continuously increased and the present stored beam current for users is 200 mA in a multi-bunch filling pattern. Orbit stability is kept at ±1 micron with a slow orbit feedback. The paper will review the operation and performance status of the different subsystems and review also the main objectives for 2012: target current of 400 mA, delivery of 3000 hours of beam to beamlines, testing of a fast orbit feedback system as well as preparations for top-up operation.

TUPPP027

Subpicosecond Laser Slicing X-Ray Source for Time-resolved Research at TPS

wiggler, laser, photon, lattice

1671

W.K. Lau, M.C. Chou, C.-S. Hwang, A.P. Lee, Y.-C. Liu, G.-H. Luo
NSRRC, Hsinchu, Taiwan
N.Y. Huang
NTHU, Hsinchu, Taiwan

The 3 GeV Taiwan Photon Source (TPS) under construction at NSRRC should be ready for user run in 2014. X-ray users in many research areas will then be benefited. However, there has been a growing interest in ultrafast time-resolved research in the island. The feasibility of using ultrafast laser for electron-beam slicing at TPS to produce sub-picosecond x-ray pulses is being investigated recently. The design and layout of a laser slicing scheme with W250 wiggler as the energy modulator in a 7 m medium straight section and EPU48 and IU22 radiators in other straight sections will be presented. It will offer the unique opportunity to gain experience in experimental techniques needed for FEL science.

TUPPP033

Exploration of a Tevatron-sized Ultimate Storage Ring

storage-ring, brightness, damping, sextupole

1683

M. Borland
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
With the Tevatron now shut down and slated for decommissioning, it is only natural to think about other possible uses for the 6.3 km tunnel. Given that the brightness of electron storage rings naively scales as radius cubed, one exciting possibility is to build a so-called ultimate storage ring light source. This paper describes a somewhat speculative exploration of this idea, showing the potential for a storage ring x-ray source of unprecedented brightness.

TUPPP037

Status of the ALS Brightness Upgrade

lattice, brightness, insertion, insertion-device

1692

C. Steier, B.J. Bailey, A. Biocca, A.T. Black, D. Colomb, N. Li, A. Madur, S. Marks, H. Nishimura, G.C. Pappas, S. Prestemon, D. Robin, S.L. Rossi, T. Scarvie, D. Schlueter, C. Sun, W. Wan
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) at Berkeley Lab while one of the earliest 3rd generation light sources remains one of the brightest sources for sof x-rays. Another multiyear upgrade of the ALS is currently under way, which includes new and replacement x-ray beamlines, a replacement of many of the original insertion devices and many upgrades to the accelerator. The accelerator upgrade that affects the ALS performance most directly is the ALS brightness upgrade, which will reduce the horizontal emittance from 6.3 to 2.2 nm (2.6 nm effective). This will result in a brightness increase by a factor of three for bendmagnet beamlines and at least a factor of two for insertion device beamlines. Magnets for this upgrade are currently under production and will be installed later this year.

TUPPP039

Vertical Dispersion Bump Design for Femto-second Slicing Beamline at the ALS

coupling, lattice, quadrupole, radiation

1698

C. Sun, C. Steier, W. Wan
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Femto-second (fs) slicing beamline has been brought to the operation at the Advanced Light Source (ALS) since 2002. It employs the resonant interaction of an electron bunch with a fs laser beam in a wiggler to energy-modulate a short section of the bunch. The induced energy modulation is then converted to a transverse displacement using a vertical dispersion bump downstream of the wiggler. Thus, the radiation from the fs pulse can be separated from the main bunch radiation. The current dispersion bump design has proved to be an effective and reliable one. However, the ALS storage ring lattice is under an upgrade to improve its brightness. After the completion of the upgrade, a new low emittance will be implemented, and the current dispersion bump design needs to be modified to provide the adequate vertical displacement, while minimizing the vertical emittance and spurious dispersion. In this paper, we present the new design of a vertical dispersion bump using Multi-Objective Genetic Algorithm (MOGA) for the ALS upgrade lattice.

TUPPP053

Investigations on the Optimum Accelerator Parameters for the Ultra-Short Bunch Operation of the Free-Electron Laser in Hamburg (FLASH)

laser, electron, simulation, space-charge

1718

M. Rehders, J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
T. Limberg, H. Schlarb, S. Schreiber
DESY, Hamburg, Germany

Funding: The project is supported by the Federal Ministry of Education and Research of Germany (BMBF) under contract No. 05K10GU2 and FSP301.
In order to produce the shortest possible radiation pulses using Free Electron Lasers like FLASH, various possibilities have been proposed during the last decade. Probably the most robust method is the generation of electron bunches that in the most extreme case are as short as a single longitudinal optical mode of the SASE (Self-Amplified Spontaneous Emission) radiation. For FLASH this means that the bunch length has to be a few fs only. As a consequence, very low bunch charges (in the order of 20 pC) have to be used. To achieve these extremely short bunch lengths, a new photo-injector laser has been installed, which allows for the generation of shorter electron bunches right at the cathode. Simulations of the electron bunches and their six-dimensional phase-space distribution have been performed to investigate the optimum accelerator parameters during injection and to determine how to realize them. First results are discussed in this contribution.

TUPPP054

RF Activation and Preliminary Beam Tests of the X-band Linearizer at the FERMI@Elettra FEL Project

FEL, klystron, linac, LLRF

1721

G. D'Auria, S. Di Mitri, G. Penco, C. Serpico
ELETTRA, Basovizza, Italy

FERMI@Elettra is a fourth generation light source facility presently in commissioning at the Elettra Laboratory in Trieste, Italy. It is based on an S-band (3 GHz), 1.5 GeV normal conducting (NC) linac, that provides ultra short e-bunches with high peak current, using two stages of magnetic compression. To linearize the beam longitudinal phase space and to improve the compression process, a forth harmonic RF structure (12 GHz) has been installed downstream the first magnetic chicane. This paper reports the RF activation of the structure and the preliminary tests performed on the beam.

TUPPP060

Injector Design for PAL-XFEL Project

gun, laser, solenoid, cathode

1732

J.H. Han, M.S. Chae, J.H. Hong, I. Hwang, H.-S. Kang, I.S. Ko, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: The Ministry of Education, Science and Technology of the Korean Government
The PAL-XFEL project has the baseline specification of FEL radiation down to 0.1 nm with a 10 GeV S-band normal conducting linac. To fulfill the requirement of the beam parameter, the S-band photoinjector was designed. Numerical optimizations for nominal and low charge operations are presented.

TUPPP062

Start to End Simulation of Three Bunch Compressor Lattice for PAL XFEL

lattice, FEL, linac, simulation

1738

H.-S. Kang, M.-H. Cho, J.H. Han, T.-H. Kang, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea
C.H. Yi
POSTECH, Pohang, Kyungbuk, Republic of Korea

The PAL XFEL is a 0.1-nm hard X-ray FEL project starting from 2011 to finish in 2014, which aims at achieving higher photon flux than 10¹² photons/pulse at 0.1 nm using a 10 GeV electron linac. The PAL XFEL is designed to have a hard x-ray undulator line at the end of linac and a branch line at 2.65 GeV point for soft X-ray undulator line. The three bunch compressor lattice (3-BC) is chosen to minimize emitance growth due to CSR and minimize correlated energy spread. The 3-BC lattice makes it possible to operate soft X-ray FEL undulator line simultaneously and independently from hard X-ray FEL undulator line.

TUPPP063

Electron-beam Optimization Studies for the FERMI@Elettra Free-electron Laser

linac, electron, simulation, alignment

1741

E. Ferrari, G. De Ninno
University of Nova Gorica, Nova Gorica, Slovenia
P. Craievich, S. Di Mitri, E. Ferrari, L. Fröhlich, G. Gaio, G. Penco, C. Spezzani, M. Trovò
ELETTRA, Basovizza, Italy

FERMI@Elettra is a single-pass free-electron laser, based on seeded high-gain harmonic generation. Presently, the first phase of the project (covering the spectral range between 100 and 20 nm) is under commissioning. The free-electron laser performance depends on the quality of the electron beam. In the case of the FERMI linear accelerator, the latter is strongly influenced both by the wake-fields present in the accelerating sections and by possible misalignments of the various accelerator components. In order to investigate and compensate these effects, we performed a study based on local trajectory bumps. We demonstrate that this approach significantly improves the electron-beam quality and, eventually, the free-electron laser performance.

TUPPP065

Progress Report on the SwissFEL Injector Test Facility

quadrupole, laser, optics, dipole

1747

T. Schietinger, M. Aiba, S. Bettoni, B. Beutner, M. Csatari, K. Doshekenov, Y.-C. Du, M.W. Guetg, C.P. Hauri, R. Ischebeck, F. Le Pimpec, N. Milas, G.L. Orlandi, M. Pedrozzi, P. Peier, E. Prat, S. Reiche, B. Smit, A. Trisorio, C. Vicario
Paul Scherrer Institut, Villigen, Switzerland

The SwissFEL injector test facility at the Paul Scherrer Institute is the principal test bed and demonstration plant for the SwissFEL project, which aims at realizing a hard-X-ray Free Electron Laser by 2017. The RF photoinjector facility has been in operation since 2010 and has recently reached its design energy of 250 MeV. A newly installed movable magnetic chicane allows longitudinal bunch compression studies. We report on the first experience with the bunch compressor and present the latest results of projected and slice emittance measurements.

Poster TUPPP065 [1.801 MB]

TUPPP068

Comparison of Compression Schemes for CLARA

FEL, linac, sextupole, cavity

1756

P.H. Williams, J.W. McKenzie
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.K. Jones, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom

CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory is proposed to be the UK’s national FEL test facility. The accelerator will be a ~250 MeV electron linac capable of producing short, high brightness electron bunches. The machine comprises a 2.5 cell RF photocathode gun, one 2 m and three 5 m normal conducting S-band (2998MHz) accelerating structures and a variable magnetic compression chicane. CLARA will be used as a test bed for novel FEL configurations. We present a comparison of acceleration and compression schemes for the candidate machine layout.

TUPPP073

Machine Parameter Studies for an FEL Facility Using STAFF

FEL, photon, undulator, linac

1768

M.W. Reinsch, B. Austin, J.N. Corlett, L.R. Doolittle, P. Emma, G. Penn, D. Prosnitz, J. Qiang, A. Sessler, M. Venturini
LBNL, Berkeley, California, USA
J.S. Wurtele
UCB, Berkeley, California, USA

Designing an FEL facility requires balancing multiple science needs, FEL and accelerator physics constraints, and engineering limitations. STAFF (System Trade Analysis for an FEL Facility) is a MATLAB program that enables the user to rapidly explore a large range of Linac and FEL design options to meet science requirements. The code uses analytical models such as the Ming Xie formulas when appropriate and look-up tables when necessary to maintain speed and flexibility. STAFF's modular design simplifies the inclusion of new physics models for FEL harmonics, wake fields, cavity higher-order modes and aspects of linac design such as the optimization of a laser heater, harmonic linearizer, and one or more bunch compressors. Code for the microbunching instability has been included as well. STAFF also supports multiple undulator technologies. STAFF permits the user to study error tolerances and multiple beamlines so as to explore the full capabilities of an entire user facility. This makes it possible to optimize the integrated system in terms of performance metrics such as photons/pulse, photons/sec and tunability range.

TUPPP074

Beam Dynamics Studies of a High-repetition Rate Linac Driver for a 4th-generation Light Source

FEL, simulation, linac, laser

1771

M. Venturini, J.N. Corlett, P. Emma, C. F. Papadopoulos, G. Penn, M. Placidi, J. Qiang, M.W. Reinsch, F. Sannibale, C. Steier, R.P. Wells
LBNL, Berkeley, California, USA

We present progress toward the design of a super-conducting linac driver of a high repetition rate FEL-based soft x-ray light source. The machine is intended to accept beams generated by the APEX* photocathode gun, operating in the MHz range, and deliver them to an array of SASE and seeded FEL beamlines. After reviewing the beam-dynamics considerations that are informing specific lattice choices we discuss the expected performance of the proposed machine design and its ability to meet the desired FEL specifications. We consider the merit of possible alternate designs (e.g., a one-stage compressor vs. a two-stage compressor) and the trade-offs between competing demands on the beam attributes (e.g., high peak current vs. acceptable energy spread).
* F. Sannibale et al., this conference.

