IPAC2011 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
MOOCB01	Study on the Realignment Plan for J-PARC Linac after the Tohoku Earthquake in Japan	DTL, linac, alignment, simulation	44
	M. Ikegami KEK, Ibaraki, Japan T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	A 9.0-magnitude earthquake struck eastern Japan on March 11, 2011, and it gave rise to damages to the buildings of the J-PARC facilities. In particular, the earthquake caused a deformation of the J-PARC linac tunnel resulting an alignment error of several tens of millimeters in both horizontal and vertical directions. It also caused a change in the relative position between the linac and other facilities of J-PARC complex. To restore the beam operation, we should establish a reasonable realignment plan for J-PARC linac taking various constraints into account and possibly tolerating some residual misalignment. In this paper, we show a study on the realignment plan for J-PARC linac including evaluation of the effect of residual misalignment with particle simulations.
	Slides MOOCB01 [2.659 MB]

MOPC002	Flow Induced Vibrations of the CLIC X-band Accelerating Structures	alignment, linac, synchrotron, resonance	65
	T.K. Charles, K. Ryan Monash University, Melbourne, Australia M.J. Boland ASCo, Clayton, Victoria, Australia G. Riddone CERN, Geneva, Switzerland A. Samoshkin JINR, Dubna, Moscow Region, Russia
	Turbulent cooling water in the Compact Linear Collider (CLIC) accelerating structures will inevitably induce some vibrations. The maximum acceptable amplitude of vibrations is small, as vibrations in the accelerating structure could lead to beam jitter and alignment difficulties. A Finite Element Analysis model is needed to identify the conditions under which turbulent instabilities and significant vibrations are induced. Due to the orders of magnitude difference between the fluid motion and the structure's motion, small vibrations of the structure will not contribute to the turbulence of the cooling fluid. Therefore the resonant conditions of the cooling channels presented in this paper, directly identify the natural frequencies of the accelerating structures to be avoided under normal operating conditions. In this paper a 2D model of the cooling channel is presented finding spots of turbulence being formed from a shear layer instability. This effect is observed through direct visualisation and wavelet analysis.

MOPC024	Construction Status of the CPHS RFQ at Tsinghua University	rfq, dipole, cavity, vacuum	122
	Q.Z. Xing, Y.J. Bai, J.C. Cai, C. Cheng, L. Du, T. Du, X. Guan, Q. Qiang, X.W. Wang, Z.F. Xiong, S.Y. Yang, H.Y. Zhang, S.X. Zheng TUB, Beijing, People's Republic of China J.H. Billen TechSource, Santa Fe, New Mexico, USA W.Q. Guan, Y. He, J. Li NUCTECH, Beijing, People's Republic of China J. Stovall CERN, Geneva, Switzerland L.M. Young AES, Medford, NY, USA
	Funding: Work supported by the “985 Project” of the Ministry of Education of China. We present, in this paper, the construction status of a Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The 3-meter-long RFQ will deliver 3 MeV protons to the downstream Drift Tube Linac (DTL) with the peak current of 50 mA, pulse length of 0.5 ms and beam duty factor of 2.5%. The RFQ has been mechanically separated into three sections. A ball-end mill, instead of a forming cutter, is adopted to machine the vane tip due to its varying radius of curvature. The precision of the numerically controlled milling machine has been verified by machining test pieces of aluminum and copper. Fine machining of the vanes was completed in July, 2011. The pre-braze tuning was completed at the beginning of this August.

MOPC044	Design of the Radiofrequency Quadrupole Coldmodel for the ESS-BILBAO Linear Accelerator	rfq, simulation, dipole, radio-frequency	175
	A. Velez, I. Bustinduy, N. Garmendia, O. Gonzalez, J.L. Munoz, D. de Cos ESS Bilbao, Bilbao, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain V. Etxebarria, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	This work will present the design of the ESS-Bilbao LINAC RFQ cold model. The process goes through the electromagnetic design of the cavity by properly setting the resonant quadrupole and dipole modes, as well as the resonance frequency. The prototype includes the vane modulation designed to accelerate a 75 mA proton beam from 75 keV to 3 MeV, with an operating frequency of 352.2 MHz. To this end, electromagnetic and electrostatic simulations have been performed by means of the commercial software COMSOL. Furthemore, results for the three components of the electrical field distribution will be presented and compared to those calculated by evaluating the 8-term multipole expansion.

MOPC049	Bead-pull Test Bench for Studying Accelerating Structures at RHUL	cavity, rfq, controls, resonance	187
	S. Molloy ESS, Lund, Sweden R. Ainsworth, G.E. Boorman Royal Holloway, University of London, Surrey, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom A. Garbayo AVS, Eibar, Gipuzkoa, Spain A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom A. Lyapin JAI, Egham, Surrey, United Kingdom P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	A bead-pull test stand has been constructed at Royal Holloway, University of London (RHUL) with the ability to provide electric field profile measurements along five degrees of freedom using the perturbation method. In this paper, we present example measurements using the test bench which include a field flatness profile of a 324MHz four vane Radio Frequency Quadrupole (RFQ) model designed as part of the Front End Test Stand (FETS) development at Rutherford Appleton Laboratory (RAL). Mechanical and operational details of the apparatus will also be described, as well as future plans for the development and usage of this facility.

MOPC061	Simulations to Flatten the Field of the FETS RFQ	rfq, simulation, cavity, dipole	223
	S.R. Lawrie, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	A high performance Radio Frequency Quadrupole (RFQ) is the next major component to be installed on the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) in the UK. The beam dynamics, RF, thermal and mechanical designs of the RFQ are almost complete and so the copper has recently been purchased with a view to start cutting metal near Summer-time. This report summarizes the simulation work performed to ensure the RF design is sound. This includes performance studies of the end-wall dipole suppression fingers, tuning the frequency of the input and output vane end regions and implementing a simple solution to remove modulation induced field tilt.

MOPC096	Design and Fabrication of a 5-Cell High Current Superconducting Cavity	cavity, HOM, simulation, dipole	301
	Y.M. Li, K.X. Liu, S.W. Quan, F. Zhu PKU/IHIP, Beijing, People's Republic of China R. Nassiri ANL, Argonne, USA
	Funding: National High Technology Research and Development program 863 (2009AA03Z206) Energy recovery linacs (ERL) is promising to achieve high average current with superior beam quality. The key component for accelerating such high current beams is the superconducting radio frequency (SRF) cavity. The design of a 1.3 GHz 5-cell high current superconducting cavity has been carried out under the cooperation between Peking University (PKU) and Argonne National Laboratory (ANL). RF properties, damping of the HOMs, multipacting and mechanical features of this cavity have been discussed and the final design is presented.

MOPC102	RF and Surface Properties of Superconducting Samples	niobium, cavity, superconductivity, superconducting-cavity	310
	T. Junginger, W. Weingarten CERN, Geneva, Switzerland T. Junginger MPI-K, Heidelberg, Germany R. Seviour Lancaster University, Lancaster, United Kingdom C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF) The surface resistance Rs of superconducting cavities can be obtained from the unloaded quality factor Q0. Since Rs varies strongly over the cavity surface its value must be interpreted as averaged over the whole cavity surface. A more convenient way to investigate the surface resistance of superconducting materials is therefore to examine small samples, because they can be manufactured cheaply, duplicated easily and used for further surface analyses. At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution, results from measurements on bulk niobium and niobium film on copper samples are presented. It is shown how different contributions to the surface resistance depend on temperature, applied RF magnetic field and frequency. Furthermore, measurements of the maximum RF magnetic field as a function of temperature and frequency in pulsed and CW operation are presented. The study is accompanied by measurements of the surface properties of the samples by various techniques.

MOPO001	Interaction Point Feedback Design and Integrated Simulations to Stabilize the CLIC Final Focus*	controls, simulation, feedback, ground-motion	475
	G. Balik, L. Brunetti, G. Deleglise, A. Jeremie, L. Pacquet IN2P3-LAPP, Annecy-le-Vieux, France A. Badel, B. Caron, R. Le Breton SYMME, Annecy-le-Vieux, France A. Latina, J. Pfingstner, D. Schulte, J. Snuverink CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) accelerator has strong precision requirements on offset position between the beams. The beam which is sensitive to ground motion needs to be stabilized to unprecedented requirements. Different Beam Based Feedback (BBF) algorithms such as Orbit Feedback (OFB) and Beam-Beam Offset Feedback (BBOF) have been designed. This paper focuses on the BBOF control which could be added to the CLIC baseline. It has been tested for different ground motion models in the presence of noises or disturbances and uses digital linear control with or without an adaptive loop. The simulations demonstrate that it is possible to achieve the required performances and quantify the maximum allowed noise level. This amount of admitted noises and disturbances is given in terms of an equivalent disturbance on the position of the magnet that controls the beam offset. Due to the limited sampling frequency of the process, the control loop is in a very small bandwidth. The study shows that these disturbances have to be lowered by other means in the higher frequency range.

MOPO026	Design, Manufacturing and Tests of Closed-loop Quadrupole Mover Prototypes for European XFEL	controls, alignment, feedback, vacuum	535
	J. Munilla, J. Calero, J.M. Cela-Ruiz, L. García-Tabarés, A. Guirao, J.L. Gutiérrez, T. Martínez de Alvaro, E. Molina Marinas, S. Sanz, F. Toral, C. Vazquez CIEMAT, Madrid, Spain
	Funding: Work partially supported by Spanish Ministry of Science and Innovation under SEI Resolution on 17-September-2009 In this report the development of a quadrupole mover with submicron repeatability is reported, which will be used in the intersections of the Undulator Systems of the European XFEL (EXFEL). It is part of the Spanish in-kind contribution to this facility. The main specifications include submicron repeatability for a 70 kg quadrupole magnet within compact dimensions and a ±1.5 mm stroke in the vertical and horizontal direction. Compact linear actuators based on 5-phase stepping motors have been chosen. Vertical actuator works in a wedge configuration to take mechanical advantage. A closed-loop control system has been developed to achieve this repeatability. For the feedback, one LVDT sensor for each axis was used. Mechanical switches are used to limit movement. In addition, hard-stops are included for emergency. Prototyping stage is done and a serial production of more than 90 devices is expected, so intense work has been done to achieve a reliable industrial production and validation. In this report, results of mechanical measurements including reproducibility, tests of different operation strategies and critical situations will be reported.

MOPO027	Status of a Study of Stabilization and Fine Positioning of CLIC Quadrupoles to the Nanometre Level*	feedback, alignment, controls, damping	538
	K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, S.M. Janssens, A.M. Kuzmin, R. Leuxe, R. Moron Ballester CERN, Geneva, Switzerland
	Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no.227579 Mechanical stability to the nanometre and below is required for the CLIC quadrupoles to frequencies as low as 1 Hz. An active stabilization and positioning system based on very stiff piezo electric actuators and inertial reference masses is under study for the Main Beam Quadrupoles (MBQ). The stiff support was selected for robustness against direct forces and for the option of incrementally repositioning the magnet with nanometre resolution. The technical feasibility was demonstrated by a representative test mass being stabilized and repositioned to the required level in the vertical and lateral direction. Technical issues were identified and the development programme of the support, sensors, and controller was continued to increase the performance, integrate the system in the overall controller, adapt to the accelerator environment, and reduce costs. The improvements are implemented in models, test benches, and design of the first stabilized prototype CLIC magnet. The characterization of vibration sources was extended to forces acting directly on the magnet, such as water-cooling induced vibrations. This paper shows the achievements, improvements, and an outlook on further R&D.

MOPO028	Modal Analysis and Measurement of Water Cooling Induced Vibrations on a CLIC Main Beam Quadrupole Prototype*	ground-motion, resonance, controls, damping	541
	K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, S.M. Janssens, R. Leuxe, M. Modena, R. Moron Ballester, M. Struik CERN, Geneva, Switzerland G. Deleglise, A. Jeremie IN2P3-LAPP, Annecy-le-Vieux, France
	Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579. To reach the Compact Linear Collider (CLIC) design luminosity, the mechanical jitter of the CLIC main beam quadrupoles should be smaller than 1.5 nm integrated root mean square (r.m.s.) displacement above 1 Hz. A stiff stabilization and nano-positioning system is being developed but the design and effectiveness of such a system will greatly depend on the stiffness of the quadrupole magnet which should be as high as possible. Modal vibration measurements were therefore performed on a first assembled prototype magnet to evaluate the different mechanical modes and their frequencies. The results were then compared with a Finite Element (FE) model. The vibrations induced by water-cooling without stabilization were measured with different flow rates. This paper describes and analyzes the measurement results.

MOPO029	Validation of a Micrometric Remotely Controlled Pre-alignment System for the CLIC Linear Collider using a Test Setup (Mock-up) with 5 Degrees of Freedom	alignment, target, controls, feedback	544
	H. Mainaud Durand, M. Anastasopoulos, J. Kemppinen, R. Leuxe, M. Sosin, S. griffet CERN, Geneva, Switzerland
	The CLIC main beam quadrupoles need to be pre-aligned within 17μm rms with respect to a straight reference line along a sliding window of 200 m. A re-adjustment system based on eccentric cam movers, which will provide stiffness to the support assembly, is being studied. The cam movers were qualified on a 1 degree of freedom (DOF) test setup, where a repeatability of adjustment below 1 μm was measured along their whole range. This paper presents the 5 DOF mock-up, built for the validation of the eccentric cam movers, as well as the first results of tests carried out: resolution of displacement along the whole range, measurements of the support eigenfrequencies.

MOPO033	Design and Development of a Laser Positioning System for TPS Magnets Alignment Inspection during the Installation on a Girder	laser, sextupole, alignment, lattice	556
	Chen, M. L. Chen, H.C. Ho, K.H. Hsu, W.Y. Lai, S.Y. Perng, Y.L. Tsai, T.C. Tseng, H.S. Wang NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	A novel optical inspection architecture is designed and developed for positioning the TPS (Taiwan Photon Source) quadrupole and sextupole magnets on the girder within 30 um. This positioning system is a laser-based scheme consists of two laser position sensing devices (PSD) and two granite blocks as the standard reference of magnets. The laser position sensing device (PSD) is mounted on an adjustable circular steel module and the module is installed in a granite block. With the PSD position being adjusted and corrected, the PSD module center can be identical to the ideal pole position of magnets on the girder within 10um. The Laser ray is also adjusted and aligned according to the ideal reference line of magnets. Finally the granite blocks are replaced with the quadrupole and sextupole magnets at installation, the assembling error of magnets can be detected from the PSD module. This paper describes the detail of the system development and testing results.

MOPS001	Electron-cloud Pinch Dynamics in Presence of Lattice Magnet Fields	electron, proton, cyclotron, simulation	586
	G. Franchetti GSI, Darmstadt, Germany F. Zimmermann CERN, Geneva, Switzerland
	The pinch of the electron cloud due to a passing proton bunch was extensively studied in a field free region and in a dipolar magnetic field. For the latter study, a strong field approximation helped to formulate the equations of motion and to understand the complex electron pinch dynamics, which exhibited some similarities with the field-free situation. Here we extend the analysis to the case of electron pinch in quadrupoles and in sextupoles. We discuss the limits of validity for the strong field approximation and we evaluate the relative magnitude of the peak tune shift along the bunch expected for the different fields.

MOPS025	Studies of Emittance Measurement by Quadrupole Variation for the IFMIF-EVEDA High Space Charge Beam	emittance, space-charge, simulation, beam-transport	652
	P.A.P. Nghiem, E. Counienc CEA/DSM/IRFU, France N. Chauvin CEA/IRFU, Gif-sur-Yvette, France C. Oliver CIEMAT, Madrid, Spain
	For the high-power (1 MW) beam of the IFMIF-EVEDA prototype accelerator, emittance measurements at nearly full power are only possible in a non-interceptive way. The method of quadrupole variation is explored here. Due to the high space charge regime, beam transport is strongly non-linear, and the classical matrix inversion is no more relevant. Inverse calculations using a multiparticle code is mandatory. In this paper, such emittance measurements are studied, aiming at checking its feasibility and evaluating its precision, taking into account the constraints of losses and quadrupole limitations.

MOPS026	Start-to-end Beam Dynamics Simulations for the Prototype Accelerator of the IFMIF/EVEDA Project	rfq, simulation, linac, solenoid	655
	N. Chauvin CEA/IRFU, Gif-sur-Yvette, France M. Comunian INFN/LNL, Legnaro (PD), Italy O. Delferrière, R.D. Duperrier, R. Gobin, A. Mosnier, P.A.P. Nghiem, D. Uriot CEA/DSM/IRFU, France C. Oliver CIEMAT, Madrid, Spain
	The EVEDA (Engineering Validation and Engineering Design Activities) phase of the IFMIF (International Fusion Materials Irradiation Facility) project consists in building, testing and operating a 125 mA/9 MeV prototype accelerator in Rokkasho-Mura (Japan). Because of high beam intensity and power, the different sections of the accelerator (injector, RFQ, MEBT, Superconducting Radio-Frequency linac and HEBT) have been optimized with the twofold objective of minimizing losses along the machine and keeping a good beam quality. Extensive start-to-end multi-particles simulations have been performed to validate the prototype accelerator design. A Monte Carlo error analysis has been carried out to study the effects of misalignments and field variations. In this paper, the results of theses beam dynamics simulations, in terms of beam emittance, halo formation and beam losses, are presented.

MOPS068	Localization of Transverse Impedance Sources in the SPS using HEADTAIL Macroparticle Simulations	impedance, lattice, simulation, ion	757
	N. Biancacci, G. Arduini, E. Métral, D. Quatraro, G. Rumolo, B. Salvant, R. Tomás CERN, Geneva, Switzerland N. Biancacci, M. Migliorati, L. Palumbo Rome University La Sapienza, Roma, Italy R. Calaga BNL, Upton, Long Island, New York, USA
	In particle accelerators, beam coupling impedance is one of the main contributors to instability phenomena that lead to particle losses and beam quality deterioration. For this reason these machines are continuously monitored and the global and local amount of impedance needs to be evaluated. In this work we present our studies on the local transverse impedance detection algorithm. The main assumptions behind the algorithm are described in order to understand limits in reconstructing the impedance location. The phase advance response matrix is analyzed in particular for the SPS lattice, studying the different response from 90,180,270 degrees phase advance sections. The thin lenses scheme is also implemented and new analytical formulas for phase advance beating were derived. This avails us to put reconstructing lenses everywhere in the lattice, and to study their positioning scheme. Limits in linear response are analyzed. This sets the upper and lower limits in reconstruction to the phase advance measurement accuracy and the linear response regime limit.

MOPS090	Observation of Beam Ion Instability in SPEAR3	ion, vacuum, emittance, single-bunch	814
	L. Wang, Y. Cai, W.J. Corbett, T.O. Raubenheimer, J.A. Safranek, J.F. Schmerge, J.J. Sebek SLAC, Menlo Park, California, USA D. Teytelman Dimtel, San Jose, USA
	Weak vertical coupled bunch instability with oscillation amplitude at μm level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.

MOPZ006	Main Magnets Design Studies for the Non-scaling Fixed Field Alternating Gradient Accelerator for a Final Acceleration Stage of the Neutrino Factory	dipole, factory, focusing, acceleration	829
	J. Pasternak STFC/RAL, Chilton, Didcot, Oxon, United Kingdom M. Aslaninejad, C. Bonţoiu, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The International Design Study of the Neutrino Factory (IDS-NF) aims to design the next generation facility for the precision neutrino oscillation searches. The non scaling Fixed Field Alternating Gradient Accelerator was prosed for the final muon beam acceleration in order to reduce the cost of the final acceleration. The superconducting magnet design based on the independent multipole coils approach using the ROXIE code is presented. The feasibility of the magnet construction together with the quench limitations are discussed.

MOPZ016	MICE Step I: First Measurement of Emittance with Particle Physics Detectors*	emittance, simulation, collider, factory	853
	L. Coney UCR, Riverside, California, USA M. Popovic Fermilab, Batavia, USA M.A. Rayner DPNC, Genève, Switzerland
	The muon ionization cooling experiment (MICE) is a strategic R&D project intending to demonstrate the only practical solution to prepare high brilliance beams necessary for a neutrino factory or muon colliders. MICE is under development at the Rutherford Appleton Laboratory (UK). It comprises a dedicated beam line to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam is measured in the upstream magnetic spectrometer with a sci-fiber tracker. A cooling cell will then follow, alternating energy loss in Li-H absorbers and RF acceleration. A second spectrometer identical to the first and a second muon identification system measure the outgoing emittance. In the 2010 run the beam and most detectors have been fully commissioned and a first measurement of the emittance of a beam with particle physics (time-of-flight) detectors has been performed. The analysis of these data should be completed by the time of the Conference. The next steps of more precise measurements, of emittance and emittance reduction (cooling), that will follow in 2011 and later, will also be outlined. Abstract is submitted by the MICE Speakers Bureau. If accepted, most likely Dr. Kaplan will present it. As a first result in a novel sector, we propose it for an oral presentation

MOPZ031	Multipass Muon RLA Return Arcs based on Linear Combined-function Magnets	linac, dipole, optics, lattice	868
	V.S. Morozov, S.A. Bogacz, Y. Roblin JLAB, Newport News, Virginia, USA K.B. Beard Muons, Inc, Batavia, USA
	Funding: Supported in part by US DOE STTR Grant DE-FG02-08ER86351. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60°-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.

MOPZ034	Proton Contamination Studies in the MICE Muon Beam Line	proton, lattice, positron, emittance	871
	S.D. Blot, Y.K. Kim University of Chicago, Chicago, Illinois, USA R.R.M. Fletcher UCR, Riverside, California, USA D.M. Kaplan Illinois Institute of Technology, Chicago, Illinois, USA C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The Muon Ionization Cooling Experiment (MICE) aims to demonstrate transverse beam emittance reduction for a muon beam. To create these muons, a titanium target is dipped into the ISIS proton accelerator at Rutherford Appleton Laboratory (UK) to create pions, which are transported and decay to muons in the MICE beamline. Beam particle identification and triggering is performed using time of flight (ToF) detectors. When running the MICE beamline with positive polarity, protons produced in the target contaminate the muon beam with a sufficiently high rate to saturate the TOF detectors. Polyethylene sheets of varying thicknesses were installed to absorb the proton impurities in the beam. Studies with pion beams at momenta of 140, 200, and 240MeV/c were performed with different proton absorber thicknesses. The results of these studies show good agreement with theoretical range plots and will be presented.

MOPZ039	Dispersion-free Regions and Insertions for EMMA	lattice, sextupole, extraction, injection	886
	B.D. Muratori, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	EMMA (Electron Machine with Many Applications) is a prototype non-scaling electron FFAG hosted at Daresbury Laboratory. Several upgrade possibilities for EMMA are explored, from creating a dispersion-free region in the ring to facilitate injection and extraction to making an insertion in EMMA by turning it into a racetrack-style machine. A dispersion-free region may be created in two separate ways. The first is by using a layout of EMMA which is naturally dispersion-free at the start and end of each cell. This means that we can arrange for periodic dispersion-free sections in every cell or in-between cells. The second is achieved through the use of sextupoles, by going off-axis in them, one has essentially a quadrupolar force which can be used to match the dispersion to zero in a particular place and for a particular energy. The benefits and drawbacks of both methods are discussed from the point of view of practicality and space in general, and applicability to EMMA in particular.

TUYA02	LHC Upgrade Plans: Options and Strategy	luminosity, cavity, collider, cryogenics	908
	L. Rossi CERN, Geneva, Switzerland
	Presentation of options for future luminosity and/or energy upgrades of the LHC ring. The presentation should cover the different ideas, short term, medium term and long term, and discuss the research programme that is needed to prepare the upgrades.
	Slides TUYA02 [5.139 MB]

TUODA01	Vertical Emittance Reduction and Preservation at the ESRF Electron Storage Ring	emittance, coupling, feedback, storage-ring	928
	A. Franchi, J. Chavanne, F. Ewald, L. Farvacque, T.P. Perron, K.B. Scheidt ESRF, Grenoble, France
	In 2010 a campaign for the reduction and preservation of low vertical emittance at the ESRF electron storage ring was undertaken: values between 20 and 30 pm have been dramatically reduced to 3.5-4.5 pm, even during beam delivery. This improvement is the result of an increased measurement precision provided by the recently upgraded beam position monitoring system, a new correction algorithm, a larger number of correctors and two independent schemes for the automatic compensation of coupling induced by a few insertion devices whenever their gaps are moved by users during beam delivery. This paper summarizes the campaign's milestones and the results updated to the first half of 2011.
	Slides TUODA01 [5.297 MB]

TUXB01	Methods and Tools to Simulate and Analyse Non-linear Dynamics in Electron Storage Rings	storage-ring, lattice, emittance, sextupole	937
	L.S. Nadolski SOLEIL, Gif-sur-Yvette, France
	This talk will present the different approaches and tools that have been recently developed while trying to understand or predict the non-linear dynamics of electron storage rings. Different algorithms have been recently used at different places to optimize the sextupole tunings, while the refinement of the models of existing machines together with more accurate measurement techniques enable now to fully understand the limitations of such facilities specially in the presence of insertion devices.
	Slides TUXB01 [7.624 MB]

TUYB02	The Challenges of Ultra-low Emittance Damping Rings	emittance, damping, electron, coupling	956
	D. L. Rubin CLASSE, Ithaca, New York, USA
	Funding: Work supported by the National Science Foundation and by the US Department of Energy under contract numbers PHY-0734867 and DE-FC02-08ER41538. In this paper we review the state of the art of the design of damping rings for linear colliders, as supported by the experimental data from ATF and CESR test damping rings. We consider implications of measurements of electron cloud dynamics and mitigation in a radiation dominated ring. The techniques developed for tuning for ultra-low emittance in these rings are summarized. Other dynamics manifested in the ultra-low emittance regime where collective effects are important are discussed.
	Slides TUYB02 [7.198 MB]

TUPC008	CLIC Two-Beam Module for the CLIC Conceptual Design and Related Experimental Program	alignment, linac, vacuum, RF-structure	1003
	A. Samoshkin, D. Gudkov, A. Solodko JINR, Dubna, Moscow Region, Russia G. Riddone CERN, Geneva, Switzerland
	The Compact LInear Collider (CLIC), being studied at CERN, involves the design and integration of many different technical systems, tightly bound and influencing each other. For the construction of two main linacs it has been decided to proceed with a modular design, and repetitive two-beam modules of a few types were defined. The modules consist of micro-precision components operating under ultra-high vacuum as required by the beam physics. For the CLIC Conceptual Design Report, the development and system integration is mainly focused on the most complex module type containing the highest number of components and technical systems. For proving the proper functioning of the needed technical systems and confirming their feasibility it has been decided to build four prototype modules and test them without beam. In addition, three modules have to be produced in parallel for tests in the CLIC Experimental Area with beam. This paper is focused on the design of the different technical systems and integration issues of the two-beam module. The experimental program for the prototype modules is also recalled.

TUPC014	System Control for the CLIC Main Beam Quadrupole Stabilization and Nano-positioning*	feedback, luminosity, ground-motion, simulation	1021
	S.M. Janssens, K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, A.M. Kuzmin, R. Leuxe, J. Pfingstner, D. Schulte, J. Snuverink CERN, Geneva, Switzerland
	The conceptual design of the active stabilization and nano-positioning of the CLIC main beam quadrupoles was validated in models and experimentally demonstrated on test benches. Although the mechanical vibrations were reduced to within the specification of 1.5 nm at 1 Hz, additional input for the stabilization system control was received from integrated luminosity simulations that included the measured stabilization transfer functions. Studies are ongoing to obtain a transfer function which is more compatible with beam based orbit feedback; it concerns the controller layout, new sensors and their combination. In addition, the gain margin must be increased in order to reach the requirements from a higher vibration background. For this purpose, the mechanical support is adapted to raise the frequency of some resonances in the system and the implementation of force sensors is considered. Furthermore, this will increase the speed of repositioning the magnets between beam pulses. This paper describes the improvements and their implementation from a controls perspective.

TUPC016	Status of the ATF2 Lattices	lattice, sextupole, multipole, optics	1027
	E. Marin, R. Tomás CERN, Geneva, Switzerland P. Bambade LAL, Orsay, France T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan A. Seryi JAI, Oxford, United Kingdom G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	The latest status for the ATF2 Nominal and Ultra-low beta lattices designs obtained to minimize the detrimental effect of the measured multipoles are presented in this paper. A set of correction knobs for the most important aberrations at the IP have been obtained for both lattices in order to perform the tuning under realistic imperfections. Starting from the tuned ATF2 Nominal lattice a squeeze sequence reducing beta_y is performed to reach the ultra-low beta lattice. Tuning results are shown for both options.

TUPC019	Beam-based Alignment of CLIC Drive Beam Decelerator using Girders Movers	alignment, simulation, dipole, extraction	1036
	G. Sterbini, D. Schulte CERN, Geneva, Switzerland
	The CLIC drive beams will provide the rf power to accelerate the colliding beams: in order to reach the design performance, an efficient transport of the drive beam has to be ensured in spite of its challenging energy spread and large current intensity. As shown in previous studies, the specifications can be met by coupling a convenient optics design with the state-of-the-art of pre-alignment and beam-based alignment techniques. In this paper we consider a novel beam-based alignment scheme that does not require quadrupole movers or dipole correctors but uses the motors already foreseen for the pre-alignment system. This implies potential savings in terms of complexity and cost at the expense of the alignment flexibility: the performance, limitations and sensitivity to pre-alignment tolerances of this method are discussed.

TUPC023	Status of Ground Motion Mitigation Techniques for CLIC	luminosity, feedback, simulation, ground-motion	1048
	J. Snuverink, K. Artoos, C.G.R.L. Collette, F. Duarte Ramos, A. Gaddi, H. Gerwig, S.M. Janssens, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland G. Balik, L. Brunetti, A. Jeremie IN2P3-LAPP, Annecy-le-Vieux, France P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom B. Caron SYMME, Annecy-le-Vieux, France J. Resta-López IFIC, Valencia, Spain
	The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques are proposed - quadrupole stabilisation and positioning, final doublet stabilisation as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of the ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) have been performed, which model the hardware and beam performance in detail. Based on the results future improvements of the mitigation techniques are suggested and simulated. It is shown that with the current design the tight luminosity budget for ground motion effects is fulfilled and accordingly, an essential feasibility issue of CLIC has been addressed.

TUPC030	Recommendation for Mitigations of the Electron Cloud Instability in the ILC	electron, vacuum, positron, emittance	1063
	M.T.F. Pivi, L. Wang SLAC, Menlo Park, California, USA L.E. Boon, K.C. Harkay ANL, Argonne, USA J.A. Crittenden, G. Dugan, M.A. Palmer CLASSE, Ithaca, New York, USA T. Demma, S. Guiducci INFN/LNF, Frascati (Roma), Italy M.A. Furman LBNL, Berkeley, California, USA K. Ohmi, K. Shibata, Y. Suetsugu, J. Urakawa KEK, Ibaraki, Japan C. Yin Vallgren Chalmers University of Technology, Chalmers Tekniska Högskola, Gothenburg, Sweden
	Funding: Work supported by the Director, Office of Science, High Energy Physics, U.S. DOE under Contract No. DE-AC02-76SF00515. Electron cloud has been identified as one of the highest priority issues for the ILC Damping Rings (DR). A working group has evaluated the electron cloud effect and instability, and mitigation solutions for the electron cloud formation. Working group deliverables include recommendations for the baseline and alternate solutions for the electron cloud mitigation in various regions of the ILC Positron DR, which is presently assumed to be the 3.2km design. Detailed studies of a range of mitigation options including coatings, clearing electrodes, grooves and novel concepts, were carried out over the previous several years by nearly 50 researchers, and the results of the studies form the basis for the recommendation. The assessments of the benefits or risks associated with the various options were based on a systematic ranking scheme. The recommendations are the result of the working group discussions held at numerous meetings and during a dedicated workshop. The mitigation choices will be also presented in a more detailed report later in 2012. In addition, a number of items requiring further investigation were identified and studies will be carried out at CesrTA and other institutions.

TUPC039	Proposals for Electron Beam Transportation Channel to Provide Homogeneous Beam Density Distribution at a Target Surface	target, electron, neutron, beam-losses	1084
	A.Y. Zelinsky, I.M. Karnaukhov NSC/KIPT, Kharkov, Ukraine W.B. Liu IHEP Beijing, Beijing, People's Republic of China
	NSC KIPT neutron source will use 64x64 mm rectangular tungsten or uranium target. To generate maximum neutron flux, prevent overheating of the target and reduce thermal stress one should provide homogeneous electron beam distribution at the target surface. In the facility transportation channel three different possibilities of electron beam density redistribution along the target surface can be realized. It can be the fast beam scanning with two dimensional scanning magnets; the method of uniform beam distribution formation with linear focusing elements (dipole and quadrupole magnets) and nonlinear focusing elements (octupole magnets), when final required rectangular beam shape with homogeneous beam density is formed at target; and combined method, when one forms the small rectangular beam with homogeneous beam density distribution and scan it over the target surface with scanning magnets. In the report the all tree methods are considered and discussed considering the layout of the NSC KIPT transportation channel. Calculation results show that the proposed transportation channel lattice can provide uniform beam of rectangular shape with sizes 64x64 mm without target overheating.

