IPAC2015 - List of Keywords (optics)

Paper	Title	Other Keywords	Page
MOBC1	Towards Ultra-Low β^* in ATF2	octupole, multipole, collider, linear-collider	38
	M. Patecki, A.V. Aloev, D.R. Bett, M. Modena, R. Tomás CERN, Geneva, Switzerland K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan E. Marín, G.R. White SLAC, Menlo Park, California, USA
	The Accelerator Test Facility 2 (ATF2) has already demonstrated the feasibility of Final Focus Systems based on the local chromaticity correction scheme and its focusing capabilities by reaching a vertical beam size at the virtual Interaction Point (IP) of less than 50 nm. The value of the chromaticity in ATF2 is comparable with the expected chromaticity in ILC, but 4 times lower than in a design of CLIC. ATF2 gives the unique possibility to test operation at CLIC chromaticity values by reducing the vertical beta function at the IP by a factor of 4 (the inverse proportionality of chromaticity with beta function value at IP is assumed). The experience collected in this way would be beneficial for both ILC and CLIC projects. Simulations show that the multipolar errors and Final Doublet fringe fields spoil the IP beam sizes at ATF2. Either increasing a value of the horizontal beta function or installing a pair of octupole magnets mitigate the impact of these aberrations. This paper summarizes the studies towards the realization of the ultra-low β^* optics in ATF2 and reports on the progress of the construction of the octupoles.
	Slides MOBC1 [1.566 MB]
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MOBC3	Electron Lenses for Experiments on Nonlinear Dynamics with Wide Stable Tune Spreads in the Fermilab Integrable Optics Test Accelerator	electron, lattice, solenoid, operation	46
	G. Stancari, K. Carlson, M.W. McGee, L.E. Nobrega, A.L. Romanov, J. Ruan, A. Valishev Fermilab, Batavia, Illinois, USA D. Noll IAP, Frankfurt am Main, Germany
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy. Recent developments in the study of integrable Hamiltonian systems have led to nonlinear accelerator lattice designs with two transverse invariants. These lattices may drastically improve the performance of high-power machines, providing wide tune spreads and Landau damping to protect the beam from instabilities, while preserving dynamic aperture. To test the feasibility of these concepts, the Integrable Optics Test Accelerator (IOTA) is being designed and built at Fermilab. One way to obtain a nonlinear integrable lattice is by using the fields generated by a magnetically confined electron beam (electron lens) overlapping with the circulating beam. The parameters of the required device are similar to the ones of existing electron lenses. We present theory, numerical simulations, and first design studies of electron lenses for nonlinear integrable optics.
	Slides MOBC3 [11.870 MB]
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MOPWA012	Study of Optimal MBA Lattice Structures for the SOLEIL Upgrade	emittance, dipole, lattice, quadrupole	106
	R. Nagaoka, P. Brunelle, F.J. Cullinan, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Within the context of a future upgrade of the SOLEIL ring, a series of lattice studies has been made with the aim of reducing the current 4 nm-rad horizontal emittance ex by more than an order of magnitude, with a dynamic aperture allowing off-axis injection. As in most upgrades, the important constraint imposed is to keep all the existing straight sections and photon source points. A particularity of SOLEIL are the short straight sections in half of the 16 double-bend cells, created in between the dipoles, which limits the number of dipoles in a MBA cell. In the previous studies, a combination of 5- and 4BA was followed, where with the use of longitudinal gradient bends (LGBs), ex ~440 pm-rad was obtained. The present paper reports on studies extended along the same strategy: In particular, the feasibility and the attainable ex are pursued with a combination of 7- and 6BA, by employing dipoles with transverse gradient and LGBs. In addition, the effectiveness of a few known nonlinear optimization methods, such as the resonance driving term cancellation, interleaved sextupoles with proper phases, and genetic algorithm-based numerical searches shall be explored.
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MOPWA015	Lattice Correction using LOCO for the ThomX Storage Ring	quadrupole, lattice, storage-ring, coupling	117
	I. Chaikovska, C. Bruni, S. Chancé, A. Variola, J.F. Zhang LAL, Orsay, France A. Loulergue SOLEIL, Gif-sur-Yvette, France
	Funding: Work is supported by the French Agence Nationale de la Recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI ThomX is a compact Compton based X-ray source under construction at LAL in Orsay (France). The ThomX accelerator facility is composed by a 50-70 MeV linac driven by 3 GHz RF gun, a transfer line and a 18 meters long Storage Ring (SR). The Compton backscattering at each revolution between the 1 nC electron bunch and the 25 mJ laser pulses stacked in the Fabry-Perot cavity results in the production of ~10¹³ photons per second with energies in the X-ray regime. This high flux of the X-rays strongly depends on the quality (beam sizes) of the electron beam at the interaction point. To guarantee this, a good knowledge and quality of the linear lattice of the ThomX SR are required. Nowadays, LOCO (Linear Optics from Closed Orbits) is a well-known and widely used algorithm to measure and restore the linear optics of the SRs and ensure the designed performances. Comparing the measured and model orbit response matrices, the linear lattice can be restored by retuning the quadrupole gradients. In this paper, we report on the LOCO analysis of the ThomX SR taking into account simulated misalignment, calibration and field errors.
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MOPWA035	Two General Orbit Theorems for Efficient Measurements of Beam Optics	closed-orbit, storage-ring, dipole, lattice	183
	B. Riemann, A. Ferrarotto, P. Hartmann, B.D. Isbarn, S. Koetter, M. Sommer, P. Towalski, T. Weis DELTA, Dortmund, Germany
	Closed-orbit perturbations and oscillating beam solutions in storage rings are closely related. While techniques exist to fit accelerator models to closed-orbit perturbations or to oscillation data, the exploitation of their relation has been limited. In this work, two orbit theorems that allow an efficient computation of optical parameters in storage rings with older hardware are derived for coupled linear beam motion. The monitor theorem is based on an uncoupled case study described by the author in an earlier work and has been generalized as well as simplified in mathematical abstraction to provide a reliable and computationally stable framework for beam optics measurements. It is based on a closed-orbit measurement utilizing 4 dipole correctors (2 for each plane). The corrector theorem allows to obtain parameters of these dipole correctors using two turn-by-turn monitors at almost arbitrary positions in the ring (which do not need to be located in a drift space), so that it is possible to uniquely resolve closed orbits into optical parameters without sophisticated lattice models.
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MOPWA038	Sensitivity of Linac Optics to Focusing and Energy Errors	focusing, linac, operation, quadrupole	193
	V. Balandin, W. Decking, N. Golubeva DESY, Hamburg, Germany
	The ability to control beam optics in the presence of such imperfections as focusing and energy gain errors is essential for a successful operation of high brightness electron linacs providing beams for free-electron lasers. We characterize the cumulative effect of these imperfections using the value of mismatch parameter calculated at the linac exit and show how it depends on the design of the focusing lattice.
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MOPWA039	Emittance Reduction Possibilities in the PETRA III Magnet Lattice	emittance, sextupole, lattice, synchrotron	197
	N. Golubeva, V. Balandin, W. Decking, R. Wanzenberg DESY, Hamburg, Germany
	PETRA III is a third generation light source that has been operated as a user facility since 2010 at DESY. An upgrade for additional beam lines has been carried out, and the recommissioning of the new beam lines is starting in spring 2015. In order to fully exploit the potential of the existing magnet lattice of the PETRA III ring, we present a study of beam optics modifications enabling the reduction of the horizontal emittance without changes of the lattice.
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MOPWA043	FEL Simulations with Ocelot	space-charge, FEL, simulation, electron	210
	I.V. Agapov, G. Geloni XFEL. EU, Hamburg, Germany M. Dohlus, I. Zagorodnov DESY, Hamburg, Germany S.I. Tomin NRC, Moscow, Russia
	Ocelot has been developed as a multiphysics simulation tool for FEL and synchrotron light source studies. In this work we highlight recent code developments focusing on electron tracking in linacs taking into account collective effects and on x-ray optics calculations
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MOPWA047	Start to End Simulation of High Current Injector using TRACEWIN Code	ion, DTL, rfq, linac	223
	S. Kumar, A. Mandal IUAC, New Delhi, India
	High Current Injector (HCI) is an alternate injector to superconducting linac at IUAC in addition to pelletron. It consists mainly of high temperature superconducting ECR ion source (PKDELIS), radio frequency quadrupole (RFQ)* and a drift tube linac (DTL). The ions of mass to charge (A/q) ratio of 6 are analysed initially and accelerated through RFQ and DTL to a total energy of 1.8 MeV/u. The different energy regimes connecting the accelerating stages are named as low, medium and high energy beam transport section (LEBT, MEBT and HEBT). The energy spread of beam increases from 0.02% at ECR source to 0.5% at the DTL exit. An ion beam of normalized transverse and longitudinal emittance of 0.03 pi mm-mrad and 0.3 keV/u-ns has been considered at the start for the simulation of ion optics using TRACEWIN* code. The whole beam transport system has been designed using GICOSY, TRANSPORT and TRACE 3D codes piecewise and TRACEWIN code is used to simulate whole ion optics from start to end including acceleration stages such as RFQ and DTL. Simulation results shows that beam can be injected through LEBT, MEBT and HEBT into LINAC without significant emittance growth and beam loss. * Sugam Kumar et al., Proc. of InPAC-2011, IUAC, New Delhi B.P. Ajith Kumar et al., Proc. of InPAC-2009, RRCAT, Indore * http://irfu.cea.fr/Sacm/logiciels/index3.php
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MOPJE028	Detailed Characterization of ALBA Quadrupoles for Beta Function Determination	quadrupole, storage-ring, synchrotron, controls	338
	Z. Martí, J. Campmany, J. Marcos, V. Massana ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain X.N. Gavaldà SOLEIL, Gif-sur-Yvette, France
	Beta function value at quadrupoles for a circular accelerator can be determined using the relationship between the machine tune and the quadrupole strength. ALBA Storage Ring quadrupoles were measured during manufacturing, to be sure that their performance fitted the specifications. However, measurements were done at a number of currents that are not enough for an accurate determination of the beta function value. In fact, at least 1% error in the calibration of the hysteresis curve slope of the quadrupole is required, and therefore new detailed measurements of the hysteresis cycle are needed. In order to make these measurements, spare quadrupoles existing at ALBA have been used. In this paper we present the results of beta function values determination using this method for ALBA storage ring.
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MOPJE033	Coupled Orbit Response Coefficients with Constant Revolution Time	storage-ring, closed-orbit, radio-frequency, diagnostics	354
	V.G. Ziemann Uppsala University, Uppsala, Sweden
	We calculate orbit response coefficients for arbitrarily coupled lattice which keep the orbit length constant as is needed to maintain synchronicity with a radio-frequency system.
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MOPJE039	Generalised Truncated Power Series Algebra for Fast Particle Accelerator Transport Maps	operation, simulation, lattice	374
	L. Deniau, C.I. Tomoiagă CERN, Geneva, Switzerland
	New Generalised Truncated Power Series Algebra (TPSA) has been developed for extending, simplifying and optimising the transport maps used by particle accelerator simulation codes. TPSA are intensively used in optics code to describe transport maps of the elements constituting the particle accelerator to any order. Generalised TPSA extend the degrees to inhomogeneous ones, where separate degrees can be specified for each variables and constrained by two total orders, one for canonical variables and one for ordinary variables. This allows to track inhomogeneous planes of the 6D phase space with many extra variables. A complete set of new formulas and data structures have been derived to address the problem of memory consumption required for efficient computation of high order TPSA, including generalised indexing, multiplication and composition of inhomogeneous multivariate polynomials. The implementation has been benchmarked against well established libraries for the common subset with TPSA, and outperforms all of them for supported differential algebra operators on low and high orders, and high number of variables.
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MOPJE044	Beam Dynamics Studies of the ELENA Electrostatic Transfer Lines	experiment, quadrupole, antiproton, simulation	385
	M.A. Fraser, W. Bartmann, R. Ostojić CERN, Geneva, Switzerland D. Barna University of Tokyo, Tokyo, Japan
	The low-energy ELENA ring at the Antiproton Decelerator (AD) facility at CERN will lower the kinetic energy of antiproton beams from 5.3 MeV to 100 keV, significantly increasing the antiproton trapping efficiency at the experiments. The antiprotons from ELENA will be distributed to two experimental areas housing several different experiments through a system of electrostatic transfer lines totalling 90 m in length. A significant optimisation of the electrostatic optical elements (deflectors, quadrupoles, and correctors) has been carried out to improve the beam quality delivered to the experiments and facilitate installation of the beam lines into the AD hall. A general overview of the beam optics is presented, including end-to-end particle tracking and error studies from the extraction point in the ELENA ring to the experiments.
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MOPJE049	Benchmarking the CERN-SPS Transverse Impedance Model with Measured Headtail Growth Rates	impedance, simulation, kicker, vacuum	402
	C. Zannini, H. Bartosik, G. Iadarola, G. Rumolo, B. Salvant CERN, Geneva, Switzerland
	The latest SPS transverse impedance model includes kicker magnets, wall impedance, transition pieces (e.g. flanges and vacuum chamber discontinuities), beam position monitors and RF cavities. The model has already been successfully benchmarked against coherent tune shift and transverse mode coupling instability measurements. In this paper we present measurements of the headtail growth rates for a wide range of negative chromaticities and for two different configurations of machine optics (nominal and low gamma transition). The measurement results are compared with HEADTAIL simulations using the wake fields obtained from the SPS transverse impedance model.
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MOPJE054	Developments of the Segment-by-Segment Technique for Optics Corrections in the LHC	simulation, coupling, betatron, quadrupole	419
	A. Langner, J.M. Coello de Portugal, P.K. Skowroński, R. Tomás CERN, Geneva, Switzerland
	Optics correction algorithms will become even more critical for the operation of the LHC at 6.5 TeV. For the computation of local corrections the segment-by-segment technique is used. We present improvements to this technique and an advanced error analysis, which increase the sensitivity for finding local corrections. Furthermore, we will investigate limitations of this method for lower beta-star optics as they will be used in the high-luminosity LHC (HL-LHC) upgrade.
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MOPJE056	OMC Software Improvements in 2014	software, GUI, simulation, operation	426
	J.M. Coello de Portugal, F.S. Carlier, A. Langner, T. Persson, P.K. Skowroński, R. Tomás CERN, Geneva, Switzerland
	We present the LHC Optics Measurement and Corrections (OMC) software developments done during 2014 on stability, performance and usability. This software is used to analyze turn-by-turn data and compute optics corrections to get the best performance of the LHC. The main developments have been an automatic local correction script to get faster and more accurate corrections in the interaction regions, a self contained test for the whole software package to avoid mistakes during the software development and the improvements in the software quality and efficiency of the Segment by Segment technique script. We also present a study of the code quality in its current status.
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MOPJE057	Optics Measurement using the N-BPM Method for the ALBA Synchrotron	quadrupole, betatron, dipole, synchrotron	430
	A. Langner, J.M. Coello de Portugal, R. Tomás CERN, Geneva, Switzerland G. Benedetti, M. Carlà, U. Iriso, Z. Martí ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	The N-BPM method recently developed for the LHC has significantly improved the precision of optics measurements which are based on beam position monitor (BPM) turn-by-turn data. The main improvement is owed to the consideration of correlations for statistical and systematic error sources, as well as increasing the amount of BPM combinations for one measurement. We present how this technique can be applied at light sources like ALBA, and compare the results with other methods.
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MOPJE065	Contribution of Optical Aberrations to Spot-size Increase with Bunch Intensity at ATF2	emittance, damping, extraction, simulation	455
	M. Patecki, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan M. Patecki Warsaw University of Technology, Warsaw, Poland G.R. White SLAC, Menlo Park, California, USA
	A primary goal of ATF2 (Accelerator Test Facility) is to demonstrate a low vertical beam size at the interaction point (IP) of about 37 nm. Measurements over the past years indicate that the ATF2 vertical beam size strongly rises with bunch intensity. Several different origins of this increase are considered, e.g. wakefields occurring between the ATF damping ring and the IP, and/or intrabeam scattering (IBS) causing the increase of transverse emittances and energy spread in the damping ring with the increase of the bunch intensity. In this paper we address the second possibility. Past measurements and simulations of the IBS effects in the ATF are used to model the intensity-dependent initial emittances and energy spread at the entrance of the final focus. Particle tracking simulations predict the IP vertical beam size growth expected from the known optical aberrations for initial beam parameters corresponding to varying bunch intensities. Comparing simulation results with emittance measurements at different locations allows us to draw some conclusions about the impact of IBS in the damping ring on the IP spot size, and about possible single-bunch wakefields in the ATF2.
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MOPJE067	Applications of PLACET2 to the CTF3 Combiner Ring	dipole, simulation, quadrupole, wiggler	462
	D. Pellegrini, R. Corsini, D. Gamba, A. Latina CERN, Geneva, Switzerland
	The CTF3 Combiner Ring (CR) is an isochronous ring that employs RF-injection to combine multiple bunch trains (up to five) into a single one with higher bunch frequency. The length of the CR plays a critical role in obtaining the correct structure of the recombined train. PLACET2: the new recirculating version of the code PLACET is particularly suited to simulate the operational scenario. In order to validate this code, three different case studies have been considered: ring-length variations due to energy detuning, fast-beam decoherence due to uncorrected chromatic effects and vertical instabilities due to bunch-to-bunch wakefield effects. The first two effects have been measured during the last run and the predictions have been validated. The instability has been compared with previous studies. The results are presented and discussed.
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MOPJE069	General Functionality for Turn-Dependent Element Properties in SixTrack	simulation, cavity, HOM, collimation	468
	K.N. Sjobak, H. Burkhardt, R. De Maria, A. Mereghetti, A. Santamaría García CERN, Geneva, Switzerland
	In order to facilitate studies of how dynamically changing element attributes affect the dynamics of the beam and beam losses, the functionality for dynamic kicks (DYNK) of SixTrack has been significantly extended. This functionality can be used for the simulation of dynamic scenarios, such as when crab cavities are switched on, orbit bumps are applied, optics are changed, or failures occur. The functionality has been extended with a more general and flexible implementation, such that arbitrary time-dependent functions can be defined and applied to different attributes of families or individual elements, directly from the user input files. This removes the need for source code manipulation, and it is compatible with LHC@Home which offers substantial computing resources from volunteers. In this paper, the functionality and implementation of DYNK is discussed, along with examples of application to the HL-LHC crab cavities.
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MOPJE074	Optimizing SLS-2 Nonlinearities Using a Multi-Objective Genetic Optimizer	sextupole, resonance, octupole, injection	486
	M.P. Ehrlichman, M. Aiba, A. Streun PSI, Villigen PSI, Switzerland
	An upgrade to the SLS is currently under development. This upgrade will likely utilize the same hall and same machine circumference, 288 m, of the SLS. Achieving a sufficiently low emittance with such a small circumference requires tight focusing and low dispersion. These conditions make chromaticity correction difficult and minimization of 1st and 2nd order non-linear driving terms does not yield sufficient dynamic aperture and Touschek lifetime. In this proceeding, we discuss the multi-objective genetic optimization method being implemented at SLS to aid the design of a chromaticity correction scheme for SLS2.
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MOPMA002	Optimising the Diamond DDBA Upgrade Lattice for Low Alpha Operation	lattice, storage-ring, injection, dynamic-aperture	525
	I.P.S. Martin, R. Bartolini DLS, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	The Diamond storage ring will be upgraded during 2016 by replacing one of the existing double bend achromat (DBA) cells with a double-DBA (DDBA) cell. One requirement of the upgrade is that following the installation of the new cell, Diamond should continue to offer dedicated user time in ‘low alpha’ mode. In this paper we describe the particular challenges relating to this task, and present the lattice design and optimisation studies undertaken so far. The paper concludes by discussing preliminary studies of adding a second DDBA cell into the storage ring. R.P. Walker et al., Proc. IPAC 2014, MOPRO103, (2014) ** I.P.S. Martin et al., Proc. IPAC 2013, MOPEA070, (2013)
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MOPMA014	Design of Superconducting CW linac for PIP-II	linac, cryomodule, beam-losses, operation	565
	A. Saini, V.A. Lebedev, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Proton Improvement Plan (PIP) -II is a proposed roadmap to upgrade existing proton accelerator complex at Fermilab. It is primarily based on construction of superconducting (SC) linear accelerator (linac) that would be capable to operate in continuous wave (CW) mode. This paper will present reference design of SC linac and discuss motivations and requirements resulting in this layout and beam optics.
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MOPMA020	Measurement and Correction of the Fermilab Booster Optics with LOCO	lattice, booster, quadrupole, dipole	586
	C.-Y. Tan, V.A. Lebedev, A.K. Triplett Fermilab, Batavia, Illinois, USA M. McAteer CERN, Geneva, Switzerland
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The optics of the original Booster lacked the ability for full optics correction and it was not until 2009 when new optics corrector packages were installed between gradient magnets that this ability became available. The optics correction method that is chosen is called LOCO (Linear Optics from Closed Orbits) that measures the orbit response from every beam position monitor (BPM) in the ring from every kick of every dipole corrector. The large data set collected allows LOCO to not only calculate the quadrupole and skew quadrupole currents that both reduces beta beatings and corrects coupling, it also finds the dipole kicker strengths, BPM calibrations and their tilts by minimizing the difference between the measured and ideal orbit response of the beam. The corrected optics have been loaded into Booster and it is currently being tested to be eventually used in normal operations.
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MOPMA028	Chromaticity and Dispersion in Nonlinear Integrable Optics	lattice, dynamic-aperture, focusing, octupole	608
	S.D. Webb, D.L. Bruhwiler RadiaSoft LLC, Boulder, Colorado, USA V.V. Danilov ORNL, Oak Ridge, Tennessee, USA S. Nagaitsev, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: This material is based upon work sup- ported by the U.S. Department of Energy, Office of Sci- ence, Office of High Energy Physics under Award Num- ber DE-SC0011340. Proton accumulator rings and other circular hadron accelerators are susceptible to intensity- driven parametric instabilities because the zero-current charged particle dynamics are characterized by a single tune. Landau damping can suppress these instabilities, which requires energy spread in the beam or introducing nonlinear magnets such as octupoles. However, this approach reduces dynamic aperture. Nonlinear integrable optics can suppress parametric instabilities independent of energy spread in the distribution, while preserving the dynamic aperture. This novel approach promises to reduce particle losses and enable order-of-magnitude increases in beam intensity. In this paper we present results, obtained using the Lie operator formalism, on how chromaticity and dispersion affect particle orbits in integrable optics. We conclude that chromaticity in general breaks the integrability, unless the vertical and horizontal chromaticities are equal. Because of this, the chromaticity correcting magnets can be weaker and fewer correcting magnet families are required, thus minimizing the impact on dynamic aperture.
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MOPMA029	Experiences Simulating Nonlinear Integrable Optics	lattice, simulation, diagnostics, emittance	611
	S.D. Webb, D.L. Bruhwiler RadiaSoft LLC, Boulder, Colorado, USA V.V. Danilov ORNL, Oak Ridge, Tennessee, USA R.A. Kishek UMD, College Park, Maryland, USA S. Nagaitsev, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0011340. With increasing interest in the nonlinear integrable optics, it is important that early experiences with simulating the lattices be shared to save time and point out potential difficulties in the simulations. We present here some details of simulating the nonlinear integrable lattices. We discuss correctly implementing and testing the elliptic element kicks, and the limits of the thin lens approximation. We also discuss generating a properly matched bunch in the transverse phase space, and how to analyze the resulting computational data from simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA029
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MOPMN001	Linear Optics and Coupling Correction with Turn-by-turn BPM Data	lattice, quadrupole, target, coupling	698
	X. Huang SLAC, Menlo Park, California, USA X. Yang BNL, Upton, Long Island, New York, USA
	We propose a method to measure and correct storage ring linear optics and coupling with turn-by-turn BPM data. The independent component analysis (ICA) is used to obtain the amplitudes and phase advances of the betatron normal modes, which are compared to their counterparts derived from the lattice model. By fitting the model to the data with quadrupole and skew quadrupole variables, the linear optics and coupling of the machine can be obtained. Simulation demonstrates that errors in the lattice and BPM parameters can be recovered with this method. Experiments on the NSLS-II storage ring show that it can find the same optics as the linear optics from closed orbit (LOCO) method.
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MOPMN003	Dynamic Aperture Studies for the LHC High Luminosity Lattice	lattice, injection, luminosity, quadrupole	705
	M. Giovannozzi, R. De Maria, E. McIntosh CERN, Geneva, Switzerland Y. Cai, Y. Nosochkov, M.-H. Wang SLAC, Menlo Park, California, USA