TUPPP088

Bunch Compressor Design for Potential FEL Operation at eRHIC

FEL, electron, simulation, linac

1795

Y.C. Jing, Y. Hao, V. Litvinenko
BNL, Upton, Long Island, New York, USA

Electron-Relativistic Heavy Ion Collider (eRHIC) is an upgrade project for the current operation of RHIC. It will provide a high quality electron beam with energy recovery scheme to collide with ion beams. One may think of taking advantage of using this electron beam for FEL operation. Bunch compressor is a crucial component to compress the beam to high peak current for undulators and CSR effect needs to be taken care of to preserve the beam quality. In this paper, authors present a novel bunch compressor design with CSR suppression scheme for the potential FEL operation at eRHIC.

TUPPR005

Linac Upgrade in Intensity and Emittance for SuperKEKB

linac, positron, electron, alignment

1819

T. Higo, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, H. Honma, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The SuperKEKB is designed to produce 40 times luminosity than that of the KEKB. In order to realize such a high luminosity, the injector linac should provide both electron and positron beams of about 4-5 nC/bunch, which is several times higher than before. In addition, their emittance requirement of the injection beam to the rings is 20 microns, which is a factor of a few tens smaller than before. The intensity and emittance of the electron beam are realized directly by developing the photo RF gun. In contrast, the positron intensity is increased by adopting a higher capture efficiency system with flux concentrator followed by large-aperture accelerators, while its emittance is reduced by a damping ring. For preserving such a low emittance of both beams toward the injection to the rings, the suppression of the emittance growth is crucial. To this end, the alignment of the accelerator components should be a few tens of microns, where we need an improvement by more than a factor 10. The beam-based alignment is definitely needed with better-resolution BPMs. In the present paper are reviewed the overall progress and perspective of the design and the associated component developments.

TUPPR008

One 233 km Tunnel for Three Rings: e⁺e^-, p-pbar, and μ⁺+μ⁻

collider, dipole, luminosity, lattice

1828

G.T. Lyons, L.M. Cremaldi, A. Datta, M. Duraisamy, T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA

Funding: Supported by DE-FG05-91ER40622
In 2001, a cost analysis was conducted to build a 233 km circumference tunnel in northern Illinois for a Very Large Hadron Collider (VLHC). Here we outline the implementations of e⁺e⁻, proton anti-proton, and μ⁺+ μ⁻ collider rings in such a tunnel using recent technological innovations. The 500 GeV e⁺e⁻ collider employs a Crab Waist Crossing, ultra low emittance damped bunches, a vertical IP focal length of 0.06 cm, 12 GV of superconducting RF, and 0.026 Tesla low coercivity, grain oriented silicon steel/concrete dipoles. The 40 TeV proton anti-proton collider uses the high intensity Fermilab anti-proton source, exploits high cross sections for proton anti-proton production of high mass states, and uses 2 Tesla 0.005% ultra low carbon steel/YBCO superconductor magnets run with liquid neon. The 40 TeV muon ring ramps the 2 Tesla superconducting magnets at 8 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 2 to 20 TeV in 72 orbits with 72% survival, and mitigates neutrino radiation with a phase shifting, roller coaster FODO lattice.*
* G. T. Lyons, http://arxiv.org/pdf/1112.1105

TUPPR011

Six-dimensional Bunch Merging for Muon Collider Cooling

simulation, kicker, collider, solenoid

1831

R.B. Palmer, R.C. Fernow
BNL, Upton, Long Island, New York, USA
D.V. Neuffer
Fermilab, Batavia, USA

Funding: Work supported by US Department of Energy under contracts DE-AC02-98CH10886 and DE-AC02-07CH11359.
Muons for a Muon Collider are diffusely produced from pion decay. They are first phase rotated into a trains of bunches. The trains are ionization cooled in all six dimensions until they can be merged into single bunches, one of each sign. They are then further cooled in six dimensions before acceleration and injection into the collider. This merging matches more efficiently into the second phase of cooling if the merging is also in six dimensions. A scheme to do this is proposed. Groups of 3, of the initial 12, bunches are merged longitudinally into 4 longer bunches, using rf with multiple harmonics. These 4 are then kicked into 4 separate (trombone) channels of different lengths to bring them to closely packed transverse locations at the same time. Here they are captured into a single bunch with now increased transverse emittance.

TUPPR029

Performance of Linear Collider Beam-Based Alignment Algorithms at FACET

linac, alignment, simulation, optics

1879

A. Latina, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The performance of future linear colliders will depend critically on beam-based alignment (BBA) and feedback systems, which will play a crucial role both in the linear and in the non-linear systems of such machines, e.g., the linac and the final-focus. Due to its characteristics, FACET is an ideal test-bench for BBA algorithms and linear collider beam-dynamics in general. We present the results of extensive computer simulations and their experimental verification.

TUPPR039

Beam Dynamics Studies for the CLIC Main Linac

wakefield, linac, damping, simulation

1903

I. Nesmiyan, R.M. Jones
UMAN, Manchester, United Kingdom
A. Latina, D. Schulte
CERN, Geneva, Switzerland

Implications of the long-range wakefield on beam quality are investigated through a detailed beam dynamics study. Injection offsets are considered and the resulting emittance dilution recorded, including systematic and random sources of error. These simulations have been conducted for damped and detuned structures (DDS) and for waveguide damped structures–both for the CLIC collider.

TUPPR057

Intrabeam Scattering Studies at the Swiss Light Source

damping, scattering, storage-ring, monitoring

1951

F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
M. Aiba, M. Böge, N. Milas, A. Streun
Paul Scherrer Institut, Villigen, Switzerland
T. Demma
INFN/LNF, Frascati (Roma), Italy

The target parameters of modern ultra-low emittance rings are entering into a regime where intra-beam scattering (IBS) becomes important and, in the case of linear collider damping rings, even a limitation for the delivered emittances. The Swiss Light Source (SLS) storage ring, as it has achieved a vertical geometrical emittance of around 2 pm at 2.4 GeV, and it has the ability to run at even lower energies, and the availability of emittance monitoring diagnostics, is an ideal test bed for IBS studies. Simulations using the classical IBS theories and tracking codes are undertaken in order to explore the possibilities and limitations for IBS measurements at the SLS. In this respect, comparison between the theories and codes is first discussed. The dependence of the output emittances, taking into account the effect of IBS, with respect to energy, bunch charge and zero current vertical and longitudinal emittance is also studied, in order to define the regimes where the IBS effect can be significant. First measurement results from the SLS running at lower energies are finally presented.

TUPPR061

First Magnetic Test of a Superconducting Nb3Sn Wiggler Magnet for CLIC

wiggler, damping, plasma, electron

1957

D. Schoerling, P. Ferracin, P. Fessia, M. Karppinen, J. Mazet, S. Russenschuck
CERN, Geneva, Switzerland
A.W. Grau
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
P. Peiffer
KIT, Karlsruhe, Germany

In the Compact Linear Collider (CLIC) the normalized horizontal and vertical emittances of the electron and positron beams must be reduced to 500 nm and 5 nm before the beams enter the 3 TeV linear accelerators. An effective way to accomplish ultra-low emittances are damping rings. Damping rings are storage rings equipped with strong wiggler magnets. In a first approximation damping wigglers are more effective the shorter the period length and the stronger the magnetic field is. Only superconducting wiggler magnets meet the demanding magnetic specifications of the CLIC damping rings. Nb-Ti damping wiggler magnets fulfill the specifications of CLIC but Nb3Sn wiggler magnets would reach higher magnetic fields leading to even better beam properties for CLIC. Moreover, they have at the same time higher thermal and magnetic margins. Therefore, Nb3Sn wiggler magnets are under investigation at CERN despite the challenging manufacturing process. This paper presents first results of Nb3Sn coils and short model tests and outlines the further plans for developing Nb3Sn wiggler magnets at CERN.

TUPPR066

Characterization of Single Particle Dynamics for the International Linear Collider Damping Ring Lattice

damping, wiggler, lattice, multipole

1972

J.P. Shanks, J.A. Crittenden, M.A. Palmer
CLASSE, Ithaca, New York, USA
D.L. Rubin
Cornell University, Ithaca, New York, USA

Funding: DOE Award DE-SC0006506
The baseline design for the International Linear Collider damping rings is a 3.2 km circumference racetrack, with 5 GeV beam energy. The transverse damping time is 26 ms and the normalized horizontal emittance 5 mm-mrad. Nearly 60 2.2-m-long superconducting wigglers per ring increase the radiation damping rate by an order of magnitude and reduce horizontal emittance by a factor of 5. We characterize the sensitivity to magnet misalignments and field errors, and establish the minimum numbers of corrector magnets and beam position monitors required for tuning vertical emittance to less than 20 nm-rad. We validate the specified tolerable guide field multipole errors consistent with adequate dynamic aperture. Tune scans are used to identify stable working points. In tracking studies we use a wiggler model based on fits to 3-dimensional field maps.

TUPPR072

Status of ESTB: A Novel Beam Test Facility at SLAC

kicker, electron, wakefield, linac

1990

M.T.F. Pivi, M.P. Dunning, H. Fieguth, C. Hast, R.H. Iverson, J. Jaros, R.K. Jobe, L. Keller, T.V.M. Maruyama, D.R. Walz, M. Woods
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515
End Station A Test Beam (ESTB) is a test beam line at SLAC in the large End Station A (ESA) experimental hall. It uses a fraction of the bunches of the 14.7 GeV electron beam from the Linac Coherent Light Source (LCLS). ESTB provides a unique test beam for particle and particle astrophysics detector research, accelerator instrumentation and accelerator R&D, development of radiation-hard detectors, and material damage studies. It has exceptionally clean and well-defined secondary electron beams, a huge experimental area and good existing conventional facilities. Recently, a new kicker magnet has been installed to divert 5 Hz of the LCLS low energy beam into the A-line. The full installation will include 4 kicker magnets to allow diversion of high energy beams. A new beam dump and a new Personnel Protection System (PPS) have been built in ESA. In stage II, a secondary hadron target will be able to produce pions up to about 12 GeV/c at 1 particle/pulse. This paper reports the progress on ESTB construction and commissioning.

TUPPR078

LEP3: A High Luminosity e⁺e⁻ Collider in the LHC Tunnel to Study the Higgs Boson

collider, luminosity, positron, synchrotron

2005

F. Zimmermann, M. Koratzinos
CERN, Geneva, Switzerland
A.P. Blondel
DPNC, Genève, Switzerland
M. Zanetti
MIT, Cambridge, Massachusetts, USA

Recent indications from two LHC experiments suggest that the Higgs boson might be light, within the mass range 115-130 GeV. Such object could be studied at an e⁺e⁻ collider with about 240 GeV centre-of-mass energy. A corresponding Higgs factory – “LEP3” - could be installed in the LHC tunnel, reducing its cost and also allowing for a second life of the two LHC general-purpose detectors. We present preliminary accelerator and beam parameters for LEP3 tailored so as to provide a peak luminosity of 10³⁴/cm²/s at each of two experiments, while respecting a number of constraints including beamstrahlung limits. At this luminosity around 20,000 Higgs events per year per experiment could be obtained for a Standard Model Higgs boson with a mass of 115-130 GeV. For the parameters considered the estimated luminosity lifetime is about 12 minutes, and the synchrotron radiation losses are 50 MW per beam. High operational efficiency requires two rings: a low emittance collider storage ring operating at constant energy, and a separate accelerator to top up the colliding beams every few minutes. The alternative of a larger ring collider installed in a new, bigger tunnel will also be discussed.

TUPPR087

Status of NSCL Cyclotron Gas Stopper

ion, cyclotron, extraction, injection

2029

N.S. Joshi, G. Bollen, M. Brodeur, D.J. Morrissey, S. Schwarz
NSCL, East Lansing, Michigan, USA

A gas-filled reverse cyclotron for the thermalization of energetic beams is under construction at NSCL/MSU. Rare isotopes produced via projectile fragmentation after in-flight separation will be injected into the device and converted into low-energy beams through buffer gas interactions as they spiral towards the center of the device. The extracted thermal beams will be used for low energy experiments such as precision mass measurements with traps or laser spectroscopy, and further transport for reacceleration. Detailed calculations have been performed to optimize the magnetic field design as well as the transport and stopping of ions inside the gas. An RF-carpet will be used to transport the thermal ions to the axial extraction point. The calculations indicate that the cyclotron gas stopper will be much more efficient for the thermalization of light and medium mass ions compared to linear gas cells. In this contribution we will discuss simulations of the overall performance and acceptance of machine, the beam matching calculations to the fragment separator emittance, and the construction status.