TUPC046	Alignment Tolerances for Vertical Emittance	emittance, lattice, closed-orbit, dipole	1102
	K.P. Wootton, R.P. Rassool, G. Taylor The University of Melbourne, Melbourne, Australia M.J. Boland, R.T. Dowd, G. LeBlanc, Y.E. Tan ASCo, Clayton, Victoria, Australia Y. Papaphilippou CERN, Geneva, Switzerland
	Alignment tolerances for the CLIC main damping ring magnetic lattice elements are presented. Tolerances are defined by the design equilibrium vertical emittance of 1 pm rad. The sensitivity of the uncorrected lattice to magnet misalignments is presented. Misalignments considered included quadrupole vertical offsets and rolls, sextupole vertical offsets, and main dipole rolls. Seeded simulations were conducted in MAD-X, and compared with expectation values calculated from theory. The lattice was found to be sensitive to betatron coupling as a result of sextupole vertical offsets in the arcs. Alignment tolerances, BPM and corrector requirements are presented also. For the same misalignment types, the equilibrium emittance of the corrected lattice is simulated. These are compared with expectation values calculated from theory. The vertical alignment tolerance of arc sextupoles is again demanding.

TUPC049	Optics considerations for the Delay Loop in the CLIC Damping Rings Complex	dipole, emittance, optics, damping	1108
	P. Zisopoulos, F. Antoniou, H. Bartosik, Y. Papaphilippou CERN, Geneva, Switzerland
	For the recombination of the two trains coming from the CLIC damping rings, a delay loop will be used in order to obtain the nominal 0.5~ns bunch spacing. The optics design of the loop is based upon an isochronous ring, in order to preserve the longitudinal beam distribution. Analytical expressions for achieving isochronous conditions in high order for Theoretical Minimum Emittance cells are obtained. A parametrisation of the quadrupole settings for achieving these conditions is presented, along with general considerations regarding the choice of bending magnet characteristics.

TUPC052	Normal Mode BPM Calibration for Ultralow-Emittance Tuning in Lepton Storage Rings	emittance, coupling, alignment, simulation	1114
	A. Wolski The University of Liverpool, Liverpool, United Kingdom D. L. Rubin, D. Sagan, J.P. Shanks CLASSE, Ithaca, New York, USA
	BPMs capable of high-resolution turn-by-turn measurements offer the possibility of new techniques for tuning for ultra-low beam emittance. In this paper, we describe how signals collected from individual buttons during resonant beam excitation can be used to calibrate BPMs to read the beam position in a normal mode coordinate system. This allows for rapid minimization of the mode II emittance, simply by correcting the mode II dispersion. Simulations indicate that the technique is effective and robust, and has the benefit of being insensitive to BPM gain and alignment errors that can limit the effectiveness of other techniques.

TUPC064	Transverse Phase Space Tomography in TRIUMF Injection Beamline	emittance, space-charge, TRIUMF, injection	1144
	Y.-N. Rao, R.A. Baartman TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada. By tomography is meant the reconstruction of a 2-dimensional distribution from a number of 1-dimensional projections. In the case of transverse phase space, one records many profiles while varying a focusing device such as a quadrupole. Our aim was to investigate the two transverse phase space distributions in our 300keV H-minus beamline. We performed a series of measurements of beam profiles as a function of the voltage of an electrostatic quadrupole and used these along with the corresponding calculated transfer matrices in an iterative program based upon the Maximum Entropy algorithm, to find the phase space distributions. As well, we made measurements using an Allison-type emittance scanner to scan both planes. In this paper we present the details of these measurements, calculations, and we compare the two techniques.

TUPC095	Bucket-by-bucket On/Off-axis Injection with Variable Field Fast Kicker	kicker, injection, dipole, emittance	1230
	T. Nakamura JASRI/SPring-8, Hyogo-ken, Japan
	Dynamic aperture of ultra-low emittance storage rings is expected to be as small as a few mm; one order smaller than that of current rings, because of their high nonlinearity. The conventional injection scheme with bump formation may not be applied for such small aperture. On-axis injection with fast magnet is one of the solutions, however, it requires the injection beam of long trains of bunches, which impose serious limitation on the injector and the filling pattern. We propose a bucket-by-bucket on-axis/off-axis injection scheme, which manipulates the injection and stored beams bucket-by-bucket with a variable field fast kicker. For on-axis injection, this scheme eliminates the limitation on injectors and filling pattern, and also it can reject the contaminated electrons from the injector to keep the bunch purity. Those advantages allow the SPring-8 XFEL low emittance linac to be an injector matched with ultra-low emittance rings like the SPring-8 II: upgrade plan of SPring-8. By changing the drive power to the kicker, it can also produce position dependent kick required for the off-axis injection, with minimal perturbation on the stored beam achieved by bucket-by-bucket scheme.

TUPC103	Monitoring of the Betatron Tune and Amplitude at Multi-batch Injection of J-PARC MR	injection, kicker, betatron, feedback	1254
	S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan M. Takagi Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan M. Tejima, T. Toyama KEK, Ibaraki, Japan
	The beam power of J-PARC Main Ring Synchrotron (MR) increased gradually from 2008, and came to be able regularly to supply the beam of 145kW February, 2011. Many of current beam losses are localized to the collimator located on the injection section. One of the problems of the beam injection is that the orbit of the beam transportation line is unstable. It causes sometimes large transverse injection error. Because the transverse injection error is essentially proportional to the amplitude of the betatron oscillation, it is possible to observe by measuring the turn-by-turn position for every bunch of injected beam by using BPMs located on the injection section. In this report, it is described the method how to measure injection error from beam position. It is also discussed about the effect of reflection wave of injection kicker magnets.

TUPC111	Design of Cavity Beam Monitor at HLS	cavity, emittance, gun, dipole	1278
	Q. Luo, Q.K. Jia, B.G. Sun, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by the Natural Science Foundation of China, National “985 Project”, China Postdoctoral Science Foundation and “the Fundamental Research Funds for the Central Universities” X-FEL requires precious control of beam position and transverse emittance. Non-destructive on-line beam diagnostic methods are required. During the upgrading of HLS a high brightness injector based on photocathode RF electron gun, which can also be used to study FEL, is installed. The cavity beam monitor system designed for the HLS photocathode RF electron gun consists of a cavity beam position monitor and a beam quadrupole moment monitor system. The cavity beam position monitor uses a re-entrant position cavity tuned to TM110 mode as position cavity and cut-through waveguides to suppress the monopole signal. Cold test results showed that position resolution of prototype BPM is better than 3 μm. Beam quadrupole moment monitor system consists of a square pill-box quadrupole moment cavity, a cylindrical pill-box reference cavity, a waveguide coupling network and a superheterodyne receiver used as front-end signal processing system. The whole system works at 5.712 GHz. Strength of quadrupole magnets is adjust to construct a matrix which can be used to work out beam parameters.

TUPC130	Beam Test Performance of the Beam Position Monitors for the TBL Line of the CTF3 at CERN	pick-up, monitoring, linac, beam-transport	1326
	J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera, A. Faus-Golfe IFIC, Valencia, Spain S. Döbert CERN, Geneva, Switzerland
	Funding: Funding Agency: FPA2010-21456-C02-01 A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the CLIC Test Facility (CTF3) at CERN. In this paper we present the results of the beam test carried out on the BPS units of the TBL in order to determine their beam performances and check the specified operational requirements. We focus particularly on the position resolution parameter which is the BPS figure of merit according to TBL demands and is expected to reach the 5um resolution at maximum beam current (28A). The beam test results of the BPS units are also compared with the parameters from their previous characterization test at lab.

TUPC136	Analysis of Fast Losses in the LHC with the BLM System	beam-losses, injection, superconducting-magnet, proton	1344
	E. Nebot Del Busto, T. Baer, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, A. Marsili, A. Nordt, M. Sapinski, R. Schmidt, B. Velghe, J. Wenninger, C. Zamantzas, F. Zimmermann CERN, Geneva, Switzerland N. Fuster Valencia University, Atomic Molecular and Nuclear Physics Department, Valencia, Spain Z. Yang EPFL, Lausanne, Switzerland
	About 3600 Ionization Chambers are located around the LHC ring to detect beam losses that could damage the equipment or quench superconducting magnets. The BLMs integrate the losses in 12 different time intervals (from 40 us to 83.8 s) allowing for different abort thresholds depending on the duration of the loss and the beam energy. The signals are also recorded in a database at 1 Hz for offline analysis. During the 2010 run, a limiting factor in the machine availability were sudden losses appearing around the ring on the ms time scale and detected exclusively by the BLM system. It is believed that such losses originate from dust particles falling into the beam, or being attracted by its strong electromagnetic field. This document describes some of the properties of these "Unidentified Falling Objects" (UFOs) putting special emphasis on their dependence on beam parameters (energy, intensity, etc). The subsequent modification of the BLM beam abort thresholds for the 2011 run that were made to avoid unnecessary beam dumps caused by these UFO losses are also discussed.

TUPC149	Measurements at the ALICE Tomography Section	emittance, injection, simulation, background	1377
	M.G. Ibison, K.M. Hock, D.J. Holder, B.D. Muratori, A. Wolski Cockcroft Institute, Warrington, Cheshire, United Kingdom M. Korostelev The University of Liverpool, Liverpool, United Kingdom
	Funding: STFC This paper reports the results of tomography measurements of the electron beam transverse phase space distribution in the ALICE accelerator at Daresbury Laboratory. These measurements have two main aims. The first is to give a detailed picture of the phase space distribution of the electron beam injected from ALICE into the EMMA prototype non-scaling FFAG accelerator. The second is to provide data for the development and testing of a variety of techniques for tomographic reconstruction. We summarize the measurement results which we have obtained and discuss the advantages and disadvantages of some different tomography methods.

TUPC150	The Effect of Space-Charge on the Tomographic Measurement of Transverse Phase-Space in the EMMA Injection Line	space-charge, injection, emittance, simulation	1380
	M.G. Ibison, M. Korostelev The University of Liverpool, Liverpool, United Kingdom K.M. Hock, D.J. Holder, B.D. Muratori, A. Wolski Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: STFC Phase-space tomography for particle beams depends upon detailed knowledge of the particle transport through specified sections of a beam line. In the simplest case, only the effects of magnets (such as quadrupoles) and drift spaces need to be taken into account; however, in certain parameter regimes (high charge density and low energy) space charge forces may play a significant role. The ALICE accelerator is the electron source for EMMA, a prototype ns-FFAG machine. Results are presented of investigations into these effects on phase-space tomography in the injection line between ALICE and EMMA. The application of suitable correction techniques* to the EMMA injection line tomography measurements in the presence of space-charge is also discussed. * D. Stratakis et al., Phys. Rev. ST Accel. Beams 9, 112801 (2006).

TUPC159	Energy Measurements with Resonant Spin Depolarisation at Diamond	electron, storage-ring, feedback, resonance	1404
	I.P.S. Martin, M. Apollonio, R.T. Fielder, G. Rehm Diamond, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	A precise knowledge of the electron beam energy is critical for the accurate determination of many light source parameters, such as momentum compaction factor, natural chromaticity, energy stability and undulator spectra. In common with other facilities, a method of energy measurement based on resonant spin depolarisation has been developed at Diamond. In this paper we report on progress towards storage ring characterisation using this method, as well as describing the diagnostics developments that have enabled these measurements to be made.

TUPC161	Cavity Beam Position Monitor System for ATF2	cavity, dipole, EPICS, extraction	1410
	S.T. Boogert, R. Ainsworth, G.E. Boorman, S. Molloy Royal Holloway, University of London, Surrey, United Kingdom A.S. Aryshev, Y. Honda, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan F.J. Cullinan, N.Y. Joshi, A. Lyapin JAI, Egham, Surrey, United Kingdom J.C. Frisch, D.J. McCormick, J. Nelson, T.J. Smith, G.R. White SLAC, Menlo Park, California, USA A. Heo, E.-S. Kim, Y.I. Kim KNU, Deagu, Republic of Korea
	The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a future high energy lepton linear collider. The ATF2 beam-line is instrumented with a total of 41 high resolution C and S band resonant cavity beam position monitors (BPM) with associated mixer electronics and digitizers. In addition 4 high resolution BPMs have been recently installed at the interaction point, we briefly describe the first operational experience of these cavities in the ATF2 beam-line. The current status of the overall BPM system is also described, with a focus on operational techniques and performance.

TUPC164	Position Determination of Closely Spaced Bunches using Cavity BPMs	cavity, single-bunch, linear-collider, collider	1419
	N.Y. Joshi, S.T. Boogert, F.J. Cullinan, A. Lyapin JAI, Egham, Surrey, United Kingdom
	Cavity Beam Position Monitor (BPM) systems with high-Q form a major part of precision position measurement diagnostics for linear accelerators with low emittance beam. Using cavity BPMs, the position resolution of less than 100 nm has been demonstrated in single bunch mode operation. In the case of closely spaced bunches, where the decay time of the cavity is comparable to the time separation between bunches, the BPM signal from a bunch is polluted by the signal induced from the previous bunches in the same bunch-train. This paper discuss our ongoing work to develop the methods to extract the position of the closely spaced bunches using cavity BPMs. A signal subtraction code is being developed to remove the signal pollution from previous bunches and to determine the individual bunch position. Another code has been developed to simulate the BPM data for the cross check. Performance of the code is studied on the experimental and simulated data. Application of the analysis techniques to the linear colliders, such as International Linear Collider (ILC) and Compact LInear Collider (CLIC), are briefly discussed.

TUPO006	Design of a Dispersive Beam Transport Line for the JETI Laser Wakefield Accelerators	undulator, radiation, electron, dipole	1455
	C. Widmann, V. Afonso Rodriguez, T. Baumbach, A. Bernhard, P. Peiffer KIT, Karlsruhe, Germany M. Kaluza, M. Nicolai IOQ, Jena, Germany R. Rossmanith Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
	Laser wakeﬁeld accelerators (LWFA) emit electrons with energies of a few 100 MeV at very short bunch lengths while having a compact design. However, electron bunches from LWFA show a larger energy spread than those of conventional accelerators. This is a challenge when using these bunches e.g. to generate radiation in an undulator. A possible strategy to cope with that is to spectrally disperse the bunch and match the resulting spatial distribution with a spatially varying undulator ﬁeld amplitude. For realizing the dispersion a pair of dipole magnets is used. The electrons leaving this dipole chicane have to meet certain requirements imposed by the undulator: In the deﬂection plane the beam has to be collimated and its energy distribution must match the undulator ﬁeld. In the other transversal plane the beam has to be focussed on the center of the undulator keeping the value of the beta function small. To include this in the compact design of the setup, a combination of specially designed quadrupole and sextupole magnets is employed. In this contribution the design of the setup and the results of the particle tracking through this chicane are presented.

TUPS032	Overview of EuCARD Accelerator and Material Research at GSI	ion, collimation, radiation, heavy-ion	1602
	J. Stadlmann, H. Kollmus, E. Mustafin, N. Pyka, P.J. Spiller, I. Strašík, N.A. Tahir, M. Tomut, C. Trautmann GSI, Darmstadt, Germany L.H.J. Bozyk TU Darmstadt, Darmstadt, Germany
	Funding: EuCARD is co-funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 227579 EuCARD is a joined accelerator R&D initiative funded by the EU. Within this program, GSI Darmstadt is performing R&D on materials for accelerators and collimators in WP8(ColMat). GSI covers prototyping and testing of a cryogenic ion catcher for FAIR's main synchrotron SIS100, simulations and studies on activation of accelerator components e.g. halo collimatiors as well as irradiation experiments on materials foreseen to be used in FAIR accelerators and the LHC upgrade program. Carbon-carbon composites, silicon carbide and copper-diamond composite samples have been irradiated with heavy ions at various GSI beamlines and their radiation induced property changes were characterized. Numerical simulations on the possible damage by LHC and SPS beams to different targets have been performed. Simulations and modelling of activation and long term radiation induced damage to accelerator components have started. A prototype ion catcher has been built and first experiments have been performed in 2011. New collaborations with other institutes and industry in the EuCARD framework have been established and findings of the joined R&D effort influence decisions in the FAIR project and LHC upgrade.

TUPS073	Top-Up Safety Simulations for the TPS Storage Ring	storage-ring, electron, sextupole, photon	1707
	H.-J. Tsai, C.C. Chiang, P.J. Chou, C.-C. Kuo NSRRC, Hsinchu, Taiwan
	TPS is a 3 GeV third generation light source and operates in the top-up injection scheme. During the top-up injection, the beamline photon shutters are always open. To ensure the radiation safety of beamline experiments, we studied the possible particle leakage to ID and neighboring bending beamlines. The effects of errors on magnets and beam chamber alignments are investigated.

TUPS094	Girder and Support System for PLS-II Project	multipole, dipole, storage-ring, alignment	1759
	H.-G. Lee, H.S. Han, J.Y. Huang, Y.-G. Jung, D.E. Kim, S.N. Kim, S.H. Nam, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea
	Pohang Accelerator Laboratory (PAL) is planning to upgrade the Pohang Light Source (PLS) which is a 3rd generation light source operating since 1995. We have designed a new steel magnet girder using new schemes to achieve long-term mechanical stability, vibration suppression and precision adjusting system. Each half cell of girder is composed of three pieces, two multipole magnet girder(MMG) and one dipole magnet girder(DMG). The storage ring girders consist of 48 multipole magnet girders and 24 dipole magnet girders. The new girder systems have been fabricated and tested. Recently the girders have been installing and testing the moving mechanism in the storage ring. In this report, the design consideration for the PLSII girder and support systems are reported.

TUPZ002	90 m β* Optics for ATLAS/ALFA	optics, emittance, luminosity, scattering	1798
	S. Cavalier, P.M. Puzo LAL, Orsay, France H. Burkhardt CERN, Geneva, Switzerland A. Peskov NNGU, Nizhny Novgorod, Russia
	We describe a high β* optics developed for the ATLAS detector at the LHC interaction regions (IR1), Roman Pots have been installed 240 m left and right of IR1 to allow to measure the absolute luminosity and the total elastic cross section for ATLAS with ALFA (Absolute Luminosity for ATLAS). Ultimately, it is planned to preform these measurements at a very high β* of 2625 m. Here we describe a new, intermediate β* = 90 m optics, which has been optimized for compatibility with the present LHC running conditions. We described the main features and expected performance of this optics for ALFA.

TUPZ021	The SPS Beam Quality Monitor, from Design to Operation	injection, extraction, dipole, luminosity	1849
	G. Papotti, T. Bohl, F. Follin, E.N. Shaposhnikova CERN, Geneva, Switzerland
	The SPS Beam Quality Monitor is a system that monitors longitudinal beam parameters on a cycle-by-cycle basis and prevents extraction to the LHC in case the specifications are not met. This avoids losses, unnecessary stress of machine protection components and luminosity degradation, additionally helping efficiency during the filling process. The system has been operational since the 2009 LHC run, checking the beam pattern, its correct position with respect to the LHC references, individual bunch lengths and stability. In this paper the algorithms used, the hardware implementation and the operational aspects are presented.

TUPZ026	Alternative Working Point(s) at Injection for the LHC	injection, coupling, optics, emittance	1861
	R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP). At present, the LHC operates with a different fractional tunes at injection and at collision energy due to improved dynamic aperture indicated by tracking studies. Therefore, a tune swing crossing the 10th order resonance is needed during the beta-squeeze. A new proposal to alter the working point to collision tunes already at injection and during an energy ramp is foreseen to avoid the tune jump. Simulations and measurements of the optics along with the beam emittances and lifetime are compared to the nominal injection tunes. Feasibility for a working point close to the 1/2 integer is also attempted.

TUPZ027	Beta* Measurement in the LHC Based on K-modulation	optics, luminosity, simulation, lattice	1864
	R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP). Accurate knowledge of the collision point optics is crucial to equalize the luminosities at the different experiments. K-modulation was successfully applied at several accelerators for measuring the lattice beta functions. In the LHC, it was proposed as an alternative method to compute the beta* at the collision points. Results of beta* measurements in the LHC based on the K-modulation technique are presented with comparisons to nominal segment-by-segment method.

TUPZ034	Impact of Arc Phase Advance on Chromatic Optics in RHIC	optics, injection, ion, proton	1885
	R. Calaga, R. Miyamoto, G. Robert-Demolaize, S.M. White BNL, Upton, Long Island, New York, USA R. De Maria, R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: This work is partially supported by the US Department of Energy through the LHC Accelerator Research program (LARP). The phase advance between the two interaction points in RHIC is optimized for dynamic aperture for a initial design beta-star. This may not hold true as RHIC presently operates with a considerably reduced beta-star. Additionally the reduction of the available beam aperture due to an enlarged chromatic beta-beating is evident. Results from phase advance scans between the two IPs to reduce the chromatic beta-beating in model and measurements are presented. Impact on the single beam lifetime and momentum aperture is compared to the nominal optics.

TUPZ039	Modelling of the AGS Using Zgoubi - Status	dipole, multipole, simulation, resonance	1897
	F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, N. Tsoupas BNL, Upton, Long Island, New York, USA
	Models of the Alternating Gradient Synchrotron, based on stepwise ray-tracing methods using both mathematical modelling or ﬁeld maps so to represent the optical elements, including the siberian snakes, are being developed based on stepwise ray-tracing numerical tools. The topic is introduced in earlier PAC and IPAC publications, a status is given here.

WEZA02	Colliders for B Factories	luminosity, emittance, sextupole, factory	1931
	H. Koiso KEK, Ibaraki, Japan
	Two new B factories, SuperB in Frascati and SuperKEKB in Tsukuba, aim at unprecedented luminosities close to 10³6/cm²/s. The designs, status, challenges, and differences between the two machines are reported. Emphasis should be put on recent developments for the B factories. The presentation should include a realistic outlook.
	Slides WEZA02 [6.796 MB]

WEPC001	Beam Based Sextupole Alignment Studies for Coupling Control at the ASLS	sextupole, coupling, storage-ring, alignment	1995
	R.T. Dowd, Y.E. Tan ASCo, Clayton, Victoria, Australia
	Offsets in sextupole magnets can be a significant source of coupling in a storage ring and hinder efforts to minimize vertical emittance. Beam offsets in the sextupoles at the Australian Synchrotron Light Source were measured using a response matrix analysis in LOCO with differing magnets strengths. These results were used to obtain an estimate of offset in each sextupole as well as estimate quadrupole contributions to coupling.

WEPC004	Comparison of the Action and Phase Analysis on LHC Orbits with Other Techniques	interaction-region, coupling, optics, simulation	2004
	J.F. Cardona UNAL, Bogota D.C, Colombia R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: DIB-Universidad Nacional de Colombia Recently acquired turn-by-turn data of the LHC is analyzed using the action and phase jump technique. The results of this analysis show a visible variation of the action and phase plots at the interaction regions from which optic error estimations can be done. In this paper error estimations will be presented and comparisons with other existing techniques in the LHC, such as the recently implemented Segment-by-segment technique, will be discussed.

WEPC005	Concept for Controlled Transverse Emittance Transfer within a Linac Ion Beam	emittance, ECR, solenoid, linac	2007
	L. Groening GSI, Darmstadt, Germany
	Generally the two transverse emittances of a linac beam are quite similar in size (round beam). However, injection into subsequent rings often imposes stronger limits for the upper allowed value to one of these emittances. Provision of flat linac beams (different transverse emittances) thus can considerable increase the injection efficiency into rings. Round-to-flat transformation has been already demonstrated for electron beams. It was also proposed for angular momentum dominated beams from Electron-Cyclotron-Resonance sources. We introduce a concept to extend the transformation to ion beams that underwent charge state stripping without requiring their extraction from an ECR source. The concept is of special interest for beams from low-charge-state / high-particle-current sources. It can be also applied to stripping of H⁻ to proton beams.

WEPC007	Large Energy Acceptance Dogleg for the European XFEL Injector	sextupole, focusing, linac, controls	2013
	N. Golubeva, V. Balandin, W. Decking DESY, Hamburg, Germany
	The option to install two injectors is foreseen at the European XFEL Facility. The injectors will be located on top of each other in the same building, both with the offset of 2.75 m with respect to the main linac axis. The translation system (dogleg) from the injector axis to the main linac axis has to fulfill very tight requirements of the chromatic properties, because the energy chirp required for the downstream bunch length compression in magnetic chicanes will be created upstream in the injector linac. In this paper we present such an large energy acceptance dogleg and discuss the optical symmetries which form the basis of its design.

WEPC008	Optics for the Beam Switchyard at the European XFEL	kicker, septum, undulator, extraction	2016
	N. Golubeva, V. Balandin, W. Decking DESY, Hamburg, Germany
	The European XFEL is planed as a multi-user facility with the possibility to distribute electron bunches of one beam pulse to different beamlines. The initial stage foresees two electron beamlines each serving its own set of undulators. The later addition of a third beamline is also considered in the design of the distribution system. In addition, the integration of the transport line to the beam abortion dump allows a flexible selection of the bunch repetition pattern for each beamline. The beam extraction, both in undulator beamlines and in the beamline to the dump, will be realized with fast kickers and a Lambertson septum. In this paper we describe the magnet lattice of the deflection arcs with simultaneous horizontal and vertical dispersions and the beam optics of the beam switchyard.

WEPC009	Design of an Antiproton Injection and Matching Beam Line for the AD Recycler Ring	antiproton, acceleration, injection, ion	2019
	O. Karamyshev, G.A. Karamysheva MPI-K, Heidelberg, Germany O. Karamyshev, A.I. Papash JINR, Dubna, Moscow Region, Russia M.R.F. Siggel-King, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328. A small antiproton recycler ring (AD-Rec) for use in the MUSASHI beamline at the CERN AD has been designed by the QUASAR Group for operation at energies between 3 and 30 keV. A highly efficient beam line for capturing the beam after extraction from the trap, transporting and injecting it into the AD Rec is very important to minimize losses and full the ring up to its space charge limit. In this contribution, the beam optical and mechanical design of the injector is presented.

WEPC011	Ion Optical Design of the Low Energy Ion Beam Facility at IUAC	ion, optics, ECR, target	2025
	A. Mandal, D. Kanjilal, S. Kumar, G. Rodrigues IUAC, New Delhi, India
	A Low Energy Ion Beam Facility (LEIBF) using fully permanent magnet ECR ion source (Nanogan) has been installed at Inter University Accelerator Centre (IUAC), New Delhi for fundamental research on Atomic and Molecular Physics, and Material Science. The accelerator consists of an ECR ion source, 400 kV accelerating column and an analyzing-cum switching magnet with three beam ports at 75, 90 and 10⁵ degrees. The complete ion optics from ECR ion source to the target has been simulated using TRANSPORT* and GICOSY** ion optics codes. The ions from the ECR source are typically extracted at 15 kV which are further accelerated by 400 kV accelerating column. The analyzing cum switching magnet has been designed to analyze different beams and to switch in a particular beam line. It is a H shaped dipole magnet having pole gap of 65 mm, maximum magnetic field of 1.5 T and radius of 529 mm for 90 degree bend. The entrance and exit edge angles for three beam lines have been optimized to obtain double focus in all beam lines. The beam is further transported to target locations using electrostatic quadrupole triplet. The details of ion optics will be presented in the paper. * K.L. Brown, D.C. Carey, Ch. Iselin and F. Rothacker: Transport, See yellow reports CERN 73-16 (1973) & CERN 80-04 (1980). ** H.Weick, GICOSY homepage, http://www-linux.gsi.de/~weick/gicosy/.

WEPC013	Tests for Low Vertical Emittance at Diamond using LET Algorithm	coupling, emittance, simulation, lattice	2031
	S.M. Liuzzo, M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma), Italy R. Bartolini JAI, Oxford, United Kingdom
	We present measurements recently performed at the Diamond Light Source, aimed at the achievement of low vertical emittance using the Low Emittance Tuning (LET) algorithm developed for a SuperB factory project presently in progress. The tests have been focused on the comparison between this method and the LOCO algorithm currently used at Diamond. Beam position monitor tilts estimate and multiple coupling response matrices have been introduced in the algorithm in order to optimize the procedure. After few iterations using vertical correctors and skew quadrupoles, very low vertical dispersion and emittance coupling, comparable to those obtained by LOCO, have been measured.

WEPC017	Vertical Beam Size Correction at the SSRF Storage Ring	coupling, betatron, emittance, simulation	2043
	M.Z. Zhang, J. Hou, B.C. Jiang, H.H. Li, S.Q. Tian SINAP, Shanghai, People's Republic of China
	Vertical beam size is an important parameter for 3rd generation light source. Correcting the vertical beam size is a realistic way to increase brightness or beam lifetime without any additional equipments in a machine under operation. The main sources of vertical beam size are betatron coupling and vertical dispersion. At the SSRF storage ring, LOCO is used for vertical dispersion and coupling measurements and corrections. The betatron coupling and vertical dispersion is corrected by skew quadrupoles that calculated by LOCO. Vertical beam size can be changed from 10s um to several um for different purposes. Touschek lifetime is also measured to testify the vertical beam size. Simulations show that if smaller vertical beam size is required, more skew quadrupoles are needed.

WEPC024	LOCO in the ALBA Storage Ring	dipole, optics, coupling, storage-ring	2055
	G. Benedetti, D. Einfeld, Z. Martí, M. Muñoz CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a 3 GeV 3rd generation light source which achieved first stored beam in February 2011, and will be commissioned during 2011. The ring comprises of 112 independent quadrupoles grouped in 14 families and 32 combined gradient dipoles powered in series. This paper reviews the process of recovering the design lattice and the symmetry of the machine, and the effects on orbit and lifetime. The main tool employ for this has been the LOCO implementation provided in the Matlab MiddleLayer. First results shows that the main effect on the symmetry is the difference between bending magnets. As this effect can not be compensated locally at present at the bendings, a global optics correction using all the quadrupoles is used.

WEPC025	Modeling Results of the ALBA Booster	booster, emittance, dipole, injection	2058
	G. Benedetti, D. Einfeld, U. Iriso, J. Marcos, Z. Martí, M. Muñoz, M. Pont CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The 3rd generation light source ALBA is in the process of being commissioned. The full energy 3 GeV booster synchrotron was commissioned in the during 2010, ramping the beam from extracted from the LINAC from an energy of 110 MeV to the 3 GeV required for injection in the storage ring. The lattice is based in combined function bending magnets, providing a small emittance beam (< 12 nmrad) at extraction. This paper reviews the agreement between the optics modeling and the measures performed during the commissioning, with special regard to the optics measurement during the ramping process. The results from the magnetic measurement for the combined magnets while ramping are included in the model to explain the movement of the tunes during the ramp.

WEPC028	Record Low Beta-beat of 10% in the LHC	optics, injection, hadron, collider	2061
	G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands M. Aiba PSI, Villigen, Switzerland R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland
	During the 2011 LHC run several measurements and correction campaigns were conducted. As a result a peak beta-beat of 10% level was achieved. This level, well below the specified tolerances of the LHC, improves the aperture margins and helps minimize the luminosity imbalance between the different experiments. A combination of local corrections at the insertion regions and an overall global correction were used to achieve this record low beta-beat. The sequence of the optics corrections and stability along the 2011 run are reported.

WEPC029	Accuracy of the LHC Optics Measurement based on AC Dipoles	dipole, optics, simulation, focusing	2064
	R. Miyamoto, R. Calaga BNL, Upton, Long Island, New York, USA R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). The tight tolerances in the LHC requires optics measurement with very good accuracy. Therefore, AC dipoles are employed as the primary devices to measure the LHC optics. The accuracy of the measurement is mainly determined by the length of the coherent signal, signal-to-noise ratio of the measurement, and the data processing to effectively suppress the noise. This paper presents numerical and experimental studies of how these factors affect the accuracy of the LHC optics measurement using the AC dipoles.

WEPC030	Measurement of Coupling Resonance Driving Terms in the LHC with AC Dipoles	dipole, kicker, optics, resonance	2067
	R. Miyamoto, R. Calaga BNL, Upton, Long Island, New York, USA M. Aiba PSI, Villigen, Switzerland R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). Transverse betatron coupling in the LHC is measured from Fourier analysis of turn-by-turn beam oscillations excited by AC dipoles. The use of the AC dipole for optics measurements induces a small systematic error which can be corrected with an appropriate data interpretation. An algorithm to apply this correction to the measurement of the coupling resonance driving terms is developed for the first time. This paper will review this new algorithm and present results of its application to the LHC.