	Funding: Work supported by the US LHC Accelerator Research Program and the DOE Contract DE-AC02-76SF00515. Research supported by FP7 HiLumi LHC, Grant Agreement 284404, http://hilumilhc.web.cern.ch. Since quite some time, dynamic aperture studies have been undertaken with the aim of specifying the required field quality of the new magnets that will be installed in the LHC ring in the framework of the high-luminosity upgrade. In this paper the latest results concerning the specification work will be presented, taking into account both injection and collision energies and the field quality contribution from all the magnets in the newly designed interaction regions.
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MOPMN010	Non-linear Magnetic Inserts for the Integrable Optics Test Accelerator	vacuum, alignment, dipole, quadrupole	724
	F.H. O'Shea, R.B. Agustsson, Y.C. Chen, E. Spranza RadiaBeam, Santa Monica, California, USA D.W. Martin, J.D. McNevin RadiaBeam Systems, Santa Monica, California, USA
	We present here a status update of the manufacture and magnetic measurements of the non-linear inserts for the Integrable Optics Test Accelerator. RadiaBeam Technologies is designing the 2-meter structure from magnetic field specifications, including pole design, measurement systems and alignment fiducialization. Herein, we will describe the current state of the project.
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MOPHA031	Implementation of a Diagnostic Pulse for Beam Optics Stability Measurements at FLASH	kicker, controls, diagnostics, betatron	850
	F. Mayet, R.W. Aßmann, S. Schreiber, M. Vogt DESY, Hamburg, Germany
	In order to monitor long-term stability of beam optics, simple and at the same time minimally invasive procedures are desirable. Using selectively kicked bunches, betatron phase advance, as well as potential growth of the betatron oscillation amplitude and the Twiss parameters alpha and beta can be extracted from BPM data. If done periodically, this data can be compiled into a long-term history that is accessible via the control system. This way it is possible to identify potential sources of beam optics errors. At FLASH the procedure could be implemented as a server/client tool. Since the whole procedure takes less than five seconds, operation is not disturbed significantly. In this work the possible implementation of the procedure is presented. It is also shown how the history data can be evaluated in order to infer possible beam optics error sources.
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MOPHA035	Beam Optics Measurements at FLASH2	extraction, undulator, linac, FEL	863
	M. Scholz, M. Vogt, J. Zemella DESY, Hamburg, Germany
	FLASH2 is a newly build second beamline at FLASH, a soft X-ray FEL at DESY, Hamburg. Unlike the existing beamline FLASH1, it is equipped with variable gap undulators. This beamline is currently being commissioned. Both undulator beamlines of FLASH are driven by a common linear accelerator. Fast kickers and a septum are installed at the end of the linac to distribute the electron bunches of every train between FLASH1 and FLASH2. A specific beam optics in the extraction arc with horizontal beam waists in the bending magnets is mandatory in order to mitigate effects from coherent synchrotron radiation (CSR). We performed various beam optics measurements to ensure that the conditions for FEL operation at FLASH2 are fulfilled. Here we will show results of measurements.
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MOPHA042	Online Studies of THz-radiation in the Bursting Regime at ANKA	synchrotron, radiation, synchrotron-radiation, bunching	882
	M. Brosi, C.M. Caselle, E. Hertle, N. Hiller, A. Kopmann, A.-S. Müller, M. Schwarz, P. Schönfeldt, J.L. Steinmann, M. Weber KIT, Eggenstein-Leopoldshafen, Germany
	Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320 The ANKA storage ring of the Karlsruhe Institute of Technology (KIT) operates in the energy range from 0.5 to 2.5 GeV and generates brilliant coherent synchrotron radiation in the THz range with a dedicated bunch length reducing optic. The producing of radiation in the so-called THz-gap is challenging, but this intense THz radiation is very attractive for certain user experiments. The high degree of compression in this so-called low-alpha optics leads to a complex longitudinal dynamics of the electron bunches. The resulting micro-bunching instability leads to time dependent fluctuations and strong bursts in the radiated THz power. The study of these fluctuations in the emitted THz radiation provides insight into the longitudinal beam dynamics. Fast THz detectors combined with KAPTURE, the dedicated KArlsruhe Pulstaking and Ultrafast Readout Electronics system developed at KIT, allow the simultaneous measurement of the radiated THz intensity for each bunch individually in a multi-bunch environment. This contribution gives an overview of the first experience gained using this setup as an online diagnostics tool.
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MOPWI001	First Results From Beam Tests of the CLIC Drive Beam Phase Feedforward Prototype at CTF3	kicker, hardware, dipole, operation	1139
	J. Roberts, P. Burrows, G.B. Christian, C. Perry JAI, Oxford, United Kingdom A. Andersson, R. Corsini, P.K. Skowroński CERN, Geneva, Switzerland A. Ghigo, F. Marcellini INFN/LNF, Frascati (Roma), Italy
	Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu-CARD, grant agreement no. 227579. In the CLIC two beam acceleration scheme 100 MV/m normal conducting cavities are fed with RF power extracted from a secondary high power but low energy drive beam. To ensure the efficiency and luminosity performance of CLIC the phase synchronisation between the high energy main beam and the drive beam must be maintained to within 0.2 degrees of 12 GHz. To reduce the drive beam phase jitter to this level a low-latency drive beam phase feedforward correction with bandwidth above 17.5 MHz is required. A prototype of this system has been installed at the CLIC test facility CTF3 to prove its feasibility, in particular the challenges of high bandwidth, high power and low latency hardware. The final commissioning and first results from operation of the complete phase feedforward system are presented here.
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MOPWI004	Novel Single Shot Bunch Length Diagnostic using Coherent Diffraction Radiation	electron, radiation, experiment, laser	1150
	R.B. Fiorito, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom A.G. Shkvarunets UMD, College Park, Maryland, USA
	Funding: European Union’s grant agreement no. 624890 and STFC Cockcroft core grant No. ST/G008248/1; US Office of Naval Research and DOD Joint Technology Office. Current beam bunch length monitors which measure the spectral content of beam-associated coherent radiation to determine the longitudinal bunch form factor usually require wide bandwidth detection or Fourier transformation of interferometric data and multiple beam pulses. The data must then be Fourier transformed to obtain the bunch length. In this contribution we discuss progress in the development of a novel single shot method that utilizes the frequency integrated angular distribution (AD) of coherent diffraction radiation (CDR) to measure the RMS bunch length directly. We also present simulation results which show how the AD changes with bunch length for several electron beam linacs, where we are planning to test this new method, our single shot measurement technique and plans for comparison to other bunch length monitors.
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MOPWI016	Development of a Versatile Bunch-length Monitor for Electron Beams at ASTA	laser, radiation, electron, linac	1181
	A.H. Lumpkin, D.J. Crawford, D.R. Edstrom, J. Ruan, J.K. Santucci, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA
	Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy. The generation of bright electron beams at the ASTA/IOTA facility at Fermilab includes implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The station will include both a Hamamatsu C5680 synchroscan streak camera and a Martin-Puplett interferometer (MPI). An Al-coated Si screen will be used to generate both optical transition radiation (OTR) and coherent transition radiation (CTR) during the beam’s interaction with the screen. A chicane bypass beamline will allow the measurement of the initial bunch length at the same downstream beamline location using OTR and the streak camera. The UV component of the drive laser has previously been characterized with a Gaussian fit σ of 3.5 ps, and the uncompressed electron beam is expected to be similar to this value at low charge per micropulse. In addition, OTR will be transported to the streak camera from the focal plane of the downstream spectrometer to provide an E-t distribution within the micropulse time scale. Commissioning of the system and initial results with beam will be presented as available. A.H. Lumpkin et al., Proceedings of FEL14, MOP021, Basel, Switzerland, www. JACoW.org.
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MOPWI027	Open XAL Control Room Experience	controls, software, operation, Windows	1214
	C.P. Chu, D.G. Maxwell, Y. Zhang FRIB, East Lansing, Michigan, USA C.K. Allen, T.A. Pelaia II, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy under Cooperative Agreement DE-SC0000661 and DE-AC05-00OR22725, the State of Michigan and Michigan State University. This paper reports the control room experience, lessons learned, and quick deployment approach for the Open XAL application environment. Open XAL is a java-based framework for building high-level accelerator applications, it is a major revision of the XAL framework which was developed at the Spallation Neutron Source (SNS). Open XAL is site neutral and may be deployed at multiple accelerator facilities. Currently, Open XAL is installed at SNS and at the Re-Accelerator facility of Michigan State University. At SNS we are in the final process of replacing the old XAL environment with Open XAL; we describe the upgrade process and our accelerator operations experience using Open XAL. At Michigan State, Open XAL has been tested during a cryomodule commissioning and result will be shown.
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TUAC2	Wideband Vertical Intra-Bunch Feedback At The SPS - 2015 Results And Path Forward	feedback, controls, kicker, simulation	1353
	C.H. Rivetta, J.E. Dusatko, J.D. Fox, O. Turgut SLAC, Menlo Park, California, USA S. De Santis LBNL, Berkeley, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP) We present experimental measurements taken from CERN SPS machine development studies with a wideband intra-bunch feedback channel prototype. The demonstration system is a digital processing system with recently installed wideband kicker and amplifier components. This new hardware extends the bandwidth up to 1GHz and allows driving and controlling multiple vertical transverse modes in the bunch. The studies are focused on both driving the bunch with spectrally controlled signals to identify a reduced model of the bunch dynamics and testing model-based feedback controllers to stabilize the bunch dynamics. The measurements are structured to validate reduced MIMO models and macro-particle simulation codes, including the dynamics and limits of the feedback channel. Noise effects and uncertainties in the model are evaluated via SPS measurements to quantify the limits of control techniques applied to stabilize the intrabunch dynamics. The design of controllers for Q26 and Q20 optics are illustrated and future control developments are described.
	Slides TUAC2 [30.936 MB]
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TUBD1	Optics Measurement and Correction during Acceleration with Beta-squeeze in RHIC	acceleration, quadrupole, injection, emittance	1380
	C. Liu, A. Marusic, M.G. Minty BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In the past, beam optics correction at RHIC has only taken place at injection and at final energy, with interpolation of corrections partially into the acceleration cycle. Recent measurements of the beam optics during acceleration and squeeze have evidenced significant beta-beats that, if corrected, could minimize undesirable emittance dilutions and maximize the spin polarization of polarized proton beams by avoiding the high-order multipole fields sampled by particles within the bunch. We recently demonstrated successfully beam optics corrections during acceleration at RHIC. We verified conclusively the superior control of the beam realized via these corrections. As a valuable by-product, these corrections have minimized the beta-beat at the profile monitors, so providing more precise measurements of the evolution of the beam emittances during acceleration.
	Slides TUBD1 [1.581 MB]
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TUPWA007	UPGRADED OPTICS FOR SIRIUS WITH IMPROVED MATCHING OF ELECTRON AND PHOTON BEAM EMITTANCES	photon, quadrupole, brightness, emittance	1407
	L. Liu, N. Milas, A.H.C. Mukai, X.R. Resende, F. H. de Sá LNLS, Campinas, Brazil
	A new optics has been designed for Sirius with improved betatron function matching in the 6 meter-long low beta straight sections for insertion devices. Both horizontal and vertical betatron functions are set to 1.5 m in the center of the section, improving the matching of the electron and undulator photon beams. In addition, the horizontal beam stay clear has also been reduced allowing for small horizontal gap devices as well as the conventional small vertical gap ones. The new design optics has been optimized to the same previous performance regarding dynamic aperture and momentum acceptance.
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TUPWA013	Linear and Nonlinear Optimizations for the ESRF Upgrade Lattice	sextupole, lattice, injection, dynamic-aperture	1422
	N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	The ESRF storage ring will be replaced in 2020 by a new hybrid multi bend achromat lattice with 134 pmrad equilibrium horizontal emittance. To determine the best working point, large scans of tunes and chromaticities have been performed, computing Touschek lifetime and dynamic aperture. From different working points, the multi-objective genetic algorithm NSGA-II has been used to optimize the nonlinear magnets values and some linear optics parameters. The analysis have been carried out on lattices with errors and corrections. The optimizations have produced lattices with longer lifetime and larger dynamic aperture for different working points with positive chromaticities.
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TUPWA019	A Canted Double Undulator System With a Wide Energy Range for EMIL	undulator, photon, betatron, permanent-magnet	1442
	J. Bahrdt, H.-J. Bäcker, W. Frentrup, S. Gottschlich, C. Rethfeldt, M. Scheer, B. Schulz HZB, Berlin, Germany
	At BESSY II a canted double undulator system for the Energy Materials In-situ Laboratory EMIL is under construction. The energy regime is covered with two undulators, an APPLE II undulator for the soft and a cryogenic permanent magnet undulator CPMU17 for the hard photons. The layout and the performance of the undulators are discussed in detail. The minimum of the vertical betatron function is shifted to the center of the CPMU17. The neighboring quadrupoles and an additional quadrupole between the undulators control the vertical betatron function. Prior to the undulator installation a testing chamber with four movable scrapers has been implemented at the CPMU17 location. Utilizing the scrapers the new asymmetric lattice optics is tested and evaulated.
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TUPWA028	Simulation Results of the Beam Transport of Ultra-Short Electron Bunches in Existing Beam Transfer Lines to Sinbad	linac, gun, electron, synchrotron	1466
	U. Dorda, R.W. Aßmann, K. Flöttmann, B. Marchetti, Y.C. Nie, J. Zhu DESY, Hamburg, Germany
	SINBAD, the upcoming accelerator R&D facility at DESY, will host multiple independent experiments on the production and acceleration of ultra-short bunches including plasma wakefield experiments. As a possible later upgrade the option to transport higher energy electrons (up to 800 MeV) or positrons (up to 400 MeV) from the existing DESY Linac 2 to the facility is studied. Though existing a possible connection using e.g. a part of the DESY synchrotron as a transfer line and other currently unused transfer-line, these machines were not designed for the desired longitudinal bunch compression and high peak current required by e.g. beam driven plasma wake-field experiments. Simulation results illustrate the modifications to the current layout that would have to be implemented and the corresponding achievable beam parameters are given.
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TUPWA033	Status of the Soft X-ray Free Electron Laser FLASH	operation, FEL, laser, photon	1482
	M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch DESY, Hamburg, Germany
	The superconducting free-electron laser FLASH at DESY routinely produces up to several thousand photon pulses per second with wavelengths in the soft X-ray and vacuum UV regime and with energies up to 0.5 mJ per pulse. In 2014 the assembly of a second undulator beamline, FLASH2, was finished. While recommissioning of the FLASH linac and the original FLASH1 beamline was finished already at the end of 2013, the commissioning of FLASH2 could only be started in early February 2014. Only a few weeks have been reserved for dedicated set up of FLASH2, and most of its commissioning has been performed parasitically during the FLASH1 user run. The first beam was extracted through the septum to the FLASH2 beamline on March 4th, 2014, and the first lasing of FLASH2 at a wavelength of about 40 nm was achieved on August 20th, while FLASH1 was lasing simultaneously with 250 bunches at 13.5 nm. We summarize here the status of the FLASH2 commissioning and the FLASH1 operation during its 5th user period.
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TUPWA034	Status of the Recommissioning of the Synchrotron Light Source PETRA III	emittance, synchrotron, lattice, operation	1485
	R. Wanzenberg, M. Bieler, M. Ebert, L. Fröhlich, J. Keil, J. Klute, G. Kube, G.K. Sahoo DESY, Hamburg, Germany
	At DESY the Synchrotron Light Source PETRA III has been extended in the North and East section of the storage ring to accommodate ten additional beam lines. The PETRA ring was converted into a dedicated synchrotron light source from 2007 to 2009. Regular user operation started in summer 2010 with a very low emittance of 1 nm at a beam energy of 6 GeV and a total beam current of 100 mA. All photon beamlines were installed in one octant of the storage ring. Nine straight sections facilitated the installation of insertion devices for 14 beam lines. Due to the high demand for additional beamlines the lattice of the ring was redesigned to accommodate 10 additional beamlines in the future. In a one year long shut-down two new experimental halls were built. The recommissioning of PETRA III started in February 2015. We are reporting the current status of synchrotron light source including the performance of the subsystems.
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TUPWA035	Progress in Optics Studies at FLASH	quadrupole, linac, FEL, free-electron-laser	1488
	J. Zemella, T. Hellert, M. Scholz, M. Vogt DESY, Hamburg, Germany
	FLASH is the superconducting soft X-ray Free Electron Laser in Hamburg at DESY, Germany. Good control over the beam optics is a key aspect of the operation of a SASE FEL. In 2013 a second beam line, FLASH2, was assembled and the modifications necessary to feed the two beam lines were installed downstream of the FLASH linac. As reported before * we started a campaign of optics consolidation. We give an update on the progress of this effort and on results. * J. Zemella, T. Hellert, M.Scholz, M.Vogt, "Measurements of the Optical Functions at FLASH", Proc. of IPAC'14, TUPRO050.
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TUPWA036	Possibility of Longitudinal Bunch Compression in Petra III	emittance, FEL, undulator, storage-ring	1492
	I.V. Agapov XFEL. EU, Hamburg, Germany S.I. Tomin NRC, Moscow, Russia R. Wanzenberg DESY, Hamburg, Germany
	A scheme of short bunch production in storage rings using a longitudinally focusing insertion was presented in . In this work we study the possibility of integrating such insertion into the PetraIII storage ring. In particular, we discuss possible optics solutions to integrate RF stations, chicane-type delay sections, and the undulators into existing ring geometry. I. Agapov and G. Geloni, proc. FEL 2014.
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TUPWA038	Optics Compensation for Variable-gap Undulator Systems at FLASH	undulator, quadrupole, FEL, electron	1499
	Ph. Amstutz, C. Lechner, T. Plath Uni HH, Hamburg, Germany S. Ackermann, J. Bödewadt, M. Vogt DESY, Hamburg, Germany
	Variable-gap undulator systems are widely used in storage rings and linear accelerators to generate soft- and hard x-ray radiation for the photon science community. For cases where the effect of undulator focusing significantly changes the electron beam optics, a compensation is needed in order to keep the optics constant in other parts of the accelerator. Since 2010, the free-electron laser (FEL) facility FLASH is equipped with two undulator sections along the same electron beamline. The first undulator is a variable-gap system used for seeding experiments, the second undulator is a fixed-gap system which serves the user facility with FEL radiation. Varying the gap in the first undulator will change the beam optics such that the FEL process in the second undulator is dramatically disturbed. For the correction of the beam optics an analytical model is used to generate feed forward tables which allows to make part of the beamline indiscernible for the subsequent sections. The method makes use of the implicit function theorem and can be used for any perturbation of the beam optics. Here, we present the method and its implementation as well as measurements performed at FLASH.
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TUPWA064	Study of Inherent Potential for Emittance Reduction at the SPring-8 Storage Ring	brilliance, emittance, storage-ring, photon	1573
	Y. Shimosaki JASRI/SPring-8, Hyogo-ken, Japan
	A design study for an upgrade project of the SPring-8, the SPring-8-II, is in progress, which is a full-scale major lattice modification. Besides the design study for the SPring-8-II, an inherent potential of achieving much higher brilliance than that of the present SPring-8 has been explored for the general evaluation. In this paper, the evaluation of the inherent potential for the SPring-8, not for the SPring-8-II, in terms of increasing the brilliance is discussed.
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TUPWA067	Status of Higher Bunch Charge Operation in Compact ERL	operation, space-charge, recirculation, emittance	1583
	T. Miyajima, K. Harada, Y. Honda, T. Miura, N. Nakamura, T. Obina, F. Qiu, H. Sakai, S. Sakanaka, M. Shimada, R. Takai, K. Umemori, M. Yamamoto KEK, Ibaraki, Japan R. Hajima, R. Nagai, N. Nishimori JAEA, Ibaraki-ken, Japan D. Lee KNU, Deagu, Republic of Korea
	In the KEK compact ERL (cERL), machine studies toward higher bunch charge operation is one of the most important issues. From January 2015 to April 2015, we carried out a higher bunch charge operation with an bunch charge of 0.5 pC for the experiment of laser compton scattering. After the study of space charge effect and optics tuning, we succeeded in the recirculation operation with the emittance, which was close to the design value. Moreover, a test operation in the injector section with the bunch charge of 7.7 pC was carried out as a preparation toward the recirculation operation with the average current of 10 mA.
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TUPWA069	Simulation Study on Bunch Compression and Decompression for the Compact ERL	sextupole, simulation, linac, emittance	1591
	N. Nakamura, K. Harada, T. Miyajima, S. Sakanaka, M. Shimada, O. Tanaka KEK, Ibaraki, Japan
	Generation of THz coherent radiation (THz-CSR) is planned for the near future at the Compact Energy Recovery Linac (cERL) in KEK where the beam recirculation and energy recovery were already achieved in February 2014 and an experiment for generation of laser-Compton scattering X-rays (LCS-X) is being prepared to start in February 2015. To achieve a ultra-short bunch less than 100 fs for generation of the THz-CSR up to 5 THz, we have studied bunch compression and decompression in the cERL mainly by using a simulation code ELEGANT. In this study, off-crest acceleration in the main superconducting linac and non-zero R56 optics in the two arc sections are used and sextupole magnets are introduced into the two arc sections for correcting T566 of the arc sections. In this paper, we will present the simulation results and the requirements for the sextupole magnets including their number and layout.
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TUPJE001	Design of Wavelength Tunable Coherent X-Ray Source	electron, radiation, target, emittance	1604
	J. Hyun Sokendai, Ibaraki, Japan K. Endo TOYAMA Co., Ltd., Zama-shi, Kanagawa, Japan K. Hayakawa, Y. Hayakawa, T. Sakai, T. Tanaka LEBRA, Funabashi, Japan I. Sato Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan M. Satoh, M. Yoshida KEK, Ibaraki, Japan
	KEK, Nihon University and TOYAMA CO., Ltd. have been developing the compact shieldless coherent X-ray source that can change the X-ray energy (3-25keV). This X-ray is the Parametric X-ray radiation (PXR) generated by relativistic charged particles passed through a single crystal. It has features that are monochromaticity, coherence and diffraction large angle for the incident beam. These indicate to the possibility for the application to the medical treatment and diagnosis. Furthermore, we try to reduce the radiation which is mainly generated when the high energy beam is damped. This system consists of an accelerating, a decelerating structure and four bending magnets (theta: 90 degree). These structures are operated under low temperature to get the high Q-value for long beam pulse. PXR is generated by colliding with a single crystal after electron beam is accelerated up to 75 MeV. The bunch passed through the crystal is transported into a decelerator structure and then is decelerated to 3 MeV there. Q-magnets are arranged that dispersion function is zero except arc sections. We calculated the beam transport, PXR intensity and emittance blow up. We'll report these details.
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TUPJE023	Consideration on the Future Major Upgrades of the SSRF Storage Ring	storage-ring, injection, cavity, emittance	1672
	Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, M.Z. Zhang SINAP, Shanghai, People's Republic of China
	The SSRF storage ring was in operation from 2008, currently it is operating at the energy of 3.5GeV, the natural emittance of 3.9 nm-rad and the beam current of 240 mA, serving for 13 beamlines with 9 IDs. There will be around 40 operated beamlines around 2020, which need some upgrade of the storage ring existing performance, such as the new lattice with superbends. And looking for the future beyond, the major upgrade towards a diffraction limited storage ring is under consideration. This paper presents the initial investigation and the proposal on the ultimate storage ring upgrade for SSRF.
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TUPJE038	Impact of Insertion Devices on the MAX IV Storage Rings	storage-ring, lattice, quadrupole, octupole	1696
	S.C. Leemann, H. Tarawneh MAX-lab, Lund, Sweden
	There will be multiple compensations employed for insertion devices in the MAX IV storage rings. Apart from well-known dipole corrections and previously detailed local and global linear optics matching, certain insertion devices in the MAX IV storage rings will also require nonlinear optics adjustments and/or skew quadrupole corrections. The goal of such corrections is ensuring sufficient dynamic aperture as well as low residual emittance coupling. This paper will present a few studies that rely on tracking through kick maps in order to quantify detrimental effects of insertion devices on dynamic aperture and vertical emittance, develop suitable countermeasures, and finally, verify restored storage ring performance.
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TUPJE044	Local Orbit Response Matrix Measurement at SLS	quadrupole, storage-ring, focusing, feedback	1713
	M. Aiba, M. Böge PSI, Villigen PSI, Switzerland
	The experimental determination of linear optics is essential to achieve a high performance ring accelerator. One of the methods, linear optics from closed orbits (LOCO), is widely employed to correct linear optics. Due to the ring nature, a quadrupole error at a location of the ring affects the entire orbit response measurement data. The orbit response, however, can be localised to a certain range of the ring when an orbit feedback (or correction) is applied to the rest of the ring. The quadrupole errors located in the range, where the feedback is acting, then have no impact, and the ring optics can be locally examined. An application of this technique to Swiss light source is discussed.
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TUPJE049	TPS Linac Relocation and Beam Test of the LTB Transfer Line	linac, electron, quadrupole, injection	1731