TUPPR088

Baseline Design of the SuperB Factory Injection System

linac, positron, electron, injection

2032

S. Guiducci, A. Bacci, M.E. Biagini, R. Boni, M. Boscolo, D. Pellegrini, M.A. Preger, P. Raimondi, A.R. Rossi, M. Zobov
INFN/LNF, Frascati (Roma), Italy
M.A. Baylac
LPSC, Grenoble, France
J. Brossard, S. Cavalier, O. Dadoun, T. Demma, P. Lepercq, E. Ngo Mandag, C. Rimbault, A. Variola
LAL, Orsay, France
J.T. Seeman
SLAC, Menlo Park, California, USA
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

The injection complex of the SuperB, B-factory project of INFN consists of a polarized electron gun, a positron production system, electron and positron linac sections, a positron damping ring and the transfer lines connecting these systems and the collider main rings. To keep the ultra high luminosity nearly constant, continuous injection of 4 GeV electrons and 7 GeV positrons in both Low Energy Ring (LER) and High Energy Ring (HER) is necessary. In this paper we describe the baseline design and the beam dynamics studies performed to evaluate the system performance.

TUPPR089

Design Study of Beam Injection for SuperKEKB Main Ring

injection, septum, synchrotron, optics

2035

T. Mori, N. Iida, M. Kikuchi, T. Mimashi, Y. Sakamoto, H. Sugimoto, S. Takasaki, M. Tawada
KEK, Ibaraki, Japan

The SuperKEKB project is in progress toward the initial physics run in the year 2015. It assumes the nano-beam scheme, in which the emittance of the colliding beams is ε=4.6 nm. The emittance of the injected beam is ε=1.46 nm. To achieve such a low emittance, it is vitally important to preserve the emittance during the transport of the beam from the linac to the main ring. One of the most difficult parts is the injection system. We are considering the synchrotron injection for the electron-line to avoid a beam blowup in the ring after injection, which is caused by a beam-beam interaction with the stored beam. The optics study for electron injection and the current R&D status for the septum magnet will be reported in this paper.

TUPPR091

Status of the 160 MeV H⁻ Injection into the CERN PSB

injection, vacuum, simulation, proton

2041

W.J.M. Weterings, B. Balhan, E. Benedetto, J. Borburgh, C. Bracco, C. Carli, B. Goddard, K. Hanke, B. Mikulec, A. Newborough, R. Noulibos, J. Tan
CERN, Geneva, Switzerland

The 160 MeV H⁻ beam from the LINAC4 will be injected into the 4 superimposed rings of the PS Booster (PSB) with an new H⁻ charge-exchange injection system. This entails a massive upgrade of the injection region. The hardware requirements and constraints, the performance specifications and the design of the H⁻ injection region are described.

TUPPR094

SPS Transverse Beam Scraping and LHC Injection Losses

injection, luminosity, proton, controls

2050

L.N. Drosdal, W. Bartmann, C. Bracco, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, E. Veyrunes
CERN, Geneva, Switzerland

Machine protection sets strict requirements for the quality of the injected beam, in particular in the transverse plane. Losses at aperture restrictions and protection elements have to be kept at a minimum. Particles in the beam tails are lost at the tight transfer line collimators and can trigger the LHC beam abort system. These particles have to be removed by scrapers in the vertical and horizontal plane in the SPS. Scraping has become vital for high intensity LHC operation. This paper shows the dependence of injection quality on the SPS scraping and discusses an improved scraper setting up strategy for better reproducibility with the current scraper system.

TUPPR097

Modeling and Simulation of LHC Beam-Based Collimator Setup

alignment, beam-losses, simulation, collider

2059

G. Valentino, N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta
R.W. Assmann, F. Burkart, S. Redaelli, A. Rossi, D. Wollmann
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

In the 2011 Large Hadron Collider run, collimators were aligned for proton and heavy ion beams using a semi-automatic setup algorithm. The algorithm provided a reduction in the beam time required for setup, an elimination of beam dumps during setup and higher accuracy with respect to manual alignment. A collimator setup simulator was developed based on a Gaussian model of the beam distribution as well as a parametric model of the beam losses. A time-varying beam loss signal can be simulated for a given collimator movement into the beam. The simulation results and comparison to measurement data obtained during collimator setups and dedicated fills for beam halo scraping are presented. The simulator will then be used to develop a fully automatic collimator alignment algorithm.

WEYA01

CLIC Status and Outlook

linac, luminosity, target, alignment

2076

S. Stapnes
CERN, Geneva, Switzerland

The Compact Linear Collider study (CLIC) is in the process of completing a Conceptual Design Report for a multi-TeV linear electron-positron collider. The CLIC-concept is based on high gradient normal-conducting accelerating structures. The RF power for the acceleration of the colliding beams is produced by a novel two beam acceleration scheme, where power is extracted from a high current drive beam that runs parallel with the main linac. In order to establish the feasibility of this concept a number of key issues have been addressed. A short summary of the progress and status of the corresponding studies will be given, as well as an outline of the preparation and work towards an implementation plan by 2016.

Slides WEYA01 [11.960 MB]

WEYA02

Studies at CesrTA of Electron-Cloud-Induced Beam Dynamics for Future Damping Rings

electron, simulation, damping, dipole

2081

G. Dugan, M.G. Billing, K.R. Butler, J.A. Crittenden, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, K.G. Sonnad, H.A. Williams
CLASSE, Ithaca, New York, USA
R.F. Campbell, R. Holtzapple, M. Randazzo
CalPoly, San Luis Obispo, California, USA
J.Y. Chu
CMU, Pittsburgh, Pennsylvania, USA
J.W. Flanagan, K. Ohmi
KEK, Ibaraki, Japan
M.A. Furman, M. Venturini
LBNL, Berkeley, California, USA
M.T.F. Pivi
SLAC, Menlo Park, California, USA

Funding: US National Science Foundation PHY-0734867, PHY-1002467, and PHY-1068662; US Dept. of Energy DE-FC02-08ER41538; and the Japan/US Cooperation Program.
Electron clouds can adversely affect the performance of accelerators, and are of particular concern for the design of future low emittance damping rings. Studies of the impact of electron clouds on the dynamics of bunch trains in CESR have been a major focus of the CESR Test Accelerator program. In this paper, we report measurements of coherent tune shifts, emittance growth, and coherent instabilities carried out using a variety of bunch currents, train configurations, beam energies, and transverse emittances, similar to the design values for the ILC damping rings. We also compare the measurements with simulations which model the effects of electron clouds on beam dynamics, to extract simulation model parameters and to quantify the validity of the simulation codes.

Slides WEYA02 [2.033 MB]

WEYA03

Overview of B-Factories

sextupole, injection, quadrupole, collider

2086

M.E. Biagini
INFN/LNF, Frascati (Roma), Italy

An overview of the two recently approved high luminosity B-Factories, the SuperB in Italy and the SuperKEKB in Japan, will be presented. The main design features to reach the very high luminosity requested and a status of progress in design and construction will be given.

Slides WEYA03 [6.151 MB]

WEYB01

The SPring-8 Angstrom Compact Free Electron Laser (SACLA)

laser, electron, undulator, FEL

2106

H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

Commissioning of the world's first compact X-ray FEL facility named SPring-8 Angstrom Compact free electron LAser (SACLA) began in the Spring of 2011 and soon demonstrated lasing at a wavelength of 0.12nm. In the autumn of 2011 laser intensity reached sub mJ/pulse in the wavelengths ranging from 0.1 to 0.3 nm. The laser power saturation was also achieved at around or longer than 0.1 nm. The official user operation will start from March 2012. This presentation will cover innovative design aspects of the SACLA construction project, events leading to key milestones in the commissioning process, a review of the present status and perspectives on future upgrades.

Slides WEYB01 [13.170 MB]

WEOBA02

Tevatron End-of-Run Beam Physics Experiments

antiproton, proton, dipole, luminosity

2128

A. Valishev
Fermilab, Batavia, USA
X. Gu, R. Miyamoto, S.M. White
BNL, Upton, Long Island, New York, USA
J. Qiang
LBNL, Berkeley, California, USA
F. Schmidt
CERN, Geneva, Switzerland

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP).
Before the Tevatron collider Run II ended in September of 2011, a two-week period was devoted to the experiments on various aspects of beam-beam interactions. The studied topics included offset collisions, coherent beam stability, effect of the bunch-length-to-beta-function ratio, and operation of AC dipole with colliding beams. In this report we summarize the results of beam experiments and supporting simulations.

Slides WEOBA02 [1.382 MB]

WEOAB02

Photocathode R&D at Cornell University

electron, vacuum, cathode, gun

2137

L. Cultrera, I.V. Bazarov, J.V. Conway, B.M. Dunham, Y. Hwang, Y. Li, X. Liu, R. Merluzzi, T.P. Moore, K.W. Smolenski
CLASSE, Ithaca, New York, USA
S.S. Karkare, J.M. Maxson, W.J. Schaff
Cornell University, Ithaca, New York, USA

Funding: This work has been supported by NSF DMR-0807731 and by DOE DE-SC0003965.
A wide R&D program is pursued at Cornell University aimed at preparation and characterization of high efficiency photocathodes for the Energy Recovery Linac photoinjector. The currently investigated photoemitters include both positive and negative electron affinity materials such as respectively bi-alkali antimonide and III-V semiconductors activated with Cs and either O or F. Analysis techniques as Scanning Auger Spectroscopy, Low Energy Electron Diffraction, Reflected High Energy Electron Diffraction and work function measurements are used to characterize the surfaces properties of the specimens. Spectral response, photoemission uniformity, electron energy distributions are used to characterize the quality of the photoelectron beam and to relate it to the measured surface properties.

Slides WEOAB02 [6.934 MB]

WEIC06

Accelerator R&D: Research for Science - Science for Society

laser, acceleration, hadron, proton

2161

N.R. Holtkamp
SLAC, Menlo Park, California, USA
S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
L. Boeh, J.E. Clayton, G. Zdasiuk
VMS GTC, Palo Alto, California, USA
S.A. Gourlay, M.S. Zisman
LBNL, Berkeley, California, USA
R.W. Hamm
R&M Technical Enterprises, Pleasanton, California, USA
S. Henderson
Fermilab, Batavia, USA
G.H. Hoffstaetter
CLASSE, Ithaca, New York, USA
L. Merminga
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
S. Ozaki
BNL, Upton, Long Island, New York, USA
F.C. Pilat
JLAB, Newport News, Virginia, USA
M. White
ANL, Argonne, USA

In September 2011 the US Senate Appropriations Committee requested a ten-year strategic plan from the Department of Energy (DOE) that would describe how accelerator R&D today could advance applications directly relevant to society. Based on the 2009 workshop "Accelerators for America’s Future" an assessment was made on how accelerator technology developed by the nation’s laboratories and universities could directly translate into a competitive strength for industrial partners and a variety of government agencies in the research, defense and national security sectors. The Office of High Energy Physics, traditionally the steward for advanced accelerator R&D within DOE, commissioned a task force under its auspices to generate and compile ideas on how best to implement strategies that would help fulfill the needs of industry and other agencies, while maintaining focus on its core mission of fundamental science investigation.

Slides WEIC06 [3.678 MB]

WEPPD042

The Grounding System at TPS

site, synchrotron, insertion, controls

2606

T.-S. Ueng, J.-C. Chang, J.-R. Chen, Y.-C. Lin
NSRRC, Hsinchu, Taiwan

An elaborately designed grounding system has been installed under the TPS construction site. The ground grid was installed sector by sector to comply with the building construction schedule. The ground resistance measurement of each sector was carried out right after the grid installation. The final ground resistance measurement for the whole grounding system was performed also right after its completion. The measured ground resistances of each sector were used to estimate the final TPS ground resistance, and it was compared to the final TPS ground measurement result. Also, the analysis with computer software is used to justify it. The low impedance of TPS grounding system, < 0.15 ohm, is to insure the safety of TPS personnel and instrumentation, also, to reduce the noise of electronic devices.