WEPC031	Optics Corrections at RHIC	optics, dipole, betatron, proton	2070
	G. Vanbavinckhove CERN, Geneva, Switzerland M. Bai, G. Robert-Demolaize BNL, Upton, Long Island, New York, USA
	Excessive beta-beat, deviation of measured beta function from the calculated beta functions based on an model, in high energy colliders can lead to large deviation of beta function at collision point as well as other adverse effects. The segment-by-segment technique was successfully demonstrated in the LHC operation for reducing the beta-beat. It was then applied to RHIC polarized proton operation in 2011. This paper reports the experimental results of optics correction at RHIC. Future plan is also presented.

WEPC034	High-level Application Programs for the TPS Commissioning and Operation at NSRRC	controls, storage-ring, target, EPICS	2079
	F.H. Tseng, H.-P. Chang, C.C. Chiang NSRRC, Hsinchu, Taiwan
	For the Taiwan Photon Source (TPS) commissioning and operation we have developed more MATLAB-based application programs and tested them on the Taiwan Light Source (TLS). These additional applications built with the MATLAB Middle Layer (MML) include beta function measurement, dispersion function measurement, chromaticity measurement, chromaticity correction, and tune control. In this paper, we will illustrate what algorithms we use in these applications and show the test results. Especially, in order to get the first beam in the TPS commissioning, we adopt the RESOLVE algorithm for the beam steering and it has been built successfully in UNIX-like systems such as Mac OSX and different Linux versions. It can provide us some exercises of error finding and correction before the TPS commissioning in 2013.

WEPC035	Double Mini-Betay Lattice for TPS Storage Ring	lattice, emittance, dynamic-aperture, multipole	2082
	M.-S. Chiu, H.-P. Chang, C.-T. Chen, C.C. Chiang, C.-C. Kuo, Y.C. Lee, H.-J. Tsai, C.H. Yang NSRRC, Hsinchu, Taiwan
	Based on our previous design of double mini-betay optics in one 12-m straight section, NSRRC plan to implement the double mini-betay lattice in three 12-m straight sections in TPS storage ring. Those three locations chosen for double mini-betay lattice still retain the symmetry of accelerator lattice. The two symmetric minima of the vertical beta function will be created in the center of three 12-m straight sections, respectively. We strived to obtain a linear lattice such that there is no significant increase in the natural emittance. Efforts were devoted to optimize the nonlinear beam dynamics with various simulation tools. Preliminary results will be reported.

WEPC037	An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade	optics, luminosity, insertion, sextupole	2088
	S.D. Fartoukh CERN, Geneva, Switzerland
	A novel optics concept has been invented and developed in the context of the LHC Upgrade studies. It offers an incredibly powerful and flexible machinery in order to squeeze beta* in a symmetric or asymmetric way (so-called “round” or “flat” optics, respectively), while perfectly controlling the chromatic aberrations induced (off-momentum beta-beating, non-linear chromaticity, spurious dispersion due to the crossing angles). The basic principles of the scheme are described and a specific path for the LHC upgrade is built accordingly, only relying on the existing and well-characterized LHC-like technology, and based on the production of flat collision optics with very small beta* (7.5 cm) in the plane perpendicular to the crossing plane.

WEPC038	Beam Line Design and Beam Measurement for TPS Linac	linac, single-bunch, diagnostics, booster	2091
	K.L. Tsai, H.-P. Chang, C.-T. Chen, C.-S. Fann, K.T. Hsu, S.Y. Hsu, C.-Y. Liao, K.-K. Lin, H.M. Shih NSRRC, Hsinchu, Taiwan K. Dunkel, C. Piel RI Research Instruments GmbH, Bergisch Gladbach, Germany
	A beam line for examining the beam quality of TPS (Taiwan Photon Source) linac was designed and constructed in NSRRC. Beam parameters, such as energy, emittance and charge etc., are verified by using the equipments setup in the beam line for this purpose. The lattice design and its manipulation for the parameter measurements are presented in this report. Preliminary results and the tools associating with the measurement are briefly described.

WEPC040	Initial 2D Investigations into the Design and Parameters of an EM Quadrupole for FETS	simulation, ion, linac, rfq	2097
	M. Larrañaga, R. Enparantza Fundación TEKNIKER, Eibar (Gipuzkoa), Spain D.C. Plostinar STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The Medium Energy Beam Transport (MEBT) line for the Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) consists of a number of quadrupoles, re-bunching cavities and a fast-slow chopping system with dedicated beam dumps, as well as diagnostics. The type and design of the quadrupoles to be used merits special attention. Due to space restrictions, a hybrid quadrupole solution has been proposed in the past. However, because of the limited range of field adjustability achievable, this approach is not ideal. In this paper, a very preliminary investigation of an electromagnetic quadrupole (EMQ) design is presented. Magnetic simulations results performed with a 2D simulation code will be discussed including magnet optimisation details.

WEPC041	Conceptual Design of a New 800 MeV H⁻ Linac for ISIS Megawatt Developments	linac, cavity, DTL, rfq	2100
	D.C. Plostinar, C.R. Prior, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H⁻ linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined. It consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV. Alternative designs are also being investigated.

WEPC042	Implementation of Double Mini-beta Optics at the Diamond Light Source	optics, injection, single-bunch, insertion	2103
	B. Singh, R.T. Fielder, I.P.S. Martin, G. Rehm Diamond, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	Funding: Diamond Light Source Ltd. We report the results of the implementation of two vertical mini-beta and horizontally focusing optics at the Diamond light source, the first in August 2010 and the second in March 2011. Commissioning results of the two optics changes and experimental characterization of the optics are compared with the expected performance and theoretical modeling. The implications of a possible third customized optics are also investigated.

WEPC048	Calibrating Transport Lines using LOCO Techniques	dipole, optics, simulation, focusing	2118
	Y. Roblin JLAB, Newport News, Virginia, USA
	Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 With the 12GeV upgrade underway at CEBAF, there is a need to recharacterize the beamlines after the modifications made to it to accommodate running at higher energies. We present a linear perturbation approach to calibrating the optics model of transport lines. This method is adapted from the LOCO method in use for storage rings. We consider the effect of quadrupole errors, dipole construction errors as well as beam position monitors and correctors calibrations. The ideal model is expanded to first order in Taylor series of the quadrupole errors. A set of difference orbits obtained by exciting the correctors along the beamline is taken, yielding the measured response matrix. An iterative procedure is invoked and the quadrupole errors as well as beam position monitors and corrector calibration factors are obtained. Here we present details of the method and results of first measurements at CEBAF in early 2011 Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes

WEPC053	Crossing of Depolarizing Resonances in Circular Electron Accelerators	resonance, polarization, electron, closed-orbit	2133
	W. Hillert, A. Balling, O. Boldt, A. Dieckmann, F. Frommberger ELSA, Bonn, Germany
	Funding: Supported by the German Research Foundation (DFG) through SFB/TR 16 In flat electron storage rings, only the vertical component of the beam polarization is preserved. During acceleration, the crossing of several depolarizing resonances may cause severe beam depolarization. Even in case of fast ramping speeds of up to 6 GeV/sec, first order effects like imperfection and intrinsic resonances have to be compensated by dedicated measures. At the accelerator facility ELSA, schemes like fast tune jumping and harmonic orbit correction are successfully applied on the fast energy ramp up to 3.2 GeV. Characteristics of the setup as well as the optimization efforts to improve the resonance compensation will be reported in detail.

WEPC054	Amplitude Dependent Tune Spread in the CR Operated as an Antiproton Collector	sextupole, beam-losses, antiproton, simulation	2136
	A. Dolinskii, C. Dimopoulou, O.E. Gorda, S.A. Litvinov, F. Nolden, M. Steck GSI, Darmstadt, Germany
	The Collector Ring is planned to be built for efficient cooling of antiprotons and rare isotopes beams. In order to accept hot antiproton beams coming from a separator large aperture magnets are required. This paper examines the effects which, may influence on the beam dynamic because of both large both betatron amplitude oscillations (240 mm mrad) and momentum spread (6%). Using analytic expressions the amplitude-dependent tune shifts driven by sextupole magnets, fringe field of quadrupole magnets and kinematics effects have been calculated. The results are compared with numerical simulations. Tracking studies for the CR operated as an antiproton collector have been performed considering the real shape of the magnetic field of the wide aperture quadrupole. We report on quantitative studies of the effects on the tune spread and its influence on the beam losses.

WEPC058	Field Properties of the ESR Magnets and their Influence on Beam Optics	dipole, betatron, sextupole, simulation	2148
	O.E. Gorda, C. Dimopoulou, A. Dolinskii, S.A. Litvinov, F. Nolden, M. Steck GSI, Darmstadt, Germany
	Machine experiments at the experimental storage ring (ESR) demonstrated that the ring acceptance is strongly restricted by field errors. Higher-order field harmonics of the dipole and quadrupole magnets have been calculated and then used in particle tracking simulations in order to find out the dynamic aperture of the ESR. To benchmark the results of numerical calculations, betatron tune measurements have been performed with a uranium beam at the energy of 400 MeV/u. The results of the magnetic field simulations for the ESR magnets and a comparison between the measured and calculated tune behavioгr are presented.

WEPC060	Magnetic Field Description in Curved Accelerator Magnets using Local Toroidal Multipoles	multipole, dipole, antiproton, synchrotron	2154
	P. Schnizer, E.S. Fischer GSI, Darmstadt, Germany B. Schnizer TUG/ITP, Graz, Austria
	Any introduction on beam dynamics describes the field homogeneity of the accelerator magnets using local derivatives. These are then typically described as plane circular multipoles or 2D harmonics; solutions to the potential equation. The high current operation, foreseen for SIS100 accelerator of FAIR, requires an in detail understanding of the different beam effects, driven by the resonance of the magnets. Therefore different multipole sets were developed and are now finalised in the Local Elliptic Toroidal Multipoles. These are a first order approximation while the plane circular ones are a zero order one in the inverse aspect ratio.

WEPC062	Second Order Achromats with Arbitrary Linear Transfer Matrices	sextupole, focusing, beam-transport, longitudinal-dynamics	2160
	V. Balandin, R. Brinkmann, W. Decking, N. Golubeva DESY, Hamburg, Germany
	The most obvious method to construct a second order achromat with an arbitrary (predefined) linear transfer matrix is to take a bend magnet system arranged in an achromat like fashion with the total transfer matrix equal to the identity matrix, attach a drift-quadrupole block with the desired linear transfer matrix and then adjust the sextupoles installed in the first part in such a way that the total system becomes a second order achromat. Unfortunately this is not always possible and, in general, the parts of such a system can not be designed independently. In this paper we give the necessary and sufficient conditions which must be satisfied for both parts of the system in order to become a second order achromat. In addition we provide some practical recommendations showing how these conditions can be fulfilled. We formulate these necessary and sufficient conditions using the group-theoretical point of view for the design of magnetic optical achromats as introduced in . V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Two Cell Repetitive Achromats and Four Cell Mirror Symmetric Achromats", Proc. IPAC'10, Kyoto, Japan (2010).

WEPC063	Apochromatic Twiss Parameters of Drift-quadrupole Systems with Symmetries	betatron, lattice, chromatic-effects, beam-transport	2163
	V. Balandin, R. Brinkmann, W. Decking, N. Golubeva DESY, Hamburg, Germany
	It was shown in , that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions. In this paper we investigate apochromatic Twiss parameters of periodic, mirror symmetric and other drift-quadrupole systems with symmetries. V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Apochromatic Beam Transport in Drift-Quadrupole Systems", Proc. IPAC'10, Kyoto, Japan (2010).

WEPC065	Design of a Low Energy Ion Beam Facility*	ion, antiproton, vacuum, injection	2169
	M.R.F. Siggel-King, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O. Karamyshev JINR/DLNP, Dubna, Moscow region, Russia G.A. Karamysheva MPI-K, Heidelberg, Germany A.I. Papash JINR, Dubna, Moscow Region, Russia M.R.F. Siggel-King The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by STFC, the EU under GA-PITN-215080, the Helmholtz Association and GSI under VH-NG-328. A small electrostatic ring, and associated electrostatic injection beamlines, are being designed and developed. The ring will make possible a variety of experiments using a choice of many types of recirculating ions (e.g., from protons, H-, and antiprotons up to and including large charged biomolecules). A reaction microscope will be incorporated into the ring to enable differential ionization experiments between the recirculating ion beam and gas jet targets. Two injection sections have been designed to cover a variety of ion sources. The facility will be portable to enable it to be moved between facilities and beamlines and it will be unique due to its combination of design elements, flexible beam properties, energy (ca 3-30 keV) and type of circulating particles. In this paper, we give an update on this project.

WEPC079	Beta-beating in the Effective Model of the LHC Using PTC	optics, alignment, injection, closed-orbit	2202
	M.C. Alabau Pons, F. Schmidt, R. Tomás CERN, Geneva, Switzerland E.H. Maclean JAI, Oxford, United Kingdom
	An effective model of the LHC optics has been developed based on measurements of magnetic field, alignment errors and closed orbit. This model utilizes the Polymorphic Tracking Code with MAD-X as front-end to allow the inclusion of harmonics to an arbitrary order in thick lattice elements. Beta-beating calculations have been performed with this model at injection optics and at 3.5 TeV squeezed optics to 3.5 m beta-function at the interaction point. The model predictions are in remarkable agreement with the measurements performed in the 2010 LHC commissioning run.

WEPC080	Non-linear Dynamics Optimization of the CLIC Damping Rings	resonance, emittance, dynamic-aperture, lattice	2205
	Y. Renier, F. Antoniou, H. Bartosik, Y. Papaphilippou CERN, Geneva, Switzerland K.P. Wootton The University of Melbourne, Melbourne, Australia
	Non-linear dynamics studies are undertaken in order to optimize the dynamic aperture of the CLIC damping rings. In this respect, advanced methods such as frequency map and resonance driving term analysis are used in order to explore the working point space with respect to single particle stability. The impact of magnet errors and misalignments, and in particular, the effect of the super-conducting damping wigglers is evaluated. Additional considerations for the working point choice are presented.

WEPC085	Multipole Fringe Fields	multipole, dipole	2211
	B.D. Muratori, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom M.J. de Loos, S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	When creating an initial model of an accelerator, one usually has to resort to a hard edge model for the quadrupoles and higher order multipoles at the start of the project. Ordinarily, it is not until much later on that one has a field map for the given multipoles. This can be rather inconvenient when one is dealing with particularly thin elements or elements which are rather close together in a beamline as the hard edge model may be inadequate for the level of precision desired. For example, in the EMMA project, the two types of quadrupoles used are so close together that they are usually described by a single field map or via hard edge models. The first method has the desired accuracy but was not available at the start of the project and the second is known to be a rough approximation. In this paper, an analytic expression is derived and presented for fringe fields for a multipole of any order with a view to applying it to cases like EMMA.

WEPC088	Embedding Finite Element Results for Accelerator Components in a Moment Approach Beam Dynamics Code*	simulation, dipole, electron, sextupole	2217
	T. Roggen, H. De Gersem, B. Masschaele KU Leuven, Kortrijk, Belgium W. Ackermann, S. Franke, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This research is funded by grant ''KUL 3E100118'' ''Electromagnetic Field Simulation for Future Particle Accelerators''. A moment based beam dynamics code has particular advantages, i.e. accuracy and efficiency, over macro-particle tracking and full particle-in-cell (PIC) codes respectively. Instead of embedding analytical descriptions of the accelerator components in the beam dynamics model, it is proposed to insert a surrogate model obtained from the finite element model of individual accelerator components. We apply the V-Code, which accepts moments up to the sixth order and accounts for space charge effects. We construct and calculate finite element and finite difference time domain models using the CST Studio Suite 2011 software package. An interface is implemented using VBA and MATLAB. As an example of the accuracy of this cascadic simulation approach, we compare the beam dynamics of an S-DALINAC quadrupole obtained by directly tracking particles to the calculated fields with the results for the cascadic approach with the V-Code. This work was performed during a three month research visit at the Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Darmstadt, Germany.

WEPC091	Studies with a Particle Tracking Code for the SIS100 Resonant Extraction System	extraction, controls, synchrotron, feedback	2220
	M.M. Kirk, G. Franchetti, H. Klingbeil, P. Moritz, N. Pyka, H. Ramakers, P.J. Spiller, H. Welker GSI, Darmstadt, Germany
	Several issues concerning the envisaged SIS100 resonant extraction at GSI can be resolved with a simulation-lead approach for which a particle tracking code was developed. Applications to date have included: design and testing of data supply algorithms for the accelerator control system; requirements analysis for the power converter ripple in the quadrupoles forming the doublet focusing; and verification of the RF Knock-Out exciter's performance.

WEPC092	Moment-Based Simulation of the S-DALINAC Recirculations*	simulation, recirculation, linac, cavity	2223
	S. Franke, W. Ackermann, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany R. Eichhorn, F. Hug, C. Klose, N. Pietralla, M. Platz TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by DFG under contract SFB 634. The Superconducting Linear Accelerator S-DALINAC installed at the institute of nuclear physics (IKP) at TU Darmstadt is designed as a re-circulating linear accelerator. The length of the beam line and the numerous accelerating structures as well as dipole and quadrupole magnets require a highly efficient numerical simulation tool in order to assist the operators by providing a detailed and almost instantaneous insight into the actual machine status. A suitable approach which enables a fast online calculation of the beam dynamics is given by the so-called moment approach where the particle distribution is represented by means of a discrete set of moments or by multiple discrete sets of moments in a multi-ensemble environment. Following this approach the V-Code simulation tool has been implemented at the Computational Electromagnetics Laboratory (TEMF) at TU Darmstadt. In this contribution an overview of the numerical model is presented together with new V-Code simulation results regarding the S-DALINAC recirculation sections.

WEPC104	Vicky : A Computer Code for Use in the Design and Simulation of Particle Accelerators	dynamic-aperture, sextupole, kicker, closed-orbit	2256
	F. Iazzourene ELETTRA, Basovizza, Italy
	Vicky is a computer code under development for designing and simulating particle accelerators. Like other existing codes, the features include machine imperfections, closed orbit correction, Twiss functions matching, chromaticity evaluation and correction, particle tracking and so on. The goal is to give the users a friendly graphical interface with widgets to perform the wished tasks, for example to plot the orbit, the Twiss functions, the tune diagram, the dynamic aperture and so on, to select and read an input file describing the considered lattice, to perform the Twiss functions matching, a closed orbit correction and so on. The code provides a description of the particle motion by 10 parameters: four beta-functions, four alpha-functions and two phase advances, that is a 4*4 generalized transverse coupling, together with an emphasis on the treatment of the complex 3D magnetic fields of the undulators used in today’s modern synchrotron radiation facilities. The code is written in C++. It uses the free packages QT for the online plots and the graphical user interface and IT++ for the mathematics. The present status and some results of its application will be presented.

WEPC109	Emittance Optimization Using Particle Swarm Algorithm*	emittance, lattice, storage-ring, synchrotron	2271
	Z. Bai, W. Li, L. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	In this paper we use a swarm intelligence algorithm, particle swarm optimization (PSO), to optimize the emittance directly. Some constraint conditions such as beta functions, fractional tunes and dispersion function, are considered in the emittance optimization. We optimize the strengths and positions of quadrupoles to search low emittances. Here an FBA lattice studied in the design of the Hefei Advanced Light Source storage ring is used as the testing lattice. The PSO is shown to be beneficial in the optimization.

WEPC115	A Global Optimization Approach Based on Symbolic Presentation of a Beam Propagator	controls, booster, focusing, induction	2280
	S.N. Andrianov, A.N. Ivanov, M. Kosovtsov, E.A. Podzyvalov St. Petersburg State University, St. Petersburg, Russia
	It is known that modern systems of beam lines consist of huge control elements even in the case of small machines. The problem of the beam line design leads us to formulate this problem as a global optimization ones. This approach allows us defining a family of appropriate solutions. On the next steps a researcher should narrow this optimal solutions set using additional methods and concepts. The symbolic presentation of necessary information plays leading role on all steps of the suggested approach. The corresponding implementation presented in the paper allows us to find the optimal sets in parameters spaces in a proper way. The corresponding applied software was used for solution of some practical probems. The described ideology implies to use distributed and parallel technologies for necessary computing and will be integrated in the Virtual Accelerator concept.

WEPC117	Symmetry Based Design for Beam Lines*	controls, target, insertion, beam-transport	2286
	S.N. Andrianov, A.N. Ivanov, M. Kosovtsov St. Petersburg State University, St. Petersburg, Russia
	Usually, the beam line design problems are solved using numerical optimization methods (for example, in the frame of so called global optimization paradigm). But this approach demonstrates enough effectiveness only after sufficient reduction of a control parameters set. In this paper we present the symmetry design concept based on symbolic computations for the corresponding beam line propagator. The combination of symbolic algebra codes (such as Maple, Mathematica, Maxima and so on) with the matrix formalism for Lie algebraic tools enables us to carry out the entire theoretical and computing processes for design of the beam line under study. For this purpose some of necessary physical requirements are formulated in the terms of the corresponding symmetry conditions. The suggested approach can be realized in both exact and approximate forms of the symmetry terms. The found conditions can sufficiently reduce the number of control parameters for the next optimization step.

WEPC156	Virtual Power Supply Control Environment for the TPS Project	power-supply, controls, EPICS, storage-ring	2349
	Y.-S. Cheng, Y.-T. Chang, J. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.-Y. Liao, C.Y. Wu NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is the latest generation of 3 GeV synchrotron light source which has been under construction since 2010. The control system infrastructure of TPS project is based upon the EPICS framework. In order to develop the control applications before power supplies of magnets delivered, it is necessary to set up the virtual control environment to develop high level application programs for the power supplies of magnets in advance. The high level application programs include operation process, degauss process and etc. for power supplies of magnet. The soft-IOCs (Input Output Controller) and various database records are needed to be built to simulate the power supply control environment. In addition, the operation interfaces of power supply will be designed and integrated according to location properties. The efforts will be described at this report.

WEPC162	Investigations into Non-linear Beam Dynamics in Electrostatic Storage Rings	lattice, focusing, dynamic-aperture, proton	2361
	D. Newton, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O.E. Gorda MPI-K, Heidelberg, Germany D. Newton The University of Liverpool, Liverpool, United Kingdom A.I. Papash JINR, Dubna, Moscow Region, Russia
	Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG-328. Electrostatic (ES) storage rings provide a cost-effective solution to the problem of confining low energy (beta << 1) charged particles and ions, whilst controlling the beam properties, for use in multi-pass experiments. However, compared to magnetic storage rings, the beam dynamics calculations for an ES ring show subtle differences, especially in the coupling of the longitudinal and transverse velocities and in the focusing properties of bending element fringe fields. Using the nominal design for a prototype ES ring, realistic trajectories (including fringe fields and non-linear field components) have been calculated and a comparison is made with linear lattice simulations. The effect of the non-linear field components on the beam parameters is discussed.

WEPC170	Handling of BLM Abort Thresholds in the LHC	beam-losses, monitoring, injection, proton	2382
	E. Nebot Del Busto, B. Dehning, E.B. Holzer, S. Jackson, G. Kruk, M. Nemcic, A. Nordt, A. Orecka, C. Roderick, M. Sapinski, A. Skaugen, C. Zamantzas CERN, Geneva, Switzerland
	The Beam Loss Monitoring system (BLM) for the LHC consists of about 3600 Ionization Chambers located around the ring. Its main purpose is to request a beam abort when the measured losses exceed a certain threshold. The BLM detectors integrate the measured signals in 12 different time intervals (running from 40 us to 83.8 s) enabling for a different set of abort thresholds depending on the duration of the beam loss. Furthermore, 32 energy levels running from 0 to 7 TeV account for the fact that the energy density of a particle shower increases with the energy of the primary particle, i.e. the beam energy. Thus, about 1.3·10⁶ thresholds must be handled and send to the appropriate processing modules for the system to function. These thresholds are highly critical for the safety of the machine and depend to a large part on human judgment, which cannot be replaced by automatic test procedures. The BLM team has defined well established procedures to compute, set and check new BLM thresholds, in order to avoid and/or find non-conformities due to manipulation. These procedures, as well as the tools developed to automate this process are described in detail in this document.

WEPC172	Beam-induced Quench Test of a LHC Main Quadrupole	simulation, beam-losses, proton, monitoring	2388
	A. Priebe, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, C. Kurfuerst, E. Nebot Del Busto, A. Nordt, M. Sapinski, J. Steckert, A.P. Verweij, C. Zamantzas CERN, Geneva, Switzerland A. Priebe EPFL, Lausanne, Switzerland
	Unexpected beam loss might lead to transition of a superconducting accelerator magnet to a normal conducting state. The LHC beam loss monitoring (BLM) system is designed to abort the beam before the energy deposited in the magnet coils reaches a quench-provoking level. In order to verify the threshold settings generated by simulation, a series of beam-induced quench tests at various beam energies have been performed. The beam losses are generated by means of an orbit bump peaked in one of the main quadrupole magnets. The analysis not only includes BLM data but also data from the electrical quench protection and cryogenic systems. The measurements are compared to Geant4 simulations of energy deposition inside the coils and corresponding BLM signal outside the cryostat. The results are also extrapolated to higher beam energies.

WEPC173	LHC Magnet Quench Test with Beam Loss Generated by Wire Scan	beam-losses, proton, simulation, electron	2391
	M. Sapinski, F. Cerutti, K. Dahlerup-Petersen, B. Dehning, J. Emery, A. Ferrari, A. Guerrero, E.B. Holzer, M. Koujili, A. Lechner, E. Nebot Del Busto, M. Scheubel, J. Steckert, A.P. Verweij, J. Wenninger CERN, Geneva, Switzerland
	Beam losses with millisecond duration have been observed in the LHC in 2010 and 2011. They are expected to be provoked by dust particles falling into the beam. These losses could compromise the LHC availability if they provoke quenches of superconducting magnets. In order to investigate the quench limits for this loss mechanism, a quench test using the wire scanner has been performed, with the wire movement through the beam mimicking a loss with similar spatial and temporal distribution as in the case of dust particles. This paper will show the conclusions reached for millisecond-duration dust-provoked quench limits. It will include details on the maximum energy deposited in the coil as estimated using FLUKA code, showing good agreement with quench limit estimated from the heat transfer code QP3. In addition, information on the damage limit for carbon wires in proton beams will be presented, following electron microscope analysis which revealed strong wire sublimation.

WEPC175	FLUKA Studies of the Asynchronous Beam Dump Effects on LHC Point 6	proton, insertion, simulation, dipole	2397
	R. Versaci, V. Boccone, B. Goddard, A. Mereghetti, R. Schmidt, V. Vlachoudis CERN, Geneva, Switzerland
	The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. FLUKA is the most widely used code for this kind of simulations at CERN because of the high reliability of its results and the ease to custom detailed simulations all along hundreds of meters of beam line. We have investigated the effects of an asynchronous beam dump on the LHC Point 6 where, beams with a stored energy of 360 MJ, can instantaneously release up to a few J cm^-3 in the cryogenic magnets which have a quench limit of the order of the mJ cm^-3. In the present paper we will briefly introduce FLUKA, describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyse the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

WEPO001	Design and Optimization of the MedAustron Synchrotron Main Dipoles	simulation, dipole, synchrotron, ion	2406
	M. Stockner, B. Langenbeck, C. Siedler EBG MedAustron, Wr. Neustadt, Austria Th. Zickler CERN, Geneva, Switzerland
	MedAustron, a future centre for ion-therapy and research in Austria will comprise an accelerator facility based on a synchrotron for the delivery of protons and light ions for cancer treatment and for clinical and non-clinical research. The main dipole for the synchrotron went through an extensive design process to meet the stringent requirements. The local and integrated field quality was optimized. The residual field levels in the magnet gap were calculated and the dynamic behaviour of the dipole magnet was studied, both in 2D and 3D, using OPERA. The pole profile has been optimized to reduce sextupolar components in the integrated field by adjusting the shims on the pole edge. A Rogowski-profile at the pole ends and the use of stainless-steel tension straps will enhance the dynamic behaviour and guarantee a small time constants. Appropriate pole-end shimming will be used to compensate for residual multi-pole components and to fine-tune the magnetic length. The results of this comprehensive design study are summarized in this paper.

WEPO003	The FERMI@Elettra Magnets	dipole, gun, electron, FEL	2409
	D. Castronovo, R. Fabris, G.L. Loda, D. Zangrando ELETTRA, Basovizza, Italy
	FERMI@Elettra is a single-pass FEL user-facility located next to the third generation synchrotron radiation facility ELETTRA in Trieste, Italy. The linear accelerator contains more than 200 magnets. This paper reports on the design, construction, magnetic measurement and installation.

WEPO012	Calculation, Design and Manufacturing of a Resistive Quadrupole for the ESS-Bilbao Transfer Lines	linac, power-supply, acceleration, DTL	2418
	I. Rodríguez, F.J. Bermejo, J.L. Munoz, D. de Cos ESS Bilbao, Bilbao, Spain
	The first stage of the ESS-Bilbao LINAC will accelerate H⁺ and H− high current beams up to 50 MeV for different applications. After the last acceleration step in the DTL, the beam will either be transported to the experimental laboratories by the means of several transfer lines, or continue to a further acceleration step in spoke cavities. The first design of one of the quadrupoles that focus the beam along the transfer lines is presented. The quadrupoles will have an aperture of 63 mm and 20 T/m maximum gradient, featuring a short iron yoke of 100 mm. All the quadrupoles of the transfer lines are expected to be similar in order to simplify the design and manufacturing processes. The iron yoke is small and highly saturated, and an optimization of the 3D harmonics in the load-line is developed to fulfil the field quality specifications. The required current density is high (about 8.2 A/mm2), therefore a water cooled hollow conductor is used to cool down the coils. The cooling and power supply requirements are calculated in this paper. The most important manufacturing indications are also presented.

WEPO014	Magnetic Design of Quadrupoles for the Medium and High Energy Beam Transport line of the LIPAC Accelerator	coupling, beam-transport, simulation, dipole	2424
	C. Oliver, B. Brañas, A. Ibarra, I. Podadera, F. Toral CIEMAT, Madrid, Spain
	Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230. The LIPAC accelerator will be a 9 MeV, 125 mA cw deuteron accelerator which will verify the validity of the design of the future IFMIF accelerator. A Medium Energy Beam Transport line (MEBT) is necessary to handle the high current beam from the RFQ to the Superconducting RF accelerating cavities (SRF) whereas a High Energy Beam Transport line (HEBT) is used to match the beam from the SRF to the beam dump. The high space charge and beam power determine the beam dynamics in both transport lines. As a consequence, magnets with strong fields in a reduced space are required. Along the transport beamlines, there are different types of quadrupoles with steerers and a dipole. Special care is devoted to maximize the integrated fields in the available space. Both 2-D and 3-D magnetic calculations are used to optimize coil configurations. Magnetic performance and cost, both of magnet and power supply, have been taken into account for final choice. In this paper, the design of the resistive quadrupoles of the MEBT and HEBT of the LIPAC accelerator is presented.

WEPO017	Status of CLIC Magnets Studies	linac, permanent-magnet, solenoid, acceleration	2433
	M. Modena CERN, Geneva, Switzerland A.S. Vorozhtsov JINR, Dubna, Moscow Region, Russia
	R&D Magnets activities for CLIC Project have now entered a new phase with the design & manufacturing of several prototypes investigating the most challenging aspects of the CLIC Project. As concerning the CLIC Magnet System, challenges can be related to pure technical aspects (e.g. the Final Focus QD0 quadrupole where a gradient of more than 550 T/m is requested) or to industrial production choices (e.g. the Main Beam Quadrupoles where compactness and high tolerances are requested for the mechanical assembly, or the Drive Beam Quadrupoles where a productions of more than 40000 units is needed). In this paper the key aspects of the magnets under studies such as the Drive Beam, Main Beam and the Final Focus quadrupoles will be presented and discussed. Results on prototypes under assembly and measured performances will also be addressed.

WEPO018	Status of the New Linac4 Magnets at CERN	linac, solenoid, DTL, simulation	2436
	Th. Zickler, F. Borgnolutti, O. Crettiez, A. Newborough, L. Vanherpe CERN, Geneva, Switzerland A.S. Vorozhtsov JINR, Dubna, Moscow Region, Russia
	Linac4 is a new H⁻ linear accelerator at CERN replacing Linac2 as injector to the PS Booster. Almost 100 electro-magnets of different types are needed for the Linac4 project. Following a detailed analysis of the requirements and constraints, several magnet designs have been studied and are well advanced. This paper presents the design considerations, main parameters and characteristics of the new Linac4 magnets and summarizes the present status.