	H.-P. Chang, A.Y. Chen, C.L. Chen, Y.-S. Cheng, C.-S. Fann, K.T. Hsu, S.Y. Hsu, K.-K. Lin, Y.C. Lin, J. Liu, K.L. Tsai NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) 150 MeV linac has been relocated from its 2011 test site to the TPS linac tunnel in 2014. After functional test of the linac hardware modules, the beam parameters were carefully examined at a 31-degree bend diagnostic beam line LTD (linac to beam dump) and compared with previous results. Then, the 150 MeV electron beam was delivered to the linac to booster transfer line (LTB) for beam commissioning. The beam optics matching at both the LTB entrance (i.e. linac exit) and the LTB exit (i.e. injection point of booster) was performed for injection optimization purpose. The LTB lattice setting was verified in the beam steering through LTD and LTB with the help of diagnostics tools such as beam profile monitors (SM) and beam position monitors (BPM). The overall performance of the linac and LTB will be described in this report. #peace@nsrrc.org.tw
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TUPJE052	Bunch Compression in the Driver Linac for the Proposed NSRRC VUV FEL	electron, linac, gun, FEL	1738
	N.Y. Huang, W.K. Lau, A.P. Lee NSRRC, Hsinchu, Taiwan A. Chao, K. Fang, M.-H. Wang, J. Wu SLAC, Menlo Park, California, USA
	A bunch compressor is designed for the S-band driver linac system of the proposed NSRRC VUV free electron laser (FEL). Instead of using a more conventional rf harmonic linearizer, one main feature of this compressor is to use electron linearization optics to correct the nonlinearity in the energy-time correlation of the electron bunch longitudinal phase space. The strategy of compressor design will be discussed by an analytical calculation and particle tracking simulation. The beam dynamics which include the collective instabilities such as the space charge effects, the wake fields and the coherent synchrotron radiation (CSR) effects are discussed.
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TUPJE070	Preliminary Experimental Investigation of Quasi Achromat Scheme at Advanced Photon Source	lattice, resonance, emittance, operation	1800
	Y. Sun, H. Shang ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. Next generation storage rings require weaker dipole magnets and stronger quadrupole focusing to achieve very low emittance. To suppress the geometric and chromatic optics aberrations introduced by the strong sextupoles, achromat and quasi achromat schemes are applied in the lattice design to improve the beam dynamics performance. In this paper, some preliminary experimental investigation of the quasi achromat scheme at the Advanced Photon Source (APS) are presented. Three different operation lattices are compared on their beam dynamics performance. Although none of these operation lattices achieve ideal quasi achromat condition, they have certain relevant features. It is observed that fewer resonances are present in the nominal operation lattice which is most close to quasi achromat required conditions.
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TUPJE074	LCLS Injector Laser Modulation to Improve FEL Operation Efficiency and Performance	laser, electron, FEL, emittance	1813
	S. Li, D.K. Bohler, W.J. Corbett, A.S. Fisher, S. Gilevich, Z. Huang, A. Li, D.F. Ratner, J. Robinson, F. Zhou SLAC, Menlo Park, California, USA R.B. Fiorito, E.J. Montgomery UMD, College Park, Maryland, USA H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom H.D. Zhang The University of Liverpool, Liverpool, United Kingdom
	In the Linear Coherent Light Source (LCLS) at SLAC, the injector laser plays an important role as the source of the electron beam for the Free Electron Laser (FEL). The injector laser strikes a copper photocathode which emits photo-electrons due to photo-electric effect. The emittance of the electron beam is highly related to the transverse shape of the injector laser. Currently the LCLS injector laser has hot spots that degrade the FEL performance. The goal of this project is to use adaptive optics to modulate the transverse shape of the injector laser, in order to produce a desired shape of electron beam. With a more controllable electron transverse profile, we can achieve lower emittance for the FEL, improve the FEL performance and operation reliability. We first present various options for adaptive optics and damage test results. Then we will discuss the shaping process with an iterative algorithm to achieve the desired shape, characterized by Zernike polynomial deconstruction.
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TUPMA001	Progress of the R&D towards a diffraction limited upgrade of the Advanced Light Source	injection, radiation, photon, lattice	1840
	C. Steier, A. Anders, D. Arbelaez, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, W.L. Waldron, E.J. Wallén, W. Wan LBNL, Berkeley, California, USA
	Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231. Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program funded by internal laboratory funds was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings (DLSR). It initially involves five areas, and focuses on the specific needs of soft x-ray facilities: vacuum system/NEG coating of small chambers, injection/pulsed magnets, RF systems/bunch lengthening, magnets/radiation production with advanced radiation devices, and beam physics design optimization. Some hardware prototypes have been built. The work will expand in the future to demonstrate necessary key technologies at the subsystem level or in beam tests and include new areas like photon beamline optics.
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TUPMA031	Dispersive Property of the Pulse Front Tilt of a Short Pulse Optical Undulator	laser, FEL, electron, undulator	1904
	M.-H. Wang, J. Wu, Z. Wu SLAC, Menlo Park, California, USA
	Funding: Work supported by the US DOE No. DE-AC02-76SF00515. A short pulse laser can be used as an optical undulator to achieve a high-gain and high-brightness X-ray free electron laser (FEL) [1]. To extend the interaction duration of electron and laser field, the electron and the laser will propagate toward each other with an small angle. In addition, to maintain the FEL lasing resonant condition, the laser pulse shape need be flattened and the pulse front will be titled. Due to the short pulse duration, the laser pulse has a broad bandwidth. In this paper, we will first describe the method of generalized Gaussian beam propagation using ray matrix. By applying the Gaussian beam ray matrix, we can study the dispersive property after the pulse front of the short laser is tilted. The results of the optics design for the proposal of SLAC Compton scattering FEL are shown as an example in this paper. [1] C. Chang, et al.,“High-brightness X-ray free-electron laser with an optical undulator by pulse shaping”. Optics Express, Vol. 21, Issue 26, pp. 32013-32018 (2013).
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TUPMA037	Commissioning of the 123 MeV Injector for 12 GeV CEBAF	cryomodule, dipole, operation, injection	1920
	Y.W. Wang, A.S. Hofler, R. Kazimi JLab, Newport News, Virginia, USA
	The injector energy needed to be raised from 67.5 MeV to 123 MeV to meet the energy requirement of the CEBAF 12 GeV upgrade. The ratio of the injector energy to the linac energy must remain 0.11284 at all times. Consequently, the injector was partially upgraded. The early injector, transport and acceleration from 130 keV to 6 MeV, is unchanged, but the downstream boost from 6 MeV to the final 123 MeV energy drove several changes. One of the two original CEBAF 25 MeV type cryomodules in the injector was upgraded to a 100 MeV capable one to provide more energy. Some trim magnets at the end of the injector were upgraded to compensate for the higher energy. The chicane region was expanded, and the full energy injector spectrometer was relocated to make room for the newly added Hall D line. Experience from the 6 GeV era indicated that the stray fields from the higher energy beam transport recombiners near the injection chicane adversely affect the injector orbit, so a study to understand and mitigate stray fields from the transport arc box supplies upgraded for 12 GeV led to shielding modifications for the beamline in the chicane region.
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TUPHA012	LOCO Application to NSLS2 SR Dispersion and Beta Beating Correction	quadrupole, storage-ring, ion, lattice	1989
	X. Yang BNL, Upton, Long Island, New York, USA X. Huang, J.A. Safranek SLAC, Menlo Park, California, USA
	During the short run in early July, 2014, we made changes to the Matlab LOCO setup for NSLS-II and applied LOCO successfully to the machine. The MML setup was verified with I/O tests for all quadrupole families. The LOCO setup was further tested with an intentional quadrupole error. After the successful LOCO correction, the rms beta beat was reduced from the initial values of 5.5% x and 5.6% y, to 1.9% x and 1.0% y, respectively. The rms horizontal dispersion error was reduced from 21 mm to 6 mm. It is critical to keep the same closed orbit for LOCO correction to take effect. Because presently some correctors are nearly saturated, closed orbit cannot be controlled for additional iterations. We expect LOCO to achieve better optics correction after the orbit control is improved.
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TUPTY019	Realistic Beam Halo Model study in the Extraction Line of ATF2	background, simulation, electron, diagnostics	2038
	N. Fuster-Martínez, A. Faus-Golfe IFIC, Valencia, Spain P. Bambade, S. Liu, S. Wallon LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan E. Marín, G.R. White SLAC, Menlo Park, California, USA
	Funding: Work supported by IDC-20101074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02 The understanding and control of the transverse beam halo distributions is an important issue to reduce sources of background noise in Future Linear Colliders (FLC) and specifically at ATF2. A realistic model of the beam halo in the old extraction line of the ATF damping ring was obtained in 2005, based on wire scanner measurements. Recently, new measurements were done in the new extraction line of ATF2, using both wire scanners, in 2013, and Optical Transition Radiation monitors (OTR), in 2014. The beam halo propagation through the ATF2 beamline by means of tracking simulations has been investigated using as input a purely Gaussian and uniform beam halo model.
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TUPTY022	Alternative Optics Design of the CLIC Damping Rings with Variable Dipole Bends and High-field Wigglers	emittance, wiggler, dipole, damping	2046
	P.S. Papadopoulou, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland
	The CLIC Damping Rings baseline design aims to reach an ultra-low horizontal normalised emittance of 500nm-rad at 2.86GeV, based on the combined effect of TME arc cells and high-field super-conducting damping wigglers, while keeping the ring as compact as possible. In this paper, an alternative design is described, based on TME cells with longitudinally variable bends and an optimized Nb3Sn high-field wiggler. The impact of these changes on ring optics parameters and the associated optimisation steps are detailed taking account the dominant effect of intrabeam scattering.
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TUPTY024	Updated Simulation Studies of Damage Limit of LHC Tertiary Collimators	proton, simulation, collimation, kicker	2053
	E. Quaranta, A. Bertarelli, R. Bruce, F. Carra, F. Cerutti, P. Gradassi, A. Lechner, S. Redaelli, E. Skordis CERN, Geneva, Switzerland
	The tertiary collimators (TCTs) in the LHC, installed in front of the experiments, in standard operation intercept fractions of 10³ halo particles. However, they risk to be hit by high-intensity primary beams in case of asynchronous beam dump. TCT damage thresholds were initially inferred from results of destructive tests on a TCT jaw, supported by numerical simulations, assuming simplified impact scenarios with one single bunch hitting the jaw with a given impact parameter. In this paper, more realistic failure conditions, including a train of bunches and taking into account the full collimation hierarchy, are used to derive updated damage limits. The results are used to update the margins in the collimation hierarchy and could thus potentially have an influence on the LHC performance.
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TUPTY035	Beam Dynamics Requirements for the Powering Scheme of the HL-LHC Triplet	quadrupole, controls, simulation, dynamic-aperture	2082
	M. Fitterer, R. De Maria, S.D. Fartoukh, M. Giovannozzi CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. For the HL-LHC, β^* values as small as 15 cm are envisaged as baseline scenario for the high luminosity insertions IR1 and IR5, thus leading to an increase of the maximum beta-functions in the inner triplet (IT). The larger beta-functions in the IT result in a higher sensitivity of the beam to any linear or non-linear, static or dynamic, field imperfections in the IT region. In this paper, we summarize accordingly the tolerances of the triplet power supplies in terms of current ripple, stability and reproducibility. Both the baseline IT powering scheme and other alternative schemes will be presented, the later reducing the tune shift caused by a current modulation and thus weakening its possible impact on the long term stability.
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TUPTY036	Crossing Scheme and Orbit Correction in IR1/5 for HL-LHC	alignment, injection, luminosity, quadrupole	2086
	M. Fitterer, R. De Maria, S.D. Fartoukh, M. Giovannozzi CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. In this paper we review the orbit correction strategy and crossing scheme adjustment for the HL-LHC orbit correctors in IR1/5 in view of the new optics and layout version HLLHCV1.1. The main objectives are to optimize the crossing scheme, in particular to reduce the strength of the orbit correctors at D2, and to validate the strength specifications of the several orbit corrector magnets involved, including a budget reserved for the correction of the orbit distortions from various sources.
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TUPTY037	HLLHCV1.1 Optics Version for the HL-LHC Upgrade	cavity, hardware, luminosity, quadrupole	2090
	R. De Maria, S.D. Fartoukh, M. Fitterer CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. The optics and layout of the HL-LHC are evolving as the new hardware is being studied and integrated, any additional requirements from the experiments detailed, and other constraints of different nature clarified. Here we present the changes of version 1.1 of the optics and layout with respect to the previous version 1.0, which include the current hardware choices and an outlook on the main resulting optics limitations and the possible future evolutions of the layout.
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TUPTY038	BPM Tolerances for HL-LHC Orbit Correction in the Inner Triplet Area	luminosity, impedance, simulation, emittance	2094
	M. Fitterer, R. De Maria CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. For the HL-LHC beam spot sizes as small as 7 mum are considered for the high luminosity insertions IR1 and IR5. In addition, the luminosity has to be levelled over several hours by changing β^* resulting in constant changes of the optics and thus orbit changes. The small beam size and the continuous optics changes in general make the alignment of the beams at the IP challenging. In order to avoid continuous luminosity scans for the alignment of the beams at the IP, the orbit correction has to rely on the readings of the BPMs in the IT region. In this paper we review the requirements on resolution and accuracy of the BPMs and compare different options for the placement of the BPMs in the IT region.
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TUPTY040	Comparison of Beam Sizes at the Collimator Locations from Measured Optics and Beam-based Collimator Alignment at the LHC	alignment, injection, flattop, betatron	2101
	G. Valentino, R. Bruce, A. Langner, S. Redaelli, R. Tomás CERN, Geneva, Switzerland
	At the LHC, the collimation hierarchy is defined in units of the betatron beam size using the sizes at each collimator location. The beam size at a given collimator can be inferred from the gap measurement during beam-based alignment campaigns, when the collimator touches a reference beam halo defined with the primary collimators. On the other hand, the beta functions at each collimator are also measured as a part of the standard LHC optics validation. This paper presents a comparison of the beam size measurements at the collimator locations applying these two techniques for different machine configurations. This work aims at determining which is the most reliable method for setting the collimator gaps at the LHC.
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TUPTY048	Changes to the Transfer Line Collimation System for the High-Luminosity LHC Beams	collimation, injection, luminosity, brightness	2124
	V. Kain, O. Aberle, C. Bracco, M.A. Fraser, F. Galleazzi, A. Kosmicki, F.L. Maciariello, M. Meddahi, F.-X. Nuiry, G.E. Steele, F.M. Velotti CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	The current LHC transfer line collimation system will not be able to provide enough protection for the high brightness beams in the high-luminosity LHC era. The new collimation system will have to attenuate more and be more robust than its predecessor. The active jaw length of the new transfer line collimators will therefore be 2.1 m instead of currently 1.2 m. The transfer line optics will have to be adjusted for the new collimator locations and larger beta functions at the collimators for absorber robustness reasons. In this paper the new design of the transfer line collimation system will be presented with its implications on transfer line optics and powering, maintainability, protection of transfer line magnets in case of beam loss on a collimator and protection of the LHC aperture
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TUPTY050	Considerations for the Beam Dump System of a 100 TeV Centre-of-mass FCC hh Collider	extraction, kicker, septum, collider	2132
	T. Kramer, M.G. Atanasov, M.J. Barnes, W. Bartmann, J. Borburgh, E. Carlier, F. Cerutti, L. Ducimetière, B. Goddard, A. Lechner, R. Losito, G.E. Steele, L.S. Stoel, J.A. Uythoven, F.M. Velotti CERN, Geneva, Switzerland
	A 100 TeV centre-of-mass energy frontier proton collider in a new tunnel of 80–100 km circumference is a central part of CERN’s Future Circular Colliders (FCC) design study. One of the major challenges for such a machine will be the beam dump system, which for each ring will have to reliably abort proton beams with stored energies in the range of 8 Gigajoule, more than an order of magnitude higher than planned for HL-LHC. The transverse proton beam energy densities are even more extreme, a factor of 100 above that of the presently operating LHC. The requirements for the beam dump subsystems are outlined, and the present technological limitations are described. First concepts for the beam dump system are presented and the feasibility is discussed, highlighting in particular the areas in which major technological progress will be needed. The potential implications on the overall machine and other key subsystems are described, including constraints on filling patterns, interlocking, beam intercepting devices and insertion design.
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TUPTY052	New Method for Validation of Aperture Margins in the LHC Triplet	kicker, vacuum, dumping, collimation	2140
	V. Chetvertkova, R. Schmidt, F.M. Velotti, D. Wollmann CERN, Geneva, Switzerland F.M. Velotti EPFL, Lausanne, Switzerland
	Funding: Work supported by COFUND grant PCOFUND-GA-2010-267194 Safety of LHC equipment including superconducting magnets depends not only on the proper functioning of the systems for machine protection, but also on the accurate adjustment of the protective devices such as collimators. In case of a failure of the extraction kicker magnets, which are part of the beam dumping system, it is important to ensure protection of the superconducting triplet magnets from missteered beam. The magnets are located to the right of Interaction Point 5 (IP5) and are protected by one set of collimators in the beam dumping insertion in IR6 and another set close to the triplet magnets. In this paper, a new method for verification of the correct collimator position with respect to the aperture is presented. It comprises the application of an extended orbit bump with identical trajectory as the beam trajectory after a deflection by the beam dump kickers. By further increasing the bump amplitude and successively moving in/out the collimators in the region of interest, the accurate positioning of the collimators can be validated. The effectiveness of the method for LHC IP5 and IP1 and both beams is discussed
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY052
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TUPTY059	First Considerations on Beam Optics and Lattice Design for the Future Electron-Positron Collider FCC-ee	emittance, collider, lattice, operation	2162
	B. Härer, B.J. Holzer, F. Zimmermann CERN, Geneva, Switzerland A.V. Bogomyagkov BINP SB RAS, Novosibirsk, Russia
	The Future Circular Collider (FCC) study includes the design of a 100-km electron positron collider (FCC-ee) with collision energies between 90 GeV and 350 GeV. This paper describes first aspects of the design and the optics of the FCC-ee collider, optimised for four different beam energies. Special emphasis is put on the need for a highly flexible magnet lattice in order to achieve the required beam emittances in each case and on the layout of the interaction region that will have to combine an advanced mini-beta concept, an effective beam separation scheme and a local chromaticity control to optimise the momentum acceptance and dynamic aperture of the ring.
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TUPTY060	The FCC-ee Study: Progress and Challenges	collider, interaction-region, synchrotron, radiation	2165
	M. Koratzinos DPNC, Genève, Switzerland S. Aumon, C. Cook, A. Doblhammer, B. Härer, B.J. Holzer, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov BINP SB RAS, Novosibirsk, Russia M. Boscolo INFN/LNF, Frascati (Roma), Italy L.E. Medina Medrano UGTO, Leon, Mexico U. Wienands SLAC, Menlo Park, California, USA
	The FCC (future circular collider) study represents a vision for the next large project in high energy physics, comprising a 80-100 km tunnel that can house a future 100TeV hadron collider. The study also includes a high luminosity e⁺e⁻ collider operating in the centre-of-mass energy range of 90-350 GeV as a possible intermediate step, the FCC-ee. The FCC-ee aims at definitive electro-weak precision measurements of the Z, W, H and top particles, and search for rare phenomena. Although FCC-ee is based on known technology, the goal performance in luminosity and energy calibration make it quite challenging. During 2014 the study went through an exploration phase and during the next three years a conceptual design report will be prepared.
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TUPTY061	Combined Operation and Staging Scenarios for the FCC-ee Lepton Collider	emittance, luminosity, collider, operation	2169
	M. Benedikt, B.J. Holzer, E. Jensen, R. Tomás, J. Wenninger, F. Zimmermann CERN, Geneva, Switzerland A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov BINP SB RAS, Novosibirsk, Russia K. Ohmi, K. Oide KEK, Ibaraki, Japan U. Wienands SLAC, Menlo Park, California, USA
	FCC-ee is a proposed high-energy electron positron circular collider that would initially occupy the 100-km FCC tunnel that will eventually house the 100 TeV FCC-hh hadron collider. The parameter range for the e⁺/e⁻ collider is large, operating at a cm energy from 90 GeV (Z-pole) to 350 GeV (t-tbar production) with the maximum beam current ranging from 1.5 A to 6 mA for each beam, corresponding to a synchrotron radiation power of 50 MW and a radiative energy loss varying from ~30 MeV/turn to ~7500 MeV/turn. This presents challenges for the rf system due to the varying rf voltage requirements and beam loading conditions. In this paper we present a possible gradual evolution of the FCC-ee complex by step-wise expansion, and possibly reconfiguration, of the superconducting RF system. The performance attainable at each step is discussed, along with the possible advantages and drawbacks.
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TUPTY066	Beam Cleaning in Experimental IRs in HL-LHC for Incoming Beam	collimation, betatron, quadrupole, background	2181
	H. Garcia Morales Royal Holloway, University of London, Surrey, United Kingdom R. Bruce, S. Redaelli CERN, Geneva, Switzerland
	The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the ffectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.
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TUPTY067	Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout	background, simulation, collimation, luminosity	2184
	R. Kwee-Hinzmann, S.M. Gibson JAI, Egham, Surrey, United Kingdom R. Bruce, F. Cerutti, L.S. Esposito, A. Lechner CERN, Geneva, Switzerland S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom
	Funding: Research supported by FP7 HiLumi LHC – Grant agreement 284404 In the High Luminosity LHC (HL-LHC), the collimation system will be upgraded in the high-luminosity experimental regions. Additional protection is planned for the Q4 and Q5 magnets that are located further upstream of the tertiary collimators that protect the inner triplet magnets. We evaluate the effect of this proposed collimation layout for the incoming beam 1 on machine-induced background in the experimental area of IR1 (ATLAS). The main scenario is the round optics with β∗ of 15 cm, but a flat scenario is also briefly discussed.
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TUPTY073	An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation	luminosity, beam-beam-effects, simulation, electron	2199
	S.D. Fartoukh CERN, Geneva, Switzerland D.N. Shatilov BINP SB RAS, Novosibirsk, Russia A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Research supported by DOE via the US-LARP program and by EU FP7 HiLumi LHC - Grant Agreement 284404 In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical β^* values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyse it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects.
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TUPTY084	Update on the MEIC Electron Collider Ring Design	electron, collider, dipole, quadrupole	2236
	F. Lin, Y.S. Derbenev, L. Harwood, A. Hutton, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands SLAC, Menlo Park, California, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work also supported by the U.S. DOE Contract No. DE-AC02-76SF00515. The electron collider ring of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is designed to accumulate and store a high-current polarized electron beam for collisions with an ion beam. We consider a design of the electron collider ring based on reusing PEP-II components, such as magnets, power supplies, vacuum system, etc. This has the potential to significantly reduce the cost and engineering effort needed to bring the project to fruition. This paper reports on an electron ring optics design considering the balance of PEP-II hardware parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and electron beam quality in terms of equilibrium emittances.
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TUPWI001	Turnkey Systems Cost Optimization by Iterative Design of Magnets and Power Supplies	quadrupole, power-supply, magnet-design, target	2239
	M. Cavellier, W. Beeckman, F. Forest, J.D. Holzmann Sigmaphi, Vannes, France
	For more than 30 years, Sigmaphi has been manufacturing magnets and power supplies. Its teams are now able to supply a complete particle beam line, from beam optics calculation to on-site installation and alignment. These combined skills allow design optimization for turnkey systems in order to reduce their purchasing and running costs. An example of successful iterative design is presented: a 70 meters beam line designed, manufactured and installed by Sigmaphi for JINR in Dubna, Russia. This design optimization allowed reducing total power consumption of the 14 quadrupoles by 7.5%.
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TUPWI031	Status of the MEIC Ion Collider Ring Design	ion, electron, collider, dipole	2307
	V.S. Morozov, Y.S. Derbenev, L. Harwood, A. Hutton, F. Lin, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands SLAC, Menlo Park, California, USA J. Gerity, T.L. Mann, P.M. McIntyre, N. Pogue, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported in part by the US DOE Contract No. DE-AC02-76SF00515. We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated super-conducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.
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TUPWI032	Progress on Optimization of the Nonlinear Beam Dynamics in the MEIC Collider Rings	sextupole, ion, distributed, dynamic-aperture	2311
	Y. Nosochkov, Y. Cai, M.K. Sullivan, M.-H. Wang, U. Wienands SLAC, Menlo Park, California, USA Y.S. Derbenev, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under US DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported by the US DOE Contract DE-AC02-76SF00515. One of the key design features of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is a small beta function at the interaction point (IP) allowing one to achieve a high luminosity of up to 10³⁴ cm^-2s^-1. The required strong beam focusing unavoidably causes large chromatic effects such as chromatic tune spread and beam smear at the IP, which need to be compensated. This paper reports recent progress in our development of a chromaticity correction scheme for the ion ring including optimization of dynamic aperture and momentum acceptance.
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Paper