WEPPD056

Ytterbium Fiber Laser System of DAW RF Gun for SuperKEKB

laser, gun, cavity, luminosity

2648

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida
KEK, Ibaraki, Japan

For obtaining higher luminosity in the SuperKEKB, the photocathode DAW-type RF gun for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 micrometer are expected generate in the photocathode RF gun by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Fiber laser especially Ytterbium(Yb) fiber have attracted attention as one of the promising practical alternatives to usual solid-state lasers, offering high energy-extraction efficiency, high repetition rate, high output power, low-cost and so on. Introducing the Ytterbium fiber laser system, we have developed a stable laser amplifier system, which could allow steady beam injection into the SuperKEKB rings. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator. To obtain the mJ-class pulse energy, a multi-pass solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPPD060

A Drive Laser for Multi-bunch Photoinjector Operation

laser, electron, brightness, cathode

2657

D.J. Gibson, C.P.J. Barty, M. J. Messerly, M.A. Prantil
LLNL, Livermore, California, USA
E. Cormier
CELIA, Talence, France

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
Numerous electron beam applications would benefit from increased average current without sacrificing beam brightness. Work is underway at LLNL to investigate the performance of X-band photoinjectors that would generate electron bunches at a rate matching the RF drive frequency, i.e. one bunch per RF cycle. A critical part of this effort involves development of photo-cathode drive laser technology. Here we present a new laser architecture that can generate pulse trains at repetition rates up to several GHz. This compact, fiber-based system is driven directly by the accelerator RF and so is inherently synchronized with the accelerating fields, and scales readily over a wide range of drive frequencies (L-band through X-band). The system will be required to produce 0.5 μJ, ~200 fs rise time, spatially and temporally shaped UV pulses designed to optimize the electron beam brightness. Presented is the current status of this system, producing pulses shorter than 2 ps from a cw source.

WEPPD069

PLS-II Linac Upgrade

linac, electron, klystron, gun

2681

B.-J. Lee, J.Y. Choi, S. Chunjarean, T. Ha, J.Y. Huang, I. Hwang, Y.D. Joo, C. Kim, M. Kim, S.H. Kim, S.J. Kwon, S.H. Nam, S.S. Park, S.J. Park, S. Shin, Y.G. Son
PAL, Pohang, Kyungbuk, Republic of Korea

This paper reports on the recent status of the Pohang Light Source (PLS)-II linac at Pohang Accelerator Laboratory (PAL). From 2009, the linac upgrade has been started increasing its energy from 2.5 GeV to 3 GeV aiming stable top-up mode operation. First, we show that the stability status of the two different types of modulators to meet the top-up condition which requires very stable modulator system in linac. Next, we introduce upgrade status those differ from their PLS (2.5 GeV) such as installation of the dual vacuum systems for the electron gun to replace it immediately, adding important diagnostic tools, and reutilization of the beam analysis system just after pre-injector. Finally we present the electron beam parameters measured by those diagnostic system.

WEPPD081

Optimization of AC Dipole Parameters for the Mu2e Extinction System

dipole, proton, magnet-design, electron

2714

E. Prebys
Fermilab, Batavia, USA

The Mu2e experiment is being planned at Fermilab to measure the rate for muons to convert to electrons in the field of an atomic nucleus with unprecedented precision. This experiment uses an 8 GeV primary proton beam consisting of short (~200 nsec FW) bunches, separated by 1.7 μs. It is vital that out-of-bunch beam be suppressed at the level of 10^-10 or less. This poster describes the parametric analysis which was done to determine the optimum harmonics and magnet specifications for this system, as well as the implications for the beam line optics.

WEPPP005

Progress on Muon Parametric-resonance Ionization Cooling Channel Development

resonance, simulation, quadrupole, betatron

2729

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA
A. Afanasev
GWU, Washington, USA
K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, USA
B. Erdelyi, J.A. Maloney
Northern Illinois University, DeKalb, Illinois, USA

Funding: Supported in part by DOE SBIR grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Parametric-resonance Ionization Cooling (PIC) is intended as the final 6D cooling stage of a high-luminosity muon collider. To implement PIC, a continuous-field twin-helix magnetic channel was developed. A 6D cooling with stochastic effects off is demonstrated in a GEANT4/G4beamline model of a system where wedge-shaped Be absorbers are placed at the appropriate dispersion points in the twin-helix channel and are followed by short rf cavities. To proceed to cooling simulations with stochastics on, compensation of the beam aberrations from one absorber to another is required. Initial results on aberration compensation using a set of various-order continuous multipole fields are presented. As another avenue to mitigate the aberration effect, we optimize the cooling channel’s period length. We observe a parasitic parametric resonance naturally occurring in the channel’s horizontal plane due to the periodic beam energy modulation caused by the absorbers and rf. We discuss options for compensating this resonance and/or properly combining it with the induced half-integer parametric resonance needed for PIC.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

WEPPP031

To the Possibility of Bound States between Two Electrons

electron, damping, positron, proton

2792

A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA

We analyze the possibility to compress dynamically the polarized electron bunch so that the distance between some electrons in the bunch comes close to the Compton wavelength, arranging a bound state, as the attraction by the magnetic momentum-induced force at this distance dominates repulsion by the electrostatic force for the appropriately prepared orientation of the magnetic moments of the electron-electron pair. This electron pair behaves like a boson now, so the restriction for the minimal emittance of the beam becomes eliminated. Some properties of such degenerated electron gas represented also.

WEPPP051

Excitation of Plasma Wakefields with Designer Bunch Trains

plasma, wakefield, laser, cathode

2828

P. Muggli
MPI, Muenchen, Germany
B.A. Allen, Y. Fang
USC, Los Angeles, California, USA
M. Babzien, M.G. Fedurin, K. Kusche, R. Malone, C. Swinson, V. Yakimenko
BNL, Upton, Long Island, New York, USA

Funding: Work supported by US Department of Energy.
Plasma can sustain multi-GV/m longitudinal electric fields that can be used for particle acceleration. In the plasma wakefield accelerator, or PWFA, the wakefields are driven by a single or a train of electron bunches with length comparable to the plasma wavelength. A train of bunches resonantly driving the wakefields can lead to energy gain by trailing particles many times the energy of the incoming drive train particles (large transformer ratio). In proof-of-principle experiments at the Brookhaven National Laboratory Accelerator Test Facility, we demonstrate by varying the plasma density over four orders of magnitude, and therefore the accelerator frequency over two orders of magnitude (~100GHz to a few THz), that trains with ~ps period resonantly drive wakefields in ~10¹⁶/cc density plasmas. We also demonstrate energy gain by a trailing witness electron bunch that follows the drive train with a variable delay. Detailed experimental results will be presented.

WEPPP061

A Method to Obtain the Frequency of the Longitudinal Dipole Oscillation for Modeling and Control in Synchrotrons with Single or Double Harmonic RF Systems

synchrotron, controls, ion, dipole

2846

J. Grieser, J. Adamy, D.E.M. Lens
TU Darmstadt, RTR, Darmstadt, Germany
H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This work was partly funded by GSI Helmholtzzentrum für Schwerionenforschung GmbH
In a heavy-ion synchrotron the bunched beam can perform longitudinal oscillations around the synchronous particle (single bunch dipole oscillation, SBDO). If disturbances/instabilities exciting the SBDO exceed the rate of Landau damping, the beam can become unstable. Furthermore, Landau damping is accompanied by an increase of the beam emittance which may be undesired. Thus, control efforts are taken to stabilize the beam and to keep the emittance small. It is known that for a single harmonic cavity and a small bunch the SBDO oscillates with the synchrotron frequency* if the oscillation amplitudes are small. For a larger bunch or a double harmonic RF systems that introduces nonlinearities**, this is no longer valid. This work shows how the frequency of the SBDO can be determined in general. As a result, the SBDO can again be modeled as a harmonic oscillator with an additional damping term to account for Landau damping. This model can be used for feedback designs which is shown by means of a simple example. As the frequency of the SBDO and the damping rate depend on the size of the bunch in phase space, it is shown how this information can be obtained from the measured beam current.
* F. Pedersen and F. Sacherer, IEEE Transactions on Nuclear Science, 24:1296–1398, 1977
** A. Hofmann and S. Myers, Proc. of the 11th International Conference on High Energy Acceleration, 1980

WEPPP072

Beam Characterization and Coherent Optical Transition Radiation Studies at the Advanced Photon Source Linac

linac, diagnostics, laser, radiation

2876

J.C. Dooling, R.R. Lindberg, N. Sereno, C.-X. Wang
ANL, Argonne, USA
A.H. Lumpkin
Fermilab, Batavia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357.
The Advanced Photon Source facility includes a 450-MeV S-band linac with the option for injection from a photocathode (PC) rf gun. A diode-pumped, twice-frequency doubled Nd:glass regen laser (263 nm) is used with the Cu PC to generate the electron beams. Characterization of these beams and studies of the microbunching instability following beam compression in the four-dipole magnetic chicane are described. A suite of diagnostics is employed including a three-screen emittance section, a FIR coherent transition radiation autocorrelator, electron spectrometers, and an optical diagnostics end station. An energy chirp impressed on the beam is used to compress the 1-2 ps, rms bunch as it passes through the chicane. With compression, bunch lengths of 170-200 fs, rms at 450 pC are measured, and coherent optical transition radiation (COTR) due to the microbunching instability is observed. Mitigation techniques of the COTR in the beam profile diagnostics are demonstrated both spectrally and temporally. At 100 pC without compression normalized transverse emittances of 1.8 and 2.7 microns are observed in the x and y planes, in reasonable agreement with initial ASTRA simulations.

WEPPP076

Analysis of Numerical Noise in Particle-In-Cell Simulations of Single-Bunch Transverse Instabilities and Feedback in the CERN SPS

simulation, feedback, pick-up, kicker

2888

R. Secondo, J.-L. Vay, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the US-DOE and the US-LHC Accelerator Research Program LARP under Contract DE-AC02-05CH11231. Used resources of NERSC and the Lawrencium cluster at LBNL
The operation at high current of the SPS at CERN is limited by transverse Single-Bunch instabilities generated by the effect of electron clouds. A model of a high bandwidth feedback control system has been implemented in the macro-particle code WARP to study bunch dynamics and identify system requirements for the efficient damping of single-bunch transverse instability. We analyze the effect of numerical noise and choice of simulation parameters on the modeling of beam dynamics, focusing in particular on the investigation of the feedback system requirements of minimum power to damp the instability and frequency bandwidth given a fixed gain. We report on simulation results and discuss the plans for the future improvements of the feedback model.

WEPPP082

Stochastic Cooling in RHIC

kicker, luminosity, pick-up, simulation

2900

J.M. Brennan, M. Blaskiewicz, K. Mernick
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Stochastic cooling is used in the Relativistic Heavy Ion Collider to increase the integrated luminosity of ion collisions by a factor of two. The cooling system has been assembled incrementally over the past several years, starting with longitudinal cooling only, then adding cooling in the vertical planes, and recently completed with cooling systems in all three phase space planes of both rings. The system operates from 6 to 9 GHz in the longitudinal planes and from 4.7 to 7.8 GHz in the transverse planes, yielding a cooling rate that overcomes Intra-Beam Scattering at the beginning of a store and reaches equilibrium with a factor of 2 reduction of emittances. The system’s components and mode of operation will be presented along with measurements of the beam parameters during stores with stochastic cooling in operation.

WEPPR008

Simulation of Controlled Longitudinal Emittance Blow-up in J-PARC RCS

simulation, resonance, cavity, extraction

2952

M. Yamamoto, M. Nomura, A. Schnase, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
E. Ezura, K. Hara, K. Hasegawa, C. Ohmori, A. Takagi, K. Takata, M. Toda, M. Yoshii
KEK, Ibaraki, Japan
T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

In the J-PARC RCS, a high intensity beam is prepared for the MR. The longitudinal beam emittance at the RCS extraction should be optimized to avoid beam loss during and after MR injection. In order to match the longitudinal emittance shape between the RCS and the MR, it is desirable to enlarge the longitudinal emittance during the RCS acceleration. We have performed the particle tracking simulation for the controlled longitudinal emittance blow up in the RCS.

WEPPR011

Numerical Simulation Study of the Montague Resonance at the CERN Proton Synchrotron

simulation, resonance, space-charge, synchrotron

2958

J. Qiang, R.D. Ryne
LBNL, Berkeley, California, USA
G. Franchetti, I. Hofmann
GSI, Darmstadt, Germany
E. Métral
CERN, Geneva, Switzerland

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP) under Contract No. DE-AC02-05CH11231.
The Montague resonance provides a coupling between the vertical and the horizontal dynamics of beams and can cause particle losses due to unequal aperture sizes of the accelerator. In this paper, we present a new numerical simulation study of a previous Montague resonance crossing experiment at the CERN PS including detailed three-dimensional space-charge effects and machine nonlinearity. The simulation reproduces the experimental data and suggests that the longitudinal synchrotron motion played an important role in enhancing transverse resonance coupling.