WEPO020	Magnetic Field Inspection and Analysis of Multipole Lattice Magnets using a Rotating-coil Measurement System*	multipole, storage-ring, sextupole, synchrotron	2442
	J.C. Jan, C.-H. Chang, Y.L. Chu, T.Y. Chung, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin NSRRC, Hsinchu, Taiwan
	A precise rotating-coil measurement system (RCS) was constructed to characterize the field quality and field center of multipole lattice magnets of Taiwan Photon Source (TPS). The mechanical center of magnets is determined by the two references of the magnet-feet and the RCS system is used to characterize the field center. The location of the magnetic field center is quantitatively accurate to better than 20 micro-meter in the horizontal direction; the granite support height of the RCS system is accurate within 5 micro-meter after artificial polishing. The measurement reproducibility of the field center was better than 10 micro-meter when the magnets were reinstalled. The relative accuracy of the multipoles components is better than 2×10^-5. This paper reports the details of the bench construction and the unit composition. The field center with RCS measurement will be compared and discussed with the 3D-coordinate-measuring machine. The multipole errors obtained from RCS will be compared with a Hall-probe measurement system.

WEPO021	Quadrupole Magnet with an Integrated Dipole Steering Element for the ISIS Beam Transport Line	dipole, target, beam-transport, proton	2445
	S.J.S. Jago, J. Shih, S.F.S. Tomlinson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S.M. Gurov BINP SB RAS, Novosibirsk, Russia
	A refurbishment of beam transport line to the original ISIS target station at the Rutherford Appleton Laboratory has recently been completed. This work involved a slight change to the optics in the area, which included the requirement for extra steering capabilities. Due to the space constraints in the region, a quadrupole magnet with an integrated dipole steering element was developed. The steering dipole consists of four saddle shaped coils situated within the bore of the quadrupole magnet providing a maximum steering angle of 2.5mrad. This paper outlines the magnetic and mechanical design of the steering element.

WEPO022	Tightening the Tolerance Budget of Core Fabrication to Achieve Higher Magnet Performance	sextupole, vacuum, dipole, scattering	2448
	N. Li, A. Madur LBNL, Berkeley, California, USA J. Jin SINAP, Shanghai, People's Republic of China
	Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231. Traditionally, laminated cores of AC magnets have been always built by the laminations that are produced by a punching die. There are 5 links in the tolerance chain when a magnet core is built by this procedure: 1. Error of punching die; 2. Error of lamination punching; 3. Error of half core stacking; 4. Error of core assembly; and 5. Error of magnet re-assembling during the installation in the accelerator. As time goes on, the Lattice physicists call for more and more ever higher magnet performance, which makes the required magnet field quality almost impossible achieve by traditional core fabrication procedures. It is the goal of this paper to describe a relatively new procedure that was first used by Buckley System Ltd, NZ and is being used at SINAP, China for ALS combined function sextupole core fabrication. The advantage of this new procedure and the fabrication issues related to this procedure will be described in this paper.

WEPO024	Design and Operation Parameters of the Superconducting Main Magnets for the SIS100 Accelerator of FAIR	dipole, sextupole, multipole, ion	2451
	E.S. Fischer, E. Floch, J. Macavei, P. Schnizer GSI, Darmstadt, Germany P.G. Akishin JINR, Dubna, Moscow Region, Russia A. Mierau TEMF, TU Darmstadt, Darmstadt, Germany
	SIS100, the worlds second large scale synchrotron for ion research, will use superferric magnets. The dipoles are of the window frame type, whose aperture was chosen as an optimum balance between the achievable field quality and AC losses at cryogenic temperatures. Analogous design optimisation was done for the quadrupole and corrector magnets as well. We present the design of the main magnets, estimate their operation parameters and define the crucial aspects to be experimentally analysed before series production, e.g. precise magnetic end field optimisation.

WEPO026	Advances in the Design of the SuperB Final Doublet	luminosity, collider, controls, positron	2454
	E. Paoloni, N. Carmignani, F. Pilo University of Pisa and INFN, Pisa, Italy S. Bettoni CERN, Geneva, Switzerland M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma), Italy F. Bosi INFN-Pisa, Pisa, Italy P. Fabbricatore, S. Farinon, R. Musenich INFN Genova, Genova, Italy M.K. Sullivan SLAC, Menlo Park, California, USA
	SuperB is an asymmetric (6.7 GeV HER, 4.18 GeV LER) e⁺ e− collider operating at the Y(4S) peak with a design peak luminosity of 10³6 Hz/cm² to be built in Italy in the very near future. The design luminosity is almost a factor hundred higher than that of the present generation comparable facilities. To get the design luminosity a novel collision scheme, the so called “large Piwinski angle with crab waist”, has been designed. The scheme requires a short focus final doublet to reduce the vertical beta function down to betay*=0.2 mm at the interaction point (IP). The final doublet will be composed by a set of permanent and superconducting (SC) quadrupoles. The SC quadrupole doublets QD0/QF1 have to be placed as close to the IP as possible. This layout is critical because the space available for the doublets is very small. An advanced design of the quadrupole has been developed, based on the double helical coil concept. The paper discusses the design concept, the construction and the results of test of a model of the superconducting quadrupole based on NbTi technology. Future developments are also presented.

WEPO027	Design Study of Final Focusing Superconducting Magnets for the SuperKEKB	solenoid, focusing, luminosity, positron	2457
	M. Tawada, N. Higashi, M. Iwasaki, H. Koiso, A. Morita, Y. Ohnishi, N. Ohuchi, K. Oide, T. Oki, K. Tsuchiya, H. Yamaoka, Z.G. Zong KEK, Ibaraki, Japan
	For SuperKEKB, which is an upgrade project of KEKB, we are studying the design of the final focus quadrupole magnets for the interaction region. The 7 GeV electrons in the high-energy ring and the 4 GeV positrons in the low-energy ring collide at one IP with a finite crossing angle of 83 mrad. For each beam, the final beam focusing system consists of the superconducting quadrupole-doublets. These quadrupole magnets have to meet specifications described below. (1) Because of the small beam separation between two beam lines, the superconducting magnet is designed with thin coils and the conductor size is required to be minimized. (2) Since the beta functions are so large, a large space with a good field quality is required. (3) These magnets must apply the focusing fields on electrons and positrons, independent each other. The quadrupole magnets in the solenoid field of the particle detector are designed without an iron yoke. Consequently, the reduction of the leakage fields from the adjacent beam lines is a critical issue to achieve large dynamic aperture. In this paper we will report the design of final focusing system.

WEPO031	The Magnetic Model of the LHC during Commissioning to Higher Beam Intensities in 2010-2011	injection, dipole, optics, sextupole	2466
	L. Deniau, N. Aquilina, L. Fiscarelli, M. Giovannozzi, P. Hagen, M. Lamont, G. Montenero, R.J. Steinhagen, M. Strzelczyk, E. Todesco, R. Tomás, W. Venturini Delsolaro, J. Wenninger CERN, Geneva, Switzerland
	The Field Description of the Large Hadron Collider (FiDeL) model is a set of semi-empirical equations linking the magnets behaviours established from magnetic measurements to the magnetic properties of the machine observed through beam measurements. The FiDeL model includes the parameterization of static components such as magnets residual magnetization, persistent currents, hysteresis and saturation as well as the decay and snap-back dynamic components. In the present paper, we outline the relationship between the beam observables (orbit, tune, chromaticity) and the model components during the commissioning to higher beam intensities in 2010-2011, with an energy of 3.5 TeV per beam. The main relevant issues are (i) the operation at 2 A/s and 10 A/s ramp rate and their influence on chromatic correction, (ii) the beta beating and its relation to the knowledge of the resistive quadrupoles transfer functions and (iii) the observed tune decay at injection energy and its possibles origins.

WEPS030	Ion Optics Alignment in the Electrostatic Double Storage Ring DESIREE	alignment, ion, optics, storage-ring	2547
	P. Löfgren, M. Blom, F. Hellberg, L. Liljeby, A. Simonsson MSL, Stockholm, Sweden P. Reinhed Stockholm University, Stockholm, Sweden
	DESIREE is a cryogenic electrostatic double storage ring under construction at Stockholm University. The two rings have similar circumference, 8.8 m and a common straight section for merged beam experiments. In each ring the ions are guided by two 160° cylindrical deflectors and four 10° deflectors and focused by four quadrupole doublets. In terms of ion optics alignment the quadrupoles are the most important factor for the ion beam acceptance and the goal is to align all quadrupoles with precision of 0.1 mm. DESIREE is constructed as a double walled cryostat with an inner and an outer vacuum chamber. All optical elements are mounted directly on the bottom of the inner chamber. For positioning of the ion optics, the bottom plate is prepared with a number of footprints where each footprint consists of four small machined surfaces that define the height and two alignment holes that define the lateral position. The optical elements were aligned on the bottom plate using a portable measuring device in combination with a level instrument. In this work we describe the alignment procedure in detail and report on the overall precision obtained and the consequence for the ion beam.

WEPS037	RF Design of a 325 MHz 4-ROD RFQ	dipole, rfq, simulation, linac	2568
	B. Koubek, A. Schempp, J.S. Schmidt IAP, Frankfurt am Main, Germany L. Groening GSI, Darmstadt, Germany
	Usually 4-ROD Radio Frequency Quadrupoles (RFQ) are built for frequencies up to 216 MHz. For higher frequencies 4-VANE structures are more common. The advantages of 4-Rod structures, the greater flexibility for tuning and being more comfortable for maintenance, are motivating the development of a 4-Rod RFQ for higher frequencies than 216 MHz. In particular a 325 MHz RFQ with an output energy of 3 MeV is needed for the proton linac for the FAIR project of GSI. This paper reports about the design studies and the latest developments of this RFQ.

WEPS050	The MEBT Design for the China Accelerator Driven System	emittance, rfq, cavity, diagnostics	2604
	H. Geng, H.F. Ouyang, J. Tang IHEP Beijing, Beijing, People's Republic of China Z. Li, S. Pei, F. Yan IHEP Beijng, Beijing, People's Republic of China
	The Medium Eneryg Beam Transport (MEBT) line plays an important role in transporting and matching the beam from the RFQ exit to the entrance to the next type of acceleration structures while provides enough beam diagnostics for beam commissing and tuning. The beam dynamics design for the 1GeV China Accelerator Driven System (CADS) is making great progress. In this paper, we will describe the design–both element choosing and beam dynamics study of the 3MeV MEBT for the CADS project.

WEPS057	Beam Dynamics Simulation in DTL with RF Quadrupole Focusing	focusing, linac, lattice, DTL	2625
	S.M. Polozov, A.S. Plastun MEPhI, Moscow, Russia
	There are a number of ion linear accelerators using RF focusing. Radio Frequency Quadrupole (RFQ) is the most useful RF linac in low energy range. Using of RFQ for medium energies is impractical because of low energy gain rate. Therefore, proposed to combine Drift Tube Linac (DTL), keeping tolerable energy gain rate, and RFQ. Such linac consists of periodic sequence of a several number of drift tubes and RF quadrupole electrodes, located in the same IH resonator. Different variants of the structure will be considered. Beam dynamics simulation will be carried out through these variants. Main parameters of the linac will be determine. The RF model design, providing combination of DTL and RFQ, will be proposed.

WEPS058	The Medium Energy Beam Transport Line (MEBT) of IFMIF/EVEDA LIPAc	rfq, cavity, SRF, vacuum	2628
	I. Podadera, J.C. Calvo, J.M. Carmona, A. Ibarra, D. Iglesias, A. Lara, C. Oliver, F. Toral CIEMAT, Madrid, Spain

Paper

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MOOCB01

Study on the Realignment Plan for J-PARC Linac after the Tohoku Earthquake in Japan

DTL, linac, alignment, simulation

44

M. Ikegami
KEK, Ibaraki, Japan
T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

A 9.0-magnitude earthquake struck eastern Japan on March 11, 2011, and it gave rise to damages to the buildings of the J-PARC facilities. In particular, the earthquake caused a deformation of the J-PARC linac tunnel resulting an alignment error of several tens of millimeters in both horizontal and vertical directions. It also caused a change in the relative position between the linac and other facilities of J-PARC complex. To restore the beam operation, we should establish a reasonable realignment plan for J-PARC linac taking various constraints into account and possibly tolerating some residual misalignment. In this paper, we show a study on the realignment plan for J-PARC linac including evaluation of the effect of residual misalignment with particle simulations.

Slides MOOCB01 [2.659 MB]

MOPC002

Flow Induced Vibrations of the CLIC X-band Accelerating Structures

alignment, linac, synchrotron, resonance

65

T.K. Charles, K. Ryan
Monash University, Melbourne, Australia
M.J. Boland
ASCo, Clayton, Victoria, Australia
G. Riddone
CERN, Geneva, Switzerland
A. Samoshkin
JINR, Dubna, Moscow Region, Russia

Turbulent cooling water in the Compact Linear Collider (CLIC) accelerating structures will inevitably induce some vibrations. The maximum acceptable amplitude of vibrations is small, as vibrations in the accelerating structure could lead to beam jitter and alignment difficulties. A Finite Element Analysis model is needed to identify the conditions under which turbulent instabilities and significant vibrations are induced. Due to the orders of magnitude difference between the fluid motion and the structure's motion, small vibrations of the structure will not contribute to the turbulence of the cooling fluid. Therefore the resonant conditions of the cooling channels presented in this paper, directly identify the natural frequencies of the accelerating structures to be avoided under normal operating conditions. In this paper a 2D model of the cooling channel is presented finding spots of turbulence being formed from a shear layer instability. This effect is observed through direct visualisation and wavelet analysis.

MOPC024

Construction Status of the CPHS RFQ at Tsinghua University

rfq, dipole, cavity, vacuum

122

Q.Z. Xing, Y.J. Bai, J.C. Cai, C. Cheng, L. Du, T. Du, X. Guan, Q. Qiang, X.W. Wang, Z.F. Xiong, S.Y. Yang, H.Y. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China
J.H. Billen
TechSource, Santa Fe, New Mexico, USA
W.Q. Guan, Y. He, J. Li
NUCTECH, Beijing, People's Republic of China
J. Stovall
CERN, Geneva, Switzerland
L.M. Young
AES, Medford, NY, USA

Funding: Work supported by the “985 Project” of the Ministry of Education of China.
We present, in this paper, the construction status of a Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The 3-meter-long RFQ will deliver 3 MeV protons to the downstream Drift Tube Linac (DTL) with the peak current of 50 mA, pulse length of 0.5 ms and beam duty factor of 2.5%. The RFQ has been mechanically separated into three sections. A ball-end mill, instead of a forming cutter, is adopted to machine the vane tip due to its varying radius of curvature. The precision of the numerically controlled milling machine has been verified by machining test pieces of aluminum and copper. Fine machining of the vanes was completed in July, 2011. The pre-braze tuning was completed at the beginning of this August.

MOPC044

Design of the Radiofrequency Quadrupole Coldmodel for the ESS-BILBAO Linear Accelerator

rfq, simulation, dipole, radio-frequency

175

A. Velez, I. Bustinduy, N. Garmendia, O. Gonzalez, J.L. Munoz, D. de Cos
ESS Bilbao, Bilbao, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
V. Etxebarria, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain

This work will present the design of the ESS-Bilbao LINAC RFQ cold model. The process goes through the electromagnetic design of the cavity by properly setting the resonant quadrupole and dipole modes, as well as the resonance frequency. The prototype includes the vane modulation designed to accelerate a 75 mA proton beam from 75 keV to 3 MeV, with an operating frequency of 352.2 MHz. To this end, electromagnetic and electrostatic simulations have been performed by means of the commercial software COMSOL. Furthemore, results for the three components of the electrical field distribution will be presented and compared to those calculated by evaluating the 8-term multipole expansion.

MOPC049

Bead-pull Test Bench for Studying Accelerating Structures at RHUL

cavity, rfq, controls, resonance

187

S. Molloy
ESS, Lund, Sweden
R. Ainsworth, G.E. Boorman
Royal Holloway, University of London, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
A. Garbayo
AVS, Eibar, Gipuzkoa, Spain
A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
A. Lyapin
JAI, Egham, Surrey, United Kingdom
P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

A bead-pull test stand has been constructed at Royal Holloway, University of London (RHUL) with the ability to provide electric field profile measurements along five degrees of freedom using the perturbation method. In this paper, we present example measurements using the test bench which include a field flatness profile of a 324MHz four vane Radio Frequency Quadrupole (RFQ) model designed as part of the Front End Test Stand (FETS) development at Rutherford Appleton Laboratory (RAL). Mechanical and operational details of the apparatus will also be described, as well as future plans for the development and usage of this facility.

MOPC061

Simulations to Flatten the Field of the FETS RFQ

rfq, simulation, cavity, dipole

223

S.R. Lawrie, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

A high performance Radio Frequency Quadrupole (RFQ) is the next major component to be installed on the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) in the UK. The beam dynamics, RF, thermal and mechanical designs of the RFQ are almost complete and so the copper has recently been purchased with a view to start cutting metal near Summer-time. This report summarizes the simulation work performed to ensure the RF design is sound. This includes performance studies of the end-wall dipole suppression fingers, tuning the frequency of the input and output vane end regions and implementing a simple solution to remove modulation induced field tilt.

MOPC096

Design and Fabrication of a 5-Cell High Current Superconducting Cavity

cavity, HOM, simulation, dipole

301

Y.M. Li, K.X. Liu, S.W. Quan, F. Zhu
PKU/IHIP, Beijing, People's Republic of China
R. Nassiri
ANL, Argonne, USA

Funding: National High Technology Research and Development program 863 (2009AA03Z206)
Energy recovery linacs (ERL) is promising to achieve high average current with superior beam quality. The key component for accelerating such high current beams is the superconducting radio frequency (SRF) cavity. The design of a 1.3 GHz 5-cell high current superconducting cavity has been carried out under the cooperation between Peking University (PKU) and Argonne National Laboratory (ANL). RF properties, damping of the HOMs, multipacting and mechanical features of this cavity have been discussed and the final design is presented.

MOPC102

RF and Surface Properties of Superconducting Samples

niobium, cavity, superconductivity, superconducting-cavity

310

T. Junginger, W. Weingarten
CERN, Geneva, Switzerland
T. Junginger
MPI-K, Heidelberg, Germany
R. Seviour
Lancaster University, Lancaster, United Kingdom
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF)
The surface resistance Rs of superconducting cavities can be obtained from the unloaded quality factor Q0. Since Rs varies strongly over the cavity surface its value must be interpreted as averaged over the whole cavity surface. A more convenient way to investigate the surface resistance of superconducting materials is therefore to examine small samples, because they can be manufactured cheaply, duplicated easily and used for further surface analyses. At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution, results from measurements on bulk niobium and niobium film on copper samples are presented. It is shown how different contributions to the surface resistance depend on temperature, applied RF magnetic field and frequency. Furthermore, measurements of the maximum RF magnetic field as a function of temperature and frequency in pulsed and CW operation are presented. The study is accompanied by measurements of the surface properties of the samples by various techniques.

MOPO001

Interaction Point Feedback Design and Integrated Simulations to Stabilize the CLIC Final Focus*

controls, simulation, feedback, ground-motion

475

G. Balik, L. Brunetti, G. Deleglise, A. Jeremie, L. Pacquet
IN2P3-LAPP, Annecy-le-Vieux, France
A. Badel, B. Caron, R. Le Breton
SYMME, Annecy-le-Vieux, France
A. Latina, J. Pfingstner, D. Schulte, J. Snuverink
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) accelerator has strong precision requirements on offset position between the beams. The beam which is sensitive to ground motion needs to be stabilized to unprecedented requirements. Different Beam Based Feedback (BBF) algorithms such as Orbit Feedback (OFB) and Beam-Beam Offset Feedback (BBOF) have been designed. This paper focuses on the BBOF control which could be added to the CLIC baseline. It has been tested for different ground motion models in the presence of noises or disturbances and uses digital linear control with or without an adaptive loop. The simulations demonstrate that it is possible to achieve the required performances and quantify the maximum allowed noise level. This amount of admitted noises and disturbances is given in terms of an equivalent disturbance on the position of the magnet that controls the beam offset. Due to the limited sampling frequency of the process, the control loop is in a very small bandwidth. The study shows that these disturbances have to be lowered by other means in the higher frequency range.

MOPO026

Design, Manufacturing and Tests of Closed-loop Quadrupole Mover Prototypes for European XFEL

controls, alignment, feedback, vacuum

535

J. Munilla, J. Calero, J.M. Cela-Ruiz, L. García-Tabarés, A. Guirao, J.L. Gutiérrez, T. Martínez de Alvaro, E. Molina Marinas, S. Sanz, F. Toral, C. Vazquez
CIEMAT, Madrid, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under SEI Resolution on 17-September-2009
In this report the development of a quadrupole mover with submicron repeatability is reported, which will be used in the intersections of the Undulator Systems of the European XFEL (EXFEL). It is part of the Spanish in-kind contribution to this facility. The main specifications include submicron repeatability for a 70 kg quadrupole magnet within compact dimensions and a ±1.5 mm stroke in the vertical and horizontal direction. Compact linear actuators based on 5-phase stepping motors have been chosen. Vertical actuator works in a wedge configuration to take mechanical advantage. A closed-loop control system has been developed to achieve this repeatability. For the feedback, one LVDT sensor for each axis was used. Mechanical switches are used to limit movement. In addition, hard-stops are included for emergency. Prototyping stage is done and a serial production of more than 90 devices is expected, so intense work has been done to achieve a reliable industrial production and validation. In this report, results of mechanical measurements including reproducibility, tests of different operation strategies and critical situations will be reported.

MOPO027

Status of a Study of Stabilization and Fine Positioning of CLIC Quadrupoles to the Nanometre Level*

feedback, alignment, controls, damping

538

K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, S.M. Janssens, A.M. Kuzmin, R. Leuxe, R. Moron Ballester
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no.227579
Mechanical stability to the nanometre and below is required for the CLIC quadrupoles to frequencies as low as 1 Hz. An active stabilization and positioning system based on very stiff piezo electric actuators and inertial reference masses is under study for the Main Beam Quadrupoles (MBQ). The stiff support was selected for robustness against direct forces and for the option of incrementally repositioning the magnet with nanometre resolution. The technical feasibility was demonstrated by a representative test mass being stabilized and repositioned to the required level in the vertical and lateral direction. Technical issues were identified and the development programme of the support, sensors, and controller was continued to increase the performance, integrate the system in the overall controller, adapt to the accelerator environment, and reduce costs. The improvements are implemented in models, test benches, and design of the first stabilized prototype CLIC magnet. The characterization of vibration sources was extended to forces acting directly on the magnet, such as water-cooling induced vibrations. This paper shows the achievements, improvements, and an outlook on further R&D.

MOPO028

Modal Analysis and Measurement of Water Cooling Induced Vibrations on a CLIC Main Beam Quadrupole Prototype*

ground-motion, resonance, controls, damping

541

K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, S.M. Janssens, R. Leuxe, M. Modena, R. Moron Ballester, M. Struik
CERN, Geneva, Switzerland
G. Deleglise, A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579.
To reach the Compact Linear Collider (CLIC) design luminosity, the mechanical jitter of the CLIC main beam quadrupoles should be smaller than 1.5 nm integrated root mean square (r.m.s.) displacement above 1 Hz. A stiff stabilization and nano-positioning system is being developed but the design and effectiveness of such a system will greatly depend on the stiffness of the quadrupole magnet which should be as high as possible. Modal vibration measurements were therefore performed on a first assembled prototype magnet to evaluate the different mechanical modes and their frequencies. The results were then compared with a Finite Element (FE) model. The vibrations induced by water-cooling without stabilization were measured with different flow rates. This paper describes and analyzes the measurement results.

MOPO029

Validation of a Micrometric Remotely Controlled Pre-alignment System for the CLIC Linear Collider using a Test Setup (Mock-up) with 5 Degrees of Freedom

alignment, target, controls, feedback

544

H. Mainaud Durand, M. Anastasopoulos, J. Kemppinen, R. Leuxe, M. Sosin, S. griffet
CERN, Geneva, Switzerland

The CLIC main beam quadrupoles need to be pre-aligned within 17μm rms with respect to a straight reference line along a sliding window of 200 m. A re-adjustment system based on eccentric cam movers, which will provide stiffness to the support assembly, is being studied. The cam movers were qualified on a 1 degree of freedom (DOF) test setup, where a repeatability of adjustment below 1 μm was measured along their whole range. This paper presents the 5 DOF mock-up, built for the validation of the eccentric cam movers, as well as the first results of tests carried out: resolution of displacement along the whole range, measurements of the support eigenfrequencies.

MOPO033

Design and Development of a Laser Positioning System for TPS Magnets Alignment Inspection during the Installation on a Girder

laser, sextupole, alignment, lattice

556

Chen, M. L. Chen, H.C. Ho, K.H. Hsu, W.Y. Lai, S.Y. Perng, Y.L. Tsai, T.C. Tseng, H.S. Wang
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

A novel optical inspection architecture is designed and developed for positioning the TPS (Taiwan Photon Source) quadrupole and sextupole magnets on the girder within 30 um. This positioning system is a laser-based scheme consists of two laser position sensing devices (PSD) and two granite blocks as the standard reference of magnets. The laser position sensing device (PSD) is mounted on an adjustable circular steel module and the module is installed in a granite block. With the PSD position being adjusted and corrected, the PSD module center can be identical to the ideal pole position of magnets on the girder within 10um. The Laser ray is also adjusted and aligned according to the ideal reference line of magnets. Finally the granite blocks are replaced with the quadrupole and sextupole magnets at installation, the assembling error of magnets can be detected from the PSD module. This paper describes the detail of the system development and testing results.

MOPS001

Electron-cloud Pinch Dynamics in Presence of Lattice Magnet Fields

electron, proton, cyclotron, simulation

586

G. Franchetti
GSI, Darmstadt, Germany
F. Zimmermann
CERN, Geneva, Switzerland

The pinch of the electron cloud due to a passing proton bunch was extensively studied in a field free region and in a dipolar magnetic field. For the latter study, a strong field approximation helped to formulate the equations of motion and to understand the complex electron pinch dynamics, which exhibited some similarities with the field-free situation. Here we extend the analysis to the case of electron pinch in quadrupoles and in sextupoles. We discuss the limits of validity for the strong field approximation and we evaluate the relative magnitude of the peak tune shift along the bunch expected for the different fields.

MOPS025

Studies of Emittance Measurement by Quadrupole Variation for the IFMIF-EVEDA High Space Charge Beam

emittance, space-charge, simulation, beam-transport

652

P.A.P. Nghiem, E. Counienc
CEA/DSM/IRFU, France
N. Chauvin
CEA/IRFU, Gif-sur-Yvette, France
C. Oliver
CIEMAT, Madrid, Spain

For the high-power (1 MW) beam of the IFMIF-EVEDA prototype accelerator, emittance measurements at nearly full power are only possible in a non-interceptive way. The method of quadrupole variation is explored here. Due to the high space charge regime, beam transport is strongly non-linear, and the classical matrix inversion is no more relevant. Inverse calculations using a multiparticle code is mandatory. In this paper, such emittance measurements are studied, aiming at checking its feasibility and evaluating its precision, taking into account the constraints of losses and quadrupole limitations.

MOPS026

Start-to-end Beam Dynamics Simulations for the Prototype Accelerator of the IFMIF/EVEDA Project

rfq, simulation, linac, solenoid

655

N. Chauvin
CEA/IRFU, Gif-sur-Yvette, France
M. Comunian
INFN/LNL, Legnaro (PD), Italy
O. Delferrière, R.D. Duperrier, R. Gobin, A. Mosnier, P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France
C. Oliver
CIEMAT, Madrid, Spain

The EVEDA (Engineering Validation and Engineering Design Activities) phase of the IFMIF (International Fusion Materials Irradiation Facility) project consists in building, testing and operating a 125 mA/9 MeV prototype accelerator in Rokkasho-Mura (Japan). Because of high beam intensity and power, the different sections of the accelerator (injector, RFQ, MEBT, Superconducting Radio-Frequency linac and HEBT) have been optimized with the twofold objective of minimizing losses along the machine and keeping a good beam quality. Extensive start-to-end multi-particles simulations have been performed to validate the prototype accelerator design. A Monte Carlo error analysis has been carried out to study the effects of misalignments and field variations. In this paper, the results of theses beam dynamics simulations, in terms of beam emittance, halo formation and beam losses, are presented.

MOPS068

Localization of Transverse Impedance Sources in the SPS using HEADTAIL Macroparticle Simulations

impedance, lattice, simulation, ion

757

N. Biancacci, G. Arduini, E. Métral, D. Quatraro, G. Rumolo, B. Salvant, R. Tomás
CERN, Geneva, Switzerland
N. Biancacci, M. Migliorati, L. Palumbo
Rome University La Sapienza, Roma, Italy
R. Calaga
BNL, Upton, Long Island, New York, USA

In particle accelerators, beam coupling impedance is one of the main contributors to instability phenomena that lead to particle losses and beam quality deterioration. For this reason these machines are continuously monitored and the global and local amount of impedance needs to be evaluated. In this work we present our studies on the local transverse impedance detection algorithm. The main assumptions behind the algorithm are described in order to understand limits in reconstructing the impedance location. The phase advance response matrix is analyzed in particular for the SPS lattice, studying the different response from 90,180,270 degrees phase advance sections. The thin lenses scheme is also implemented and new analytical formulas for phase advance beating were derived. This avails us to put reconstructing lenses everywhere in the lattice, and to study their positioning scheme. Limits in linear response are analyzed. This sets the upper and lower limits in reconstruction to the phase advance measurement accuracy and the linear response regime limit.

MOPS090

Observation of Beam Ion Instability in SPEAR3

ion, vacuum, emittance, single-bunch

814

L. Wang, Y. Cai, W.J. Corbett, T.O. Raubenheimer, J.A. Safranek, J.F. Schmerge, J.J. Sebek
SLAC, Menlo Park, California, USA
D. Teytelman
Dimtel, San Jose, USA

Weak vertical coupled bunch instability with oscillation amplitude at μm level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.

MOPZ006

Main Magnets Design Studies for the Non-scaling Fixed Field Alternating Gradient Accelerator for a Final Acceleration Stage of the Neutrino Factory

dipole, factory, focusing, acceleration

829

J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
M. Aslaninejad, C. Bonţoiu, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The International Design Study of the Neutrino Factory (IDS-NF) aims to design the next generation facility for the precision neutrino oscillation searches. The non scaling Fixed Field Alternating Gradient Accelerator was prosed for the final muon beam acceleration in order to reduce the cost of the final acceleration. The superconducting magnet design based on the independent multipole coils approach using the ROXIE code is presented. The feasibility of the magnet construction together with the quench limitations are discussed.

MOPZ016

MICE Step I: First Measurement of Emittance with Particle Physics Detectors*

emittance, simulation, collider, factory

853

L. Coney
UCR, Riverside, California, USA
M. Popovic
Fermilab, Batavia, USA
M.A. Rayner
DPNC, Genève, Switzerland

The muon ionization cooling experiment (MICE) is a strategic R&D project intending to demonstrate the only practical solution to prepare high brilliance beams necessary for a neutrino factory or muon colliders. MICE is under development at the Rutherford Appleton Laboratory (UK). It comprises a dedicated beam line to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam is measured in the upstream magnetic spectrometer with a sci-fiber tracker. A cooling cell will then follow, alternating energy loss in Li-H absorbers and RF acceleration. A second spectrometer identical to the first and a second muon identification system measure the outgoing emittance. In the 2010 run the beam and most detectors have been fully commissioned and a first measurement of the emittance of a beam with particle physics (time-of-flight) detectors has been performed. The analysis of these data should be completed by the time of the Conference. The next steps of more precise measurements, of emittance and emittance reduction (cooling), that will follow in 2011 and later, will also be outlined.
Abstract is submitted by the MICE Speakers Bureau.
If accepted, most likely Dr. Kaplan will present it.
As a first result in a novel sector, we propose it for an oral presentation

MOPZ031

Multipass Muon RLA Return Arcs based on Linear Combined-function Magnets

linac, dipole, optics, lattice

868

V.S. Morozov, S.A. Bogacz, Y. Roblin
JLAB, Newport News, Virginia, USA
K.B. Beard
Muons, Inc, Batavia, USA

Funding: Supported in part by US DOE STTR Grant DE-FG02-08ER86351. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60°-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.