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MOBC1

Towards Ultra-Low β^* in ATF2

octupole, multipole, collider, linear-collider

38

M. Patecki, A.V. Aloev, D.R. Bett, M. Modena, R. Tomás
CERN, Geneva, Switzerland
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
E. Marín, G.R. White
SLAC, Menlo Park, California, USA

The Accelerator Test Facility 2 (ATF2) has already demonstrated the feasibility of Final Focus Systems based on the local chromaticity correction scheme and its focusing capabilities by reaching a vertical beam size at the virtual Interaction Point (IP) of less than 50 nm. The value of the chromaticity in ATF2 is comparable with the expected chromaticity in ILC, but 4 times lower than in a design of CLIC. ATF2 gives the unique possibility to test operation at CLIC chromaticity values by reducing the vertical beta function at the IP by a factor of 4 (the inverse proportionality of chromaticity with beta function value at IP is assumed). The experience collected in this way would be beneficial for both ILC and CLIC projects. Simulations show that the multipolar errors and Final Doublet fringe fields spoil the IP beam sizes at ATF2. Either increasing a value of the horizontal beta function or installing a pair of octupole magnets mitigate the impact of these aberrations. This paper summarizes the studies towards the realization of the ultra-low β^* optics in ATF2 and reports on the progress of the construction of the octupoles.