WEPPR013

Design of an Electrostatic Extraction Section for the University of Maryland Electron Ring

extraction, simulation, electron, lattice

2964

K.J. Ruisard
Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
B.L. Beaudoin, I. Haber, R.A. Kishek, T.W. Koeth
UMD, College Park, Maryland, USA

Funding: This work is supported by the US Dept. of Energy Office of High Energy Physics.
The University of Maryland Electron Ring (UMER) is a 11.5 meter circumference, 10 keV, electron storage ring dedicated to the study of the physics space-charge-dominated beams transported over long path lengths. The intensity of the space charge in UMER can be varied by aperturing the injected beam current from 0.6 mA to 100 mA. Recently, the electron beam has been transported over one thousand turns. To fully characterize the transverse and longitudinal evolution of the beam on a turn-by-turn basis, extraction and transport to a diagnostic station is required. We present the design of a pulsed electric extraction system that satisfies the challenging constraint of fitting the hardware within the dense magnet lattice. The extraction system must universally accommodate the range beam intensities and minimize any disruption to the circulating beam

WEPPR015

Intrabeam Scattering Studies at CesrTA

scattering, electron, positron, lattice

2970

M. P. Ehrlichman
Cornell University, Ithaca, New York, USA
F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
W. Hartung, M.A. Palmer, D.P. Peterson, N.T. Rider, D. L. Rubin, J.P. Shanks, C.R. Strohman, S. Wang
CLASSE, Ithaca, New York, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: NSF Award (PHY-0734867) NSF Award (PHY-1002467) Japan/US Cooperation Program Education and lifelong learning, co-financed by Greece and the European Union
Intrabeam scattering dilutes the emittance of low energy, low emittance rings. Because CesrTA can be operated at low energies with low transverse emittances and high bunch intensity, it is an ideal laboratory for the study of IBS effects. Furthermore, CesrTA is instrumented for accurate beam size measurements in all three dimensions, providing the possibility of a complete determination of the intensity dependence of emittances. Models based on classical IBS theories and multi-particle simulations are used to estimate the effect of IBS at CesrTA at different beam emittances, intensities and energies. The first measurements from machine studies at CesrTA are presented.

WEPPR016

Potential for Luminosity Improvement for Low-energy RHIC Operation

luminosity, space-charge, electron, ion

2973

A.V. Fedotov
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
At the Brookhaven National Laboratory, a physics program, motivated by the search of the QCD phase transition critical point, requires operation of the Relativistic Heavy Ion Collider (RHIC) with heavy ions at very low beam energies corresponding to 2.5-20 GeV/n. Several physics runs were already successfully performed at these low energies. However, the luminosity is very low at lowest energies of interest (< 10 GeV/n) limited by the intra-beam scattering and space-charge, as well as by machine nonlinearities. At these low energies, electron cooling is very effective in counteracting luminosity degradation due to the IBS, while it is less effective against other limitations. Overall potential luminosity improvement for low-energy RHIC operation from cooling is summarized for various energies, taking into account all these limitations as well as beam lifetime measured during the low-energy RHIC runs. We also explore a possibility of further luminosity improvement under the space-charge limitation.

WEPPR024

Motion of Charged Particle Dense Bunch in Nonuniform External Fields

vacuum, resonance, focusing

2985

H.Y. Barminova
ITEP, Moscow, Russia
A.S. Chikhachev
Allrussian Electrotechnical Institute, Moskow, Russia

At the output of a linear resonance accelerator, a charged particle beam consists of a bunch series, with the relation between bunch length and transverse bunch size changing widely. It is of importance to describe bunch dynamics in a selfconsistent manner*,** . Usually the charged bunch is described as ellipsoid with uniform density. Such description allows easy consideration of its own bunch fields. In the case of a nonstationary distribution it is difficult to build distribution function describing 3D-ellipsoid with uniform density** . In this paper such function is found for bunch formed as rotation ellipsoid. Radii ellipsoid equations are obtained for a bunch moving in nonuniform stationary external fields.
* A.S. Chikhachev. Kinetic theory of quasystationary state of charged particle beams. Moscow,2001.
** I.M. Kapchinsky. Theory of linear resonanse accelerators. Particle dynamics. Moscow,1982.

WEPPR025

Effective Emittance Growth in Beam with Gaussian Density Profile

plasma, electromagnetic-fields

2988

H.Y. Barminova
ITEP, Moscow, Russia

In a continuous beam with nonuniform charge density profile transverse oscillations are nonlinear resulting in effective emittance growth. It is of great practical interest to find this growth scaling law in the case of beam with Gaussian density distribution. To study the effect for a sheet beam with parabolic density profile, a fully kinetic and self-consistent model was built. The model allows one to obtain equations for envelope radius and rms emittance in a self-consistent manner, as the KV-model does it. The only model requirement is a special type of distribution function depending on the integral of nonlinear motion equations that automatically satisfies the Vlasov equation. The envelope equation is proved to be an ODE of 4th order. It was solved by the Runge-Kutta method. The beam parameter range was found where rms emittance growth is absent. The stationary equilibrium solution was found, too. The stability of solutions near equilibrium one was studied. An analysis of results shows that when there is no energy dissipation in the channel, rms emittance rises due to phase mixing between envelope oscillations and density distribution shape oscillations.

WEPPR029

Alternative Cavity for H E Part of the Project X linac

cavity, HOM, linac, cryomodule

2997

A. Lunin, A. Saini, N. Solyak, A.I. Sukhanov, V.P. Yakovlev
Fermilab, Batavia, USA

An alternative superconducting elliptical cavity is suggested for High Energy (HE) part of the Project X linac. The cavity is suitable to operate at CW regime with high beam current (10 mA), which is critical for Accelerator-Driven Subcritical (ADS) systems and for intense muon source for future Neutrino Factory or Muon Collider. We present the algorithm of the cavity shape optimization, comprehensive tolerances analysis and the solution for monopole High Order Modes (HOM) damping. Based on these results we estimated the probabilities of cryogenic losses per cryomodule and a growth of the beam longitudinal emittance due to the resonance excitation of monopole HOMs in the HE linac for Project X.

WEPPR031

Injector Beam Dynamics for a High-repetition Rate 4th-generation Light Source

electron, space-charge, gun, linac

3000

C. F. Papadopoulos, J.N. Corlett, P. Emma, D. Filippetto, G. Penn, J. Qiang, M.W. Reinsch, F. Sannibale, C. Steier, M. Venturini, R.P. Wells
LBNL, Berkeley, California, USA

Funding: This work was supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
We report on the beam dynamics studies and optimization methods for a high-repetition (1 MHz) photoinjector based on a VHF normal conducting electron source. The simultaneous goals of beam compression and preservation of 6-dimensional beam brightness have to be achieved in the injector, in order to accommodate a linac driven FEL light source. For this, a parallel, multiobjective optimization algorithm is used. We discuss the relative merits of different injector design points, as well as the constraints imposed on the beam dynamics by technical considerations such as the high repetition rate.

WEPPR032

Simulation Studies of Adiabatic Thermal Beams in a Periodic Solenoidal Focusing Field

simulation, focusing, vacuum, plasma

3003

C. Chen, T.J. Barton, D.M. Field, K.M. Lang
MIT, Cambridge, Massachusetts, USA

Funding: Research supported by DOE Grant No. DE-FG02-95ER40919, Grant No. DE-FG02-05ER54836, and MIT Undergraduate Research Opportunity Program.
Self-consistent simulations are performed to verify the theoretical predictions of adiabatic thermal beams in periodic solenoidal magnetic focusing fields*,**. In particular, results are obtained for adiabatic thermal beams that do not rotate in the Larmor frame. For such beams, the theoretical predictions of the rms beam envelope, the conservation of the rms thermal emittance, the adiabatic equation of state, and the Debye length are verified in the self-consistent simulations.
*K.R. Samokhvalova, J. Zhou and C. Chen, Phys. Plasma 14, 103102 (2007).
**J. Zhou, K.R. Samokhvalova and C. Chen, Phys. Plasma 15, 023102 (2008).

WEPPR033

Performance of Low-Energy Magnetic Bunch Compression for the ASTA Photoinjector at Fermilab

simulation, dipole, cryomodule, collective-effects

3006

C.R. Prokop, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
B.E. Carlsten
LANL, Los Alamos, New Mexico, USA
M.D. Church
Fermilab, Batavia, USA

Funding: LANL LDRD program, project 20110067DR -U.S. DOE Contract No. DE-FG02-08ER41532 and DE-AC02-07CH11359.
The Advanced Superconducting Test Accelerator (ASTA) at Fermilab incorporates a magnetic bunch compressor chicane to compress the 40-MeV electron bunches generated in the photoinjector. In this paper, we present a numerical analysis and parametric study of the bunch compressor's performance for various operating scenarios. The beam dynamics simulations, carried out with Astra, Impact-Z and CSRTrack, are compared against each other. Finally, an operating regime with low phase space dilutions is suggested based on the simulation results.

WEPPR034

Longitudinal Phase Space Measurement for the Advanced Superconducting Test Accelerator Photoinjector

diagnostics, simulation, cavity, collimation

3009

C.R. Prokop, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
M.D. Church, Y.-E. Sun
Fermilab, Batavia, USA

Funding: LANL LDRD program, project 20110067DR -U.S. DOE Contract No. DE-FG02-08ER41532 and DE-AC02-07CH11359.
The Advanced Superconducting Test Accelerator (ASTA) at Fermilab uses a high-brightness photoinjector capable of producing electron bunches with charges up to 3.2 nC, to be used in support of a variety of advanced accelerator R&D experiments. The photoinjector incorporates an extensive diagnostics suites including a single-shot longitudinal-phase-space diagnostics composed of a horizontally deflecting cavity followed by a vertical spectrometer. In this paper, we present the design, optimization, and performance analysis (including detrimental collective effects) of the longitudinal phase space diagnostics and especially compare two possible choices of deflecting cavity frequencies.

WEPPR039

Nonlinear Lattice for Space-Charge Dominated Beam Transport with Suppressed Emittance Growth

quadrupole, focusing, space-charge, lattice

3021

Y.K. Batygin, A. Scheinker
LANL, Los Alamos, New Mexico, USA

We present a feasible design for the implementation of a beam emittance growth suppressing lattice for space-charge dominated beams. Our analysis is based on original derivations developed in *. We present a FODO focusing channel with quadrupole and duodecapole components which on average create the ﬁeld required to match the high-brightness beam with the structure. Matched beam exhibits smaller emittance growth than that in regular quadrupole focusing channel. Numerical results demonstrate the lattice’s performance in preventing halo formation of a nonuniform space charge dominated beam.
* Y. Batygin, Phys. Rev. E, 57, 5, p. 6020 (1998).

WEPPR040

Intensity Effects of the FACET Beam in the SLAC Linac

linac, quadrupole, wakefield, alignment

3024

F.-J. Decker, N. Lipkowitz, J. Sheppard, G.R. White, U. Wienands, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515.
The beam for FACET (Facility for Advanced aCcelerator Experimental Tests) at SLAC requires an energy-time correlation ("chirp") along the linac, so it can be compressed in two chicanes, one at the mid point in sector 10 and one W-shaped chicane just before the FACET experimental area. The induced correlation has the opposite sign to the typical used for BNS damping, and therefore any orbit variations away from the center kick the tail of the beam more than the head, causing a shear in the beam and emittance growth. Any dispersion created along the linac has similar effects due to the high (>1.2% rms) energy spread necessary for compression. The initial huge emittances could be reduced by a factor of 10, but were still bigger than expected by a factor of 2-3. Normalized emittance of 2 um-rad in Sector 2 blew up to 150 um-rad in Sector 11 but could be reduced to about 6-12 um-rad for the vertical plane although the results were not very stable. Investigating possible root causes for this, we found locations where up to 10 mm dispersion was created along the linac, which were finally verified with strong steering and up to 7 mm settling of the linac accelerator at these locations.

WEPPR041

Design of a Compact Linear Accelerator for the Ultrafast Electron Diffraction Facility

electron, gun, linac, space-charge

3027

M. Mamtimin, A.W. Hunt, Y. Kim, D.P. Wells
IAC, Pocatello, IDAHO, USA

Ultrafast Electron Diffraction (UED) is a powerful tool to find 3-dimensional structures and dynamical transitions of chemical or biological samples with a femtosecond-range temporal resolution and an angstrom-range spatial resolution. Due to the columbic field of electrons, UED can provide a higher cross section and a higher time resolution than those of the ultrafast photon diffraction with X-ray Free Electron Lasers (XFELs). In this paper, we describe the design concepts and ASTRA simulation results of a compact linac for an UED facility.