MOPZ034

Proton Contamination Studies in the MICE Muon Beam Line

proton, lattice, positron, emittance

871

S.D. Blot, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
R.R.M. Fletcher
UCR, Riverside, California, USA
D.M. Kaplan
Illinois Institute of Technology, Chicago, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The Muon Ionization Cooling Experiment (MICE) aims to demonstrate transverse beam emittance reduction for a muon beam. To create these muons, a titanium target is dipped into the ISIS proton accelerator at Rutherford Appleton Laboratory (UK) to create pions, which are transported and decay to muons in the MICE beamline. Beam particle identification and triggering is performed using time of flight (ToF) detectors. When running the MICE beamline with positive polarity, protons produced in the target contaminate the muon beam with a sufficiently high rate to saturate the TOF detectors. Polyethylene sheets of varying thicknesses were installed to absorb the proton impurities in the beam. Studies with pion beams at momenta of 140, 200, and 240MeV/c were performed with different proton absorber thicknesses. The results of these studies show good agreement with theoretical range plots and will be presented.

MOPZ039

Dispersion-free Regions and Insertions for EMMA

lattice, sextupole, extraction, injection

886

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

EMMA (Electron Machine with Many Applications) is a prototype non-scaling electron FFAG hosted at Daresbury Laboratory. Several upgrade possibilities for EMMA are explored, from creating a dispersion-free region in the ring to facilitate injection and extraction to making an insertion in EMMA by turning it into a racetrack-style machine. A dispersion-free region may be created in two separate ways. The first is by using a layout of EMMA which is naturally dispersion-free at the start and end of each cell. This means that we can arrange for periodic dispersion-free sections in every cell or in-between cells. The second is achieved through the use of sextupoles, by going off-axis in them, one has essentially a quadrupolar force which can be used to match the dispersion to zero in a particular place and for a particular energy. The benefits and drawbacks of both methods are discussed from the point of view of practicality and space in general, and applicability to EMMA in particular.

TUYA02

LHC Upgrade Plans: Options and Strategy

luminosity, cavity, collider, cryogenics

908

L. Rossi
CERN, Geneva, Switzerland

Presentation of options for future luminosity and/or energy upgrades of the LHC ring. The presentation should cover the different ideas, short term, medium term and long term, and discuss the research programme that is needed to prepare the upgrades.

Slides TUYA02 [5.139 MB]

TUODA01

Vertical Emittance Reduction and Preservation at the ESRF Electron Storage Ring

emittance, coupling, feedback, storage-ring

928

A. Franchi, J. Chavanne, F. Ewald, L. Farvacque, T.P. Perron, K.B. Scheidt
ESRF, Grenoble, France

In 2010 a campaign for the reduction and preservation of low vertical emittance at the ESRF electron storage ring was undertaken: values between 20 and 30 pm have been dramatically reduced to 3.5-4.5 pm, even during beam delivery. This improvement is the result of an increased measurement precision provided by the recently upgraded beam position monitoring system, a new correction algorithm, a larger number of correctors and two independent schemes for the automatic compensation of coupling induced by a few insertion devices whenever their gaps are moved by users during beam delivery. This paper summarizes the campaign's milestones and the results updated to the first half of 2011.

Slides TUODA01 [5.297 MB]

TUXB01

Methods and Tools to Simulate and Analyse Non-linear Dynamics in Electron Storage Rings

storage-ring, lattice, emittance, sextupole

937

L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

This talk will present the different approaches and tools that have been recently developed while trying to understand or predict the non-linear dynamics of electron storage rings. Different algorithms have been recently used at different places to optimize the sextupole tunings, while the refinement of the models of existing machines together with more accurate measurement techniques enable now to fully understand the limitations of such facilities specially in the presence of insertion devices.

Slides TUXB01 [7.624 MB]

TUYB02

The Challenges of Ultra-low Emittance Damping Rings

emittance, damping, electron, coupling

956

D. L. Rubin
CLASSE, Ithaca, New York, USA

Funding: Work supported by the National Science Foundation and by the US Department of Energy under contract numbers PHY-0734867 and DE-FC02-08ER41538.
In this paper we review the state of the art of the design of damping rings for linear colliders, as supported by the experimental data from ATF and CESR test damping rings. We consider implications of measurements of electron cloud dynamics and mitigation in a radiation dominated ring. The techniques developed for tuning for ultra-low emittance in these rings are summarized. Other dynamics manifested in the ultra-low emittance regime where collective effects are important are discussed.

Slides TUYB02 [7.198 MB]

TUPC008

CLIC Two-Beam Module for the CLIC Conceptual Design and Related Experimental Program

alignment, linac, vacuum, RF-structure

1003

A. Samoshkin, D. Gudkov, A. Solodko
JINR, Dubna, Moscow Region, Russia
G. Riddone
CERN, Geneva, Switzerland

The Compact LInear Collider (CLIC), being studied at CERN, involves the design and integration of many different technical systems, tightly bound and influencing each other. For the construction of two main linacs it has been decided to proceed with a modular design, and repetitive two-beam modules of a few types were defined. The modules consist of micro-precision components operating under ultra-high vacuum as required by the beam physics. For the CLIC Conceptual Design Report, the development and system integration is mainly focused on the most complex module type containing the highest number of components and technical systems. For proving the proper functioning of the needed technical systems and confirming their feasibility it has been decided to build four prototype modules and test them without beam. In addition, three modules have to be produced in parallel for tests in the CLIC Experimental Area with beam. This paper is focused on the design of the different technical systems and integration issues of the two-beam module. The experimental program for the prototype modules is also recalled.

TUPC014

System Control for the CLIC Main Beam Quadrupole Stabilization and Nano-positioning*

feedback, luminosity, ground-motion, simulation

1021

S.M. Janssens, K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, A.M. Kuzmin, R. Leuxe, J. Pfingstner, D. Schulte, J. Snuverink
CERN, Geneva, Switzerland

The conceptual design of the active stabilization and nano-positioning of the CLIC main beam quadrupoles was validated in models and experimentally demonstrated on test benches. Although the mechanical vibrations were reduced to within the specification of 1.5 nm at 1 Hz, additional input for the stabilization system control was received from integrated luminosity simulations that included the measured stabilization transfer functions. Studies are ongoing to obtain a transfer function which is more compatible with beam based orbit feedback; it concerns the controller layout, new sensors and their combination. In addition, the gain margin must be increased in order to reach the requirements from a higher vibration background. For this purpose, the mechanical support is adapted to raise the frequency of some resonances in the system and the implementation of force sensors is considered. Furthermore, this will increase the speed of repositioning the magnets between beam pulses. This paper describes the improvements and their implementation from a controls perspective.

TUPC016

Status of the ATF2 Lattices

lattice, sextupole, multipole, optics

1027

E. Marin, R. Tomás
CERN, Geneva, Switzerland
P. Bambade
LAL, Orsay, France
T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
A. Seryi
JAI, Oxford, United Kingdom
G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

The latest status for the ATF2 Nominal and Ultra-low beta lattices designs obtained to minimize the detrimental effect of the measured multipoles are presented in this paper. A set of correction knobs for the most important aberrations at the IP have been obtained for both lattices in order to perform the tuning under realistic imperfections. Starting from the tuned ATF2 Nominal lattice a squeeze sequence reducing beta_y is performed to reach the ultra-low beta lattice. Tuning results are shown for both options.

TUPC019

Beam-based Alignment of CLIC Drive Beam Decelerator using Girders Movers

alignment, simulation, dipole, extraction

1036

G. Sterbini, D. Schulte
CERN, Geneva, Switzerland

The CLIC drive beams will provide the rf power to accelerate the colliding beams: in order to reach the design performance, an efficient transport of the drive beam has to be ensured in spite of its challenging energy spread and large current intensity. As shown in previous studies, the specifications can be met by coupling a convenient optics design with the state-of-the-art of pre-alignment and beam-based alignment techniques. In this paper we consider a novel beam-based alignment scheme that does not require quadrupole movers or dipole correctors but uses the motors already foreseen for the pre-alignment system. This implies potential savings in terms of complexity and cost at the expense of the alignment flexibility: the performance, limitations and sensitivity to pre-alignment tolerances of this method are discussed.

TUPC023

Status of Ground Motion Mitigation Techniques for CLIC

luminosity, feedback, simulation, ground-motion

1048

J. Snuverink, K. Artoos, C.G.R.L. Collette, F. Duarte Ramos, A. Gaddi, H. Gerwig, S.M. Janssens, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
G. Balik, L. Brunetti, A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
B. Caron
SYMME, Annecy-le-Vieux, France
J. Resta-López
IFIC, Valencia, Spain

The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques are proposed - quadrupole stabilisation and positioning, final doublet stabilisation as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of the ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) have been performed, which model the hardware and beam performance in detail. Based on the results future improvements of the mitigation techniques are suggested and simulated. It is shown that with the current design the tight luminosity budget for ground motion effects is fulfilled and accordingly, an essential feasibility issue of CLIC has been addressed.

TUPC030

Recommendation for Mitigations of the Electron Cloud Instability in the ILC

electron, vacuum, positron, emittance

1063

M.T.F. Pivi, L. Wang
SLAC, Menlo Park, California, USA
L.E. Boon, K.C. Harkay
ANL, Argonne, USA
J.A. Crittenden, G. Dugan, M.A. Palmer
CLASSE, Ithaca, New York, USA
T. Demma, S. Guiducci
INFN/LNF, Frascati (Roma), Italy
M.A. Furman
LBNL, Berkeley, California, USA
K. Ohmi, K. Shibata, Y. Suetsugu, J. Urakawa
KEK, Ibaraki, Japan
C. Yin Vallgren
Chalmers University of Technology, Chalmers Tekniska Högskola, Gothenburg, Sweden

Funding: Work supported by the Director, Office of Science, High Energy Physics, U.S. DOE under Contract No. DE-AC02-76SF00515.
Electron cloud has been identified as one of the highest priority issues for the ILC Damping Rings (DR). A working group has evaluated the electron cloud effect and instability, and mitigation solutions for the electron cloud formation. Working group deliverables include recommendations for the baseline and alternate solutions for the electron cloud mitigation in various regions of the ILC Positron DR, which is presently assumed to be the 3.2km design. Detailed studies of a range of mitigation options including coatings, clearing electrodes, grooves and novel concepts, were carried out over the previous several years by nearly 50 researchers, and the results of the studies form the basis for the recommendation. The assessments of the benefits or risks associated with the various options were based on a systematic ranking scheme. The recommendations are the result of the working group discussions held at numerous meetings and during a dedicated workshop. The mitigation choices will be also presented in a more detailed report later in 2012. In addition, a number of items requiring further investigation were identified and studies will be carried out at CesrTA and other institutions.

TUPC039

Proposals for Electron Beam Transportation Channel to Provide Homogeneous Beam Density Distribution at a Target Surface

target, electron, neutron, beam-losses

1084

A.Y. Zelinsky, I.M. Karnaukhov
NSC/KIPT, Kharkov, Ukraine
W.B. Liu
IHEP Beijing, Beijing, People's Republic of China

NSC KIPT neutron source will use 64x64 mm rectangular tungsten or uranium target. To generate maximum neutron flux, prevent overheating of the target and reduce thermal stress one should provide homogeneous electron beam distribution at the target surface. In the facility transportation channel three different possibilities of electron beam density redistribution along the target surface can be realized. It can be the fast beam scanning with two dimensional scanning magnets; the method of uniform beam distribution formation with linear focusing elements (dipole and quadrupole magnets) and nonlinear focusing elements (octupole magnets), when final required rectangular beam shape with homogeneous beam density is formed at target; and combined method, when one forms the small rectangular beam with homogeneous beam density distribution and scan it over the target surface with scanning magnets. In the report the all tree methods are considered and discussed considering the layout of the NSC KIPT transportation channel. Calculation results show that the proposed transportation channel lattice can provide uniform beam of rectangular shape with sizes 64x64 mm without target overheating.

TUPC046

Alignment Tolerances for Vertical Emittance

emittance, lattice, closed-orbit, dipole

1102

K.P. Wootton, R.P. Rassool, G. Taylor
The University of Melbourne, Melbourne, Australia
M.J. Boland, R.T. Dowd, G. LeBlanc, Y.E. Tan
ASCo, Clayton, Victoria, Australia
Y. Papaphilippou
CERN, Geneva, Switzerland

Alignment tolerances for the CLIC main damping ring magnetic lattice elements are presented. Tolerances are defined by the design equilibrium vertical emittance of 1 pm rad. The sensitivity of the uncorrected lattice to magnet misalignments is presented. Misalignments considered included quadrupole vertical offsets and rolls, sextupole vertical offsets, and main dipole rolls. Seeded simulations were conducted in MAD-X, and compared with expectation values calculated from theory. The lattice was found to be sensitive to betatron coupling as a result of sextupole vertical offsets in the arcs. Alignment tolerances, BPM and corrector requirements are presented also. For the same misalignment types, the equilibrium emittance of the corrected lattice is simulated. These are compared with expectation values calculated from theory. The vertical alignment tolerance of arc sextupoles is again demanding.

TUPC049

Optics considerations for the Delay Loop in the CLIC Damping Rings Complex

dipole, emittance, optics, damping

1108

P. Zisopoulos, F. Antoniou, H. Bartosik, Y. Papaphilippou
CERN, Geneva, Switzerland

For the recombination of the two trains coming from the CLIC damping rings, a delay loop will be used in order to obtain the nominal 0.5~ns bunch spacing. The optics design of the loop is based upon an isochronous ring, in order to preserve the longitudinal beam distribution. Analytical expressions for achieving isochronous conditions in high order for Theoretical Minimum Emittance cells are obtained. A parametrisation of the quadrupole settings for achieving these conditions is presented, along with general considerations regarding the choice of bending magnet characteristics.

TUPC052

Normal Mode BPM Calibration for Ultralow-Emittance Tuning in Lepton Storage Rings

emittance, coupling, alignment, simulation

1114

A. Wolski
The University of Liverpool, Liverpool, United Kingdom
D. L. Rubin, D. Sagan, J.P. Shanks
CLASSE, Ithaca, New York, USA

BPMs capable of high-resolution turn-by-turn measurements offer the possibility of new techniques for tuning for ultra-low beam emittance. In this paper, we describe how signals collected from individual buttons during resonant beam excitation can be used to calibrate BPMs to read the beam position in a normal mode coordinate system. This allows for rapid minimization of the mode II emittance, simply by correcting the mode II dispersion. Simulations indicate that the technique is effective and robust, and has the benefit of being insensitive to BPM gain and alignment errors that can limit the effectiveness of other techniques.

TUPC064

Transverse Phase Space Tomography in TRIUMF Injection Beamline

emittance, space-charge, TRIUMF, injection

1144

Y.-N. Rao, R.A. Baartman
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada.
By tomography is meant the reconstruction of a 2-dimensional distribution from a number of 1-dimensional projections. In the case of transverse phase space, one records many profiles while varying a focusing device such as a quadrupole. Our aim was to investigate the two transverse phase space distributions in our 300keV H-minus beamline. We performed a series of measurements of beam profiles as a function of the voltage of an electrostatic quadrupole and used these along with the corresponding calculated transfer matrices in an iterative program based upon the Maximum Entropy algorithm, to find the phase space distributions. As well, we made measurements using an Allison-type emittance scanner to scan both planes. In this paper we present the details of these measurements, calculations, and we compare the two techniques.

TUPC095

Bucket-by-bucket On/Off-axis Injection with Variable Field Fast Kicker

kicker, injection, dipole, emittance

1230

T. Nakamura
JASRI/SPring-8, Hyogo-ken, Japan

Dynamic aperture of ultra-low emittance storage rings is expected to be as small as a few mm; one order smaller than that of current rings, because of their high nonlinearity. The conventional injection scheme with bump formation may not be applied for such small aperture. On-axis injection with fast magnet is one of the solutions, however, it requires the injection beam of long trains of bunches, which impose serious limitation on the injector and the filling pattern. We propose a bucket-by-bucket on-axis/off-axis injection scheme, which manipulates the injection and stored beams bucket-by-bucket with a variable field fast kicker. For on-axis injection, this scheme eliminates the limitation on injectors and filling pattern, and also it can reject the contaminated electrons from the injector to keep the bunch purity. Those advantages allow the SPring-8 XFEL low emittance linac to be an injector matched with ultra-low emittance rings like the SPring-8 II: upgrade plan of SPring-8. By changing the drive power to the kicker, it can also produce position dependent kick required for the off-axis injection, with minimal perturbation on the stored beam achieved by bucket-by-bucket scheme.

TUPC103

Monitoring of the Betatron Tune and Amplitude at Multi-batch Injection of J-PARC MR

injection, kicker, betatron, feedback

1254

S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan
M. Takagi
Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
M. Tejima, T. Toyama
KEK, Ibaraki, Japan

The beam power of J-PARC Main Ring Synchrotron (MR) increased gradually from 2008, and came to be able regularly to supply the beam of 145kW February, 2011. Many of current beam losses are localized to the collimator located on the injection section. One of the problems of the beam injection is that the orbit of the beam transportation line is unstable. It causes sometimes large transverse injection error. Because the transverse injection error is essentially proportional to the amplitude of the betatron oscillation, it is possible to observe by measuring the turn-by-turn position for every bunch of injected beam by using BPMs located on the injection section. In this report, it is described the method how to measure injection error from beam position. It is also discussed about the effect of reflection wave of injection kicker magnets.

TUPC111

Design of Cavity Beam Monitor at HLS

cavity, emittance, gun, dipole

1278

Q. Luo, Q.K. Jia, B.G. Sun, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by the Natural Science Foundation of China, National “985 Project”, China Postdoctoral Science Foundation and “the Fundamental Research Funds for the Central Universities”
X-FEL requires precious control of beam position and transverse emittance. Non-destructive on-line beam diagnostic methods are required. During the upgrading of HLS a high brightness injector based on photocathode RF electron gun, which can also be used to study FEL, is installed. The cavity beam monitor system designed for the HLS photocathode RF electron gun consists of a cavity beam position monitor and a beam quadrupole moment monitor system. The cavity beam position monitor uses a re-entrant position cavity tuned to TM110 mode as position cavity and cut-through waveguides to suppress the monopole signal. Cold test results showed that position resolution of prototype BPM is better than 3 μm. Beam quadrupole moment monitor system consists of a square pill-box quadrupole moment cavity, a cylindrical pill-box reference cavity, a waveguide coupling network and a superheterodyne receiver used as front-end signal processing system. The whole system works at 5.712 GHz. Strength of quadrupole magnets is adjust to construct a matrix which can be used to work out beam parameters.

TUPC130

Beam Test Performance of the Beam Position Monitors for the TBL Line of the CTF3 at CERN

pick-up, monitoring, linac, beam-transport

1326

J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera, A. Faus-Golfe
IFIC, Valencia, Spain
S. Döbert
CERN, Geneva, Switzerland

Funding: Funding Agency: FPA2010-21456-C02-01
A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the CLIC Test Facility (CTF3) at CERN. In this paper we present the results of the beam test carried out on the BPS units of the TBL in order to determine their beam performances and check the specified operational requirements. We focus particularly on the position resolution parameter which is the BPS figure of merit according to TBL demands and is expected to reach the 5um resolution at maximum beam current (28A). The beam test results of the BPS units are also compared with the parameters from their previous characterization test at lab.

TUPC136

Analysis of Fast Losses in the LHC with the BLM System

beam-losses, injection, superconducting-magnet, proton

1344

E. Nebot Del Busto, T. Baer, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, A. Marsili, A. Nordt, M. Sapinski, R. Schmidt, B. Velghe, J. Wenninger, C. Zamantzas, F. Zimmermann
CERN, Geneva, Switzerland
N. Fuster
Valencia University, Atomic Molecular and Nuclear Physics Department, Valencia, Spain
Z. Yang
EPFL, Lausanne, Switzerland

About 3600 Ionization Chambers are located around the LHC ring to detect beam losses that could damage the equipment or quench superconducting magnets. The BLMs integrate the losses in 12 different time intervals (from 40 us to 83.8 s) allowing for different abort thresholds depending on the duration of the loss and the beam energy. The signals are also recorded in a database at 1 Hz for offline analysis. During the 2010 run, a limiting factor in the machine availability were sudden losses appearing around the ring on the ms time scale and detected exclusively by the BLM system. It is believed that such losses originate from dust particles falling into the beam, or being attracted by its strong electromagnetic field. This document describes some of the properties of these "Unidentified Falling Objects" (UFOs) putting special emphasis on their dependence on beam parameters (energy, intensity, etc). The subsequent modification of the BLM beam abort thresholds for the 2011 run that were made to avoid unnecessary beam dumps caused by these UFO losses are also discussed.

TUPC149

Measurements at the ALICE Tomography Section

emittance, injection, simulation, background

1377

M.G. Ibison, K.M. Hock, D.J. Holder, B.D. Muratori, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Korostelev
The University of Liverpool, Liverpool, United Kingdom

Funding: STFC
This paper reports the results of tomography measurements of the electron beam transverse phase space distribution in the ALICE accelerator at Daresbury Laboratory. These measurements have two main aims. The first is to give a detailed picture of the phase space distribution of the electron beam injected from ALICE into the EMMA prototype non-scaling FFAG accelerator. The second is to provide data for the development and testing of a variety of techniques for tomographic reconstruction. We summarize the measurement results which we have obtained and discuss the advantages and disadvantages of some different tomography methods.

TUPC150

The Effect of Space-Charge on the Tomographic Measurement of Transverse Phase-Space in the EMMA Injection Line

space-charge, injection, emittance, simulation

1380

M.G. Ibison, M. Korostelev
The University of Liverpool, Liverpool, United Kingdom
K.M. Hock, D.J. Holder, B.D. Muratori, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: STFC
Phase-space tomography for particle beams depends upon detailed knowledge of the particle transport through specified sections of a beam line. In the simplest case, only the effects of magnets (such as quadrupoles) and drift spaces need to be taken into account; however, in certain parameter regimes (high charge density and low energy) space charge forces may play a significant role. The ALICE accelerator is the electron source for EMMA, a prototype ns-FFAG machine. Results are presented of investigations into these effects on phase-space tomography in the injection line between ALICE and EMMA. The application of suitable correction techniques* to the EMMA injection line tomography measurements in the presence of space-charge is also discussed.
* D. Stratakis et al., Phys. Rev. ST Accel. Beams 9, 112801 (2006).

TUPC159

Energy Measurements with Resonant Spin Depolarisation at Diamond

electron, storage-ring, feedback, resonance

1404

I.P.S. Martin, M. Apollonio, R.T. Fielder, G. Rehm
Diamond, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

A precise knowledge of the electron beam energy is critical for the accurate determination of many light source parameters, such as momentum compaction factor, natural chromaticity, energy stability and undulator spectra. In common with other facilities, a method of energy measurement based on resonant spin depolarisation has been developed at Diamond. In this paper we report on progress towards storage ring characterisation using this method, as well as describing the diagnostics developments that have enabled these measurements to be made.

TUPC161

Cavity Beam Position Monitor System for ATF2

cavity, dipole, EPICS, extraction

1410

S.T. Boogert, R. Ainsworth, G.E. Boorman, S. Molloy
Royal Holloway, University of London, Surrey, United Kingdom
A.S. Aryshev, Y. Honda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
F.J. Cullinan, N.Y. Joshi, A. Lyapin
JAI, Egham, Surrey, United Kingdom
J.C. Frisch, D.J. McCormick, J. Nelson, T.J. Smith, G.R. White
SLAC, Menlo Park, California, USA
A. Heo, E.-S. Kim, Y.I. Kim
KNU, Deagu, Republic of Korea

The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a future high energy lepton linear collider. The ATF2 beam-line is instrumented with a total of 41 high resolution C and S band resonant cavity beam position monitors (BPM) with associated mixer electronics and digitizers. In addition 4 high resolution BPMs have been recently installed at the interaction point, we briefly describe the first operational experience of these cavities in the ATF2 beam-line. The current status of the overall BPM system is also described, with a focus on operational techniques and performance.

TUPC164

Position Determination of Closely Spaced Bunches using Cavity BPMs

cavity, single-bunch, linear-collider, collider

1419

N.Y. Joshi, S.T. Boogert, F.J. Cullinan, A. Lyapin
JAI, Egham, Surrey, United Kingdom

Cavity Beam Position Monitor (BPM) systems with high-Q form a major part of precision position measurement diagnostics for linear accelerators with low emittance beam. Using cavity BPMs, the position resolution of less than 100 nm has been demonstrated in single bunch mode operation. In the case of closely spaced bunches, where the decay time of the cavity is comparable to the time separation between bunches, the BPM signal from a bunch is polluted by the signal induced from the previous bunches in the same bunch-train. This paper discuss our ongoing work to develop the methods to extract the position of the closely spaced bunches using cavity BPMs. A signal subtraction code is being developed to remove the signal pollution from previous bunches and to determine the individual bunch position. Another code has been developed to simulate the BPM data for the cross check. Performance of the code is studied on the experimental and simulated data. Application of the analysis techniques to the linear colliders, such as International Linear Collider (ILC) and Compact LInear Collider (CLIC), are briefly discussed.

TUPO006

Design of a Dispersive Beam Transport Line for the JETI Laser Wakefield Accelerators

undulator, radiation, electron, dipole

1455

C. Widmann, V. Afonso Rodriguez, T. Baumbach, A. Bernhard, P. Peiffer
KIT, Karlsruhe, Germany
M. Kaluza, M. Nicolai
IOQ, Jena, Germany
R. Rossmanith
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

Laser wakeﬁeld accelerators (LWFA) emit electrons with energies of a few 100 MeV at very short bunch lengths while having a compact design. However, electron bunches from LWFA show a larger energy spread than those of conventional accelerators. This is a challenge when using these bunches e.g. to generate radiation in an undulator. A possible strategy to cope with that is to spectrally disperse the bunch and match the resulting spatial distribution with a spatially varying undulator ﬁeld amplitude. For realizing the dispersion a pair of dipole magnets is used. The electrons leaving this dipole chicane have to meet certain requirements imposed by the undulator: In the deﬂection plane the beam has to be collimated and its energy distribution must match the undulator ﬁeld. In the other transversal plane the beam has to be focussed on the center of the undulator keeping the value of the beta function small. To include this in the compact design of the setup, a combination of specially designed quadrupole and sextupole magnets is employed. In this contribution the design of the setup and the results of the particle tracking through this chicane are presented.

TUPS032

Overview of EuCARD Accelerator and Material Research at GSI

ion, collimation, radiation, heavy-ion

1602

J. Stadlmann, H. Kollmus, E. Mustafin, N. Pyka, P.J. Spiller, I. Strašík, N.A. Tahir, M. Tomut, C. Trautmann
GSI, Darmstadt, Germany
L.H.J. Bozyk
TU Darmstadt, Darmstadt, Germany

Funding: EuCARD is co-funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 227579
EuCARD is a joined accelerator R&D initiative funded by the EU. Within this program, GSI Darmstadt is performing R&D on materials for accelerators and collimators in WP8(ColMat). GSI covers prototyping and testing of a cryogenic ion catcher for FAIR's main synchrotron SIS100, simulations and studies on activation of accelerator components e.g. halo collimatiors as well as irradiation experiments on materials foreseen to be used in FAIR accelerators and the LHC upgrade program. Carbon-carbon composites, silicon carbide and copper-diamond composite samples have been irradiated with heavy ions at various GSI beamlines and their radiation induced property changes were characterized. Numerical simulations on the possible damage by LHC and SPS beams to different targets have been performed. Simulations and modelling of activation and long term radiation induced damage to accelerator components have started. A prototype ion catcher has been built and first experiments have been performed in 2011. New collaborations with other institutes and industry in the EuCARD framework have been established and findings of the joined R&D effort influence decisions in the FAIR project and LHC upgrade.

TUPS073

Top-Up Safety Simulations for the TPS Storage Ring

storage-ring, electron, sextupole, photon

1707

H.-J. Tsai, C.C. Chiang, P.J. Chou, C.-C. Kuo
NSRRC, Hsinchu, Taiwan

TPS is a 3 GeV third generation light source and operates in the top-up injection scheme. During the top-up injection, the beamline photon shutters are always open. To ensure the radiation safety of beamline experiments, we studied the possible particle leakage to ID and neighboring bending beamlines. The effects of errors on magnets and beam chamber alignments are investigated.

TUPS094

Girder and Support System for PLS-II Project

multipole, dipole, storage-ring, alignment

1759

H.-G. Lee, H.S. Han, J.Y. Huang, Y.-G. Jung, D.E. Kim, S.N. Kim, S.H. Nam, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) is planning to upgrade the Pohang Light Source (PLS) which is a 3rd generation light source operating since 1995. We have designed a new steel magnet girder using new schemes to achieve long-term mechanical stability, vibration suppression and precision adjusting system. Each half cell of girder is composed of three pieces, two multipole magnet girder(MMG) and one dipole magnet girder(DMG). The storage ring girders consist of 48 multipole magnet girders and 24 dipole magnet girders. The new girder systems have been fabricated and tested. Recently the girders have been installing and testing the moving mechanism in the storage ring. In this report, the design consideration for the PLSII girder and support systems are reported.

TUPZ002

90 m β* Optics for ATLAS/ALFA

optics, emittance, luminosity, scattering

1798

S. Cavalier, P.M. Puzo
LAL, Orsay, France
H. Burkhardt
CERN, Geneva, Switzerland
A. Peskov
NNGU, Nizhny Novgorod, Russia

We describe a high β* optics developed for the ATLAS detector at the LHC interaction regions (IR1), Roman Pots have been installed 240 m left and right of IR1 to allow to measure the absolute luminosity and the total elastic cross section for ATLAS with ALFA (Absolute Luminosity for ATLAS). Ultimately, it is planned to preform these measurements at a very high β* of 2625 m. Here we describe a new, intermediate β* = 90 m optics, which has been optimized for compatibility with the present LHC running conditions. We described the main features and expected performance of this optics for ALFA.

TUPZ021

The SPS Beam Quality Monitor, from Design to Operation

injection, extraction, dipole, luminosity

1849

G. Papotti, T. Bohl, F. Follin, E.N. Shaposhnikova
CERN, Geneva, Switzerland

The SPS Beam Quality Monitor is a system that monitors longitudinal beam parameters on a cycle-by-cycle basis and prevents extraction to the LHC in case the specifications are not met. This avoids losses, unnecessary stress of machine protection components and luminosity degradation, additionally helping efficiency during the filling process. The system has been operational since the 2009 LHC run, checking the beam pattern, its correct position with respect to the LHC references, individual bunch lengths and stability. In this paper the algorithms used, the hardware implementation and the operational aspects are presented.

TUPZ026

Alternative Working Point(s) at Injection for the LHC

injection, coupling, optics, emittance

1861

R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP).
At present, the LHC operates with a different fractional tunes at injection and at collision energy due to improved dynamic aperture indicated by tracking studies. Therefore, a tune swing crossing the 10th order resonance is needed during the beta-squeeze. A new proposal to alter the working point to collision tunes already at injection and during an energy ramp is foreseen to avoid the tune jump. Simulations and measurements of the optics along with the beam emittances and lifetime are compared to the nominal injection tunes. Feasibility for a working point close to the 1/2 integer is also attempted.

TUPZ027

Beta* Measurement in the LHC Based on K-modulation

optics, luminosity, simulation, lattice

1864

R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP).
Accurate knowledge of the collision point optics is crucial to equalize the luminosities at the different experiments. K-modulation was successfully applied at several accelerators for measuring the lattice beta functions. In the LHC, it was proposed as an alternative method to compute the beta* at the collision points. Results of beta* measurements in the LHC based on the K-modulation technique are presented with comparisons to nominal segment-by-segment method.

TUPZ034

Impact of Arc Phase Advance on Chromatic Optics in RHIC

optics, injection, ion, proton

1885

R. Calaga, R. Miyamoto, G. Robert-Demolaize, S.M. White
BNL, Upton, Long Island, New York, USA
R. De Maria, R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: This work is partially supported by the US Department of Energy through the LHC Accelerator Research program (LARP).
The phase advance between the two interaction points in RHIC is optimized for dynamic aperture for a initial design beta-star. This may not hold true as RHIC presently operates with a considerably reduced beta-star. Additionally the reduction of the available beam aperture due to an enlarged chromatic beta-beating is evident. Results from phase advance scans between the two IPs to reduce the chromatic beta-beating in model and measurements are presented. Impact on the single beam lifetime and momentum aperture is compared to the nominal optics.

TUPZ039

Modelling of the AGS Using Zgoubi - Status

dipole, multipole, simulation, resonance

1897

F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Models of the Alternating Gradient Synchrotron, based on stepwise ray-tracing methods using both mathematical modelling or ﬁeld maps so to represent the optical elements, including the siberian snakes, are being developed based on stepwise ray-tracing numerical tools. The topic is introduced in earlier PAC and IPAC publications, a status is given here.