Slides MOBC1 [1.566 MB]

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MOBC3

Electron Lenses for Experiments on Nonlinear Dynamics with Wide Stable Tune Spreads in the Fermilab Integrable Optics Test Accelerator

electron, lattice, solenoid, operation

46

G. Stancari, K. Carlson, M.W. McGee, L.E. Nobrega, A.L. Romanov, J. Ruan, A. Valishev
Fermilab, Batavia, Illinois, USA
D. Noll
IAP, Frankfurt am Main, Germany

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy.
Recent developments in the study of integrable Hamiltonian systems have led to nonlinear accelerator lattice designs with two transverse invariants. These lattices may drastically improve the performance of high-power machines, providing wide tune spreads and Landau damping to protect the beam from instabilities, while preserving dynamic aperture. To test the feasibility of these concepts, the Integrable Optics Test Accelerator (IOTA) is being designed and built at Fermilab. One way to obtain a nonlinear integrable lattice is by using the fields generated by a magnetically confined electron beam (electron lens) overlapping with the circulating beam. The parameters of the required device are similar to the ones of existing electron lenses. We present theory, numerical simulations, and first design studies of electron lenses for nonlinear integrable optics.

Slides MOBC3 [11.870 MB]

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MOPWA012

Study of Optimal MBA Lattice Structures for the SOLEIL Upgrade

emittance, dipole, lattice, quadrupole

106

R. Nagaoka, P. Brunelle, F.J. Cullinan, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Within the context of a future upgrade of the SOLEIL ring, a series of lattice studies has been made with the aim of reducing the current 4 nm-rad horizontal emittance ex by more than an order of magnitude, with a dynamic aperture allowing off-axis injection. As in most upgrades, the important constraint imposed is to keep all the existing straight sections and photon source points. A particularity of SOLEIL are the short straight sections in half of the 16 double-bend cells, created in between the dipoles, which limits the number of dipoles in a MBA cell. In the previous studies, a combination of 5- and 4BA was followed, where with the use of longitudinal gradient bends (LGBs), ex ~440 pm-rad was obtained. The present paper reports on studies extended along the same strategy: In particular, the feasibility and the attainable ex are pursued with a combination of 7- and 6BA, by employing dipoles with transverse gradient and LGBs. In addition, the effectiveness of a few known nonlinear optimization methods, such as the resonance driving term cancellation, interleaved sextupoles with proper phases, and genetic algorithm-based numerical searches shall be explored.

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MOPWA015

Lattice Correction using LOCO for the ThomX Storage Ring

quadrupole, lattice, storage-ring, coupling

117

I. Chaikovska, C. Bruni, S. Chancé, A. Variola, J.F. Zhang
LAL, Orsay, France
A. Loulergue
SOLEIL, Gif-sur-Yvette, France

Funding: Work is supported by the French Agence Nationale de la Recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI
ThomX is a compact Compton based X-ray source under construction at LAL in Orsay (France). The ThomX accelerator facility is composed by a 50-70 MeV linac driven by 3 GHz RF gun, a transfer line and a 18 meters long Storage Ring (SR). The Compton backscattering at each revolution between the 1 nC electron bunch and the 25 mJ laser pulses stacked in the Fabry-Perot cavity results in the production of ~10¹³ photons per second with energies in the X-ray regime. This high flux of the X-rays strongly depends on the quality (beam sizes) of the electron beam at the interaction point. To guarantee this, a good knowledge and quality of the linear lattice of the ThomX SR are required. Nowadays, LOCO (Linear Optics from Closed Orbits) is a well-known and widely used algorithm to measure and restore the linear optics of the SRs and ensure the designed performances. Comparing the measured and model orbit response matrices, the linear lattice can be restored by retuning the quadrupole gradients. In this paper, we report on the LOCO analysis of the ThomX SR taking into account simulated misalignment, calibration and field errors.

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MOPWA035

Two General Orbit Theorems for Efficient Measurements of Beam Optics

closed-orbit, storage-ring, dipole, lattice

183

B. Riemann, A. Ferrarotto, P. Hartmann, B.D. Isbarn, S. Koetter, M. Sommer, P. Towalski, T. Weis
DELTA, Dortmund, Germany

Closed-orbit perturbations and oscillating beam solutions in storage rings are closely related. While techniques exist to fit accelerator models to closed-orbit perturbations or to oscillation data, the exploitation of their relation has been limited. In this work, two orbit theorems that allow an efficient computation of optical parameters in storage rings with older hardware are derived for coupled linear beam motion. The monitor theorem is based on an uncoupled case study described by the author in an earlier work and has been generalized as well as simplified in mathematical abstraction to provide a reliable and computationally stable framework for beam optics measurements. It is based on a closed-orbit measurement utilizing 4 dipole correctors (2 for each plane). The corrector theorem allows to obtain parameters of these dipole correctors using two turn-by-turn monitors at almost arbitrary positions in the ring (which do not need to be located in a drift space), so that it is possible to uniquely resolve closed orbits into optical parameters without sophisticated lattice models.

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MOPWA038

Sensitivity of Linac Optics to Focusing and Energy Errors

focusing, linac, operation, quadrupole

193

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

The ability to control beam optics in the presence of such imperfections as focusing and energy gain errors is essential for a successful operation of high brightness electron linacs providing beams for free-electron lasers. We characterize the cumulative effect of these imperfections using the value of mismatch parameter calculated at the linac exit and show how it depends on the design of the focusing lattice.

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MOPWA039

Emittance Reduction Possibilities in the PETRA III Magnet Lattice

emittance, sextupole, lattice, synchrotron

197

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

PETRA III is a third generation light source that has been operated as a user facility since 2010 at DESY. An upgrade for additional beam lines has been carried out, and the recommissioning of the new beam lines is starting in spring 2015. In order to fully exploit the potential of the existing magnet lattice of the PETRA III ring, we present a study of beam optics modifications enabling the reduction of the horizontal emittance without changes of the lattice.

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MOPWA043

FEL Simulations with Ocelot

space-charge, FEL, simulation, electron

210

I.V. Agapov, G. Geloni
XFEL. EU, Hamburg, Germany
M. Dohlus, I. Zagorodnov
DESY, Hamburg, Germany
S.I. Tomin
NRC, Moscow, Russia

Ocelot has been developed as a multiphysics simulation tool for FEL and synchrotron light source studies. In this work we highlight recent code developments focusing on electron tracking in linacs taking into account collective effects and on x-ray optics calculations

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MOPWA047

Start to End Simulation of High Current Injector using TRACEWIN Code

ion, DTL, rfq, linac

223

S. Kumar, A. Mandal
IUAC, New Delhi, India

High Current Injector (HCI) is an alternate injector to superconducting linac at IUAC in addition to pelletron. It consists mainly of high temperature superconducting ECR ion source (PKDELIS), radio frequency quadrupole (RFQ)* and a drift tube linac (DTL)**. The ions of mass to charge (A/q) ratio of 6 are analysed initially and accelerated through RFQ and DTL to a total energy of 1.8 MeV/u. The different energy regimes connecting the accelerating stages are named as low, medium and high energy beam transport section (LEBT, MEBT and HEBT). The energy spread of beam increases from 0.02% at ECR source to 0.5% at the DTL exit. An ion beam of normalized transverse and longitudinal emittance of 0.03 pi mm-mrad and 0.3 keV/u-ns has been considered at the start for the simulation of ion optics using TRACEWIN*** code. The whole beam transport system has been designed using GICOSY, TRANSPORT and TRACE 3D codes piecewise and TRACEWIN code is used to simulate whole ion optics from start to end including acceleration stages such as RFQ and DTL. Simulation results shows that beam can be injected through LEBT, MEBT and HEBT into LINAC without significant emittance growth and beam loss.
* Sugam Kumar et al., Proc. of InPAC-2011, IUAC, New Delhi
** B.P. Ajith Kumar et al., Proc. of InPAC-2009, RRCAT, Indore
*** http://irfu.cea.fr/Sacm/logiciels/index3.php

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MOPJE028

Detailed Characterization of ALBA Quadrupoles for Beta Function Determination

quadrupole, storage-ring, synchrotron, controls

338

Z. Martí, J. Campmany, J. Marcos, V. Massana
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
X.N. Gavaldà
SOLEIL, Gif-sur-Yvette, France

Beta function value at quadrupoles for a circular accelerator can be determined using the relationship between the machine tune and the quadrupole strength. ALBA Storage Ring quadrupoles were measured during manufacturing, to be sure that their performance fitted the specifications. However, measurements were done at a number of currents that are not enough for an accurate determination of the beta function value. In fact, at least 1% error in the calibration of the hysteresis curve slope of the quadrupole is required, and therefore new detailed measurements of the hysteresis cycle are needed. In order to make these measurements, spare quadrupoles existing at ALBA have been used. In this paper we present the results of beta function values determination using this method for ALBA storage ring.

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MOPJE033

Coupled Orbit Response Coefficients with Constant Revolution Time

storage-ring, closed-orbit, radio-frequency, diagnostics

354

V.G. Ziemann
Uppsala University, Uppsala, Sweden

We calculate orbit response coefficients for arbitrarily coupled lattice which keep the orbit length constant as is needed to maintain synchronicity with a radio-frequency system.

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MOPJE039

Generalised Truncated Power Series Algebra for Fast Particle Accelerator Transport Maps

operation, simulation, lattice

374

L. Deniau, C.I. Tomoiagă
CERN, Geneva, Switzerland

New Generalised Truncated Power Series Algebra (TPSA) has been developed for extending, simplifying and optimising the transport maps used by particle accelerator simulation codes. TPSA are intensively used in optics code to describe transport maps of the elements constituting the particle accelerator to any order. Generalised TPSA extend the degrees to inhomogeneous ones, where separate degrees can be specified for each variables and constrained by two total orders, one for canonical variables and one for ordinary variables. This allows to track inhomogeneous planes of the 6D phase space with many extra variables. A complete set of new formulas and data structures have been derived to address the problem of memory consumption required for efficient computation of high order TPSA, including generalised indexing, multiplication and composition of inhomogeneous multivariate polynomials. The implementation has been benchmarked against well established libraries for the common subset with TPSA, and outperforms all of them for supported differential algebra operators on low and high orders, and high number of variables.

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MOPJE044

Beam Dynamics Studies of the ELENA Electrostatic Transfer Lines

experiment, quadrupole, antiproton, simulation

385

M.A. Fraser, W. Bartmann, R. Ostojić
CERN, Geneva, Switzerland
D. Barna
University of Tokyo, Tokyo, Japan

The low-energy ELENA ring at the Antiproton Decelerator (AD) facility at CERN will lower the kinetic energy of antiproton beams from 5.3 MeV to 100 keV, significantly increasing the antiproton trapping efficiency at the experiments. The antiprotons from ELENA will be distributed to two experimental areas housing several different experiments through a system of electrostatic transfer lines totalling 90 m in length. A significant optimisation of the electrostatic optical elements (deflectors, quadrupoles, and correctors) has been carried out to improve the beam quality delivered to the experiments and facilitate installation of the beam lines into the AD hall. A general overview of the beam optics is presented, including end-to-end particle tracking and error studies from the extraction point in the ELENA ring to the experiments.

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MOPJE049

Benchmarking the CERN-SPS Transverse Impedance Model with Measured Headtail Growth Rates

impedance, simulation, kicker, vacuum

402

C. Zannini, H. Bartosik, G. Iadarola, G. Rumolo, B. Salvant
CERN, Geneva, Switzerland

The latest SPS transverse impedance model includes kicker magnets, wall impedance, transition pieces (e.g. flanges and vacuum chamber discontinuities), beam position monitors and RF cavities. The model has already been successfully benchmarked against coherent tune shift and transverse mode coupling instability measurements. In this paper we present measurements of the headtail growth rates for a wide range of negative chromaticities and for two different configurations of machine optics (nominal and low gamma transition). The measurement results are compared with HEADTAIL simulations using the wake fields obtained from the SPS transverse impedance model.

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MOPJE054

Developments of the Segment-by-Segment Technique for Optics Corrections in the LHC

simulation, coupling, betatron, quadrupole

419

A. Langner, J.M. Coello de Portugal, P.K. Skowroński, R. Tomás
CERN, Geneva, Switzerland

Optics correction algorithms will become even more critical for the operation of the LHC at 6.5 TeV. For the computation of local corrections the segment-by-segment technique is used. We present improvements to this technique and an advanced error analysis, which increase the sensitivity for finding local corrections. Furthermore, we will investigate limitations of this method for lower beta-star optics as they will be used in the high-luminosity LHC (HL-LHC) upgrade.

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MOPJE056

OMC Software Improvements in 2014

software, GUI, simulation, operation

426

J.M. Coello de Portugal, F.S. Carlier, A. Langner, T. Persson, P.K. Skowroński, R. Tomás
CERN, Geneva, Switzerland

We present the LHC Optics Measurement and Corrections (OMC) software developments done during 2014 on stability, performance and usability. This software is used to analyze turn-by-turn data and compute optics corrections to get the best performance of the LHC. The main developments have been an automatic local correction script to get faster and more accurate corrections in the interaction regions, a self contained test for the whole software package to avoid mistakes during the software development and the improvements in the software quality and efficiency of the Segment by Segment technique script. We also present a study of the code quality in its current status.

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MOPJE057

Optics Measurement using the N-BPM Method for the ALBA Synchrotron

quadrupole, betatron, dipole, synchrotron

430

A. Langner, J.M. Coello de Portugal, R. Tomás
CERN, Geneva, Switzerland
G. Benedetti, M. Carlà, U. Iriso, Z. Martí
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The N-BPM method recently developed for the LHC has significantly improved the precision of optics measurements which are based on beam position monitor (BPM) turn-by-turn data. The main improvement is owed to the consideration of correlations for statistical and systematic error sources, as well as increasing the amount of BPM combinations for one measurement. We present how this technique can be applied at light sources like ALBA, and compare the results with other methods.

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MOPJE065

Contribution of Optical Aberrations to Spot-size Increase with Bunch Intensity at ATF2

emittance, damping, extraction, simulation

455

M. Patecki, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
M. Patecki
Warsaw University of Technology, Warsaw, Poland
G.R. White
SLAC, Menlo Park, California, USA

A primary goal of ATF2 (Accelerator Test Facility) is to demonstrate a low vertical beam size at the interaction point (IP) of about 37 nm. Measurements over the past years indicate that the ATF2 vertical beam size strongly rises with bunch intensity. Several different origins of this increase are considered, e.g. wakefields occurring between the ATF damping ring and the IP, and/or intrabeam scattering (IBS) causing the increase of transverse emittances and energy spread in the damping ring with the increase of the bunch intensity. In this paper we address the second possibility. Past measurements and simulations of the IBS effects in the ATF are used to model the intensity-dependent initial emittances and energy spread at the entrance of the final focus. Particle tracking simulations predict the IP vertical beam size growth expected from the known optical aberrations for initial beam parameters corresponding to varying bunch intensities. Comparing simulation results with emittance measurements at different locations allows us to draw some conclusions about the impact of IBS in the damping ring on the IP spot size, and about possible single-bunch wakefields in the ATF2.

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MOPJE067

Applications of PLACET2 to the CTF3 Combiner Ring

dipole, simulation, quadrupole, wiggler

462

D. Pellegrini, R. Corsini, D. Gamba, A. Latina
CERN, Geneva, Switzerland

The CTF3 Combiner Ring (CR) is an isochronous ring that employs RF-injection to combine multiple bunch trains (up to five) into a single one with higher bunch frequency. The length of the CR plays a critical role in obtaining the correct structure of the recombined train. PLACET2: the new recirculating version of the code PLACET is particularly suited to simulate the operational scenario. In order to validate this code, three different case studies have been considered: ring-length variations due to energy detuning, fast-beam decoherence due to uncorrected chromatic effects and vertical instabilities due to bunch-to-bunch wakefield effects. The first two effects have been measured during the last run and the predictions have been validated. The instability has been compared with previous studies. The results are presented and discussed.