WEPPR049

The Impact of Fill Patterns on the Fast Ion Instability in the ILC Damping Ring

ion, damping, feedback, electron

3036

G.X. Xia
MPI-P, München, Germany

The ions produced via collisional ionization of the residual gas molecules in vacuum pipe with the circulating electron beam have deleterious effect on the beam properties and may become a limiting factor in the machine’s performance. In this paper, the various beam fill patterns are investigated and their effects on the fast ion instability are discussed. The simulations show that an optimal fill pattern can reduce growth rate of the fast ion instability significantly.

WEPPR061

Thresholds of Longitudinal Single Bunch Instability in Single and Double RF Systems in the CERN SPS

simulation, impedance, damping, synchrotron

3066

T. Argyropoulos, T. Bohl, J. Esteban Muller, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland
C.M. Bhat
Fermilab, Batavia, USA

A fourth harmonic RF system is used in the SPS as a Landau cavity, in order to stabilize the high intensity LHC proton beam against the longitudinal instabilities. Numerous studies proved that operating the two RF systems, through the whole cycle, in bunch shortening mode is necessary to provide a good quality beam at extraction to the LHC. Furthermore, it was shown that the choice of RF parameters as voltage amplitude ratio and relative phase are critical for the beam stability. This paper presents the results of single bunch measurements performed in single and double RF systems with various RF settings and compares them with the results of macroparticle simulations for the SPS impedance model.

WEPPR066

Effects of the External Wakefield from the CLIC PETS

linac, wakefield, luminosity, dipole

3078

A. Latina, D. Schulte
CERN, Geneva, Switzerland
J. Gao, Y. Wang
IHEP, Beijing, People's Republic of China

The CLIC main linac accelerating structures will be powered by the Power Extraction and Transfer Structure (PETS) located in the drive beam decelerators. Misalignments of the PETS will excite dipolar modes in the couplers of the main linac structures that will kick the beam leading to beam quality degradation. In this paper, the impact of such dipolar kicks is studied, and tolerances, based on analytical estimations, are found both in the single- and the multi-bunch regimes. Numerical simulation obtained using the tracking code PLACET are shown to confirm the analytical estimates.

WEPPR067

Study of Fundamental Mode Multipolar Kicks in Double- and Single-feed Power Couplers for the CLIC Main Linac Accelerating Structure

linac, simulation, multipole, cavity

3081

A. Latina, A. Grudiev, D. Schulte
CERN, Geneva, Switzerland

Multipolar kicks from the fundamental mode have been calculated in the CLIC baseline accelerating structure with double–feed input and output power couplers. The influence of such multipolar kicks on the main linac beam dynamics has been investigated. Furthermore, an alternative design of the couplers with single-feed has been studied and compared with the double-feed. Such an alternative would significantly simplify the waveguide system of the main linac but potentially introduce an harmful dipolar kick from the fundamental mode. The geometry of the coupler has been optimized in order to minimize such a dipolar kick and keep it below threshold levels determined with beam dynamics simulations. Influence of the higher order multipoles has been investigated as well and acceptable levels have been determined.

WEPPR072

Increasing Instability Thresholds in the SPS by Lowering Transition Energy

optics, injection, extraction, coupling

3096

H. Bartosik, G. Arduini, T. Argyropoulos, T. Bohl, S. Cettour-Cave, K. Cornelis, J. Esteban Muller, W. Höfle, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova
CERN, Geneva, Switzerland

A new optics for the SPS with lower transition energy was tested experimentally during 2010-2011, showing a significant increase of the single bunch instability thresholds at injection, due to the 3-fold increase of the slip factor. This paper summarizes the series of performed machine studies for different LHC bunch structures and intensities. In particular, the search of the TMCI threshold in the new optics is presented. Observations on the longitudinal multi-bunch stability are compared between the nominal and the low-transition optics. Finally, optics variants with higher vertical tunes are discussed, which can allow to further increase the TMCI and vertical instability thresholds by reducing the vertical beta function.

WEPPR076

Positron Options for the Linac-ring LHeC

target, positron, electron, laser

3108

F. Zimmermann, O.S. Brüning, Y. Papaphilippou, D. Schulte, P. Sievers
CERN, Geneva, Switzerland
H.-H. Braun
Paul Scherrer Institut, Villigen, Switzerland
E.V. Bulyak
NSC/KIPT, Kharkov, Ukraine
M. Klein
The University of Liverpool, Liverpool, United Kingdom
L. Rinolfi
JUAS, Archamps, France
A. Variola, Z.F. Zomer
LAL, Orsay, France
V. Yakimenko
BNL, Upton, Long Island, New York, USA

The full physics program of a future Large Hadron electron Collider (LHeC) requires both pe⁺ and pe- collisions. For a pulsed 140-GeV or an ERL-based 60-GeV Linac-Ring LHeC this implies a challenging rate of, respectively, about 1.8·10¹⁵ or 4.4·10¹⁶ e+/s at the collision point, which is about 300 or 7000 times the past SLC rate. We consider providing this e⁺ rate through a combination of measures: (1) Reducing the required production rate from the e⁺ target through colliding e⁺ (and the LHC protons) several times before deceleration, by reusing the e⁺ over several acceleration/deceleration cycles, and by cooling them, e.g., with a compact tri-ring scheme or a conventional damping ring in the SPS tunnel. (2) Using an advanced target, e.g., W-granules, rotating wheel, sliced-rod converter, or liquid metal jet, for converting gamma rays to e+. (3) Selecting the most powerful of several proposed gamma sources, namely Compton ERL, Compton storage ring, coherent pair production in a strong laser, or high-field undulator radiation from the high-energy lepton beam. We describe the various concepts, present example parameters, estimate the electrical power required, and mention open questions.

WEPPR081

The Collective Effects of the Short Pulsed X-Ray (SPX) System in the Advanced Photon Source Upgrade

impedance, cavity, simulation, collective-effects

3117

Y.-C. Chae, M. Borland
ANL, Argonne, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
The Advanced Photon Source is a 7-GeV hard x-ray synchrotron light source. The APS Upgrade specifies a short-pulse x-ray (SPX) as well as additional beamlines delivering higher brightness and flux. In order to achieve this goal we plan to use S-band superconducting cavities. The performance of such a system based on the zero-current simulation is well established; here, we included the effect of wakefields generated by the SPX system. While the SPX system is off, we are interested in how much current we can store in the single bunch, because the SPX contributes a significant amount of broadband impedance to the ring. With the SPX system on, we are interested in how much vertical emittance will increase, which in turn will enlarge the x-ray pulse length. We report the results of both cases when the SPX system is installed in the ring for the APS Upgrade.

WEPPR087

Dependence of Beam Instabilities Caused by Electron Clouds at CesrTA Due to Variations in Chromaticity, Bunch Current and Train Length

betatron, electron, feedback, positron

3135

M.G. Billing, G. Dugan, M.J. Forster, D.L. Kreinick, R.E. Meller, M.A. Palmer, G. Ramirez, M.C. Rendina, N.T. Rider, J.P. Sikora, K.G. Sonnad, H.A. Williams
CLASSE, Ithaca, New York, USA
J.Y. Chu
CMU, Pittsburgh, Pennsylvania, USA
J.W. Flanagan
KEK, Ibaraki, Japan
R. Holtzapple, M. Randazzo
CalPoly, San Luis Obispo, California, USA

Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867 and the Lepton Collider R&D Coop Agreement: NSF Award PHY-1002467.
Electron cloud-induced beam dynamics is being studied at CESRTA under various conditions. These measurements detect the the coherent self-excited spectrum for each bunch within a train and bunch-by-bunch beam size. In the position spectrum coherent betatron dipole and head-tail motion is detectable for each individual bunch within the train with a sensitivity for the motion of 1.1 (2) microns-rms in the vertical (horizontal) direction for a 1 mA bunch current. These techniques are utilized to study the electron cloud-related interactions, which cause the growth of coherent motion and beam size along the train. We report on the observations and results from studies of the instability growth vs. changes in chromaticity, the current per bunch and the length of the train.

WEPPR089

Experimental Progress: Current Filamentation Instability Study

plasma, simulation, electron, radiation

3141

B.A. Allen, P. Muggli
USC, Los Angeles, California, USA
M. Babzien, M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
C. Huang
LANL, Los Alamos, New Mexico, USA
J.L. Martins, L.O. Silva
IPFN, Lisbon, Portugal
W.B. Mori
UCLA, Los Angeles, California, USA

Funding: Work supported by: National Science Foundation and US Department of Energy.
Current Filamentation Instability, CFI, is of central importance for the propagation of relativistic electron beams in plasmas. CFI has potential relevance to astrophysics, magnetic field and radiation generation in the afterglow of gamma ray bursts, and inertial confinement fusion, energy transport in the fast-igniter concept. An experimental study of this instability is underway at the Accelerator Test Facility, ATF, at Brookhaven National Laboratory with the 60MeV electron beam and centimeter length capillary discharge plasma. The experimental program includes the systematic study and characterization of the instability as a function of beam (charge, transverse and longitudinal profile) and plasma (plasma density) parameters. Specifically, the transverse beam profile is measured directly at the plasma exit using optical transition radiation from a thin gold-coated silicon window. Experimental results show the reduction of the beam transverse size and the appearance of multiple (1-4) filaments and are a function of the plasma density. We will present simulation and experimental results, provide discussion of these results and outline next steps in the experiment.

WEPPR091

Multi-Particle Simulation Codes Implementation to Include Models of a Novel Single-bunch Feedback System and Intra-beam Scattering

feedback, simulation, electron, damping

3147

M.T.F. Pivi, A. Chao, C.H. Rivetta
SLAC, Menlo Park, California, USA
F. Antoniou, K.S.B. Li, Y. Papaphilippou
CERN, Geneva, Switzerland
M. Boscolo, T. Demma
INFN/LNF, Frascati (Roma), Italy
K.G. Sonnad
CLASSE, Ithaca, New York, USA

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
The beam tracking codes C-MAD and HEAD-TAIL have been enhanced to include a detailed model of a single-bunch feedback system. Such a system is under development to mitigate the electron cloud and the transverse mode coupling instability (TMCI) in the SPS and LHC at CERN. This paper presents the model of the feedback sub-systems: receiver, processing channel, filter, amplifier and kicker, which takes into account the frequency response, noise, mismatching and technological limits. With a realistic model of the hardware, it is possible to study the prototypes installed in the SPS and design a novel feedback system. The C-MAD code, which is parallel and optimized for speed, now also includes radiation damping and quantum excitation and a detailed model of Intra-Beam Scattering (IBS) based on the Zenkevich-Bolshakov algorithm, to investigate the IBS during damping and its effect on the beam distribution, especially the beam tails, that analytical methods cannot investigate. Intra-beam scattering is a limiting factor for ultra-low emittance rings such as CLIC and Super-B.

THYB01

Beam-beam Limit in a Hadron Collider

luminosity, simulation, resonance, collider

3208

K. Ohmi
KEK, Ibaraki, Japan

Beam-beam limit phenomenon is observed in degradation of luminosity lifetime and/or beam life time in hadron colliders, especially in LHC. We focus the luminosity degradation in this paper. Various effects to degrade the luminosity grow severe in a high beam intensity. Coherent beam-beam instability, incoherent beam-beam emittance growth and those cupeled with lattice errors, external noises, intra-beam scattering. The beam-beam limit in an ideal machine and a machine with above errors is discussed with theory and simulation. Experimental results are reviewed and compare with the theory and simulations.

Slides THYB01 [4.712 MB]

THYB03

Collective Effects in the LHC and its Injector Complex

luminosity, linac, impedance, injection

3218

E. Métral
CERN, Geneva, Switzerland

Operation during 4-8 hours at a constant luminosity of five times the nominal one (with “leveling”) is required for the CERN HL-(High Luminosity)-LHC project to be able to reach integrated luminosities of ~ 250 fb-1 per year and ~ 3 ab-1 twelve years after the upgrade. This means that the potential peak luminosity should be at least two times larger than the leveled one, i.e. a factor more than ten compared to the nominal case is contemplated. Even though the LHC had a bold beginning, reaching one third of the nominal peak luminosity at the end of the 2011 run, a factor more than thirty remains to be gained, which will be achieved only if all the collective effects are deeply understood and mastered both in the LHC and its injectors. The observations made during the 2010-2011 runs are first reviewed and compared to predictions to try and identify possible bottlenecks. The lessons learned and the possible solutions and/or mitigation measures to implement in the HL-LHC and the LHC Injectors Upgrade (LIU) projects are then discussed.