WEZA02

Colliders for B Factories

luminosity, emittance, sextupole, factory

1931

H. Koiso
KEK, Ibaraki, Japan

Two new B factories, SuperB in Frascati and SuperKEKB in Tsukuba, aim at unprecedented luminosities close to 10³6/cm²/s. The designs, status, challenges, and differences between the two machines are reported. Emphasis should be put on recent developments for the B factories. The presentation should include a realistic outlook.

Slides WEZA02 [6.796 MB]

WEPC001

Beam Based Sextupole Alignment Studies for Coupling Control at the ASLS

sextupole, coupling, storage-ring, alignment

1995

R.T. Dowd, Y.E. Tan
ASCo, Clayton, Victoria, Australia

Offsets in sextupole magnets can be a significant source of coupling in a storage ring and hinder efforts to minimize vertical emittance. Beam offsets in the sextupoles at the Australian Synchrotron Light Source were measured using a response matrix analysis in LOCO with differing magnets strengths. These results were used to obtain an estimate of offset in each sextupole as well as estimate quadrupole contributions to coupling.

WEPC004

Comparison of the Action and Phase Analysis on LHC Orbits with Other Techniques

interaction-region, coupling, optics, simulation

2004

J.F. Cardona
UNAL, Bogota D.C, Colombia
R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: DIB-Universidad Nacional de Colombia
Recently acquired turn-by-turn data of the LHC is analyzed using the action and phase jump technique. The results of this analysis show a visible variation of the action and phase plots at the interaction regions from which optic error estimations can be done. In this paper error estimations will be presented and comparisons with other existing techniques in the LHC, such as the recently implemented Segment-by-segment technique, will be discussed.

WEPC005

Concept for Controlled Transverse Emittance Transfer within a Linac Ion Beam

emittance, ECR, solenoid, linac

2007

L. Groening
GSI, Darmstadt, Germany

Generally the two transverse emittances of a linac beam are quite similar in size (round beam). However, injection into subsequent rings often imposes stronger limits for the upper allowed value to one of these emittances. Provision of flat linac beams (different transverse emittances) thus can considerable increase the injection efficiency into rings. Round-to-flat transformation has been already demonstrated for electron beams. It was also proposed for angular momentum dominated beams from Electron-Cyclotron-Resonance sources. We introduce a concept to extend the transformation to ion beams that underwent charge state stripping without requiring their extraction from an ECR source. The concept is of special interest for beams from low-charge-state / high-particle-current sources. It can be also applied to stripping of H⁻ to proton beams.

WEPC007

Large Energy Acceptance Dogleg for the European XFEL Injector

sextupole, focusing, linac, controls

2013

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

The option to install two injectors is foreseen at the European XFEL Facility. The injectors will be located on top of each other in the same building, both with the offset of 2.75 m with respect to the main linac axis. The translation system (dogleg) from the injector axis to the main linac axis has to fulfill very tight requirements of the chromatic properties, because the energy chirp required for the downstream bunch length compression in magnetic chicanes will be created upstream in the injector linac. In this paper we present such an large energy acceptance dogleg and discuss the optical symmetries which form the basis of its design.

WEPC008

Optics for the Beam Switchyard at the European XFEL

kicker, septum, undulator, extraction

2016

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

The European XFEL is planed as a multi-user facility with the possibility to distribute electron bunches of one beam pulse to different beamlines. The initial stage foresees two electron beamlines each serving its own set of undulators. The later addition of a third beamline is also considered in the design of the distribution system. In addition, the integration of the transport line to the beam abortion dump allows a flexible selection of the bunch repetition pattern for each beamline. The beam extraction, both in undulator beamlines and in the beamline to the dump, will be realized with fast kickers and a Lambertson septum. In this paper we describe the magnet lattice of the deflection arcs with simultaneous horizontal and vertical dispersions and the beam optics of the beam switchyard.

WEPC009

Design of an Antiproton Injection and Matching Beam Line for the AD Recycler Ring

antiproton, acceleration, injection, ion

2019

O. Karamyshev, G.A. Karamysheva
MPI-K, Heidelberg, Germany
O. Karamyshev, A.I. Papash
JINR, Dubna, Moscow Region, Russia
M.R.F. Siggel-King, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328.
A small antiproton recycler ring (AD-Rec) for use in the MUSASHI beamline at the CERN AD has been designed by the QUASAR Group for operation at energies between 3 and 30 keV. A highly efficient beam line for capturing the beam after extraction from the trap, transporting and injecting it into the AD Rec is very important to minimize losses and full the ring up to its space charge limit. In this contribution, the beam optical and mechanical design of the injector is presented.

WEPC011

Ion Optical Design of the Low Energy Ion Beam Facility at IUAC

ion, optics, ECR, target

2025

A. Mandal, D. Kanjilal, S. Kumar, G. Rodrigues
IUAC, New Delhi, India

A Low Energy Ion Beam Facility (LEIBF) using fully permanent magnet ECR ion source (Nanogan) has been installed at Inter University Accelerator Centre (IUAC), New Delhi for fundamental research on Atomic and Molecular Physics, and Material Science. The accelerator consists of an ECR ion source, 400 kV accelerating column and an analyzing-cum switching magnet with three beam ports at 75, 90 and 10⁵ degrees. The complete ion optics from ECR ion source to the target has been simulated using TRANSPORT* and GICOSY** ion optics codes. The ions from the ECR source are typically extracted at 15 kV which are further accelerated by 400 kV accelerating column. The analyzing cum switching magnet has been designed to analyze different beams and to switch in a particular beam line. It is a H shaped dipole magnet having pole gap of 65 mm, maximum magnetic field of 1.5 T and radius of 529 mm for 90 degree bend. The entrance and exit edge angles for three beam lines have been optimized to obtain double focus in all beam lines. The beam is further transported to target locations using electrostatic quadrupole triplet. The details of ion optics will be presented in the paper.
* K.L. Brown, D.C. Carey, Ch. Iselin and F. Rothacker: Transport, See yellow reports CERN 73-16 (1973) & CERN 80-04 (1980).
** H.Weick, GICOSY homepage, http://www-linux.gsi.de/~weick/gicosy/.

WEPC013

Tests for Low Vertical Emittance at Diamond using LET Algorithm

coupling, emittance, simulation, lattice

2031

S.M. Liuzzo, M.E. Biagini, P. Raimondi
INFN/LNF, Frascati (Roma), Italy
R. Bartolini
JAI, Oxford, United Kingdom

We present measurements recently performed at the Diamond Light Source, aimed at the achievement of low vertical emittance using the Low Emittance Tuning (LET) algorithm developed for a SuperB factory project presently in progress. The tests have been focused on the comparison between this method and the LOCO algorithm currently used at Diamond. Beam position monitor tilts estimate and multiple coupling response matrices have been introduced in the algorithm in order to optimize the procedure. After few iterations using vertical correctors and skew quadrupoles, very low vertical dispersion and emittance coupling, comparable to those obtained by LOCO, have been measured.

WEPC017

Vertical Beam Size Correction at the SSRF Storage Ring

coupling, betatron, emittance, simulation

2043

M.Z. Zhang, J. Hou, B.C. Jiang, H.H. Li, S.Q. Tian
SINAP, Shanghai, People's Republic of China

Vertical beam size is an important parameter for 3rd generation light source. Correcting the vertical beam size is a realistic way to increase brightness or beam lifetime without any additional equipments in a machine under operation. The main sources of vertical beam size are betatron coupling and vertical dispersion. At the SSRF storage ring, LOCO is used for vertical dispersion and coupling measurements and corrections. The betatron coupling and vertical dispersion is corrected by skew quadrupoles that calculated by LOCO. Vertical beam size can be changed from 10s um to several um for different purposes. Touschek lifetime is also measured to testify the vertical beam size. Simulations show that if smaller vertical beam size is required, more skew quadrupoles are needed.

WEPC024

LOCO in the ALBA Storage Ring

dipole, optics, coupling, storage-ring

2055

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

ALBA is a 3 GeV 3rd generation light source which achieved first stored beam in February 2011, and will be commissioned during 2011. The ring comprises of 112 independent quadrupoles grouped in 14 families and 32 combined gradient dipoles powered in series. This paper reviews the process of recovering the design lattice and the symmetry of the machine, and the effects on orbit and lifetime. The main tool employ for this has been the LOCO implementation provided in the Matlab MiddleLayer. First results shows that the main effect on the symmetry is the difference between bending magnets. As this effect can not be compensated locally at present at the bendings, a global optics correction using all the quadrupoles is used.

WEPC025

Modeling Results of the ALBA Booster

booster, emittance, dipole, injection

2058

G. Benedetti, D. Einfeld, U. Iriso, J. Marcos, Z. Martí, M. Muñoz, M. Pont
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The 3rd generation light source ALBA is in the process of being commissioned. The full energy 3 GeV booster synchrotron was commissioned in the during 2010, ramping the beam from extracted from the LINAC from an energy of 110 MeV to the 3 GeV required for injection in the storage ring. The lattice is based in combined function bending magnets, providing a small emittance beam (< 12 nmrad) at extraction. This paper reviews the agreement between the optics modeling and the measures performed during the commissioning, with special regard to the optics measurement during the ramping process. The results from the magnetic measurement for the combined magnets while ramping are included in the model to explain the movement of the tunes during the ramp.

WEPC028

Record Low Beta-beat of 10% in the LHC

optics, injection, hadron, collider

2061

G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands
M. Aiba
PSI, Villigen, Switzerland
R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland

During the 2011 LHC run several measurements and correction campaigns were conducted. As a result a peak beta-beat of 10% level was achieved. This level, well below the specified tolerances of the LHC, improves the aperture margins and helps minimize the luminosity imbalance between the different experiments. A combination of local corrections at the insertion regions and an overall global correction were used to achieve this record low beta-beat. The sequence of the optics corrections and stability along the 2011 run are reported.

WEPC029

Accuracy of the LHC Optics Measurement based on AC Dipoles

dipole, optics, simulation, focusing

2064

R. Miyamoto, R. Calaga
BNL, Upton, Long Island, New York, USA
R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
The tight tolerances in the LHC requires optics measurement with very good accuracy. Therefore, AC dipoles are employed as the primary devices to measure the LHC optics. The accuracy of the measurement is mainly determined by the length of the coherent signal, signal-to-noise ratio of the measurement, and the data processing to effectively suppress the noise. This paper presents numerical and experimental studies of how these factors affect the accuracy of the LHC optics measurement using the AC dipoles.

WEPC030

Measurement of Coupling Resonance Driving Terms in the LHC with AC Dipoles

dipole, kicker, optics, resonance

2067

R. Miyamoto, R. Calaga
BNL, Upton, Long Island, New York, USA
M. Aiba
PSI, Villigen, Switzerland
R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
Transverse betatron coupling in the LHC is measured from Fourier analysis of turn-by-turn beam oscillations excited by AC dipoles. The use of the AC dipole for optics measurements induces a small systematic error which can be corrected with an appropriate data interpretation. An algorithm to apply this correction to the measurement of the coupling resonance driving terms is developed for the first time. This paper will review this new algorithm and present results of its application to the LHC.

WEPC031

Optics Corrections at RHIC

optics, dipole, betatron, proton

2070

G. Vanbavinckhove
CERN, Geneva, Switzerland
M. Bai, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Excessive beta-beat, deviation of measured beta function from the calculated beta functions based on an model, in high energy colliders can lead to large deviation of beta function at collision point as well as other adverse effects. The segment-by-segment technique was successfully demonstrated in the LHC operation for reducing the beta-beat. It was then applied to RHIC polarized proton operation in 2011. This paper reports the experimental results of optics correction at RHIC. Future plan is also presented.

WEPC034

High-level Application Programs for the TPS Commissioning and Operation at NSRRC

controls, storage-ring, target, EPICS

2079

F.H. Tseng, H.-P. Chang, C.C. Chiang
NSRRC, Hsinchu, Taiwan

For the Taiwan Photon Source (TPS) commissioning and operation we have developed more MATLAB-based application programs and tested them on the Taiwan Light Source (TLS). These additional applications built with the MATLAB Middle Layer (MML) include beta function measurement, dispersion function measurement, chromaticity measurement, chromaticity correction, and tune control. In this paper, we will illustrate what algorithms we use in these applications and show the test results. Especially, in order to get the first beam in the TPS commissioning, we adopt the RESOLVE algorithm for the beam steering and it has been built successfully in UNIX-like systems such as Mac OSX and different Linux versions. It can provide us some exercises of error finding and correction before the TPS commissioning in 2013.

WEPC035

Double Mini-Betay Lattice for TPS Storage Ring

lattice, emittance, dynamic-aperture, multipole

2082

M.-S. Chiu, H.-P. Chang, C.-T. Chen, C.C. Chiang, C.-C. Kuo, Y.C. Lee, H.-J. Tsai, C.H. Yang
NSRRC, Hsinchu, Taiwan

Based on our previous design of double mini-betay optics in one 12-m straight section, NSRRC plan to implement the double mini-betay lattice in three 12-m straight sections in TPS storage ring. Those three locations chosen for double mini-betay lattice still retain the symmetry of accelerator lattice. The two symmetric minima of the vertical beta function will be created in the center of three 12-m straight sections, respectively. We strived to obtain a linear lattice such that there is no significant increase in the natural emittance. Efforts were devoted to optimize the nonlinear beam dynamics with various simulation tools. Preliminary results will be reported.

WEPC037

An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade

optics, luminosity, insertion, sextupole

2088

S.D. Fartoukh
CERN, Geneva, Switzerland

A novel optics concept has been invented and developed in the context of the LHC Upgrade studies. It offers an incredibly powerful and flexible machinery in order to squeeze beta* in a symmetric or asymmetric way (so-called “round” or “flat” optics, respectively), while perfectly controlling the chromatic aberrations induced (off-momentum beta-beating, non-linear chromaticity, spurious dispersion due to the crossing angles). The basic principles of the scheme are described and a specific path for the LHC upgrade is built accordingly, only relying on the existing and well-characterized LHC-like technology, and based on the production of flat collision optics with very small beta* (7.5 cm) in the plane perpendicular to the crossing plane.

WEPC038

Beam Line Design and Beam Measurement for TPS Linac

linac, single-bunch, diagnostics, booster

2091

K.L. Tsai, H.-P. Chang, C.-T. Chen, C.-S. Fann, K.T. Hsu, S.Y. Hsu, C.-Y. Liao, K.-K. Lin, H.M. Shih
NSRRC, Hsinchu, Taiwan
K. Dunkel, C. Piel
RI Research Instruments GmbH, Bergisch Gladbach, Germany

A beam line for examining the beam quality of TPS (Taiwan Photon Source) linac was designed and constructed in NSRRC. Beam parameters, such as energy, emittance and charge etc., are verified by using the equipments setup in the beam line for this purpose. The lattice design and its manipulation for the parameter measurements are presented in this report. Preliminary results and the tools associating with the measurement are briefly described.

WEPC040

Initial 2D Investigations into the Design and Parameters of an EM Quadrupole for FETS

simulation, ion, linac, rfq

2097

M. Larrañaga, R. Enparantza
Fundación TEKNIKER, Eibar (Gipuzkoa), Spain
D.C. Plostinar
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The Medium Energy Beam Transport (MEBT) line for the Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) consists of a number of quadrupoles, re-bunching cavities and a fast-slow chopping system with dedicated beam dumps, as well as diagnostics. The type and design of the quadrupoles to be used merits special attention. Due to space restrictions, a hybrid quadrupole solution has been proposed in the past. However, because of the limited range of field adjustability achievable, this approach is not ideal. In this paper, a very preliminary investigation of an electromagnetic quadrupole (EMQ) design is presented. Magnetic simulations results performed with a 2D simulation code will be discussed including magnet optimisation details.

WEPC041

Conceptual Design of a New 800 MeV H⁻ Linac for ISIS Megawatt Developments

linac, cavity, DTL, rfq

2100

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H⁻ linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined. It consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV. Alternative designs are also being investigated.

WEPC042

Implementation of Double Mini-beta Optics at the Diamond Light Source

optics, injection, single-bunch, insertion

2103

B. Singh, R.T. Fielder, I.P.S. Martin, G. Rehm
Diamond, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

Funding: Diamond Light Source Ltd.
We report the results of the implementation of two vertical mini-beta and horizontally focusing optics at the Diamond light source, the first in August 2010 and the second in March 2011. Commissioning results of the two optics changes and experimental characterization of the optics are compared with the expected performance and theoretical modeling. The implications of a possible third customized optics are also investigated.

WEPC048

Calibrating Transport Lines using LOCO Techniques

dipole, optics, simulation, focusing

2118

Y. Roblin
JLAB, Newport News, Virginia, USA

Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
With the 12GeV upgrade underway at CEBAF, there is a need to recharacterize the beamlines after the modifications made to it to accommodate running at higher energies. We present a linear perturbation approach to calibrating the optics model of transport lines. This method is adapted from the LOCO method in use for storage rings. We consider the effect of quadrupole errors, dipole construction errors as well as beam position monitors and correctors calibrations. The ideal model is expanded to first order in Taylor series of the quadrupole errors. A set of difference orbits obtained by exciting the correctors along the beamline is taken, yielding the measured response matrix. An iterative procedure is invoked and the quadrupole errors as well as beam position monitors and corrector calibration factors are obtained. Here we present details of the method and results of first measurements at CEBAF in early 2011 Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes

WEPC053

Crossing of Depolarizing Resonances in Circular Electron Accelerators

resonance, polarization, electron, closed-orbit

2133

W. Hillert, A. Balling, O. Boldt, A. Dieckmann, F. Frommberger
ELSA, Bonn, Germany

Funding: Supported by the German Research Foundation (DFG) through SFB/TR 16
In flat electron storage rings, only the vertical component of the beam polarization is preserved. During acceleration, the crossing of several depolarizing resonances may cause severe beam depolarization. Even in case of fast ramping speeds of up to 6 GeV/sec, first order effects like imperfection and intrinsic resonances have to be compensated by dedicated measures. At the accelerator facility ELSA, schemes like fast tune jumping and harmonic orbit correction are successfully applied on the fast energy ramp up to 3.2 GeV. Characteristics of the setup as well as the optimization efforts to improve the resonance compensation will be reported in detail.

WEPC054

Amplitude Dependent Tune Spread in the CR Operated as an Antiproton Collector

sextupole, beam-losses, antiproton, simulation

2136

A. Dolinskii, C. Dimopoulou, O.E. Gorda, S.A. Litvinov, F. Nolden, M. Steck
GSI, Darmstadt, Germany

The Collector Ring is planned to be built for efficient cooling of antiprotons and rare isotopes beams. In order to accept hot antiproton beams coming from a separator large aperture magnets are required. This paper examines the effects which, may influence on the beam dynamic because of both large both betatron amplitude oscillations (240 mm mrad) and momentum spread (6%). Using analytic expressions the amplitude-dependent tune shifts driven by sextupole magnets, fringe field of quadrupole magnets and kinematics effects have been calculated. The results are compared with numerical simulations. Tracking studies for the CR operated as an antiproton collector have been performed considering the real shape of the magnetic field of the wide aperture quadrupole. We report on quantitative studies of the effects on the tune spread and its influence on the beam losses.

WEPC058

Field Properties of the ESR Magnets and their Influence on Beam Optics

dipole, betatron, sextupole, simulation

2148

O.E. Gorda, C. Dimopoulou, A. Dolinskii, S.A. Litvinov, F. Nolden, M. Steck
GSI, Darmstadt, Germany

Machine experiments at the experimental storage ring (ESR) demonstrated that the ring acceptance is strongly restricted by field errors. Higher-order field harmonics of the dipole and quadrupole magnets have been calculated and then used in particle tracking simulations in order to find out the dynamic aperture of the ESR. To benchmark the results of numerical calculations, betatron tune measurements have been performed with a uranium beam at the energy of 400 MeV/u. The results of the magnetic field simulations for the ESR magnets and a comparison between the measured and calculated tune behavioгr are presented.

WEPC060

Magnetic Field Description in Curved Accelerator Magnets using Local Toroidal Multipoles

multipole, dipole, antiproton, synchrotron

2154

P. Schnizer, E.S. Fischer
GSI, Darmstadt, Germany
B. Schnizer
TUG/ITP, Graz, Austria

Any introduction on beam dynamics describes the field homogeneity of the accelerator magnets using local derivatives. These are then typically described as plane circular multipoles or 2D harmonics; solutions to the potential equation. The high current operation, foreseen for SIS100 accelerator of FAIR, requires an in detail understanding of the different beam effects, driven by the resonance of the magnets. Therefore different multipole sets were developed and are now finalised in the Local Elliptic Toroidal Multipoles. These are a first order approximation while the plane circular ones are a zero order one in the inverse aspect ratio.

WEPC062

Second Order Achromats with Arbitrary Linear Transfer Matrices

sextupole, focusing, beam-transport, longitudinal-dynamics

2160

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

The most obvious method to construct a second order achromat with an arbitrary (predefined) linear transfer matrix is to take a bend magnet system arranged in an achromat like fashion with the total transfer matrix equal to the identity matrix, attach a drift-quadrupole block with the desired linear transfer matrix and then adjust the sextupoles installed in the first part in such a way that the total system becomes a second order achromat. Unfortunately this is not always possible and, in general, the parts of such a system can not be designed independently. In this paper we give the necessary and sufficient conditions which must be satisfied for both parts of the system in order to become a second order achromat. In addition we provide some practical recommendations showing how these conditions can be fulfilled. We formulate these necessary and sufficient conditions using the group-theoretical point of view for the design of magnetic optical achromats as introduced in *.
* V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Two Cell Repetitive Achromats and Four Cell Mirror Symmetric Achromats", Proc. IPAC'10, Kyoto, Japan (2010).

WEPC063

Apochromatic Twiss Parameters of Drift-quadrupole Systems with Symmetries

betatron, lattice, chromatic-effects, beam-transport

2163

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

It was shown in *, that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions. In this paper we investigate apochromatic Twiss parameters of periodic, mirror symmetric and other drift-quadrupole systems with symmetries.
* V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Apochromatic Beam Transport in Drift-Quadrupole Systems", Proc. IPAC'10, Kyoto, Japan (2010).

WEPC065

Design of a Low Energy Ion Beam Facility*

ion, antiproton, vacuum, injection

2169

M.R.F. Siggel-King, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev
JINR/DLNP, Dubna, Moscow region, Russia
G.A. Karamysheva
MPI-K, Heidelberg, Germany
A.I. Papash
JINR, Dubna, Moscow Region, Russia
M.R.F. Siggel-King
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by STFC, the EU under GA-PITN-215080, the Helmholtz Association and GSI under VH-NG-328.
A small electrostatic ring, and associated electrostatic injection beamlines, are being designed and developed. The ring will make possible a variety of experiments using a choice of many types of recirculating ions (e.g., from protons, H-, and antiprotons up to and including large charged biomolecules). A reaction microscope will be incorporated into the ring to enable differential ionization experiments between the recirculating ion beam and gas jet targets. Two injection sections have been designed to cover a variety of ion sources. The facility will be portable to enable it to be moved between facilities and beamlines and it will be unique due to its combination of design elements, flexible beam properties, energy (ca 3-30 keV) and type of circulating particles. In this paper, we give an update on this project.

WEPC079

Beta-beating in the Effective Model of the LHC Using PTC

optics, alignment, injection, closed-orbit

2202

M.C. Alabau Pons, F. Schmidt, R. Tomás
CERN, Geneva, Switzerland
E.H. Maclean
JAI, Oxford, United Kingdom

An effective model of the LHC optics has been developed based on measurements of magnetic field, alignment errors and closed orbit. This model utilizes the Polymorphic Tracking Code with MAD-X as front-end to allow the inclusion of harmonics to an arbitrary order in thick lattice elements. Beta-beating calculations have been performed with this model at injection optics and at 3.5 TeV squeezed optics to 3.5 m beta-function at the interaction point. The model predictions are in remarkable agreement with the measurements performed in the 2010 LHC commissioning run.

WEPC080

Non-linear Dynamics Optimization of the CLIC Damping Rings

resonance, emittance, dynamic-aperture, lattice

2205

Y. Renier, F. Antoniou, H. Bartosik, Y. Papaphilippou
CERN, Geneva, Switzerland
K.P. Wootton
The University of Melbourne, Melbourne, Australia

Non-linear dynamics studies are undertaken in order to optimize the dynamic aperture of the CLIC damping rings. In this respect, advanced methods such as frequency map and resonance driving term analysis are used in order to explore the working point space with respect to single particle stability. The impact of magnet errors and misalignments, and in particular, the effect of the super-conducting damping wigglers is evaluated. Additional considerations for the working point choice are presented.

WEPC085

Multipole Fringe Fields

multipole, dipole

2211

B.D. Muratori, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.J. de Loos, S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

When creating an initial model of an accelerator, one usually has to resort to a hard edge model for the quadrupoles and higher order multipoles at the start of the project. Ordinarily, it is not until much later on that one has a field map for the given multipoles. This can be rather inconvenient when one is dealing with particularly thin elements or elements which are rather close together in a beamline as the hard edge model may be inadequate for the level of precision desired. For example, in the EMMA project, the two types of quadrupoles used are so close together that they are usually described by a single field map or via hard edge models. The first method has the desired accuracy but was not available at the start of the project and the second is known to be a rough approximation. In this paper, an analytic expression is derived and presented for fringe fields for a multipole of any order with a view to applying it to cases like EMMA.

WEPC088

Embedding Finite Element Results for Accelerator Components in a Moment Approach Beam Dynamics Code*

simulation, dipole, electron, sextupole

2217

T. Roggen, H. De Gersem, B. Masschaele
KU Leuven, Kortrijk, Belgium
W. Ackermann, S. Franke, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This research is funded by grant ''KUL 3E100118'' ''Electromagnetic Field Simulation for Future Particle Accelerators''.
A moment based beam dynamics code has particular advantages, i.e. accuracy and efficiency, over macro-particle tracking and full particle-in-cell (PIC) codes respectively. Instead of embedding analytical descriptions of the accelerator components in the beam dynamics model, it is proposed to insert a surrogate model obtained from the finite element model of individual accelerator components. We apply the V-Code, which accepts moments up to the sixth order and accounts for space charge effects. We construct and calculate finite element and finite difference time domain models using the CST Studio Suite 2011 software package. An interface is implemented using VBA and MATLAB. As an example of the accuracy of this cascadic simulation approach, we compare the beam dynamics of an S-DALINAC quadrupole obtained by directly tracking particles to the calculated fields with the results for the cascadic approach with the V-Code.
This work was performed during a three month research visit at the Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Darmstadt, Germany.

WEPC091

Studies with a Particle Tracking Code for the SIS100 Resonant Extraction System

extraction, controls, synchrotron, feedback

2220

M.M. Kirk, G. Franchetti, H. Klingbeil, P. Moritz, N. Pyka, H. Ramakers, P.J. Spiller, H. Welker
GSI, Darmstadt, Germany

Several issues concerning the envisaged SIS100 resonant extraction at GSI can be resolved with a simulation-lead approach for which a particle tracking code was developed. Applications to date have included: design and testing of data supply algorithms for the accelerator control system; requirements analysis for the power converter ripple in the quadrupoles forming the doublet focusing; and verification of the RF Knock-Out exciter's performance.

WEPC092

Moment-Based Simulation of the S-DALINAC Recirculations*

simulation, recirculation, linac, cavity

2223

S. Franke, W. Ackermann, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany
R. Eichhorn, F. Hug, C. Klose, N. Pietralla, M. Platz
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG under contract SFB 634.
The Superconducting Linear Accelerator S-DALINAC installed at the institute of nuclear physics (IKP) at TU Darmstadt is designed as a re-circulating linear accelerator. The length of the beam line and the numerous accelerating structures as well as dipole and quadrupole magnets require a highly efficient numerical simulation tool in order to assist the operators by providing a detailed and almost instantaneous insight into the actual machine status. A suitable approach which enables a fast online calculation of the beam dynamics is given by the so-called moment approach where the particle distribution is represented by means of a discrete set of moments or by multiple discrete sets of moments in a multi-ensemble environment. Following this approach the V-Code simulation tool has been implemented at the Computational Electromagnetics Laboratory (TEMF) at TU Darmstadt. In this contribution an overview of the numerical model is presented together with new V-Code simulation results regarding the S-DALINAC recirculation sections.

WEPC104

Vicky : A Computer Code for Use in the Design and Simulation of Particle Accelerators

dynamic-aperture, sextupole, kicker, closed-orbit

2256

F. Iazzourene
ELETTRA, Basovizza, Italy

Vicky is a computer code under development for designing and simulating particle accelerators. Like other existing codes, the features include machine imperfections, closed orbit correction, Twiss functions matching, chromaticity evaluation and correction, particle tracking and so on. The goal is to give the users a friendly graphical interface with widgets to perform the wished tasks, for example to plot the orbit, the Twiss functions, the tune diagram, the dynamic aperture and so on, to select and read an input file describing the considered lattice, to perform the Twiss functions matching, a closed orbit correction and so on. The code provides a description of the particle motion by 10 parameters: four beta-functions, four alpha-functions and two phase advances, that is a 4*4 generalized transverse coupling, together with an emphasis on the treatment of the complex 3D magnetic fields of the undulators used in today’s modern synchrotron radiation facilities. The code is written in C++. It uses the free packages QT for the online plots and the graphical user interface and IT++ for the mathematics. The present status and some results of its application will be presented.

WEPC109

Emittance Optimization Using Particle Swarm Algorithm*

emittance, lattice, storage-ring, synchrotron

2271

Z. Bai, W. Li, L. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

In this paper we use a swarm intelligence algorithm, particle swarm optimization (PSO), to optimize the emittance directly. Some constraint conditions such as beta functions, fractional tunes and dispersion function, are considered in the emittance optimization. We optimize the strengths and positions of quadrupoles to search low emittances. Here an FBA lattice studied in the design of the Hefei Advanced Light Source storage ring is used as the testing lattice. The PSO is shown to be beneficial in the optimization.

WEPC115

A Global Optimization Approach Based on Symbolic Presentation of a Beam Propagator

controls, booster, focusing, induction

2280

S.N. Andrianov, A.N. Ivanov, M. Kosovtsov, E.A. Podzyvalov
St. Petersburg State University, St. Petersburg, Russia

It is known that modern systems of beam lines consist of huge control elements even in the case of small machines. The problem of the beam line design leads us to formulate this problem as a global optimization ones. This approach allows us defining a family of appropriate solutions. On the next steps a researcher should narrow this optimal solutions set using additional methods and concepts. The symbolic presentation of necessary information plays leading role on all steps of the suggested approach. The corresponding implementation presented in the paper allows us to find the optimal sets in parameters spaces in a proper way. The corresponding applied software was used for solution of some practical probems. The described ideology implies to use distributed and parallel technologies for necessary computing and will be integrated in the Virtual Accelerator concept.

WEPC117

Symmetry Based Design for Beam Lines*

controls, target, insertion, beam-transport

2286

S.N. Andrianov, A.N. Ivanov, M. Kosovtsov
St. Petersburg State University, St. Petersburg, Russia

Usually, the beam line design problems are solved using numerical optimization methods (for example, in the frame of so called global optimization paradigm). But this approach demonstrates enough effectiveness only after sufficient reduction of a control parameters set. In this paper we present the symmetry design concept based on symbolic computations for the corresponding beam line propagator. The combination of symbolic algebra codes (such as Maple, Mathematica, Maxima and so on) with the matrix formalism for Lie algebraic tools enables us to carry out the entire theoretical and computing processes for design of the beam line under study. For this purpose some of necessary physical requirements are formulated in the terms of the corresponding symmetry conditions. The suggested approach can be realized in both exact and approximate forms of the symmetry terms. The found conditions can sufficiently reduce the number of control parameters for the next optimization step.

WEPC156

Virtual Power Supply Control Environment for the TPS Project

power-supply, controls, EPICS, storage-ring

2349

Y.-S. Cheng, Y.-T. Chang, J. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.-Y. Liao, C.Y. Wu
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is the latest generation of 3 GeV synchrotron light source which has been under construction since 2010. The control system infrastructure of TPS project is based upon the EPICS framework. In order to develop the control applications before power supplies of magnets delivered, it is necessary to set up the virtual control environment to develop high level application programs for the power supplies of magnets in advance. The high level application programs include operation process, degauss process and etc. for power supplies of magnet. The soft-IOCs (Input Output Controller) and various database records are needed to be built to simulate the power supply control environment. In addition, the operation interfaces of power supply will be designed and integrated according to location properties. The efforts will be described at this report.