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MOPJE069

General Functionality for Turn-Dependent Element Properties in SixTrack

simulation, cavity, HOM, collimation

468

K.N. Sjobak, H. Burkhardt, R. De Maria, A. Mereghetti, A. Santamaría García
CERN, Geneva, Switzerland

In order to facilitate studies of how dynamically changing element attributes affect the dynamics of the beam and beam losses, the functionality for dynamic kicks (DYNK) of SixTrack has been significantly extended. This functionality can be used for the simulation of dynamic scenarios, such as when crab cavities are switched on, orbit bumps are applied, optics are changed, or failures occur. The functionality has been extended with a more general and flexible implementation, such that arbitrary time-dependent functions can be defined and applied to different attributes of families or individual elements, directly from the user input files. This removes the need for source code manipulation, and it is compatible with LHC@Home which offers substantial computing resources from volunteers. In this paper, the functionality and implementation of DYNK is discussed, along with examples of application to the HL-LHC crab cavities.

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MOPJE074

Optimizing SLS-2 Nonlinearities Using a Multi-Objective Genetic Optimizer

sextupole, resonance, octupole, injection

486

M.P. Ehrlichman, M. Aiba, A. Streun
PSI, Villigen PSI, Switzerland

An upgrade to the SLS is currently under development. This upgrade will likely utilize the same hall and same machine circumference, 288 m, of the SLS. Achieving a sufficiently low emittance with such a small circumference requires tight focusing and low dispersion. These conditions make chromaticity correction difficult and minimization of 1st and 2nd order non-linear driving terms does not yield sufficient dynamic aperture and Touschek lifetime. In this proceeding, we discuss the multi-objective genetic optimization method being implemented at SLS to aid the design of a chromaticity correction scheme for SLS2.

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MOPMA002

Optimising the Diamond DDBA Upgrade Lattice for Low Alpha Operation

lattice, storage-ring, injection, dynamic-aperture

525

I.P.S. Martin, R. Bartolini
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

The Diamond storage ring will be upgraded during 2016 by replacing one of the existing double bend achromat (DBA) cells with a double-DBA (DDBA) cell*. One requirement of the upgrade is that following the installation of the new cell, Diamond should continue to offer dedicated user time in ‘low alpha’ mode**. In this paper we describe the particular challenges relating to this task, and present the lattice design and optimisation studies undertaken so far. The paper concludes by discussing preliminary studies of adding a second DDBA cell into the storage ring.
* R.P. Walker et al., Proc. IPAC 2014, MOPRO103, (2014)
** I.P.S. Martin et al., Proc. IPAC 2013, MOPEA070, (2013)

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MOPMA014

Design of Superconducting CW linac for PIP-II

linac, cryomodule, beam-losses, operation

565

A. Saini, V.A. Lebedev, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Proton Improvement Plan (PIP) -II is a proposed roadmap to upgrade existing proton accelerator complex at Fermilab. It is primarily based on construction of superconducting (SC) linear accelerator (linac) that would be capable to operate in continuous wave (CW) mode. This paper will present reference design of SC linac and discuss motivations and requirements resulting in this layout and beam optics.

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MOPMA020

Measurement and Correction of the Fermilab Booster Optics with LOCO

lattice, booster, quadrupole, dipole

586

C.-Y. Tan, V.A. Lebedev, A.K. Triplett
Fermilab, Batavia, Illinois, USA
M. McAteer
CERN, Geneva, Switzerland

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The optics of the original Booster lacked the ability for full optics correction and it was not until 2009 when new optics corrector packages were installed between gradient magnets that this ability became available. The optics correction method that is chosen is called LOCO (Linear Optics from Closed Orbits) that measures the orbit response from every beam position monitor (BPM) in the ring from every kick of every dipole corrector. The large data set collected allows LOCO to not only calculate the quadrupole and skew quadrupole currents that both reduces beta beatings and corrects coupling, it also finds the dipole kicker strengths, BPM calibrations and their tilts by minimizing the difference between the measured and ideal orbit response of the beam. The corrected optics have been loaded into Booster and it is currently being tested to be eventually used in normal operations.

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MOPMA028

Chromaticity and Dispersion in Nonlinear Integrable Optics

lattice, dynamic-aperture, focusing, octupole

608

S.D. Webb, D.L. Bruhwiler
RadiaSoft LLC, Boulder, Colorado, USA
V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
S. Nagaitsev, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: This material is based upon work sup- ported by the U.S. Department of Energy, Office of Sci- ence, Office of High Energy Physics under Award Num- ber DE-SC0011340.
Proton accumulator rings and other circular hadron accelerators are susceptible to intensity- driven parametric instabilities because the zero-current charged particle dynamics are characterized by a single tune. Landau damping can suppress these instabilities, which requires energy spread in the beam or introducing nonlinear magnets such as octupoles. However, this approach reduces dynamic aperture. Nonlinear integrable optics can suppress parametric instabilities independent of energy spread in the distribution, while preserving the dynamic aperture. This novel approach promises to reduce particle losses and enable order-of-magnitude increases in beam intensity. In this paper we present results, obtained using the Lie operator formalism, on how chromaticity and dispersion affect particle orbits in integrable optics. We conclude that chromaticity in general breaks the integrability, unless the vertical and horizontal chromaticities are equal. Because of this, the chromaticity correcting magnets can be weaker and fewer correcting magnet families are required, thus minimizing the impact on dynamic aperture.

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MOPMA029

Experiences Simulating Nonlinear Integrable Optics

lattice, simulation, diagnostics, emittance

611

S.D. Webb, D.L. Bruhwiler
RadiaSoft LLC, Boulder, Colorado, USA
V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
R.A. Kishek
UMD, College Park, Maryland, USA
S. Nagaitsev, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0011340.
With increasing interest in the nonlinear integrable optics, it is important that early experiences with simulating the lattices be shared to save time and point out potential difficulties in the simulations. We present here some details of simulating the nonlinear integrable lattices. We discuss correctly implementing and testing the elliptic element kicks, and the limits of the thin lens approximation. We also discuss generating a properly matched bunch in the transverse phase space, and how to analyze the resulting computational data from simulations.

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MOPMN001

Linear Optics and Coupling Correction with Turn-by-turn BPM Data

lattice, quadrupole, target, coupling

698

X. Huang
SLAC, Menlo Park, California, USA
X. Yang
BNL, Upton, Long Island, New York, USA

We propose a method to measure and correct storage ring linear optics and coupling with turn-by-turn BPM data. The independent component analysis (ICA) is used to obtain the amplitudes and phase advances of the betatron normal modes, which are compared to their counterparts derived from the lattice model. By fitting the model to the data with quadrupole and skew quadrupole variables, the linear optics and coupling of the machine can be obtained. Simulation demonstrates that errors in the lattice and BPM parameters can be recovered with this method. Experiments on the NSLS-II storage ring show that it can find the same optics as the linear optics from closed orbit (LOCO) method.

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MOPMN003

Dynamic Aperture Studies for the LHC High Luminosity Lattice

lattice, injection, luminosity, quadrupole

705

M. Giovannozzi, R. De Maria, E. McIntosh
CERN, Geneva, Switzerland
Y. Cai, Y. Nosochkov, M.-H. Wang
SLAC, Menlo Park, California, USA

Funding: Work supported by the US LHC Accelerator Research Program and the DOE Contract DE-AC02-76SF00515. Research supported by FP7 HiLumi LHC, Grant Agreement 284404, http://hilumilhc.web.cern.ch.
Since quite some time, dynamic aperture studies have been undertaken with the aim of specifying the required field quality of the new magnets that will be installed in the LHC ring in the framework of the high-luminosity upgrade. In this paper the latest results concerning the specification work will be presented, taking into account both injection and collision energies and the field quality contribution from all the magnets in the newly designed interaction regions.

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MOPMN010

Non-linear Magnetic Inserts for the Integrable Optics Test Accelerator

vacuum, alignment, dipole, quadrupole

724

F.H. O'Shea, R.B. Agustsson, Y.C. Chen, E. Spranza
RadiaBeam, Santa Monica, California, USA
D.W. Martin, J.D. McNevin
RadiaBeam Systems, Santa Monica, California, USA

We present here a status update of the manufacture and magnetic measurements of the non-linear inserts for the Integrable Optics Test Accelerator. RadiaBeam Technologies is designing the 2-meter structure from magnetic field specifications, including pole design, measurement systems and alignment fiducialization. Herein, we will describe the current state of the project.

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MOPHA031

Implementation of a Diagnostic Pulse for Beam Optics Stability Measurements at FLASH

kicker, controls, diagnostics, betatron

850

F. Mayet, R.W. Aßmann, S. Schreiber, M. Vogt
DESY, Hamburg, Germany

In order to monitor long-term stability of beam optics, simple and at the same time minimally invasive procedures are desirable. Using selectively kicked bunches, betatron phase advance, as well as potential growth of the betatron oscillation amplitude and the Twiss parameters alpha and beta can be extracted from BPM data. If done periodically, this data can be compiled into a long-term history that is accessible via the control system. This way it is possible to identify potential sources of beam optics errors. At FLASH the procedure could be implemented as a server/client tool. Since the whole procedure takes less than five seconds, operation is not disturbed significantly. In this work the possible implementation of the procedure is presented. It is also shown how the history data can be evaluated in order to infer possible beam optics error sources.

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MOPHA035

Beam Optics Measurements at FLASH2

extraction, undulator, linac, FEL

863

M. Scholz, M. Vogt, J. Zemella
DESY, Hamburg, Germany

FLASH2 is a newly build second beamline at FLASH, a soft X-ray FEL at DESY, Hamburg. Unlike the existing beamline FLASH1, it is equipped with variable gap undulators. This beamline is currently being commissioned. Both undulator beamlines of FLASH are driven by a common linear accelerator. Fast kickers and a septum are installed at the end of the linac to distribute the electron bunches of every train between FLASH1 and FLASH2. A specific beam optics in the extraction arc with horizontal beam waists in the bending magnets is mandatory in order to mitigate effects from coherent synchrotron radiation (CSR). We performed various beam optics measurements to ensure that the conditions for FEL operation at FLASH2 are fulfilled. Here we will show results of measurements.

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MOPHA042

Online Studies of THz-radiation in the Bursting Regime at ANKA

synchrotron, radiation, synchrotron-radiation, bunching

882

M. Brosi, C.M. Caselle, E. Hertle, N. Hiller, A. Kopmann, A.-S. Müller, M. Schwarz, P. Schönfeldt, J.L. Steinmann, M. Weber
KIT, Eggenstein-Leopoldshafen, Germany

Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320
The ANKA storage ring of the Karlsruhe Institute of Technology (KIT) operates in the energy range from 0.5 to 2.5 GeV and generates brilliant coherent synchrotron radiation in the THz range with a dedicated bunch length reducing optic. The producing of radiation in the so-called THz-gap is challenging, but this intense THz radiation is very attractive for certain user experiments. The high degree of compression in this so-called low-alpha optics leads to a complex longitudinal dynamics of the electron bunches. The resulting micro-bunching instability leads to time dependent fluctuations and strong bursts in the radiated THz power. The study of these fluctuations in the emitted THz radiation provides insight into the longitudinal beam dynamics. Fast THz detectors combined with KAPTURE, the dedicated KArlsruhe Pulstaking and Ultrafast Readout Electronics system developed at KIT, allow the simultaneous measurement of the radiated THz intensity for each bunch individually in a multi-bunch environment. This contribution gives an overview of the first experience gained using this setup as an online diagnostics tool.

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MOPWI001

First Results From Beam Tests of the CLIC Drive Beam Phase Feedforward Prototype at CTF3

kicker, hardware, dipole, operation

1139

J. Roberts, P. Burrows, G.B. Christian, C. Perry
JAI, Oxford, United Kingdom
A. Andersson, R. Corsini, P.K. Skowroński
CERN, Geneva, Switzerland
A. Ghigo, F. Marcellini
INFN/LNF, Frascati (Roma), Italy

Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu-CARD, grant agreement no. 227579.
In the CLIC two beam acceleration scheme 100 MV/m normal conducting cavities are fed with RF power extracted from a secondary high power but low energy drive beam. To ensure the efficiency and luminosity performance of CLIC the phase synchronisation between the high energy main beam and the drive beam must be maintained to within 0.2 degrees of 12 GHz. To reduce the drive beam phase jitter to this level a low-latency drive beam phase feedforward correction with bandwidth above 17.5 MHz is required. A prototype of this system has been installed at the CLIC test facility CTF3 to prove its feasibility, in particular the challenges of high bandwidth, high power and low latency hardware. The final commissioning and first results from operation of the complete phase feedforward system are presented here.

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MOPWI004

Novel Single Shot Bunch Length Diagnostic using Coherent Diffraction Radiation

electron, radiation, experiment, laser

1150

R.B. Fiorito, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.G. Shkvarunets
UMD, College Park, Maryland, USA

Funding: European Union’s grant agreement no. 624890 and STFC Cockcroft core grant No. ST/G008248/1; US Office of Naval Research and DOD Joint Technology Office.
Current beam bunch length monitors which measure the spectral content of beam-associated coherent radiation to determine the longitudinal bunch form factor usually require wide bandwidth detection or Fourier transformation of interferometric data and multiple beam pulses. The data must then be Fourier transformed to obtain the bunch length. In this contribution we discuss progress in the development of a novel single shot method that utilizes the frequency integrated angular distribution (AD) of coherent diffraction radiation (CDR) to measure the RMS bunch length directly. We also present simulation results which show how the AD changes with bunch length for several electron beam linacs, where we are planning to test this new method, our single shot measurement technique and plans for comparison to other bunch length monitors.

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MOPWI016

Development of a Versatile Bunch-length Monitor for Electron Beams at ASTA

laser, radiation, electron, linac

1181

A.H. Lumpkin, D.J. Crawford, D.R. Edstrom, J. Ruan, J.K. Santucci, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA

Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy.
The generation of bright electron beams at the ASTA/IOTA facility at Fermilab includes implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The station will include both a Hamamatsu C5680 synchroscan streak camera and a Martin-Puplett interferometer (MPI). An Al-coated Si screen will be used to generate both optical transition radiation (OTR) and coherent transition radiation (CTR) during the beam’s interaction with the screen. A chicane bypass beamline will allow the measurement of the initial bunch length at the same downstream beamline location using OTR and the streak camera. The UV component of the drive laser has previously been characterized with a Gaussian fit σ of 3.5 ps*, and the uncompressed electron beam is expected to be similar to this value at low charge per micropulse. In addition, OTR will be transported to the streak camera from the focal plane of the downstream spectrometer to provide an E-t distribution within the micropulse time scale. Commissioning of the system and initial results with beam will be presented as available.
*A.H. Lumpkin et al., Proceedings of FEL14, MOP021, Basel, Switzerland, www. JACoW.org.

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MOPWI027

Open XAL Control Room Experience

controls, software, operation, Windows

1214

C.P. Chu, D.G. Maxwell, Y. Zhang
FRIB, East Lansing, Michigan, USA
C.K. Allen, T.A. Pelaia II, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: This material is based upon work supported by the U.S. Department of Energy under Cooperative Agreement DE-SC0000661 and DE-AC05-00OR22725, the State of Michigan and Michigan State University.
This paper reports the control room experience, lessons learned, and quick deployment approach for the Open XAL application environment. Open XAL is a java-based framework for building high-level accelerator applications, it is a major revision of the XAL framework which was developed at the Spallation Neutron Source (SNS). Open XAL is site neutral and may be deployed at multiple accelerator facilities. Currently, Open XAL is installed at SNS and at the Re-Accelerator facility of Michigan State University. At SNS we are in the final process of replacing the old XAL environment with Open XAL; we describe the upgrade process and our accelerator operations experience using Open XAL. At Michigan State, Open XAL has been tested during a cryomodule commissioning and result will be shown.

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TUAC2

Wideband Vertical Intra-Bunch Feedback At The SPS - 2015 Results And Path Forward

feedback, controls, kicker, simulation

1353

C.H. Rivetta, J.E. Dusatko, J.D. Fox, O. Turgut
SLAC, Menlo Park, California, USA
S. De Santis
LBNL, Berkeley, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP)
We present experimental measurements taken from CERN SPS machine development studies with a wideband intra-bunch feedback channel prototype. The demonstration system is a digital processing system with recently installed wideband kicker and amplifier components. This new hardware extends the bandwidth up to 1GHz and allows driving and controlling multiple vertical transverse modes in the bunch. The studies are focused on both driving the bunch with spectrally controlled signals to identify a reduced model of the bunch dynamics and testing model-based feedback controllers to stabilize the bunch dynamics. The measurements are structured to validate reduced MIMO models and macro-particle simulation codes, including the dynamics and limits of the feedback channel. Noise effects and uncertainties in the model are evaluated via SPS measurements to quantify the limits of control techniques applied to stabilize the intrabunch dynamics. The design of controllers for Q26 and Q20 optics are illustrated and future control developments are described.

Slides TUAC2 [30.936 MB]

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TUBD1

Optics Measurement and Correction during Acceleration with Beta-squeeze in RHIC

acceleration, quadrupole, injection, emittance

1380

C. Liu, A. Marusic, M.G. Minty
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the past, beam optics correction at RHIC has only taken place at injection and at final energy, with interpolation of corrections partially into the acceleration cycle. Recent measurements of the beam optics during acceleration and squeeze have evidenced significant beta-beats that, if corrected, could minimize undesirable emittance dilutions and maximize the spin polarization of polarized proton beams by avoiding the high-order multipole fields sampled by particles within the bunch. We recently demonstrated successfully beam optics corrections during acceleration at RHIC. We verified conclusively the superior control of the beam realized via these corrections. As a valuable by-product, these corrections have minimized the beta-beat at the profile monitors, so providing more precise measurements of the evolution of the beam emittances during acceleration.

Slides TUBD1 [1.581 MB]

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TUPWA007

UPGRADED OPTICS FOR SIRIUS WITH IMPROVED MATCHING OF ELECTRON AND PHOTON BEAM EMITTANCES

photon, quadrupole, brightness, emittance

1407

L. Liu, N. Milas, A.H.C. Mukai, X.R. Resende, F. H. de Sá
LNLS, Campinas, Brazil

A new optics has been designed for Sirius with improved betatron function matching in the 6 meter-long low beta straight sections for insertion devices. Both horizontal and vertical betatron functions are set to 1.5 m in the center of the section, improving the matching of the electron and undulator photon beams. In addition, the horizontal beam stay clear has also been reduced allowing for small horizontal gap devices as well as the conventional small vertical gap ones. The new design optics has been optimized to the same previous performance regarding dynamic aperture and momentum acceptance.