Slides THYB03 [34.295 MB]

THEPPB003

A 1 GeV CW FFAG High Intensity Proton Driver

space-charge, simulation, cyclotron, focusing

3234

S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
C. Johnstone
Fermilab, Batavia, USA

The drive for high beam power, high duty cycle, and reliable beams at reasonable cost has focused world attention on fixed-field accelerators, notably Fixed-Field Alternating Gradient accelerators (FFAGs). High-intensity GeV proton drivers are of particular interest, as these encounter duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotron. Recently, the concept of isochronous orbits has been explored and developed for non-scaling FFAGs using powerful new methodologies in FFAG accelerator design. These new breeds of FFAGs have been identified by international collaborations for serious study thanks to their potential applications including Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste. The extreme reliability requirements for ADS mandate CW operation capability and the FFAG’s strong focusing, particularly in the vertical, will serve to mitigate the effect of space charge (as compared with the weak-focusing cyclotron). This paper reports on these new advances in FFAG accelerator technology and presents a stable, 0.25-1GeV isochronous FFAG for an accelerator driven subcritical reactor.

THEPPB005

Study on the Injection Optimization and Transverse Coupling for CSNS/RCS

injection, beam-losses, collimation, coupling

3240

M.Y. Huang, J. Qiu, S. Wang, S.Y. Xu
IHEP, Beijing, People's Republic of China

The injection system of the China Spallation Neutron Source uses H⁻ stripping and phase space painting method to fill large ring acceptance with the linac beam of small emittance. The emittance evolution, beam losses, and collimation efficiency during the injection procedures for different injection parameters, such as the injection emittances, starting injection time, twiss parameters and momentum spread, were studied, and then the optimized injection parameters was obtained. In addition, the phase space painting scheme which also affect the emittance evolution and beam losses were simulated and the optimization range of phase space painting were obtained. There will be wobble in the power supply of the injection bumps, and the wobble effects were presented. In order to study the transverse coupling, the injection procedures for different betatron tunes and momentum spreads were studied.

THPPD018

Precision Magnet Measurements for X-band Accelerator Quadrupole Triplets

quadrupole, alignment, dipole, controls

3536

R.A. Marsh, S.G. Anderson, J.P. Armstrong
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

THPPD045

High Temperature Superconducting Magnets for Efficient Low Energy Beam Transport Systems

solenoid, ion, rfq, vacuum

3614

J.H. Nipper, G. Flanagan, R.P. Johnson
Muons, Inc, Batavia, USA
M. Popovic
Fermilab, Batavia, USA

Modern ion accelerators and ion implantation systems need very short, highly versatile, Low Energy Beam Transport (LEBT) systems. The need for reliable and continuous operation requires LEBT designs to be simple and robust. The energy efficiency of available high temperature superconductors (HTS), with efficient and simple cryocooler refrigeration, is an additional attraction. Innovative, compact LEBT systems based on solenoids designed and built with high-temperature superconductor will be developed using computer models and prototyped. The parameters will be chosen to make this type of LEBT useful in a variety of ion accelerators, ion implantation systems, cancer therapy synchrotrons, and research accelerators, including the ORNL SNS. The benefits of solenoids made with HTS will be evaluated with analytical and numerical calculations for a two-solenoid configuration, as will be used in the SNS prototype LEBT that will replace the electrostatic one at SNS, and a single solenoid configuration, as was proposed for the Fermilab proton driver that will be most applicable to ion implantation applications.

THPPD076

Evaluation of Components for the High Precision Inductive Adder for the CLIC Damping Rings

damping, kicker, collider, luminosity

3692

J. Holma, M.J. Barnes
CERN, Geneva, Switzerland

The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse generators for the damping ring kickers must provide extremely flat, high-voltage pulses. The specifications for the extraction kickers of the CLIC damping rings are particularly demanding: the flattop of the output pulse must be 160 ns duration, 12.5 kV and 250 A, with a combined ripple and droop of not more than ±0.02 %. An inductive adder allows the use of different modulation techniques and is therefore a very promising approach to meeting the specifications. In addition to semiconductors working in their saturated region, semiconductors working in their linear region are needed for applying analogue modulation techniques. Simulations have been carried out to define component specifications for the inductive adder: this paper reports the results of tests and measurements of various components.

THPPD083

Analysis of Kicker Noise Induced Beam Emittance Growth

kicker, high-voltage, injection, monitoring

3710

W. Zhang, L. A. Ahrens, I. Blackler, M. Blaskiewicz, J.M. Brennan, W. Fischer, H. Hahn, H. Huang, N.A. Kling, M. Lafky, G.J. Marr, K. Mernick, J.-L. Mi, M.G. Minty, C. Naylor, T. Roser, J. Sandberg, T.C. Shrey, B. Van Kuik, A. Zelenski
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Over the last few years, physicists have suspected the presence of noise acting on the RHIC beams observable as occasional emittance growth at high beam energies. While the noise was sporadic in the past, it became more persistent during the run-11 setup period. An investigation diagnosed the source as originating from the RHIC abort kicker system. Once identified the issue was quickly resolved. We report in this paper the investigation result, circuit analysis, measured and simulated waveforms, solutions, and future plans.

THPPP001

High Intensity Intermediate Charge State Heavy Ions in Synchrotrons

injection, ion, septum, heavy-ion

3719

P.J. Spiller, U. Blell, L.H.J. Bozyk, H. Reich-Sprenger, J. Stadlmann
GSI, Darmstadt, Germany
Y. El-Hayek
FIAS, Frankfurt am Main, Germany

In order to reach the desired FAIR intensities for heavy ions, SIS18 and SIS100 have to be operated with intermediate charge states. Operation with intermediate charge state heavy ions at the intensity level of about 1011 ions per cycle has never been demonstrated elsewhere and requires a dedicated machine design. After partially completing the upgrade program of SIS18, the number of intermediate charge state heavy ions accelerated to the FAIR booster energy of 200 MeV/u, could be increased by a factor of 70. The specific challenge for the SIS18 and SIS100 booster operation is the high cross section for ionization of the intermediate charge state heavy ions, in combination with gas desorption processes and the dynamic vacuum pressure. The achieved progress in minimizing the ionization beam loss underlines that the chosen technical strategies described in this report are appropriate. The latest intensity records and results from the machine development programs are presented.

THPPP005

Space Charge Effect in the Presence of x-y Coupling in J-PARC MR

coupling, lattice, space-charge, simulation

3731

K. Ohmi
KEK, Ibaraki, Japan
S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

It is crucial issue to suppress beam loss due to space charge force in J-PARC MR. We focus x-y coupling as a source of the beam loss. x-y coupling is measured by turn-by-turn beam position monitors in J-PARC MR. A space charge simulation under the measured x-y coupling evaluates the beam loss. Tolerance of x-y coupling and how to improve the beam loss are discussed.

THPPP007

Proton-Beam Emittance Growth in SPS Coasts

cavity, vacuum, proton, simulation

3737

R. Calaga, L. Ficcadenti, E. Métral, R. Tomás, J. Tückmantel, F. Zimmermann
CERN, Geneva, Switzerland

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
Proton-beam transverse emittance growth rates have been measured during SPS coasts to assess the possibility of using the SPS as a testbed for the LHC prototype crab cavities. The SPS measurements in coasts were performed at different beam energies, for varying RF voltage, beam intensity, and chromaticity. Results from these measurements are presented with potential explanations for the observed emittance growth.

THPPP008

The ELENA Project: Progress in the Design

extraction, electron, vacuum, antiproton

3740

T. Eriksson, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, C. Carli, R. Kersevan, M. Martini, S. Maury, S. Pasinelli, G. Tranquille
CERN, Geneva, Switzerland
W. Oelert
Forschungszentrum Jülich GmbH, Institut fur Nuklearchemie (INC), Jülich, Germany

The Extra Low ENergy Antiproton ring (ELENA) project started in June 2011 and is aimed at substantially increasing the number of antiprotons delivered to the Antiproton Decelerator (AD) physics community. ELENA will be a small machine that receives antiprotons from AD at 5.3 MeV kinetic energy and decelerates them further down to 100 keV. It will be equipped with an electron cooler to avoid beam losses during deceleration and to reduce beam phase space at extraction. Design work is progressing with emphasis on machine parameters and design as well as infrastructure, ring, transfer lines and vital subsystem design.

THPPP018

Operation of the LHC at High Luminosity and High Stored Energy

luminosity, injection, vacuum, radiation

3767

J. Wenninger, R. Alemany-Fernandez, G. Arduini, R.W. Assmann, B.J. Holzer, E.B. Holzer, V. Kain, M. Lamont, A. Macpherson, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli Camillocci, J.A. Uythoven, W. Venturini Delsolaro
CERN, Geneva, Switzerland

In 2011 the operation of the Large Hadron Collider LHC entered its first year of high luminosity production at a beam energy of 3.5 TeV. In the first months of 2011 the number of bunches was progressively increased to 1380, followed by a reduction of the transverse emittance, an increase of the bunch population and a reduction of the betatron function at the collision points. The performance improvements steps that were accumulated in 2011 eventually brought the peak luminosity to 3.6·10³³ cm^-2s⁻¹. The integrated luminosity delivered to each of the high luminosity experiments amounted to 5.6 fb-1, a factor of 5 above the initial target defined in 2010. The operational experience with high intensity and high luminosity at the LHC will be presented here, together with the issues that had to be tackled on the road to high intensity and luminosity.

THPPP022

Coalescing at 8 GeV in the Fermilab Main Injector

simulation, LLRF, synchrotron, space-charge

3779

D.J. Scott, D. Capista, I. Kourbanis, K. Seiya, M.-J. Yang
Fermilab, Batavia, USA

For Project X, it is planned to inject a beam of 3 10¹¹ particles per bunch into the Main Injector. To prepare for this by studying the effects of higher intensity bunches in the Main Injector it is necessary to perform coalescing at 8 GeV. The results of a series of experiments and simulations of 8 GeV coalescing are presented. To increase the coalescing efficiency adiabatic reduction of the 53 MHz RF is required, resulting in ~70% coalescing efficiency of 5 initial bunches. Data using wall current monitors has been taken to compare previous work and new simulations for 53 MHz RF reduction, bunch rotations and coalescing, good agreement between experiment and simulation was found. Possible schemes to increase the coalescing efficiency and generate even higher intensity bunches are discussed. These require improving the timing resolution of the low level RF and/or tuning the adiabatic voltage reduction of the 53 MHz.

THPPP033

New Developments for the Present and Future GSI Linacs

linac, ion, cavity, proton

3806

L. Groening, W.A. Barth, G. Clemente, V. Gettmann, B. Schlitt
GSI, Darmstadt, Germany
M. Amberg, K. Aulenbacher, S. Mickat
HIM, Mainz, Germany
F.D. Dziuba, H. Podlech, U. Ratzinger, C. Xiao
IAP, Frankfurt am Main, Germany

For more than three decades, GSI has successfully operated the Universal Linear Accelerator (UNILAC), providing ions from protons to uranium at energies from 3 to 11 MeV/u. The UNILAC will serve for a comparable period as injector for the upcoming FAIR facility which will ask for short pulses of high peak currents of heavy ions. The UNILAC Alvarez-type DTL has been in operation since the earliest days of the machine, and it needs to be replaced to assure reliable operation for FAIR. This new DTL will serve the needs of FAIR, while demands of high duty cycles of moderate currents of intermediate-mass ions will be met by construction of a dedicated superconducting cw-linac. FAIR requires additionally provision of primary protons for its pbar physics program. A dedicated proton linac is under design for that task. The contribution will present the future linacs to be operated at GSI. Finally we introduce a novel method to provide flat ion beams for injection into machines having flat injection acceptances.

THPPP042

The First Step of RFQ Development in KBSI

rfq, ion, quadrupole, dipole

3829

J.W. Ok, S. Choi, B.C. Kim, B.S. Lee, J.Y. Park, M. Won, J.H. Yoon
Korea Basic Science Institute, Busan, Republic of Korea

The RFQ for accelerating an ion beam is being developed in Korea Basic Science Institute (KBSI). The KBSI RFQ is designed to accelerate 1 mA lithium beam (Q/A=3/7) at 88 MHz. It is considered to be a 4-vane RFQ structure. The injection beam energy into RFQ is 12 keV/u, the output beam energy downstream from RFQ is 300 keV/u. The RFQ has to show stable operation, meet availability, and have the minimum losses so as to guarantee the best performance/cost ratio. At the first step, two dimensional geometry structure was studied using SUPERFISH code for the resonance frequency of quadrupole and dipole modes. Three dimensional field distributions were investigated by CST microwave studio. The beam dynamics in RFQ accelerator were studied using PARMTEQM code. Based on these results, the structural analysis should be studied and a cold model will be fabricated and investigated. The practical KBSI RFQ will be manufactured in next year.