WEPC162

Investigations into Non-linear Beam Dynamics in Electrostatic Storage Rings

lattice, focusing, dynamic-aperture, proton

2361

D. Newton, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O.E. Gorda
MPI-K, Heidelberg, Germany
D. Newton
The University of Liverpool, Liverpool, United Kingdom
A.I. Papash
JINR, Dubna, Moscow Region, Russia

Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG-328.
Electrostatic (ES) storage rings provide a cost-effective solution to the problem of confining low energy (beta << 1) charged particles and ions, whilst controlling the beam properties, for use in multi-pass experiments. However, compared to magnetic storage rings, the beam dynamics calculations for an ES ring show subtle differences, especially in the coupling of the longitudinal and transverse velocities and in the focusing properties of bending element fringe fields. Using the nominal design for a prototype ES ring, realistic trajectories (including fringe fields and non-linear field components) have been calculated and a comparison is made with linear lattice simulations. The effect of the non-linear field components on the beam parameters is discussed.

WEPC170

Handling of BLM Abort Thresholds in the LHC

beam-losses, monitoring, injection, proton

2382

E. Nebot Del Busto, B. Dehning, E.B. Holzer, S. Jackson, G. Kruk, M. Nemcic, A. Nordt, A. Orecka, C. Roderick, M. Sapinski, A. Skaugen, C. Zamantzas
CERN, Geneva, Switzerland

The Beam Loss Monitoring system (BLM) for the LHC consists of about 3600 Ionization Chambers located around the ring. Its main purpose is to request a beam abort when the measured losses exceed a certain threshold. The BLM detectors integrate the measured signals in 12 different time intervals (running from 40 us to 83.8 s) enabling for a different set of abort thresholds depending on the duration of the beam loss. Furthermore, 32 energy levels running from 0 to 7 TeV account for the fact that the energy density of a particle shower increases with the energy of the primary particle, i.e. the beam energy. Thus, about 1.3·10⁶ thresholds must be handled and send to the appropriate processing modules for the system to function. These thresholds are highly critical for the safety of the machine and depend to a large part on human judgment, which cannot be replaced by automatic test procedures. The BLM team has defined well established procedures to compute, set and check new BLM thresholds, in order to avoid and/or find non-conformities due to manipulation. These procedures, as well as the tools developed to automate this process are described in detail in this document.

WEPC172

Beam-induced Quench Test of a LHC Main Quadrupole

simulation, beam-losses, proton, monitoring

2388

A. Priebe, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, C. Kurfuerst, E. Nebot Del Busto, A. Nordt, M. Sapinski, J. Steckert, A.P. Verweij, C. Zamantzas
CERN, Geneva, Switzerland
A. Priebe
EPFL, Lausanne, Switzerland

Unexpected beam loss might lead to transition of a superconducting accelerator magnet to a normal conducting state. The LHC beam loss monitoring (BLM) system is designed to abort the beam before the energy deposited in the magnet coils reaches a quench-provoking level. In order to verify the threshold settings generated by simulation, a series of beam-induced quench tests at various beam energies have been performed. The beam losses are generated by means of an orbit bump peaked in one of the main quadrupole magnets. The analysis not only includes BLM data but also data from the electrical quench protection and cryogenic systems. The measurements are compared to Geant4 simulations of energy deposition inside the coils and corresponding BLM signal outside the cryostat. The results are also extrapolated to higher beam energies.

WEPC173

LHC Magnet Quench Test with Beam Loss Generated by Wire Scan

beam-losses, proton, simulation, electron

2391

M. Sapinski, F. Cerutti, K. Dahlerup-Petersen, B. Dehning, J. Emery, A. Ferrari, A. Guerrero, E.B. Holzer, M. Koujili, A. Lechner, E. Nebot Del Busto, M. Scheubel, J. Steckert, A.P. Verweij, J. Wenninger
CERN, Geneva, Switzerland

Beam losses with millisecond duration have been observed in the LHC in 2010 and 2011. They are expected to be provoked by dust particles falling into the beam. These losses could compromise the LHC availability if they provoke quenches of superconducting magnets. In order to investigate the quench limits for this loss mechanism, a quench test using the wire scanner has been performed, with the wire movement through the beam mimicking a loss with similar spatial and temporal distribution as in the case of dust particles. This paper will show the conclusions reached for millisecond-duration dust-provoked quench limits. It will include details on the maximum energy deposited in the coil as estimated using FLUKA code, showing good agreement with quench limit estimated from the heat transfer code QP3. In addition, information on the damage limit for carbon wires in proton beams will be presented, following electron microscope analysis which revealed strong wire sublimation.

WEPC175

FLUKA Studies of the Asynchronous Beam Dump Effects on LHC Point 6

proton, insertion, simulation, dipole

2397

R. Versaci, V. Boccone, B. Goddard, A. Mereghetti, R. Schmidt, V. Vlachoudis
CERN, Geneva, Switzerland

The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. FLUKA is the most widely used code for this kind of simulations at CERN because of the high reliability of its results and the ease to custom detailed simulations all along hundreds of meters of beam line. We have investigated the effects of an asynchronous beam dump on the LHC Point 6 where, beams with a stored energy of 360 MJ, can instantaneously release up to a few J cm^-3 in the cryogenic magnets which have a quench limit of the order of the mJ cm^-3. In the present paper we will briefly introduce FLUKA, describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyse the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

WEPO001

Design and Optimization of the MedAustron Synchrotron Main Dipoles

simulation, dipole, synchrotron, ion

2406

M. Stockner, B. Langenbeck, C. Siedler
EBG MedAustron, Wr. Neustadt, Austria
Th. Zickler
CERN, Geneva, Switzerland

MedAustron, a future centre for ion-therapy and research in Austria will comprise an accelerator facility based on a synchrotron for the delivery of protons and light ions for cancer treatment and for clinical and non-clinical research. The main dipole for the synchrotron went through an extensive design process to meet the stringent requirements. The local and integrated field quality was optimized. The residual field levels in the magnet gap were calculated and the dynamic behaviour of the dipole magnet was studied, both in 2D and 3D, using OPERA. The pole profile has been optimized to reduce sextupolar components in the integrated field by adjusting the shims on the pole edge. A Rogowski-profile at the pole ends and the use of stainless-steel tension straps will enhance the dynamic behaviour and guarantee a small time constants. Appropriate pole-end shimming will be used to compensate for residual multi-pole components and to fine-tune the magnetic length. The results of this comprehensive design study are summarized in this paper.

WEPO003

The FERMI@Elettra Magnets

dipole, gun, electron, FEL

2409

D. Castronovo, R. Fabris, G.L. Loda, D. Zangrando
ELETTRA, Basovizza, Italy

FERMI@Elettra is a single-pass FEL user-facility located next to the third generation synchrotron radiation facility ELETTRA in Trieste, Italy. The linear accelerator contains more than 200 magnets. This paper reports on the design, construction, magnetic measurement and installation.

WEPO012

Calculation, Design and Manufacturing of a Resistive Quadrupole for the ESS-Bilbao Transfer Lines

linac, power-supply, acceleration, DTL

2418

I. Rodríguez, F.J. Bermejo, J.L. Munoz, D. de Cos
ESS Bilbao, Bilbao, Spain

The first stage of the ESS-Bilbao LINAC will accelerate H⁺ and H− high current beams up to 50 MeV for different applications. After the last acceleration step in the DTL, the beam will either be transported to the experimental laboratories by the means of several transfer lines, or continue to a further acceleration step in spoke cavities. The first design of one of the quadrupoles that focus the beam along the transfer lines is presented. The quadrupoles will have an aperture of 63 mm and 20 T/m maximum gradient, featuring a short iron yoke of 100 mm. All the quadrupoles of the transfer lines are expected to be similar in order to simplify the design and manufacturing processes. The iron yoke is small and highly saturated, and an optimization of the 3D harmonics in the load-line is developed to fulfil the field quality specifications. The required current density is high (about 8.2 A/mm2), therefore a water cooled hollow conductor is used to cool down the coils. The cooling and power supply requirements are calculated in this paper. The most important manufacturing indications are also presented.

WEPO014

Magnetic Design of Quadrupoles for the Medium and High Energy Beam Transport line of the LIPAC Accelerator

coupling, beam-transport, simulation, dipole

2424

C. Oliver, B. Brañas, A. Ibarra, I. Podadera, F. Toral
CIEMAT, Madrid, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230.
The LIPAC accelerator will be a 9 MeV, 125 mA cw deuteron accelerator which will verify the validity of the design of the future IFMIF accelerator. A Medium Energy Beam Transport line (MEBT) is necessary to handle the high current beam from the RFQ to the Superconducting RF accelerating cavities (SRF) whereas a High Energy Beam Transport line (HEBT) is used to match the beam from the SRF to the beam dump. The high space charge and beam power determine the beam dynamics in both transport lines. As a consequence, magnets with strong fields in a reduced space are required. Along the transport beamlines, there are different types of quadrupoles with steerers and a dipole. Special care is devoted to maximize the integrated fields in the available space. Both 2-D and 3-D magnetic calculations are used to optimize coil configurations. Magnetic performance and cost, both of magnet and power supply, have been taken into account for final choice. In this paper, the design of the resistive quadrupoles of the MEBT and HEBT of the LIPAC accelerator is presented.

WEPO017

Status of CLIC Magnets Studies

linac, permanent-magnet, solenoid, acceleration

2433

M. Modena
CERN, Geneva, Switzerland
A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

R&D Magnets activities for CLIC Project have now entered a new phase with the design & manufacturing of several prototypes investigating the most challenging aspects of the CLIC Project. As concerning the CLIC Magnet System, challenges can be related to pure technical aspects (e.g. the Final Focus QD0 quadrupole where a gradient of more than 550 T/m is requested) or to industrial production choices (e.g. the Main Beam Quadrupoles where compactness and high tolerances are requested for the mechanical assembly, or the Drive Beam Quadrupoles where a productions of more than 40000 units is needed). In this paper the key aspects of the magnets under studies such as the Drive Beam, Main Beam and the Final Focus quadrupoles will be presented and discussed. Results on prototypes under assembly and measured performances will also be addressed.

WEPO018

Status of the New Linac4 Magnets at CERN

linac, solenoid, DTL, simulation

2436

Th. Zickler, F. Borgnolutti, O. Crettiez, A. Newborough, L. Vanherpe
CERN, Geneva, Switzerland
A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

Linac4 is a new H⁻ linear accelerator at CERN replacing Linac2 as injector to the PS Booster. Almost 100 electro-magnets of different types are needed for the Linac4 project. Following a detailed analysis of the requirements and constraints, several magnet designs have been studied and are well advanced. This paper presents the design considerations, main parameters and characteristics of the new Linac4 magnets and summarizes the present status.

WEPO020

Magnetic Field Inspection and Analysis of Multipole Lattice Magnets using a Rotating-coil Measurement System*

multipole, storage-ring, sextupole, synchrotron

2442

J.C. Jan, C.-H. Chang, Y.L. Chu, T.Y. Chung, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin
NSRRC, Hsinchu, Taiwan

A precise rotating-coil measurement system (RCS) was constructed to characterize the field quality and field center of multipole lattice magnets of Taiwan Photon Source (TPS). The mechanical center of magnets is determined by the two references of the magnet-feet and the RCS system is used to characterize the field center. The location of the magnetic field center is quantitatively accurate to better than 20 micro-meter in the horizontal direction; the granite support height of the RCS system is accurate within 5 micro-meter after artificial polishing. The measurement reproducibility of the field center was better than 10 micro-meter when the magnets were reinstalled. The relative accuracy of the multipoles components is better than 2×10^-5. This paper reports the details of the bench construction and the unit composition. The field center with RCS measurement will be compared and discussed with the 3D-coordinate-measuring machine. The multipole errors obtained from RCS will be compared with a Hall-probe measurement system.

WEPO021

Quadrupole Magnet with an Integrated Dipole Steering Element for the ISIS Beam Transport Line

dipole, target, beam-transport, proton

2445

S.J.S. Jago, J. Shih, S.F.S. Tomlinson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.M. Gurov
BINP SB RAS, Novosibirsk, Russia

A refurbishment of beam transport line to the original ISIS target station at the Rutherford Appleton Laboratory has recently been completed. This work involved a slight change to the optics in the area, which included the requirement for extra steering capabilities. Due to the space constraints in the region, a quadrupole magnet with an integrated dipole steering element was developed. The steering dipole consists of four saddle shaped coils situated within the bore of the quadrupole magnet providing a maximum steering angle of 2.5mrad. This paper outlines the magnetic and mechanical design of the steering element.

WEPO022

Tightening the Tolerance Budget of Core Fabrication to Achieve Higher Magnet Performance

sextupole, vacuum, dipole, scattering

2448

N. Li, A. Madur
LBNL, Berkeley, California, USA
J. Jin
SINAP, Shanghai, People's Republic of China

Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231.
Traditionally, laminated cores of AC magnets have been always built by the laminations that are produced by a punching die. There are 5 links in the tolerance chain when a magnet core is built by this procedure: 1. Error of punching die; 2. Error of lamination punching; 3. Error of half core stacking; 4. Error of core assembly; and 5. Error of magnet re-assembling during the installation in the accelerator. As time goes on, the Lattice physicists call for more and more ever higher magnet performance, which makes the required magnet field quality almost impossible achieve by traditional core fabrication procedures. It is the goal of this paper to describe a relatively new procedure that was first used by Buckley System Ltd, NZ and is being used at SINAP, China for ALS combined function sextupole core fabrication. The advantage of this new procedure and the fabrication issues related to this procedure will be described in this paper.

WEPO024

Design and Operation Parameters of the Superconducting Main Magnets for the SIS100 Accelerator of FAIR

dipole, sextupole, multipole, ion

2451

E.S. Fischer, E. Floch, J. Macavei, P. Schnizer
GSI, Darmstadt, Germany
P.G. Akishin
JINR, Dubna, Moscow Region, Russia
A. Mierau
TEMF, TU Darmstadt, Darmstadt, Germany

SIS100, the worlds second large scale synchrotron for ion research, will use superferric magnets. The dipoles are of the window frame type, whose aperture was chosen as an optimum balance between the achievable field quality and AC losses at cryogenic temperatures. Analogous design optimisation was done for the quadrupole and corrector magnets as well. We present the design of the main magnets, estimate their operation parameters and define the crucial aspects to be experimentally analysed before series production, e.g. precise magnetic end field optimisation.

WEPO026

Advances in the Design of the SuperB Final Doublet

luminosity, collider, controls, positron

2454

E. Paoloni, N. Carmignani, F. Pilo
University of Pisa and INFN, Pisa, Italy
S. Bettoni
CERN, Geneva, Switzerland
M.E. Biagini, P. Raimondi
INFN/LNF, Frascati (Roma), Italy
F. Bosi
INFN-Pisa, Pisa, Italy
P. Fabbricatore, S. Farinon, R. Musenich
INFN Genova, Genova, Italy
M.K. Sullivan
SLAC, Menlo Park, California, USA

SuperB is an asymmetric (6.7 GeV HER, 4.18 GeV LER) e⁺ e− collider operating at the Y(4S) peak with a design peak luminosity of 10³6 Hz/cm² to be built in Italy in the very near future. The design luminosity is almost a factor hundred higher than that of the present generation comparable facilities. To get the design luminosity a novel collision scheme, the so called “large Piwinski angle with crab waist”, has been designed. The scheme requires a short focus final doublet to reduce the vertical beta function down to betay*=0.2 mm at the interaction point (IP). The final doublet will be composed by a set of permanent and superconducting (SC) quadrupoles. The SC quadrupole doublets QD0/QF1 have to be placed as close to the IP as possible. This layout is critical because the space available for the doublets is very small. An advanced design of the quadrupole has been developed, based on the double helical coil concept. The paper discusses the design concept, the construction and the results of test of a model of the superconducting quadrupole based on NbTi technology. Future developments are also presented.

WEPO027

Design Study of Final Focusing Superconducting Magnets for the SuperKEKB

solenoid, focusing, luminosity, positron

2457

M. Tawada, N. Higashi, M. Iwasaki, H. Koiso, A. Morita, Y. Ohnishi, N. Ohuchi, K. Oide, T. Oki, K. Tsuchiya, H. Yamaoka, Z.G. Zong
KEK, Ibaraki, Japan

For SuperKEKB, which is an upgrade project of KEKB, we are studying the design of the final focus quadrupole magnets for the interaction region. The 7 GeV electrons in the high-energy ring and the 4 GeV positrons in the low-energy ring collide at one IP with a finite crossing angle of 83 mrad. For each beam, the final beam focusing system consists of the superconducting quadrupole-doublets. These quadrupole magnets have to meet specifications described below. (1) Because of the small beam separation between two beam lines, the superconducting magnet is designed with thin coils and the conductor size is required to be minimized. (2) Since the beta functions are so large, a large space with a good field quality is required. (3) These magnets must apply the focusing fields on electrons and positrons, independent each other. The quadrupole magnets in the solenoid field of the particle detector are designed without an iron yoke. Consequently, the reduction of the leakage fields from the adjacent beam lines is a critical issue to achieve large dynamic aperture. In this paper we will report the design of final focusing system.

WEPO031

The Magnetic Model of the LHC during Commissioning to Higher Beam Intensities in 2010-2011

injection, dipole, optics, sextupole

2466

L. Deniau, N. Aquilina, L. Fiscarelli, M. Giovannozzi, P. Hagen, M. Lamont, G. Montenero, R.J. Steinhagen, M. Strzelczyk, E. Todesco, R. Tomás, W. Venturini Delsolaro, J. Wenninger
CERN, Geneva, Switzerland

The Field Description of the Large Hadron Collider (FiDeL) model is a set of semi-empirical equations linking the magnets behaviours established from magnetic measurements to the magnetic properties of the machine observed through beam measurements. The FiDeL model includes the parameterization of static components such as magnets residual magnetization, persistent currents, hysteresis and saturation as well as the decay and snap-back dynamic components. In the present paper, we outline the relationship between the beam observables (orbit, tune, chromaticity) and the model components during the commissioning to higher beam intensities in 2010-2011, with an energy of 3.5 TeV per beam. The main relevant issues are (i) the operation at 2 A/s and 10 A/s ramp rate and their influence on chromatic correction, (ii) the beta beating and its relation to the knowledge of the resistive quadrupoles transfer functions and (iii) the observed tune decay at injection energy and its possibles origins.

WEPS030

Ion Optics Alignment in the Electrostatic Double Storage Ring DESIREE

alignment, ion, optics, storage-ring

2547

P. Löfgren, M. Blom, F. Hellberg, L. Liljeby, A. Simonsson
MSL, Stockholm, Sweden
P. Reinhed
Stockholm University, Stockholm, Sweden

DESIREE is a cryogenic electrostatic double storage ring under construction at Stockholm University. The two rings have similar circumference, 8.8 m and a common straight section for merged beam experiments. In each ring the ions are guided by two 160° cylindrical deflectors and four 10° deflectors and focused by four quadrupole doublets. In terms of ion optics alignment the quadrupoles are the most important factor for the ion beam acceptance and the goal is to align all quadrupoles with precision of 0.1 mm. DESIREE is constructed as a double walled cryostat with an inner and an outer vacuum chamber. All optical elements are mounted directly on the bottom of the inner chamber. For positioning of the ion optics, the bottom plate is prepared with a number of footprints where each footprint consists of four small machined surfaces that define the height and two alignment holes that define the lateral position. The optical elements were aligned on the bottom plate using a portable measuring device in combination with a level instrument. In this work we describe the alignment procedure in detail and report on the overall precision obtained and the consequence for the ion beam.

WEPS037

RF Design of a 325 MHz 4-ROD RFQ

dipole, rfq, simulation, linac

2568

B. Koubek, A. Schempp, J.S. Schmidt
IAP, Frankfurt am Main, Germany
L. Groening
GSI, Darmstadt, Germany

Usually 4-ROD Radio Frequency Quadrupoles (RFQ) are built for frequencies up to 216 MHz. For higher frequencies 4-VANE structures are more common. The advantages of 4-Rod structures, the greater flexibility for tuning and being more comfortable for maintenance, are motivating the development of a 4-Rod RFQ for higher frequencies than 216 MHz. In particular a 325 MHz RFQ with an output energy of 3 MeV is needed for the proton linac for the FAIR project of GSI. This paper reports about the design studies and the latest developments of this RFQ.

WEPS050

The MEBT Design for the China Accelerator Driven System

emittance, rfq, cavity, diagnostics

2604

H. Geng, H.F. Ouyang, J. Tang
IHEP Beijing, Beijing, People's Republic of China
Z. Li, S. Pei, F. Yan
IHEP Beijng, Beijing, People's Republic of China

The Medium Eneryg Beam Transport (MEBT) line plays an important role in transporting and matching the beam from the RFQ exit to the entrance to the next type of acceleration structures while provides enough beam diagnostics for beam commissing and tuning. The beam dynamics design for the 1GeV China Accelerator Driven System (CADS) is making great progress. In this paper, we will describe the design–both element choosing and beam dynamics study of the 3MeV MEBT for the CADS project.

WEPS057

Beam Dynamics Simulation in DTL with RF Quadrupole Focusing

focusing, linac, lattice, DTL

2625

S.M. Polozov, A.S. Plastun
MEPhI, Moscow, Russia

There are a number of ion linear accelerators using RF focusing. Radio Frequency Quadrupole (RFQ) is the most useful RF linac in low energy range. Using of RFQ for medium energies is impractical because of low energy gain rate. Therefore, proposed to combine Drift Tube Linac (DTL), keeping tolerable energy gain rate, and RFQ. Such linac consists of periodic sequence of a several number of drift tubes and RF quadrupole electrodes, located in the same IH resonator. Different variants of the structure will be considered. Beam dynamics simulation will be carried out through these variants. Main parameters of the linac will be determine. The RF model design, providing combination of DTL and RFQ, will be proposed.

WEPS058

The Medium Energy Beam Transport Line (MEBT) of IFMIF/EVEDA LIPAc

rfq, cavity, SRF, vacuum

2628

I. Podadera, J.C. Calvo, J.M. Carmona, A. Ibarra, D. Iglesias, A. Lara, C. Oliver, F. Toral
CIEMAT, Madrid, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230.
The IFMIF-EVEDA Linear IFMIF Prototype Accelerator (LIPAc)will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology that will be used in the future IFMIF accelerator. The acceleration of the beam will be carried out in two stages. An RFQ will increase the energy up to 5 MeV before a Superconducting RF (SRF) linac made of a chain of eight Half Wave Resonators bring the particles to the final energy. Between both stages, a Medium Energy Beam Transport line (MEBT) is in charge of transporting and matching the beam between the RFQ and the SRF. The transverse focusing of the beam is controlled by five quadrupole magnets with integrated steerers, grouped in one triplet and one doublet. Two buncher cavities surrounding the doublet handle the longitudinal dynamics. Two movable collimators are also included to purify the beam optics coming out the RFQ and avoid losses in the SRF. From the inputs of the beam dynamics group, CIEMAT is in charge of designing, manufacturing and integrating all the components of the beamline. In this contribution, the MEBT subsystem will be described and the main objectives and issues for each component will be discussed.

WEPS060

Design and Optimization of ESS LINAC

linac, cavity, proton, cryomodule

2634

M. Eshraqi
ESS, Lund, Sweden

The {\sc linac} of the European Spallation Source will accelerate the proton beam to its final energy mainly by using superconducting structures. Therefore choosing the right transition energy between these superconducting structures as well as choosing the cavity length and number of cells which enhances the acceleration is of great importance. Two types of {\sc linac}s will be studied, a {\sc linac} with superconducting quadrupoles and a {\sc linac} with normal conducting, resistive, quadrupoles. The procedure to find the optimized {\sc linac} will be described here.

WEPS061

ESS LINAC, Design and Beam Dynamics

linac, cavity, emittance, proton

2637

M. Eshraqi, H. Danared
ESS, Lund, Sweden

The European Spallation Source, {\sc ESS}, will use a linear accelerator delivering a high intensity proton beam with an average beam power of 5~MW to the target station at 2.5~GeV in long pulses of 2~msec. The ESS {\sc Linac} will use two types of superconducting cavities, spoke resonators at low energy and elliptical cavities at high energies. The possibilities to upgrade to a higher power {\sc Linac} at fixed energy are considered. This paper will present a review of the superconducting {\sc Linac} design and the beam dynamics studies.

WEPS063

Compersation of Effect of Malfunctioning Spoke Resonators on Ess Beam Quality

cavity, linac, DTL, proton

2643

M. Eshraqi
ESS, Lund, Sweden

The {\sc linac} of the European Spallation Source will accelerate the proton beam to 2.5~GeV, 98\% of this energy is gained using superconducting structures. The superconducting {\sc linac} is composed of two types of cavities, double spoke resonators and five-cell elliptical cavities. The {\sc linac}, which is five times more powerful than the most powerful existing {\sc linac}, and the spoke cavities that have never been used at such a scale make it necessary to study the effect of one or a few spoke resonators not functioning properly and to find a solution where the defect is compensated by retuning of the neighbouring cavities.

WEPS069

The C70 ARRONAX and Beam Lines Status

cyclotron, simulation, target, proton

2661

F. Poirier, F. Haddad
SUBATECH, Nantes, France
S. Auduc, S. Girault, C. Huet, E. Mace, F. Poirier
Cyclotron ARRONAX, Saint-Herblain, France
J.L. Delvaux
IBA, Louvain-la-Neuve, Belgium

Funding: The cyclotron ARRONAX is supported by the Regional Council of Pays de la Loire, local authorities, the French government and the European Union.
The C70 Arronax project is a high intensity (up to 350 ·10^-6 A) and high energy (70 MeV) multi-particle cyclotron aiming at R&D on material and radiolysis, and production of rare radioisotopes. The project began its hands-on phase in December 2010, and is now undergoing beam lines’ modification in experimental halls for both present and future experiments. Characterization of the beams at the end of the beam lines is of particular importance to determine the capacity of the cyclotron for the end-line experimental users. A program of beam characterization is being performed based on dedicated diagnostics, e.g. beam profilers, Faraday cups, alumina foils, and also on a series of Geant4 beam simulations. The results of the measurements, along with the simulations, are detailed in this report for proton and alpha particle beams, as well as the future prospects of the characterization program.

WEPS086

Three-lens Lattices for Extending the Energy Range of Non-scaling FFAGs

lattice, closed-orbit, optics, synchrotron

2709

S.J. Brooks
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

In this paper it is found that a three-quadrupole focussing system can be morphed continuously through FFD, FDF and DFF variants and back again while maintaining stable optics and even keeping the two transverse tunes constant. This relates to non-scaling FFAGs, where the magnet gradients define both the focussing and the variation of the field with momentum as the closed orbit sweeps across it. A two-lens focussing system cannot change the sign of either gradient without becoming unstable, meaning non-scaling FFAGs built with such a lattice eventually encounter too large a magnetic field at low energies. However, a theoretical system of magnet field variations using three lenses, with a potentially unlimited energy range and fixed tunes is presented here.

WEPS101

Lattice Design of a RCS as Possible Alternative to the PS Booster Upgrade

lattice, injection, space-charge, booster

2745

M. Fitterer, M. Benedikt, H. Burkhardt, C. Carli, R. Garoby, B. Goddard, K. Hanke, H.O. Schönauer
CERN, Geneva, Switzerland
A.-S. Müller
KIT, Karlsruhe, Germany

In the framework of the LHC Injectors Upgrade (LIU) a new rapid cycling synchrotron as alternative to the PS Booster has been proposed. In this paper we present the lattice constraints and requirement as well as the current status of the RCS lattice design and beam dynamics studies.

WEPS102

Latest News on the Beam Dynamics Design of SPL

cavity, linac, emittance, lattice

2748

P.A. Posocco, M. Eshraqi, A.M. Lombardi
CERN, Geneva, Switzerland

SPL is a superconducting H− LINAC under study at CERN. The SPL is designed to accelerate the 160 MeV beam of LINAC4 to 5 GeV, and is composed of two fami¬lies of 704.4 MHz elliptical cavities with geometrical betas of 0.65 and 1.0. Two families of cryo-modules are considered: the low-beta cryo-module houses 3 low-beta cavities, whereas the high-beta one houses 8 cavities. The transverse focusing is performed with normal-conducting quadrupoles arranged in 2 different lattices: FD0 at lower and F0D0 at higher energies. The regular lattices are in-terrupted at the transition between low beta and high beta cryo-modules and for extracting medium energy beams at 1.4 and 2.5 GeV, where the change of the transverse lattice is performed. In this paper the latest beam dynamics studies will be presented together with the sensitivity of the SPL performance to RF errors, alignment tolerances and quadrupole high order components.

WEPZ009

Parametric-Resonance Ionization Cooling in Twin-Helix

resonance, simulation, multipole, betatron

2784

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA
A. Afanasev, 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. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/ G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

WEPZ013

Design Status of LHeC Linac-Ring Interaction Region

proton, electron, optics, dipole

2796

R. Tomás, J.L. Abelleira, S. Russenschuck, F. Zimmermann
CERN, Geneva, Switzerland
N.R. Bernard
UCLA, Los Angeles, California, USA

The ECFA-CERN-NuPECC design study for a Large Hadron electron Collider (LHeC) based on the LHC, considers two options, using a ring accelerator like LEP on top of the LHC or adding a recirculating energy-recovery linac tangential to the LHC. In order to obtain the required luminosity with an e^- beam from a linac, with average lepton beam current limited to a few mA, reaching the smallest possible proton beam size is essential. Another constraint is imposed by the need to separate e^- and p beams after the collision without losing too much luminosity from a crossing angle. A further constraint is that the ep collision should occur simultaneously to pp collisions at other LHC interaction points such that the second LHC proton beam must be accommodated in the interaction region too. We present a conceptual layout using detector-integrated combination-separation dipoles and challenging Nb3Sn technology quadrupoles for focusing the colliding proton beam and providing a low-field “hole” to accommodate both the non-colliding proton beam and the lepton beam, and the optics for all three beams. We discuss synchrotron radiation fluxes and the chromatic correction for the lepton final focus.

THOAA01

Beam Diagnostics Commissioning at CNAO

proton, extraction, synchrotron, diagnostics

2848

H. Caracciolo, G. Balbinot, G. Bazzano, J. Bosser, M. Caldara, A. Parravicini, M. Pullia, C. Viviani
CNAO Foundation, Milan, Italy

The National Centre for Oncological Hadrontherapy (CNAO) is the first Italian facility for the treatment of deep located tumors with proton and carbon ion beams using active scanning. The commissioning with proton beams is concluded and CNAO is going to start treating patients with protons; in the meantime the machine commissioning with carbon ions beam is going on. Beam diagnostics instrumentation is fundamental to measure beam properties along the lines from sources to patients. Some significant measurements performed during proton beam commissioning and the performances achieved with the CNAO beam diagnostic systems are presented in this paper.

Slides THOAA01 [4.827 MB]

THOAA03

Overview of LHC Beam Loss Measurements

beam-losses, luminosity, proton, collimation

2854

B. Dehning, A.E. Dabrowski, M. Dabrowski, E. Effinger, J. Emery, E. Fadakis, V. Grishin, E.B. Holzer, S. Jackson, G. Kruk, C. Kurfuerst, A. Marsili, M. Misiowiec, E. Nebot Del Busto, A. Nordt, A. Priebe, C. Roderick, M. Sapinski, C. Zamantzas
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria

The LHC beam loss monitoring system based on ionization chambers is used for machine protection, quench prevention and accelerator optimization. After one full year of operation it can be stated that its main functionality, that of the protection of equipment, has proven to be very robust with no issues observed for hundreds of critical beam loss events and the number of false beam aborts well below expectation. In addition the injection, dump and collimation system make regular use of the published loss measurements for system analysis and optimisation, such as the determination of collimation efficiency in order to identify possible intensity limitations as early as possible. Intentional magnet quenches have been performed to verify both the calibration accuracy of the system and the accuracy of the loss pattern predictions from simulations. Tests have also been performed with fast loss detectors based on single- and polycrystalline CVD diamond, which are capable of providing nanosecond resolution time loss structure. This presentation will cover all of these aspects and give an outlook on future performance.