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TUPWA013

Linear and Nonlinear Optimizations for the ESRF Upgrade Lattice

sextupole, lattice, injection, dynamic-aperture

1422

N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

The ESRF storage ring will be replaced in 2020 by a new hybrid multi bend achromat lattice with 134 pmrad equilibrium horizontal emittance. To determine the best working point, large scans of tunes and chromaticities have been performed, computing Touschek lifetime and dynamic aperture. From different working points, the multi-objective genetic algorithm NSGA-II has been used to optimize the nonlinear magnets values and some linear optics parameters. The analysis have been carried out on lattices with errors and corrections. The optimizations have produced lattices with longer lifetime and larger dynamic aperture for different working points with positive chromaticities.

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TUPWA019

A Canted Double Undulator System With a Wide Energy Range for EMIL

undulator, photon, betatron, permanent-magnet

1442

J. Bahrdt, H.-J. Bäcker, W. Frentrup, S. Gottschlich, C. Rethfeldt, M. Scheer, B. Schulz
HZB, Berlin, Germany

At BESSY II a canted double undulator system for the Energy Materials In-situ Laboratory EMIL is under construction. The energy regime is covered with two undulators, an APPLE II undulator for the soft and a cryogenic permanent magnet undulator CPMU17 for the hard photons. The layout and the performance of the undulators are discussed in detail. The minimum of the vertical betatron function is shifted to the center of the CPMU17. The neighboring quadrupoles and an additional quadrupole between the undulators control the vertical betatron function. Prior to the undulator installation a testing chamber with four movable scrapers has been implemented at the CPMU17 location. Utilizing the scrapers the new asymmetric lattice optics is tested and evaulated.

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TUPWA028

Simulation Results of the Beam Transport of Ultra-Short Electron Bunches in Existing Beam Transfer Lines to Sinbad

linac, gun, electron, synchrotron

1466

U. Dorda, R.W. Aßmann, K. Flöttmann, B. Marchetti, Y.C. Nie, J. Zhu
DESY, Hamburg, Germany

SINBAD, the upcoming accelerator R&D facility at DESY, will host multiple independent experiments on the production and acceleration of ultra-short bunches including plasma wakefield experiments. As a possible later upgrade the option to transport higher energy electrons (up to 800 MeV) or positrons (up to 400 MeV) from the existing DESY Linac 2 to the facility is studied. Though existing a possible connection using e.g. a part of the DESY synchrotron as a transfer line and other currently unused transfer-line, these machines were not designed for the desired longitudinal bunch compression and high peak current required by e.g. beam driven plasma wake-field experiments. Simulation results illustrate the modifications to the current layout that would have to be implemented and the corresponding achievable beam parameters are given.

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TUPWA033

Status of the Soft X-ray Free Electron Laser FLASH

operation, FEL, laser, photon

1482

M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
DESY, Hamburg, Germany

The superconducting free-electron laser FLASH at DESY routinely produces up to several thousand photon pulses per second with wavelengths in the soft X-ray and vacuum UV regime and with energies up to 0.5 mJ per pulse. In 2014 the assembly of a second undulator beamline, FLASH2, was finished. While recommissioning of the FLASH linac and the original FLASH1 beamline was finished already at the end of 2013, the commissioning of FLASH2 could only be started in early February 2014. Only a few weeks have been reserved for dedicated set up of FLASH2, and most of its commissioning has been performed parasitically during the FLASH1 user run. The first beam was extracted through the septum to the FLASH2 beamline on March 4th, 2014, and the first lasing of FLASH2 at a wavelength of about 40 nm was achieved on August 20th, while FLASH1 was lasing simultaneously with 250 bunches at 13.5 nm. We summarize here the status of the FLASH2 commissioning and the FLASH1 operation during its 5th user period.

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TUPWA034

Status of the Recommissioning of the Synchrotron Light Source PETRA III

emittance, synchrotron, lattice, operation

1485

R. Wanzenberg, M. Bieler, M. Ebert, L. Fröhlich, J. Keil, J. Klute, G. Kube, G.K. Sahoo
DESY, Hamburg, Germany

At DESY the Synchrotron Light Source PETRA III has been extended in the North and East section of the storage ring to accommodate ten additional beam lines. The PETRA ring was converted into a dedicated synchrotron light source from 2007 to 2009. Regular user operation started in summer 2010 with a very low emittance of 1 nm at a beam energy of 6 GeV and a total beam current of 100 mA. All photon beamlines were installed in one octant of the storage ring. Nine straight sections facilitated the installation of insertion devices for 14 beam lines. Due to the high demand for additional beamlines the lattice of the ring was redesigned to accommodate 10 additional beamlines in the future. In a one year long shut-down two new experimental halls were built. The recommissioning of PETRA III started in February 2015. We are reporting the current status of synchrotron light source including the performance of the subsystems.

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TUPWA035

Progress in Optics Studies at FLASH

quadrupole, linac, FEL, free-electron-laser

1488

J. Zemella, T. Hellert, M. Scholz, M. Vogt
DESY, Hamburg, Germany

FLASH is the superconducting soft X-ray Free Electron Laser in Hamburg at DESY, Germany. Good control over the beam optics is a key aspect of the operation of a SASE FEL. In 2013 a second beam line, FLASH2, was assembled and the modifications necessary to feed the two beam lines were installed downstream of the FLASH linac. As reported before * we started a campaign of optics consolidation. We give an update on the progress of this effort and on results.
* J. Zemella, T. Hellert, M.Scholz, M.Vogt, "Measurements of the Optical Functions at FLASH", Proc. of IPAC'14, TUPRO050.

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TUPWA036

Possibility of Longitudinal Bunch Compression in Petra III

emittance, FEL, undulator, storage-ring

1492

I.V. Agapov
XFEL. EU, Hamburg, Germany
S.I. Tomin
NRC, Moscow, Russia
R. Wanzenberg
DESY, Hamburg, Germany

A scheme of short bunch production in storage rings using a longitudinally focusing insertion was presented in *. In this work we study the possibility of integrating such insertion into the PetraIII storage ring. In particular, we discuss possible optics solutions to integrate RF stations, chicane-type delay sections, and the undulators into existing ring geometry.
* I. Agapov and G. Geloni, proc. FEL 2014.

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TUPWA038

Optics Compensation for Variable-gap Undulator Systems at FLASH

undulator, quadrupole, FEL, electron

1499

Ph. Amstutz, C. Lechner, T. Plath
Uni HH, Hamburg, Germany
S. Ackermann, J. Bödewadt, M. Vogt
DESY, Hamburg, Germany

Variable-gap undulator systems are widely used in storage rings and linear accelerators to generate soft- and hard x-ray radiation for the photon science community. For cases where the effect of undulator focusing significantly changes the electron beam optics, a compensation is needed in order to keep the optics constant in other parts of the accelerator. Since 2010, the free-electron laser (FEL) facility FLASH is equipped with two undulator sections along the same electron beamline. The first undulator is a variable-gap system used for seeding experiments, the second undulator is a fixed-gap system which serves the user facility with FEL radiation. Varying the gap in the first undulator will change the beam optics such that the FEL process in the second undulator is dramatically disturbed. For the correction of the beam optics an analytical model is used to generate feed forward tables which allows to make part of the beamline indiscernible for the subsequent sections. The method makes use of the implicit function theorem and can be used for any perturbation of the beam optics. Here, we present the method and its implementation as well as measurements performed at FLASH.

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TUPWA064

Study of Inherent Potential for Emittance Reduction at the SPring-8 Storage Ring

brilliance, emittance, storage-ring, photon

1573

Y. Shimosaki
JASRI/SPring-8, Hyogo-ken, Japan

A design study for an upgrade project of the SPring-8, the SPring-8-II, is in progress, which is a full-scale major lattice modification. Besides the design study for the SPring-8-II, an inherent potential of achieving much higher brilliance than that of the present SPring-8 has been explored for the general evaluation. In this paper, the evaluation of the inherent potential for the SPring-8, not for the SPring-8-II, in terms of increasing the brilliance is discussed.

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TUPWA067

Status of Higher Bunch Charge Operation in Compact ERL

operation, space-charge, recirculation, emittance

1583

T. Miyajima, K. Harada, Y. Honda, T. Miura, N. Nakamura, T. Obina, F. Qiu, H. Sakai, S. Sakanaka, M. Shimada, R. Takai, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima, R. Nagai, N. Nishimori
JAEA, Ibaraki-ken, Japan
D. Lee
KNU, Deagu, Republic of Korea

In the KEK compact ERL (cERL), machine studies toward higher bunch charge operation is one of the most important issues. From January 2015 to April 2015, we carried out a higher bunch charge operation with an bunch charge of 0.5 pC for the experiment of laser compton scattering. After the study of space charge effect and optics tuning, we succeeded in the recirculation operation with the emittance, which was close to the design value. Moreover, a test operation in the injector section with the bunch charge of 7.7 pC was carried out as a preparation toward the recirculation operation with the average current of 10 mA.

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TUPWA069

Simulation Study on Bunch Compression and Decompression for the Compact ERL

sextupole, simulation, linac, emittance

1591

N. Nakamura, K. Harada, T. Miyajima, S. Sakanaka, M. Shimada, O. Tanaka
KEK, Ibaraki, Japan

Generation of THz coherent radiation (THz-CSR) is planned for the near future at the Compact Energy Recovery Linac (cERL) in KEK where the beam recirculation and energy recovery were already achieved in February 2014 and an experiment for generation of laser-Compton scattering X-rays (LCS-X) is being prepared to start in February 2015. To achieve a ultra-short bunch less than 100 fs for generation of the THz-CSR up to 5 THz, we have studied bunch compression and decompression in the cERL mainly by using a simulation code ELEGANT. In this study, off-crest acceleration in the main superconducting linac and non-zero R56 optics in the two arc sections are used and sextupole magnets are introduced into the two arc sections for correcting T566 of the arc sections. In this paper, we will present the simulation results and the requirements for the sextupole magnets including their number and layout.

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TUPJE001

Design of Wavelength Tunable Coherent X-Ray Source

electron, radiation, target, emittance

1604

J. Hyun
Sokendai, Ibaraki, Japan
K. Endo
TOYAMA Co., Ltd., Zama-shi, Kanagawa, Japan
K. Hayakawa, Y. Hayakawa, T. Sakai, T. Tanaka
LEBRA, Funabashi, Japan
I. Sato
Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan
M. Satoh, M. Yoshida
KEK, Ibaraki, Japan

KEK, Nihon University and TOYAMA CO., Ltd. have been developing the compact shieldless coherent X-ray source that can change the X-ray energy (3-25keV). This X-ray is the Parametric X-ray radiation (PXR) generated by relativistic charged particles passed through a single crystal. It has features that are monochromaticity, coherence and diffraction large angle for the incident beam. These indicate to the possibility for the application to the medical treatment and diagnosis. Furthermore, we try to reduce the radiation which is mainly generated when the high energy beam is damped. This system consists of an accelerating, a decelerating structure and four bending magnets (theta: 90 degree). These structures are operated under low temperature to get the high Q-value for long beam pulse. PXR is generated by colliding with a single crystal after electron beam is accelerated up to 75 MeV. The bunch passed through the crystal is transported into a decelerator structure and then is decelerated to 3 MeV there. Q-magnets are arranged that dispersion function is zero except arc sections. We calculated the beam transport, PXR intensity and emittance blow up. We'll report these details.

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TUPJE023

Consideration on the Future Major Upgrades of the SSRF Storage Ring

storage-ring, injection, cavity, emittance

1672

Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, M.Z. Zhang
SINAP, Shanghai, People's Republic of China

The SSRF storage ring was in operation from 2008, currently it is operating at the energy of 3.5GeV, the natural emittance of 3.9 nm-rad and the beam current of 240 mA, serving for 13 beamlines with 9 IDs. There will be around 40 operated beamlines around 2020, which need some upgrade of the storage ring existing performance, such as the new lattice with superbends. And looking for the future beyond, the major upgrade towards a diffraction limited storage ring is under consideration. This paper presents the initial investigation and the proposal on the ultimate storage ring upgrade for SSRF.

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TUPJE038

Impact of Insertion Devices on the MAX IV Storage Rings

storage-ring, lattice, quadrupole, octupole

1696

S.C. Leemann, H. Tarawneh
MAX-lab, Lund, Sweden

There will be multiple compensations employed for insertion devices in the MAX IV storage rings. Apart from well-known dipole corrections and previously detailed local and global linear optics matching, certain insertion devices in the MAX IV storage rings will also require nonlinear optics adjustments and/or skew quadrupole corrections. The goal of such corrections is ensuring sufficient dynamic aperture as well as low residual emittance coupling. This paper will present a few studies that rely on tracking through kick maps in order to quantify detrimental effects of insertion devices on dynamic aperture and vertical emittance, develop suitable countermeasures, and finally, verify restored storage ring performance.

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TUPJE044

Local Orbit Response Matrix Measurement at SLS

quadrupole, storage-ring, focusing, feedback

1713

M. Aiba, M. Böge
PSI, Villigen PSI, Switzerland

The experimental determination of linear optics is essential to achieve a high performance ring accelerator. One of the methods, linear optics from closed orbits (LOCO), is widely employed to correct linear optics. Due to the ring nature, a quadrupole error at a location of the ring affects the entire orbit response measurement data. The orbit response, however, can be localised to a certain range of the ring when an orbit feedback (or correction) is applied to the rest of the ring. The quadrupole errors located in the range, where the feedback is acting, then have no impact, and the ring optics can be locally examined. An application of this technique to Swiss light source is discussed.

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TUPJE049

TPS Linac Relocation and Beam Test of the LTB Transfer Line

linac, electron, quadrupole, injection

1731

H.-P. Chang, A.Y. Chen, C.L. Chen, Y.-S. Cheng, C.-S. Fann, K.T. Hsu, S.Y. Hsu, K.-K. Lin, Y.C. Lin, J. Liu, K.L. Tsai
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) 150 MeV linac has been relocated from its 2011 test site to the TPS linac tunnel in 2014. After functional test of the linac hardware modules, the beam parameters were carefully examined at a 31-degree bend diagnostic beam line LTD (linac to beam dump) and compared with previous results. Then, the 150 MeV electron beam was delivered to the linac to booster transfer line (LTB) for beam commissioning. The beam optics matching at both the LTB entrance (i.e. linac exit) and the LTB exit (i.e. injection point of booster) was performed for injection optimization purpose. The LTB lattice setting was verified in the beam steering through LTD and LTB with the help of diagnostics tools such as beam profile monitors (SM) and beam position monitors (BPM). The overall performance of the linac and LTB will be described in this report.
#peace@nsrrc.org.tw

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TUPJE052

Bunch Compression in the Driver Linac for the Proposed NSRRC VUV FEL

electron, linac, gun, FEL

1738

N.Y. Huang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan
A. Chao, K. Fang, M.-H. Wang, J. Wu
SLAC, Menlo Park, California, USA

A bunch compressor is designed for the S-band driver linac system of the proposed NSRRC VUV free electron laser (FEL). Instead of using a more conventional rf harmonic linearizer, one main feature of this compressor is to use electron linearization optics to correct the nonlinearity in the energy-time correlation of the electron bunch longitudinal phase space. The strategy of compressor design will be discussed by an analytical calculation and particle tracking simulation. The beam dynamics which include the collective instabilities such as the space charge effects, the wake fields and the coherent synchrotron radiation (CSR) effects are discussed.

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TUPJE070

Preliminary Experimental Investigation of Quasi Achromat Scheme at Advanced Photon Source

lattice, resonance, emittance, operation

1800

Y. Sun, H. Shang
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Next generation storage rings require weaker dipole magnets and stronger quadrupole focusing to achieve very low emittance. To suppress the geometric and chromatic optics aberrations introduced by the strong sextupoles, achromat and quasi achromat schemes are applied in the lattice design to improve the beam dynamics performance. In this paper, some preliminary experimental investigation of the quasi achromat scheme at the Advanced Photon Source (APS) are presented. Three different operation lattices are compared on their beam dynamics performance. Although none of these operation lattices achieve ideal quasi achromat condition, they have certain relevant features. It is observed that fewer resonances are present in the nominal operation lattice which is most close to quasi achromat required conditions.

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TUPJE074

LCLS Injector Laser Modulation to Improve FEL Operation Efficiency and Performance

laser, electron, FEL, emittance

1813

S. Li, D.K. Bohler, W.J. Corbett, A.S. Fisher, S. Gilevich, Z. Huang, A. Li, D.F. Ratner, J. Robinson, F. Zhou
SLAC, Menlo Park, California, USA
R.B. Fiorito, E.J. Montgomery
UMD, College Park, Maryland, USA
H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

In the Linear Coherent Light Source (LCLS) at SLAC, the injector laser plays an important role as the source of the electron beam for the Free Electron Laser (FEL). The injector laser strikes a copper photocathode which emits photo-electrons due to photo-electric effect. The emittance of the electron beam is highly related to the transverse shape of the injector laser. Currently the LCLS injector laser has hot spots that degrade the FEL performance. The goal of this project is to use adaptive optics to modulate the transverse shape of the injector laser, in order to produce a desired shape of electron beam. With a more controllable electron transverse profile, we can achieve lower emittance for the FEL, improve the FEL performance and operation reliability. We first present various options for adaptive optics and damage test results. Then we will discuss the shaping process with an iterative algorithm to achieve the desired shape, characterized by Zernike polynomial deconstruction.

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TUPMA001

Progress of the R&D towards a diffraction limited upgrade of the Advanced Light Source

injection, radiation, photon, lattice

1840

C. Steier, A. Anders, D. Arbelaez, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, W.L. Waldron, E.J. Wallén, W. Wan
LBNL, Berkeley, California, USA

Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231.
Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program funded by internal laboratory funds was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings (DLSR). It initially involves five areas, and focuses on the specific needs of soft x-ray facilities: vacuum system/NEG coating of small chambers, injection/pulsed magnets, RF systems/bunch lengthening, magnets/radiation production with advanced radiation devices, and beam physics design optimization. Some hardware prototypes have been built. The work will expand in the future to demonstrate necessary key technologies at the subsystem level or in beam tests and include new areas like photon beamline optics.