THPPP048

Linac4 - Low Energy Beam Measurements

solenoid, rfq, ion, linac

3847

L.M. Hein, G. Bellodi, J.-B. Lallement, A.M. Lombardi, O. Midttun, P.A. Posocco, R. Scrivens
CERN, Geneva, Switzerland

Linac4 is a160 MeV normal-conducting linear accelerator for negative Hydrogen ions (H−), which will replace the 50 MeV proton Linac (Linac2) as linear injector for the CERN accelerators. The low energy part, comprising a 45 keV Low Energy Beam Transport system (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) is being assembled in a dedicated test stand for pre-commissioning with a proton beam. During 2011 extensive measurements were done after the source and after the LEBT with the aim of preparing the RFQ commissioning and validating the simulation tools, indispensable for future source upgrades. The measurements have been thoroughly simulated with a multi-particle code, including 2D magnetic field maps, error studies, steering studies and the generation of beam distribution from measurements. Emittance, acceptance and transmission measurements will be presented and compared to the results of the simulations.

THPPP050

HIE-ISOLDE SC Linac: Operational Aspects and Commissioning Preparation

linac, diagnostics, cryomodule, ion

3853

D. Voulot, E. Bravin, M.A. Fraser, B. Goddard, Y. Kadi, D. Lanaia, A.S. Parfenova, M. Pasini, A.G. Sosa, F. Zocca
CERN, Geneva, Switzerland

In the framework of the HIE-ISOLDE project, the REX linac will be upgraded in stages to 5.5 MeV/u and 10 MeV/u using superconducting (SC) quarter-wave cavities. The linac lattice is now frozen and the beam dynamics has been checked. The beam properties at the output of the NC linac for the different stages have been measured and are compatible with the SC linac acceptance. The high-energy beam transfer design is being finalised and a study has been launched for a buncher/chopper system allowing 100 ns bunch spacing for time-of-flight measurements. A compact diagnostic box for the inter-cryomodule region is under development and a new Si-detector based monitor for energy and phase measurements has been tested.

THPPP065

The FNAL Injector Upgrade Status

rfq, extraction, beam-transport, vacuum

3886

C.-Y. Tan, D.S. Bollinger, K.L. Duel, P.R. Karns, J.R. Lackey, W. Pellico, V.E. Scarpine, R.E. Tomlin
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The new FNAL H⁻ injector upgrade is currently being tested before installation in the Spring 2012 shutdown of the accelerator complex. This line consists of an H⁻ source, low energy beam transport (LEBT) and 200 MHz RFQ. Beam measurements have been performed to validate the design before installation. The results of the beam measurements are presented in this paper.

THPPP067

H⁻ Beam Loss and Evidence for Intrabeam Stripping in the LANSCE Linac

linac, ion, electron, radiation

3892

L. Rybarcyk, C.T. Kelsey, R.C. McCrady, X. Pang
LANL, Los Alamos, New Mexico, USA

Funding: U.S. Dept. of Energy, NNSA, under contract DE-AC52-06NA25396.
The LANSCE accelerator complex is a multi-beam, multi-user facility that provides high-intensity H⁺ and H⁻ particle beams for a variety of user programs. At the heart of the facility is a room temperature linac that is comprised of 100-MeV drift tube and 800-MeV coupled cavity linac (CCL) structures. Although both beams are similar in intensity and emittance, the beam-loss monitors along the CCL show a trend of increased loss for H⁻ that is not present for H⁺. This difference is attributed to stripping mechanisms that affect H⁻ and not H⁺. We present the results of an analysis of H⁻ beam loss along the CCL that incorporates beam spill measurements, beam dynamics simulations, analytical models and radiation transport estimates using the MCNPX code. The results indicate a significant fraction of these additional losses result from intrabeam stripping.

THPPP074

Chopping High Intensity Proton Beams Using a Pulsed Wien Filter

focusing, proton, dipole, beam-transport

3907

C. Wiesner, L.P. Chau, H. Dinter, M. Droba, O. Meusel, I. Müller, D. Noll, U. Ratzinger
IAP, Frankfurt am Main, Germany

Chopping high intensity beams at low energies poses substantial challenges. A novel ExB chopper system for proton beams of up to 200 mA at energies of 120 keV is being developed for the accelerator driven neutron source FRANZ*. It uses a Wien filter-type ExB configuration consisting of a static magnetic deflection field and a pulsed electric compensation field to deliver 100 ns beam pulses. The setup minimizes the risk of voltage breakdowns and provides secure beam dumping outside the transport line. In order to prevent beam aberrations and emittance growth careful matching of electric and magnetic deflection forces is required. Detailed numerical studies for the field design and their effects on beam transport were conducted. An H-type dipole magnet with special transverse and longitudinal pole contours was manufactured and combined with shielding tubes to shape the magnetic field. The electric field is driven by a HV pulse generator providing ±6 kV at a repetition rate of 250 kHz. Accurate layout of the deflector plates is required in order to tackle the issues of field quality, cooling and spark prevention. Transport simulations and beam deflection experiments are presented.
* U. Ratzinger et al., "The Driver Linac of the Neutron Source FRANZ," Proc. of IPAC2011, WEPS040, P. 2577 (2011).

THPPP080

Beam Halo Reduction in the J-PARC 3-GeV RCS

injection, bunching, extraction, linac

3918

H. Hotchi, H. Harada, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, T. Koseki, Y. Sato, M.J. Shirakata
KEK, Ibaraki, Japan
K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The J-PARC RCS (3-GeV rapid cycling synchrotron) has two functions as a proton driver to the MLF (Materials and life science facility) and an injector to the MR (50-GeV main ring synchrotron). One of important issues in the current RCS bam tuning is to suppress the beam halo formation, which is essential especially to reduce the beam loss at the MR. In this paper, we present beam study results on the formation mechanism and reduction of the beam halo in the RCS.

THPPP088

Beam Loss Studies of the ISIS Synchrotron Using ORBIT

simulation, acceleration, injection, synchrotron

3942

D.J. Adams
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
I.S.K. Gardner, B. Jones, B.G. Pine, A. Seville, H. V. Smith, C.M. Warsop, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS synchrotron forms part of the accelerator chain for the Spallation Neutron Source at RAL, UK. The synchrotron is an 800 MeV, 50Hz , RCS accelerating ~2.8·10¹³ protons per cycle. Beam loss is localized in two super periods of the ring using a system of collimators. The injection and acceleration processes, vacuum vessels and collimation systems have been modeled using the particle tracking code ORBIT. This paper presents simulation results in comparison to measurements of longitudinal profiles and beam loss.

THPPP091

Status of the Project-X CW Linac Design

linac, cryomodule, lattice, rfq

3948

J.-F. Ostiguy, P. Berrutti, J.-P. Carneiro, V.A. Lebedev, S. Nagaitsev, A. Saini, B.G. Shteynas, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Superconducting CW linac was proposed for Project X to accelerate H⁻ beam from 2.1 MeV to 3 GeV with nominal peak and average currents of respectively 5 mA and 1 mA. Linac built of 5 different families of resonators: half-wave, spoke (2), and elliptical (2) working at 162.5 MHz 325 MHz and 650 MHz to cover all energy range. Cavities and focusing elements are assembled in cryomodules. In baseline design all cryomodules are separated by short warm sections. It makes machine more reliable and maintainable and provide space for beam diagnostics and collimation. A long (~10m) gap between cryomodules at1 GeV is also being considered to provide space for beam extraction for nuclear experimental program. In paper we present the latest lattice of the linac baseline design and results of beam studies for this lattice. We briefly compare performance of the baseline design with alternative one without half-wave resonator section.

THPPP092

Progress of the Front-End System Development for Project X at LBNL

rfq, ion-source, ion, simulation

3951

D. Li, M.D. Hoff, Q. Ji, A.R. Lambert, T. Schenkel, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA
S. Nagaitsev, L.R. Prost, G.V. Romanov, A.V. Shemyakin
Fermilab, Batavia, USA
C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
A multi-MW proton facility, Project X has been proposed and is currently under development at Fermilab. Project X is a key accelerator complex for intensity frontier of future high energy physics programs in the US. In collaboration with Fermilab, LBNL takes the responsibility in the development and design studies of the front-end system for Project X. The front-end system would consist of H⁻ ion source(s), low-energy beam transport (LEBT), 162.5 MHz normal conducting CW Radio-Frequency-Quadrupole (RFQ) accelerator, medium-energy beam transport (MEBT), and beam chopper(s). In this paper, we will review and present recent progress of the front-end system studies, which will include the RFQ beam dynamics design, RF structure design, thermal and mechanical analyses and fabrication plan, LEBT simulation studies and concept for LEBT chopper.

THPPR017

The First Development of an EPICS Control System for the IAC Accelerators

power-supply, EPICS, controls, linac

4002

A. Andrews, C.F. Eckman, A.W. Hunt, Y. Kim, D.P. Wells
IAC, Pocatello, IDAHO, USA
K.H. Kim
SLAC, Menlo Park, California, USA

At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating 15 low energy accelerators for nuclear physics applications and medical isotope production. But those accelerator do not have good computer based system to control the various accelerator components remotely. To obtain stable accelerator operations with a good reproducibility, we adapted the EPICS accelerator control system. After developing one full set of the EPICS accelerator control system for various components, we will apply the same EPICS control system for all other operating accelerators at the IAC. Since January 2011, we have been developing an EPICS control system for a 16 MeV S-band linac by collaborating with SLAC control group. In this paper, we describe our first EPICS accelerator control system to control magnet power supplies of the S-band linac at the IAC.

THPPR039

Controlled Transverse Blow-Up of High-energy Proton Beams for Aperture Measurements and Loss Maps

injection, feedback, resonance, proton

4059

W. Höfle, R.W. Assmann, S. Redaelli, R. Schmidt, D. Valuch, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

A technique was developed to blow-up transversely in a controlled way high energy proton beams in the LHC. The technique is based on band limited white noise excitation that is injected into the transverse damper feedback loop. The injected signal can be gated to selectively blow-up individual trains of bunches. The speed of transverse blow-up can be precisely controlled. This opens the possibility to perform safely and efficiently aperture measurements and loss maps with high intensity bunch trains well above stored beam energies that are considered to be safe. In particular, lengthy procedures for measurements at top energy, otherwise requiring multiple fills of individual bunches, can be avoided. In this paper, the method is presented and results from beam measurements are discussed and compared with alternative blow-up methods.

THPPR042

Optimisation of an Inverse Compton Scattering Experiment with a Real Time Detection Scheme Based on a Radio Luminescent Screen and Comparison of the X-rays Beam Characteristics with Simulations

electron, photon, laser, scattering

4068

A.S. Chauchat, JP. Brasile
TCS, Colombes, France
A. Binet, V. Le Flanchec, J-P. Nègre
CEA/DAM/DIF, Arpajon, France
J.-M. Ortega
LCP/CLIO, Orsay, Cedex, France

To optimize the detection of an 11-keV X-Ray beam produced by Inverse Compton Scattering at the ELSA facility*, with a 17 MeV electron beam and a 532 nm laser, we demonstrate the use of a very sensitive detection scheme, based on a radio luminescent screen used in the spontaneous emission regime. It has proven to be very sensitive and very effective to detect 11-keV X-Rays while rejecting the overall ambient noise produced in a harder spectral range. It allowed us to optimize the electron-photon interaction probability by observing in real time the effect of both beams transport parameters. We could then compare simulation results with experimental measurements that appear to be in good agreement.
*A.S. Chauchat et al. Instrumentation developments for production and characterization of Inverse Compton Scattering X-rays and first results with a 17 MeV electron beam, NIMA, V.622, I.1, P.129-135

FRXBB01

Femtosecond Electron Guns for Ultrafast Electron Diffraction

electron, gun, laser, cathode

4170

J. Yang, K. Kan, T. Kondoh, N. Naruse, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

This talk should describe the development of electron guns for producing femtosecond electron pulses with low (<0.1 micron) emittance, for ultrafast electron diffraction. Comparisons should be made between the systems developed by groups in Asia, Europe and America, outlining any similarities and contrasts. The focus should be on the technology for generating, accelerating, and controlling the bunches, but some description of the science applications should also be included. Finally, prospects for future developments should be considered.

Slides FRXBB01 [7.004 MB]