Slides THOAA03 [1.972 MB]

THOAB03

Commissioning of the Ion Beam Gantry at HIT

ion, proton, dipole, heavy-ion

2874

M. Galonska, R. Cee, Th. Haberer, K. Höppner, A. Peters, S. Scheloske, T. Winkelmann
HIT, Heidelberg, Germany

The Heidelberg Ion Beam Therapy Facility (HIT) is the first dedicated proton and carbon cancer therapy facility in Europe. It uses a full 3D intensity controlled raster scanning dose delivering method. The ion energy ranges from ca. 50 to 430 MeV/u corresponding to ion penetration depths of 20 to 300 mm in water. The HIT facility comprises the only heavy ion gantry worldwide designed for the beam transport of beams demanding a magnetic rigidity from 1 to 6.6 Tm. The gantry rotation of 360° enables beam scanning patient treatment from arbitrary directions. The libraries of carbon and proton pencil beams at the gantry are now offered with the whole variety of ion beam properties, i.e. 255 energy steps, 4 beam foci, 360°, and 10 intensities (10⁶-1010/spill). The beam has to be adjusted only for a fraction of possible combinations of energy, focus, and gantry angle. These are taken as base points for a calculation of an overall number of about 37,000 different set values per ion type, and one intensity step according to the data supply model. This paper gives an outline on the practical concepts and results of adjusting the required beam properties independent of the gantry angle.

Slides THOAB03 [4.526 MB]

THPC002

Implementation of a Low-Emittance Optics for the LNLS UVX Storage Ring

optics, emittance, lattice, storage-ring

2907

F. H. de Sá, L. Liu, X.R. Resende
LNLS, Campinas, Brazil

In this report we describe the theoretical optimization and implementation of a low-emittance optics for the LNLS UVX storage ring. The emittance is reduced by letting the dispersion be distributed everywhere while keeping the low vertical beta feature. The optimization strategy is based on a series of quadrupole strength scans and selection of points satisfying a number of criteria. The new mode reduces the emittance from 100 nm.rad to 40 nm.rad, including the effects of the already installed insertion devices, and keeps the working point in the same quadrant as the present operation BBY6T mode. Tests have shown a reduction of approximately 20% in the horizontal and vertical beam sizes in the middle of the dipoles, in agreement with the theoretical emittance reduction.

THPC010

Recent Developments at the Metrology Light Source

injection, feedback, synchrotron, vacuum

2927

J. Feikes, T. Birke, O. Dressler, D.B. Engel, F. Falkenstern, B. Franksen, A. Heugel, H.-G. Hoberg, F. Hoffmann, J. Kuszynski, J. Rahn, M. Ries, P.O. Schmid, T. Schneegans, D. Schüler, G. Wüstefeld
HZB, Berlin, Germany
K.B. Bürkmann-Gehrlein, V. Dürr, H.G. Glass, G. Schindhelm
BESSY GmbH, Berlin, Germany
R. Klein
PTB, Berlin, Germany

The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, owns the electron storage ring Metrology Light Source (MLS) which was built and is operated by the Helmholtz-Zentrum Berlin [1, 2]. The MLS has been in regular user operation since April 2008 and supports synchrotron-radiation-based metrology and technological developments in the IR, UV, VUV and EUV spectral range. Here we report on recent progress to develop the MLS into a reliable, flexible and stable user facility.

THPC012

Mitigating the Pertubations Caused by U 180 at the Metrology Light Source

undulator, dipole, optics, focusing

2930

P.O. Schmid, D.B. Engel, J. Feikes, M. Ries, G. Wüstefeld
HZB, Berlin, Germany

The Metrology Light Source is equipped with an electromagnetic undulator with a period length of 180 mm. User requests demand operation of this undulator in a wide energy range from 100 MeV through 629 MeV for user and dedicated low alpha modes. Mitigating the pertubations caused by the undulator to an acceptable level for all user requests, requires each quadrupole in the lattice to be powered individually. To what extend this recently implemented capability allows the restoration of the main properties of the machine optics for various settings of the undulator is presented in this document.

THPC026

Low Momentum Compaction Optics for Elettra

optics, emittance, lattice, sextupole

2963

E. Karantzoulis, A. Carniel, S. Krecic
ELETTRA, Basovizza, Italy

The DBA optics lattice of Elettra, the third generation Italian light source is closer to DBA minimum emittance condition than any other similar lattice. At the same time, although the lattice is also optimized for large acceptance, it is very inflexible to any changes like the reduction of the momentum compaction (very desirable to the IR and SR-FEL beam lines). Nevertheless a solution has been found and consists in abandoning the achromat condition and reversing the polarity of some quadrupole and sextupole families. This special optics and its applications to Elettra are presented and discussed.

THPC043

Status of SESAME Project

booster, vacuum, EPICS, controls

2999

A. Nadji
SESAME, Amman, Jordan

This paper reports on the progress which has been made on the construction of the SESAME accelerator complex. The construction of the shielding wall has been finished on March 2011. According to plan, the preparation works and tenders of the conventional facilities have been launched such as the cooling system, electrical distribution systems, PSS system and so on. The commissioning of the Microtron at full energy and the installation of the booster are the next millstones to accomplish. The booster upgrade plan has started which consists of replacing all bending magnets vacuum chamber with new one, BPM Libera Electronics, new control system based on EPICS, new timing system, new electronics for tune measurement. The site acceptance test of the new power supplies of the booster with their tracking electronics is planned to take place in July 2011. The magnet system of the storage ring has been reviewed and the manufacturing tendering is foreseen before the end of 2011.

THPC056

Orbit Studies during ALBA Commissioning

feedback, coupling, alignment, brilliance

3020

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

The 3rd generation light source ALBA is in the commissioning stage. This paper review the results of the commissioning concerning the transversal beam behavior, in particular the orbit correction system, results from the beam based alignment (BBA), and coupling. The orbit control system of ALBA consists of 88 horizontal and vertical correctors, mounted as extra coils in the sextupole magnets, up to 10⁴ LIBERA BPMs (brilliance version). The correctors magnets would be used for both static orbit correction and for the fast orbit feedback mode, providing up to 1 mrad of correction in the static case. In phase one of the commissioning, the orbit has been corrected down to values of 50 um rms, with an estimated emittance ratio in the order of 1% .

THPC061

Comparison of Linear Optics Correction Means at the SLS

optics, betatron, storage-ring, closed-orbit

3032

M. Aiba, M. Böge, J.T.M. Chrin, N. Milas, T. Schilcher, A. Streun
PSI, Villigen, Switzerland

The experimental determination of linear optics is a fundamental prerequisite to achieving a high performance storage ring. In order to further enhance SLS performance and to simulataneously reveal the limitations of the various techniques, we perform a systematic study of linear optics optimization using various independent methods. These include an analysis of the orbit reponse (LOCO), turn-by-turn data, and the response of the tune, whose correction is accomplished using the standard SLS procedure of varying the quadrupole strengths. A comparison of results from these procedures, which use fully independent observables, provides us with a valuable cross-check. For example, the betatron phase advances between BPMs, which is independent of BPM calibration, confirms the optics correction as determined from LOCO. The linear optics are hence better optimized, and these procedures, LOCO in particular, further serve to expose any previously hidden mis-calibration of parameters e.g. from BPMs and corrector magnets. Systematic errors from turn-by-turn data could also be vastly reduced by a better synchronization of the BPM triggers with the electron beam.

THPC062

SLS Vertical Emittance Tuning

alignment, coupling, emittance, betatron

3035

M. Böge, M. Aiba, N. Milas, A. Streun
PSI, Villigen, Switzerland
S.M. Liuzzo
INFN/LNF, Frascati (Roma), Italy

To establish ultra-small vertical emittances (<1pmrad @2.86GeV) is one important aim of future linear collider damping ring optimization studies* at the SLS. By utilizing various correction techniques the SLS is already close to this goal with emittances of <2pm.rad @2.4GeV under the constraint of maintaining user operation conditions. One of the limiting contributions is the remaining spurious vertical dispersion eta_y of ~1.4mm which can be reduced by careful re-alignment and the application of dispersion-free steering techniques. The latter require orbit manipulations which are only partially compatible with the user operation mode. A first application of dispersion-free steering techniques demonstrates that eta_y can be reduced to <1mm at the expense of large orbit excursions which require a simultaneous betatron-coupling correction by means of skew quadrupoles in order to benefit in terms of a further reduction of vertical emittance. Therefore possible girder and magnet misalignments are analyzed in simulation which allows to localize the sources of eta_y and to eliminate them by re-alignment. Following this path the goal to achieve emittances close to 1pmrad is within reach.
* In January 2011 the EU-project TIARA (Test Infrastructure and Accelerator Research Area) started with contributions from the SLS as part of the SVET (SLS Vertical Emittance Tuning) work package WP6.

THPC067

Tolerance Studies of the Max-IV Linac

linac, emittance, dipole, sextupole

3047

P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, J.K. Jones, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Eriksson, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

The MAX IV linac will be used both for injection and top up into two storage rings, and as a high brightness injector for a Short Pulse Facility (SPF) and an FEL (in phase 2). We briefly describe the layout, optics and bunch compression / linearization scheme of the linac. We then investigate the robustness of the design to element errors.

THPC069

Studies to Optimize the Diamond Light Source Booster Synchrotron as a 100 MeV Storage Ring

booster, synchrotron, storage-ring, linac

3053

C. Christou, M.T. Heron, J. Rowland
Diamond, Oxfordshire, United Kingdom
S. Gayadeen
University of Oxford, Oxford, United Kingdom

The injection chain for the Diamond Synchrotron Light Source consists of a 100 MeV Linac and 3 GeV booster synchrotron. These were commissioned in 2005 and 2006 respectively, and have provided acceptable performance as an injector since then. To advance a programme of work in evaluating and optimizing new control algorithms for orbit stability on the Diamond Storage Ring it was decided to use the booster synchrotron as a test platform by operating it in DC mode at 100 MeV. In support of this work and to improve the operational performance of the booster a series of studies have been carried out to better understand and characterize it. This work and the results will be presented.

THPC074

Dynamic Aperture and Tolerances for PEP-X Ultimate Storage Ring Design

sextupole, dynamic-aperture, resonance, coupling

3065

M.-H. Wang, Y. Cai, R.O. Hettel, Y. Nosochkov
SLAC, Menlo Park, California, USA
M. Borland
ANL, Argonne, USA

Funding: Work supported by the Department of Energy Contract DE-AC02-76SF00515.
A lattice for the PEP-X ultimate storage ring light source[1], having 11 pm-rad natural emittance at a beam energy of 4.5 GeV at zero current, using 90 m of damping wiggler and fitting into the existing 2.2-km PEP-II tunnel, has been recently designed[2]. Such a low emittance lattice requires very strong sextupoles for chromaticity correction, which in turn introduce strong non-linear field effects that limit the beam dynamic aperture. In order to maximize the dynamic aperture we choose the cell phases to cancel the third and fourth order geometric resonances in each 8-cell arc. Four families of chromatic sextupoles and six families of geometric (or harmonic) sextupoles are added to correct the chromatic and amplitude-dependent tunes. To find the best settings of the ten sextupole families, we use a Multi-Objective Genetic Optimizer employing elegant[3] to optimize the beam lifetime and dynamic aperture simultaneously. Then we evaluate dynamic aperture reduction caused by magnetic field multipole errors, magnet fabrication errors and misalignments. A sufficient dynamic aperture is obtained for injection, as well as workable beam lifetime[2].

THPC076

FEL Performance with Focusing Lattice Magnets Alignment Errors

FEL, radiation, alignment, simulation

3071

V.G. Khachatryan, M. Ivanyan
CANDLE, Yerevan, Armenia

At the European XFEL the alignemnet errors of the undulator section quadrupole magnets will be corrected by applying beam based quadrupole alignment methods. Numerical simulations of the SASE process have been conducted to evaluate the FEL power reduction due to residual quadrupole alignment errors. FEL simulations with focusing lattice errors allow choosing an optimal error correction method in terms of FEL performance.

THPC116

Surface Analysis of a Degraded NEA-GaAs Photocathode by Temperature Programmed Desorption Technique

vacuum, cathode, electron, ion

3158

H. Iijima, M. Kuriki, Y.M. Masumoto
HU/AdSM, Higashi-Hiroshima, Japan

A GaAs photocathode activated the surface to negative electron affinity (NEA) is an important device for high-average-current electron accelerators, such as a next-generation light source based on an energy recovery linac. It is well known that the quantum efficiency of the NEA-GaAs photocathode is decaying with time elapsing, even if the electron beam is not extracted. The degradation is mainly caused by adsorption of residual gases in a vacuum chamber. Previously a few investigators reported that the quantum efficiency of the photocathode was rapidly degraded by water or carbon dioxide vapor. In order to analyze such surface states, we have measured desorption of gases from the degraded NEA-GaAs photocathode by using of temperature programmed desorption (TPD) technique with a quadrupole mass spectrometer. The desorption peaks of hydrogen, carbon oxide and carbon dioxide from the degraded NEA surface were observed, while that of water was not observed.

THPC153

Recent Progress in Insertion Devices at the ESRF

undulator, multipole, insertion, insertion-device

3245

J. Chavanne, G. Lebec, C. Penel, F. Revol
ESRF, Grenoble, France

Insertion Device activities at the ESRF are presently driven by the upgrade of more than ten beamlines. The concept of canted undulators is part of the requirements in a number of cases. Permanent Magnet Steerers (PMS) will be used to create canting angles of up to 5.4 mrad. The magnetic structure of PMS has been fully optimized to minimise space occupancy and magnetic perturbations induced on neighbouring undulators. The measured field quality of PMS recently constructed will be presented. The development of undulators dedicated to high photon energy is still being pursued. Following on from the successful operation since 2008 of a first Cryogenic Permanent Magnet Undulator (CPMU) installed in the ID6 beamline, a second device has been constructed. This 2 m long device has a period of 18 mm and will be operated at 145 K. The field measurements at cryogenic temperature are discussed hereafter.

THPC155

Modification of the BESSY II Optic for the Implementation of a Small Gap Undulator

undulator, optics, cryogenics, sextupole

3251

J. Bahrdt, K.B. Bürkmann-Gehrlein, V. Dürr, W. Frentrup, A. Gaupp, A. Jankowiak, P. Kuske, J. Rahn, M. Scheer, P.O. Schmid, G. Wüstefeld
HZB, Berlin, Germany

At BESSY there is an increasing demand for photons in the range from 60 eV to 8 keV available at the same experimental station. The photons will be produced by a combination of two adjacent undulators, one of them will be a small period cryogenic undulator. Several optics schemes for the 1.7 GeV BESSY II storage ring are discussed to install the undulators. Two types of straight sections exist. A high beta straight with betax_min=15 m and betay_min=4.5 m and a low beta straight with betax_min=betay_min=1 m. We discuss the present plan, which clearly favours a small detuning of an existing low beta straight to shift the low beta waist to the centre of the low gap undulator, with only minor impact to the machine.

THPC170

Magnetic Characterization of FEL-2 Undulators for the FERMI@Elettra Free-electron Laser

undulator, FEL, multipole, sextupole

3296

M. Kokole
KYTE, Sezana, Slovenia
B. Diviacco
ELETTRA, Basovizza, Italy
T. Milharcic, M. Zambelli
KYMA, Trieste, Italy
G. Soregaroli, M. Tedeschi
Euromisure srl, Pieve S. Giacomo (Cremona), Italy

Kyma Srl is the spin-off company of Sincrotrone Trieste, Elettra laboratory, set up in 2007 together with the two industrial partners Cosylab d.d. and Euromisure SpA, in order to design and manufacture the undulators for the FERMI@Elettra project in Trieste, Italy. The insertion devices, for FEL-2 line, manufactured and characterized so far are the following: Modulator, 3.2 m linearly polarized undulator, three 55.2 mm APPLE-II variable polarization undulators, each 2.4 m long and six 34.8 mm APPLE-II undulators also each 2.4 m long. All the above devices have been characterized, both from the mechanical and the magnetic point of view. The measured parameters are in good agreement with the design values. This paper presents the most relevant changes in design from FEL-1 to FEL-2 line and results of the magnetic measurements carried out on all the above undulators.

THPO007

Operation Status of SSRF Power Supplies and Interlocks for Top-up Operation

power-supply, controls, storage-ring, HOM

3349

R. Li, C.L. Guo, M.M. Huang, T.J. Shen
SINAP, Shanghai, People's Republic of China

Digital switching mode magnet power supplies are used in SSRF accelerators which have been operating since 2008. Summary of the operation and maintenance of these power supplies will be shared over here. The availability of the power supplies is increased steadily over the past 4 years. And the power supplies interlocks for the SSRF top-up operation will be also introduced in this paper.

THPO012

Using a High Precision Programmable DC Power Supply of TPS Magnet

power-supply, controls, storage-ring, sextupole

3358

Y.S. Wong, J.C. Huang, K.-B. Liu, W.S. Wen
NSRRC, Hsinchu, Taiwan

Taiwan government had been announcement to set up a third-generation synchrotron radiation light source in February 2010. It should be installed with 10³² sets of magnet power supplies for the storage ring and 152 sets for the injector. In the storage ring, high precision DC power supply for 48 dipoles magnets , 240 quadrupole magnets and 168 sextupole magnets. The main windings of quadrupole and sextupole magnets are powered by individual power supplies. In the booster rings, one set of dynamic power supply for the dipole magnets and four sets for quadrupole magnets run at the biased 3Hz quasi sinusoidal wave. The Taiwan photon source (TPS) plan was completed indication national synchrotron radiation research central (NSRRC) technical capability to build at its present site in seven years a 3~3.3 GeV electron energy, 518 meter circumference, low-emittance synchrotron storage ring which will offer one of the world's brightest synchrotron x-ray sources, provide cutting-edge experimental facilities and novel multidisciplinary scientific research opportunities, enhance world-class academic research, as well as create Taiwan's scientific research marvels in the twenty-first century.

THPO020

TPS Digital Corrector Magnet Power Converter based on FPGA

feedback, controls, dipole, booster

3382

Y.D. Li, Y.-C. Chien, K.-B. Liu
NSRRC, Hsinchu, Taiwan

This thesis presents the design and implementation of a FPGA-based fully digital-controlled programmable power supply.

THPS030

Layout and Optics of the MedAustron High Energy Beam Transfer Line

optics, proton, extraction, synchrotron

3484

U. Dorda, P.J. Bryant
CERN, Geneva, Switzerland
M. Benedikt
EBG MedAustron, Wr. Neustadt, Austria

The MedAustron accelerator complex, which is currently in its final design stage at CERN, is based on the optical principles developed within the Proton Ion Medical Machine study (PIMMS) [bryantpimms]. This paper describes how these principles are practically applied in the layout and optics of the High Energy Beam Transfer line (HEBT) of the MedAustron accelerator facility. Special attention is directed to the optics of the gantry which is designed to fit into the PSI gantry-2 hardware layout, which is foreseen to be copied in collaboration with PSI.

THPS031

The Beam Expander System for the European Spallation Source

target, octupole, multipole, proton

3487

H.D. Thomsen, A.I.S. Holm, S.P. Møller
ISA, Aarhus, Denmark

At the European Spallation Source (ESS), neutrons are produced by high energy (2.5 GeV) protons impinging on a target. The lifetime of the target is highly dependent on the beam footprint. In general, the lower the average current density, the longer the lifetime of the target will be. A detailed study of two different expander systems suggested to be used to obtain the desired beam footprint has been undertaken. For reference, a system of quadrupole defocusing is used. The two systems under study are expansion of the beam by magnetic multipoles and raster scanning (painting) of the narrow linac beam over the target area. The designs, specifications, and comparative risks of the three systems will be described.

THPS033

Skew Quadrupole Effects on Multi-turn injection Efficiency in the SIS18

septum, injection, emittance, coupling

3490

W.M. Daqa, I. Hofmann, J. Struckmeier
GSI, Darmstadt, Germany

Funding: DAAD ( Deutscher Akademischer Austausch Dienst)
One goal of the SIS18 upgrade scheme is concerned about improving the multi-turn injection (MTI) efficiency, in order to reach the required intensities at the targets and to operate effectively as a booster for SIS100. To improve the limitation of the MTI scheme, there were successful attempts in AGS and PS boosters, to use the skew injection scheme and later it was suggested for SIS18. The strength of the skew quadrupoles is optimized together with the horizontal tune, the difference in horizontal to vertical tunes, the incoming beam parameters and the geometrical limitation of SIS lattice. A good optimization implies the emittance exchange, due to linear coupling, to take place partially and just before the return of the beamlet back to its original position at the septum. The present work was done by simulation using the code PARMTRA and compared with measurements. The results show that, depending on the working point, the skew injection scheme can improve the MTI efficiency from 2% up to 12%, taking into account the loss on the septum from inside and on the vertical acceptance.

THPS046

Transport Beam Lines for NICA Accelerator Complex

booster, collider, ion, lattice

3526

O.S. Kozlov, A.V. Eliseev, I.N. Meshkov, V.A. Mikhailov, A.O. Sidorin, N.D. Topilin, G.V. Trubnikov, A. Tuzikov
JINR, Dubna, Moscow Region, Russia

In the last years Nuclotron-based Ion Collider fAcility (NICA) project is being developed by Joint Institute for Nuclear Research (JINR), Dubna, Russia. The goal of the project is to construct new accelerator complex that will be used for colliding ion beams on first stage and colliding polarized proton/deuteron beams on second stage of the project. NICA accelerator complex will consist of two linear accelerators, two superconducting synchrotrons, two superconducting storage rings of the collider and transport beamlines. Geometry and magnetic system of NICA beamlines are presented in this report. Results of beam dynamics simulations within the beamlines are considered.

THPS050

The High Energy Beam Transport System for the European Spallation Source

target, linac, collimation, octupole

3538

A.I.S. Holm, S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark

As part of the accelerator design update for the European Spallation Source (ESS), we present results from a detailed study of the High Energy Beam Transport (HEBT) line. The HEBT is a transport line around 100 m long, which connects the 2.5-GeV linac to the target. The linac will deliver a current of 50 mA, a pulse length of 2 ms and a repetition rate of 20 Hz, and losses are of utmost importance. Presumably, the HEBT will continue the 10 m period focusing structure of the linac. Two bends – overall, achromatic – will be needed to connect the different vertical levels between the linac and the target. A number of design aspects will be discussed here: space for future linac cryostats, the need and location for collimation, the location of the tuning beam dump and the associated beam optics, and the beam expander system, which provide the desired beam footprint on the target (see also separate contribution). A proposed design including options will be described together with hardware specifications.

THPS054

Injection and Extraction Considerations for a 2 GeV RCS at CERN

extraction, injection, septum, kicker

3550

W. Bartmann, B. Balhan, J. Borburgh, L. Ducimetière, M. Fitterer, B. Goddard, L. Sermeus
CERN, Geneva, Switzerland

Conceptual studies have been made for a 2 GeV RCS at CERN as a possible replacement of the four-ring PS Booster. The lattice design has to accommodate suitable straight sections for a 160 MeV H⁻ charge exchange injection system, and for a 2 GeV fast extraction system. The design constraints for the injection and extraction systems are described, together with the proposed concepts and potential equipment limitations. In particular, the features of different possible H⁻ injection configurations are compared.

THPS074

Design of Superconducting Rotating-gantry for Heavy-ion Therapy

superconducting-magnet, ion, heavy-ion, dipole

3601

Y. Iwata, T. Furukawa, A. I. Itano, K. Mizushima, K. Noda, T. Shirai
NIRS, Chiba-shi, Japan
N. Amemiya
KUEE, Kyoto, Japan
T. Obana
NIFS, Gifu, Japan
T. Ogitsu
KEK, Ibaraki, Japan
T. Tosaka, I. Watanabe
Toshiba, Tokyo, Japan
M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Tumor therapy using energetic carbon ions, as provided by the HIMAC, has been performed since June 1994, and more than 5000 patients were treated until now. With the successful clinical results, we constructed a new treatment facility. The new facility has three treatment rooms; two of them have both horizontal and vertical fixed-irradiation-ports, and the other has a rotating-gantry-port. For all the ports, a scanning-irradiation method is applied. The fixed-irradiation-ports were constructed and commissioned, and we are now designing the rotating gantry. This isocentric rotating-gantry can transport heavy ions having 430 MeV/u to the isocenter with irradiation angles of 0-360 degrees. For the magnets, combined-function superconducting-magnets will be employed. The use of the superconducting magnets allowed us to design the compact gantry; the length and radius of the gantry would be approximately 12m and 5m, which are comparable to those of the existing proton gantries. A part of the superconducting magnets will be constructed within this fiscal year. The design of the rotating gantry, including the beam optics as well as details of the superconducting magnets, will be presented.

THPS086

Compact Beam Delivery Systems for Ion Beam Therapy

ion, simulation, beam-transport, focusing

3633

C. Sun, D. Arbelaez, S. Caspi, D. Robin, A. Sessler, W. Wan
LBNL, Berkeley, California, USA
M. Yoon
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: Work supported by the United States Department of Energy under Contract No. DE-AC02-05CH11231
In this paper we present a coil winding concept for a large aperture, combined-function 90 degree magnet that allows for a significantly more compact carbon ion gantry. The winding concept enables the reduction in the size and weight of the magnet without compromising the important beam transport properties. Alternatively, a small aperture gantry requires a post-gantry scanner. We present a compact design for a post-gantry point-to-parallel scanning system.

THPZ003

The SuperB Project: Accelerator Status and R&D

feedback, luminosity, emittance, injection

3684

M.E. Biagini, S. Bini, R. Boni, M. Boscolo, B. Buonomo, T. Demma, E. Di Pasquale, A. Drago, L.G. Foggetta, S. Guiducci, S.M. Liuzzo, G. Mazzitelli, L. Pellegrino, M.A. Preger, P. Raimondi, U. Rotundo, C. Sanelli, M. Serio, A. Stecchi, A. Stella, S. Tomassini, M. Zobov
INFN/LNF, Frascati (Roma), Italy
M.A. Baylac, O. Bourrion, J.-M. De Conto, N. Monseu, C. Vescovi
LPSC, Grenoble, France
K.J. Bertsche, A. Brachmann, Y. Cai, A. Chao, M.H. Donald, R.C. Field, A.S. Fisher, D. Kharakh, A. Krasnykh, K.C. Moffeit, Y. Nosochkov, A. Novokhatski, M.T.F. Pivi, J.T. Seeman, M.K. Sullivan, S.P. Weathersby, A.W. Weidemann, U. Wienands, W. Wittmer, G. Yocky
SLAC, Menlo Park, California, USA
S. Bettoni
PSI, Villigen, Switzerland
A.V. Bogomyagkov, I. Koop, E.B. Levichev, S.A. Nikitin, I.N. Okunev, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin, P. Vobly
BINP SB RAS, Novosibirsk, Russia
B. Bolzon, M. Esposito
CERN, Geneva, Switzerland
F. Bosi
INFN-Pisa, Pisa, Italy
L. Brunetti, A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
A. Chancé
CEA, Gif-sur-Yvette, France
P. Fabbricatore, S. Farinon, R. Musenich
INFN Genova, Genova, Italy
E. Paoloni
University of Pisa and INFN, Pisa, Italy
C. Rimbault, A. Variola
LAL, Orsay, France
Y. Zhang
IHEP Beijing, Beijing, People's Republic of China

The SuperB collider project has been recently approved by the Italian Government as part of the National Research Plan. SuperB is a high luminosity (10³6 cm^-2 s^-1) asymmetric e⁺e⁻ collider at the Y(4S) energy. The design is based on a “large Piwinski angle and Crab Waist” scheme already successfully tested at the DAΦNE Phi-Factory in Frascati, Italy. The project combines the challenges of high luminosity colliders and state-of-the-art synchrotron light sources, with two beams (e⁺ at 6.7 and e^- at 4.2 GeV) with extremely low emittances and small beam sizes at the Interaction Point. As unique features, the electron beam will be longitudinally polarized at the IP and the rings will be able to ramp down to collide at the tau/charm energy threshold with one tenth the luminosity. The relatively low beam currents (about 2 A) will allow for low running (power) costs compared to similar machines. The insertion of beam lines for synchrotron radiation users is the latest feature included in the design. The lattice has been recently modified to accommodate insertion devices for X-rays production. A status of the project and a description of R&D in progress will be presented.

THPZ006

SuperKEKB Interaction Region Modeling

solenoid, multipole, focusing, lattice

3690

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

In the SuperKEKB interaction region(IR) design, the beam-line intersects solenoid-axis with large angle and the superconducting final focusing quadrupole magnets are installed into each beam-lines without iron-shield. Because of these features, the emittance and dynamic aperture evaluation have to consider the solenoid fringe field and the leakage multipole field of another beam-line magnet, respectively. The IR lattice modeling and the magnetic field handling of both solenoid and multipole field would be reported in this article.

THPZ012

Luminosity Enhancement and Performance in BEPCII

luminosity, background, optics, coupling

3708

Q. Qin, J. Cao, J. Cheng, Y.L. Chi, H. Dong, Z. Duan, D. Ji, W. Kang, S.P. Li, L. Ma, H. Qu, C.H. Wang, G.W. Wang, J.Q. Wang, X.H. Wang, Y. Wei, J. Xing, G. Xu, C.H. Yu, J. Yue, C. Zhang, Y. Zhang
IHEP Beijing, Beijing, People's Republic of China

The Beijing Electron Positron Collider (BEPC) was upgraded to a factory-like machine –- BEPCII, during last several years. From last November, the BEPCII was commissioned again for its luminosity. Efforts on optics correction including optimizing the strengths of superconducting quadrupoles near the IP, orbits correction concerning beam energy, etc, make the transvers tunes possible to move very close to half integer, bringing a big luminosity increase. The background of the detector is also reduced with beam commissioning, and finally fit the requirements of data taking. Further luminosity commissioing, including coupling optimization, beta-waist tuning, was carried on, and the luminosity reached 6.49·10³² cm^-2 s^-1 during routine operation. Some measures of luminosity enhancement and the luminosity related accelerator physics issues will be discussed.

THPZ016

Interaction Region Design for a Ring-Ring LHeC

electron, optics, luminosity, proton

3720

L.N.S. Thompson, R. Appleby
UMAN, Manchester, United Kingdom
N.R. Bernard
UCLA, Los Angeles, California, USA
M. Fitterer
KIT, Karlsruhe, Germany
B.J. Holzer
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom
P. Kostka
DESY Zeuthen, Zeuthen, Germany
L.N.S. Thompson
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The Large Hadron Electron Collider project is a proposal to study e-p and e-A interactions at the LHC. Using one of the LHC's proton beams, an electron beam of relatively low energy and moderately high intensity provides high luminosity TeV-scale e-p collisions at one of the LHC interaction points, running simultaneously with existing experiments. Two designs are studied; an electron ring situated in the LHC tunnel, and an electron linac. The focus of this paper is on the ring design. Designing an e-p machine presents interesting accelerator physics and design challenges, particularly when considering the interaction region. These include coupled optics, beam separation and unconventional mini-beta focusing schemes. Designs are constrained by an array of interdependent factors, including beam-beam interaction, detector dimensions and acceptance, luminosity and synchrotron radiation. Methods of addressing these complex issues are discussed. The current designs for the LHeC Ring-Ring interaction region and long straight section are presented and discussed, in the context of the project goals and design challenges encountered. Future developments and work are also discussed.

THPZ028

Upgrade Studies for the LHC Collimators

collimation, alignment, proton, betatron

3750

A. Rossi, R.W. Assmann, D. Wollmann
CERN, Geneva, Switzerland

The Phase-I LHC Collimation System has to be upgraded to work at high intensity and energy. Theoretical and engineering studies are focusing on different regions of the machine. The IR3 combined momentum and betatron cleaning, initially approved for installation, has presently been kept as fallback solution in case radiation to equipment limits LHC performance. The installation of collimators in the dispersion suppressor section DS3 has been delayed. In this paper we present predictions with matched optics and the effect of machine imperfections on the collimation performance with IR3 combined cleaning, with and without DS3 collimators.

THPZ032

Evaluation of the Combined Betatron and Momentum Cleaning in Point 3 in Terms of Cleaning Efficiency and Energy Deposition for the LHC Collimation Upgrade

betatron, collimation, beam-losses, proton

3762

L. Lari, R.W. Assmann, V. Boccone, M. Brugger, F. Cerutti, A. Ferrari, A. Rossi, R. Versaci, V. Vlachoudis, D. Wollmann
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain
A. Mereghetti
UMAN, Manchester, United Kingdom

Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program.
The Phase I LHC Collimation System Upgrade could include moving part of the Betatron Cleaning from LHC Point 7 to Point 3 to improve both operation flexibility and intensity reach. In addition, the partial relocation of beam losses from the current Betatron cleaning region at Point 7 will mitigate the risks of Single Event Upsets to equipment installed in adjacent and partly not adequate shielded areas. A combined Betatron and Momentum Cleaning scenario at Point 3 implies the installation of new collimators and a new collimator aperture layout. This paper shows the whole LHC Collimator Efficiency variation with the new layout proposed at different beam energies. As part of the evaluation, energy deposition distribution in the IR3 region gives indications about the effect of this new implementation not only on the collimators themselves but also on the other beam line elements.