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TUPMA031

Dispersive Property of the Pulse Front Tilt of a Short Pulse Optical Undulator

laser, FEL, electron, undulator

1904

M.-H. Wang, J. Wu, Z. Wu
SLAC, Menlo Park, California, USA

Funding: Work supported by the US DOE No. DE-AC02-76SF00515.
A short pulse laser can be used as an optical undulator to achieve a high-gain and high-brightness X-ray free electron laser (FEL) [1]. To extend the interaction duration of electron and laser field, the electron and the laser will propagate toward each other with an small angle. In addition, to maintain the FEL lasing resonant condition, the laser pulse shape need be flattened and the pulse front will be titled. Due to the short pulse duration, the laser pulse has a broad bandwidth. In this paper, we will first describe the method of generalized Gaussian beam propagation using ray matrix. By applying the Gaussian beam ray matrix, we can study the dispersive property after the pulse front of the short laser is tilted. The results of the optics design for the proposal of SLAC Compton scattering FEL are shown as an example in this paper.
[1] C. Chang, et al.,“High-brightness X-ray free-electron laser with an optical undulator by pulse shaping”. Optics Express, Vol. 21, Issue 26, pp. 32013-32018 (2013).

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TUPMA037

Commissioning of the 123 MeV Injector for 12 GeV CEBAF

cryomodule, dipole, operation, injection

1920

Y.W. Wang, A.S. Hofler, R. Kazimi
JLab, Newport News, Virginia, USA

The injector energy needed to be raised from 67.5 MeV to 123 MeV to meet the energy requirement of the CEBAF 12 GeV upgrade. The ratio of the injector energy to the linac energy must remain 0.11284 at all times. Consequently, the injector was partially upgraded. The early injector, transport and acceleration from 130 keV to 6 MeV, is unchanged, but the downstream boost from 6 MeV to the final 123 MeV energy drove several changes. One of the two original CEBAF 25 MeV type cryomodules in the injector was upgraded to a 100 MeV capable one to provide more energy. Some trim magnets at the end of the injector were upgraded to compensate for the higher energy. The chicane region was expanded, and the full energy injector spectrometer was relocated to make room for the newly added Hall D line. Experience from the 6 GeV era indicated that the stray fields from the higher energy beam transport recombiners near the injection chicane adversely affect the injector orbit, so a study to understand and mitigate stray fields from the transport arc box supplies upgraded for 12 GeV led to shielding modifications for the beamline in the chicane region.

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TUPHA012

LOCO Application to NSLS2 SR Dispersion and Beta Beating Correction

quadrupole, storage-ring, ion, lattice

1989

X. Yang
BNL, Upton, Long Island, New York, USA
X. Huang, J.A. Safranek
SLAC, Menlo Park, California, USA

During the short run in early July, 2014, we made changes to the Matlab LOCO setup for NSLS-II and applied LOCO successfully to the machine. The MML setup was verified with I/O tests for all quadrupole families. The LOCO setup was further tested with an intentional quadrupole error. After the successful LOCO correction, the rms beta beat was reduced from the initial values of 5.5% x and 5.6% y, to 1.9% x and 1.0% y, respectively. The rms horizontal dispersion error was reduced from 21 mm to 6 mm. It is critical to keep the same closed orbit for LOCO correction to take effect. Because presently some correctors are nearly saturated, closed orbit cannot be controlled for additional iterations. We expect LOCO to achieve better optics correction after the orbit control is improved.

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TUPTY019

Realistic Beam Halo Model study in the Extraction Line of ATF2

background, simulation, electron, diagnostics

2038

N. Fuster-Martínez, A. Faus-Golfe
IFIC, Valencia, Spain
P. Bambade, S. Liu, S. Wallon
LAL, Orsay, France
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
E. Marín, G.R. White
SLAC, Menlo Park, California, USA

Funding: Work supported by IDC-20101074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02
The understanding and control of the transverse beam halo distributions is an important issue to reduce sources of background noise in Future Linear Colliders (FLC) and specifically at ATF2. A realistic model of the beam halo in the old extraction line of the ATF damping ring was obtained in 2005, based on wire scanner measurements. Recently, new measurements were done in the new extraction line of ATF2, using both wire scanners, in 2013, and Optical Transition Radiation monitors (OTR), in 2014. The beam halo propagation through the ATF2 beamline by means of tracking simulations has been investigated using as input a purely Gaussian and uniform beam halo model.

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TUPTY022

Alternative Optics Design of the CLIC Damping Rings with Variable Dipole Bends and High-field Wigglers

emittance, wiggler, dipole, damping

2046

P.S. Papadopoulou, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

The CLIC Damping Rings baseline design aims to reach an ultra-low horizontal normalised emittance of 500nm-rad at 2.86GeV, based on the combined effect of TME arc cells and high-field super-conducting damping wigglers, while keeping the ring as compact as possible. In this paper, an alternative design is described, based on TME cells with longitudinally variable bends and an optimized Nb3Sn high-field wiggler. The impact of these changes on ring optics parameters and the associated optimisation steps are detailed taking account the dominant effect of intrabeam scattering.

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TUPTY024

Updated Simulation Studies of Damage Limit of LHC Tertiary Collimators

proton, simulation, collimation, kicker

2053

E. Quaranta, A. Bertarelli, R. Bruce, F. Carra, F. Cerutti, P. Gradassi, A. Lechner, S. Redaelli, E. Skordis
CERN, Geneva, Switzerland

The tertiary collimators (TCTs) in the LHC, installed in front of the experiments, in standard operation intercept fractions of 10³ halo particles. However, they risk to be hit by high-intensity primary beams in case of asynchronous beam dump. TCT damage thresholds were initially inferred from results of destructive tests on a TCT jaw, supported by numerical simulations, assuming simplified impact scenarios with one single bunch hitting the jaw with a given impact parameter. In this paper, more realistic failure conditions, including a train of bunches and taking into account the full collimation hierarchy, are used to derive updated damage limits. The results are used to update the margins in the collimation hierarchy and could thus potentially have an influence on the LHC performance.

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TUPTY035

Beam Dynamics Requirements for the Powering Scheme of the HL-LHC Triplet

quadrupole, controls, simulation, dynamic-aperture

2082

M. Fitterer, R. De Maria, S.D. Fartoukh, M. Giovannozzi
CERN, Geneva, Switzerland

Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
For the HL-LHC, β^* values as small as 15 cm are envisaged as baseline scenario for the high luminosity insertions IR1 and IR5, thus leading to an increase of the maximum beta-functions in the inner triplet (IT). The larger beta-functions in the IT result in a higher sensitivity of the beam to any linear or non-linear, static or dynamic, field imperfections in the IT region. In this paper, we summarize accordingly the tolerances of the triplet power supplies in terms of current ripple, stability and reproducibility. Both the baseline IT powering scheme and other alternative schemes will be presented, the later reducing the tune shift caused by a current modulation and thus weakening its possible impact on the long term stability.

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TUPTY036

Crossing Scheme and Orbit Correction in IR1/5 for HL-LHC

alignment, injection, luminosity, quadrupole

2086

M. Fitterer, R. De Maria, S.D. Fartoukh, M. Giovannozzi
CERN, Geneva, Switzerland

Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
In this paper we review the orbit correction strategy and crossing scheme adjustment for the HL-LHC orbit correctors in IR1/5 in view of the new optics and layout version HLLHCV1.1. The main objectives are to optimize the crossing scheme, in particular to reduce the strength of the orbit correctors at D2, and to validate the strength specifications of the several orbit corrector magnets involved, including a budget reserved for the correction of the orbit distortions from various sources.

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TUPTY037

HLLHCV1.1 Optics Version for the HL-LHC Upgrade

cavity, hardware, luminosity, quadrupole

2090

R. De Maria, S.D. Fartoukh, M. Fitterer
CERN, Geneva, Switzerland

Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
The optics and layout of the HL-LHC are evolving as the new hardware is being studied and integrated, any additional requirements from the experiments detailed, and other constraints of different nature clarified. Here we present the changes of version 1.1 of the optics and layout with respect to the previous version 1.0, which include the current hardware choices and an outlook on the main resulting optics limitations and the possible future evolutions of the layout.

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TUPTY038

BPM Tolerances for HL-LHC Orbit Correction in the Inner Triplet Area

luminosity, impedance, simulation, emittance

2094

M. Fitterer, R. De Maria
CERN, Geneva, Switzerland

Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
For the HL-LHC beam spot sizes as small as 7 mum are considered for the high luminosity insertions IR1 and IR5. In addition, the luminosity has to be levelled over several hours by changing β^* resulting in constant changes of the optics and thus orbit changes. The small beam size and the continuous optics changes in general make the alignment of the beams at the IP challenging. In order to avoid continuous luminosity scans for the alignment of the beams at the IP, the orbit correction has to rely on the readings of the BPMs in the IT region. In this paper we review the requirements on resolution and accuracy of the BPMs and compare different options for the placement of the BPMs in the IT region.

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TUPTY040

Comparison of Beam Sizes at the Collimator Locations from Measured Optics and Beam-based Collimator Alignment at the LHC

alignment, injection, flattop, betatron

2101

G. Valentino, R. Bruce, A. Langner, S. Redaelli, R. Tomás
CERN, Geneva, Switzerland

At the LHC, the collimation hierarchy is defined in units of the betatron beam size using the sizes at each collimator location. The beam size at a given collimator can be inferred from the gap measurement during beam-based alignment campaigns, when the collimator touches a reference beam halo defined with the primary collimators. On the other hand, the beta functions at each collimator are also measured as a part of the standard LHC optics validation. This paper presents a comparison of the beam size measurements at the collimator locations applying these two techniques for different machine configurations. This work aims at determining which is the most reliable method for setting the collimator gaps at the LHC.

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TUPTY048

Changes to the Transfer Line Collimation System for the High-Luminosity LHC Beams

collimation, injection, luminosity, brightness

2124

V. Kain, O. Aberle, C. Bracco, M.A. Fraser, F. Galleazzi, A. Kosmicki, F.L. Maciariello, M. Meddahi, F.-X. Nuiry, G.E. Steele, F.M. Velotti
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

The current LHC transfer line collimation system will not be able to provide enough protection for the high brightness beams in the high-luminosity LHC era. The new collimation system will have to attenuate more and be more robust than its predecessor. The active jaw length of the new transfer line collimators will therefore be 2.1 m instead of currently 1.2 m. The transfer line optics will have to be adjusted for the new collimator locations and larger beta functions at the collimators for absorber robustness reasons. In this paper the new design of the transfer line collimation system will be presented with its implications on transfer line optics and powering, maintainability, protection of transfer line magnets in case of beam loss on a collimator and protection of the LHC aperture

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TUPTY050

Considerations for the Beam Dump System of a 100 TeV Centre-of-mass FCC hh Collider

extraction, kicker, septum, collider

2132

T. Kramer, M.G. Atanasov, M.J. Barnes, W. Bartmann, J. Borburgh, E. Carlier, F. Cerutti, L. Ducimetière, B. Goddard, A. Lechner, R. Losito, G.E. Steele, L.S. Stoel, J.A. Uythoven, F.M. Velotti
CERN, Geneva, Switzerland

A 100 TeV centre-of-mass energy frontier proton collider in a new tunnel of 80–100 km circumference is a central part of CERN’s Future Circular Colliders (FCC) design study. One of the major challenges for such a machine will be the beam dump system, which for each ring will have to reliably abort proton beams with stored energies in the range of 8 Gigajoule, more than an order of magnitude higher than planned for HL-LHC. The transverse proton beam energy densities are even more extreme, a factor of 100 above that of the presently operating LHC. The requirements for the beam dump subsystems are outlined, and the present technological limitations are described. First concepts for the beam dump system are presented and the feasibility is discussed, highlighting in particular the areas in which major technological progress will be needed. The potential implications on the overall machine and other key subsystems are described, including constraints on filling patterns, interlocking, beam intercepting devices and insertion design.

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TUPTY052

New Method for Validation of Aperture Margins in the LHC Triplet

kicker, vacuum, dumping, collimation

2140

V. Chetvertkova, R. Schmidt, F.M. Velotti, D. Wollmann
CERN, Geneva, Switzerland
F.M. Velotti
EPFL, Lausanne, Switzerland

Funding: Work supported by COFUND grant PCOFUND-GA-2010-267194
Safety of LHC equipment including superconducting magnets depends not only on the proper functioning of the systems for machine protection, but also on the accurate adjustment of the protective devices such as collimators. In case of a failure of the extraction kicker magnets, which are part of the beam dumping system, it is important to ensure protection of the superconducting triplet magnets from missteered beam. The magnets are located to the right of Interaction Point 5 (IP5) and are protected by one set of collimators in the beam dumping insertion in IR6 and another set close to the triplet magnets. In this paper, a new method for verification of the correct collimator position with respect to the aperture is presented. It comprises the application of an extended orbit bump with identical trajectory as the beam trajectory after a deflection by the beam dump kickers. By further increasing the bump amplitude and successively moving in/out the collimators in the region of interest, the accurate positioning of the collimators can be validated. The effectiveness of the method for LHC IP5 and IP1 and both beams is discussed

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TUPTY059

First Considerations on Beam Optics and Lattice Design for the Future Electron-Positron Collider FCC-ee

emittance, collider, lattice, operation

2162

B. Härer, B.J. Holzer, F. Zimmermann
CERN, Geneva, Switzerland
A.V. Bogomyagkov
BINP SB RAS, Novosibirsk, Russia

The Future Circular Collider (FCC) study includes the design of a 100-km electron positron collider (FCC-ee) with collision energies between 90 GeV and 350 GeV. This paper describes first aspects of the design and the optics of the FCC-ee collider, optimised for four different beam energies. Special emphasis is put on the need for a highly flexible magnet lattice in order to achieve the required beam emittances in each case and on the layout of the interaction region that will have to combine an advanced mini-beta concept, an effective beam separation scheme and a local chromaticity control to optimise the momentum acceptance and dynamic aperture of the ring.

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TUPTY060

The FCC-ee Study: Progress and Challenges

collider, interaction-region, synchrotron, radiation

2165

M. Koratzinos
DPNC, Genève, Switzerland
S. Aumon, C. Cook, A. Doblhammer, B. Härer, B.J. Holzer, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
M. Boscolo
INFN/LNF, Frascati (Roma), Italy
L.E. Medina Medrano
UGTO, Leon, Mexico
U. Wienands
SLAC, Menlo Park, California, USA

The FCC (future circular collider) study represents a vision for the next large project in high energy physics, comprising a 80-100 km tunnel that can house a future 100TeV hadron collider. The study also includes a high luminosity e⁺e⁻ collider operating in the centre-of-mass energy range of 90-350 GeV as a possible intermediate step, the FCC-ee. The FCC-ee aims at definitive electro-weak precision measurements of the Z, W, H and top particles, and search for rare phenomena. Although FCC-ee is based on known technology, the goal performance in luminosity and energy calibration make it quite challenging. During 2014 the study went through an exploration phase and during the next three years a conceptual design report will be prepared.

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TUPTY061

Combined Operation and Staging Scenarios for the FCC-ee Lepton Collider

emittance, luminosity, collider, operation

2169

M. Benedikt, B.J. Holzer, E. Jensen, R. Tomás, J. Wenninger, F. Zimmermann
CERN, Geneva, Switzerland
A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
K. Ohmi, K. Oide
KEK, Ibaraki, Japan
U. Wienands
SLAC, Menlo Park, California, USA

FCC-ee is a proposed high-energy electron positron circular collider that would initially occupy the 100-km FCC tunnel that will eventually house the 100 TeV FCC-hh hadron collider. The parameter range for the e⁺/e⁻ collider is large, operating at a cm energy from 90 GeV (Z-pole) to 350 GeV (t-tbar production) with the maximum beam current ranging from 1.5 A to 6 mA for each beam, corresponding to a synchrotron radiation power of 50 MW and a radiative energy loss varying from ~30 MeV/turn to ~7500 MeV/turn. This presents challenges for the rf system due to the varying rf voltage requirements and beam loading conditions. In this paper we present a possible gradual evolution of the FCC-ee complex by step-wise expansion, and possibly reconfiguration, of the superconducting RF system. The performance attainable at each step is discussed, along with the possible advantages and drawbacks.

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TUPTY066

Beam Cleaning in Experimental IRs in HL-LHC for Incoming Beam

collimation, betatron, quadrupole, background

2181

H. Garcia Morales
Royal Holloway, University of London, Surrey, United Kingdom
R. Bruce, S. Redaelli
CERN, Geneva, Switzerland

The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the ffectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.

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TUPTY067

Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout

background, simulation, collimation, luminosity

2184

R. Kwee-Hinzmann, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
R. Bruce, F. Cerutti, L.S. Esposito, A. Lechner
CERN, Geneva, Switzerland
S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom

Funding: Research supported by FP7 HiLumi LHC – Grant agreement 284404
In the High Luminosity LHC (HL-LHC), the collimation system will be upgraded in the high-luminosity experimental regions. Additional protection is planned for the Q4 and Q5 magnets that are located further upstream of the tertiary collimators that protect the inner triplet magnets. We evaluate the effect of this proposed collimation layout for the incoming beam 1 on machine-induced background in the experimental area of IR1 (ATLAS). The main scenario is the round optics with β∗ of 15 cm, but a flat scenario is also briefly discussed.

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TUPTY073

An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation

luminosity, beam-beam-effects, simulation, electron

2199

S.D. Fartoukh
CERN, Geneva, Switzerland
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Research supported by DOE via the US-LARP program and by EU FP7 HiLumi LHC - Grant Agreement 284404
In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical β^* values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyse it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects.

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TUPTY084

Update on the MEIC Electron Collider Ring Design

electron, collider, dipole, quadrupole

2236

F. Lin, Y.S. Derbenev, L. Harwood, A. Hutton, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands
SLAC, Menlo Park, California, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work also supported by the U.S. DOE Contract No. DE-AC02-76SF00515.
The electron collider ring of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is designed to accumulate and store a high-current polarized electron beam for collisions with an ion beam. We consider a design of the electron collider ring based on reusing PEP-II components, such as magnets, power supplies, vacuum system, etc. This has the potential to significantly reduce the cost and engineering effort needed to bring the project to fruition. This paper reports on an electron ring optics design considering the balance of PEP-II hardware parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and electron beam quality in terms of equilibrium emittances.

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TUPWI001

Turnkey Systems Cost Optimization by Iterative Design of Magnets and Power Supplies

quadrupole, power-supply, magnet-design, target

2239

M. Cavellier, W. Beeckman, F. Forest, J.D. Holzmann
Sigmaphi, Vannes, France

For more than 30 years, Sigmaphi has been manufacturing magnets and power supplies. Its teams are now able to supply a complete particle beam line, from beam optics calculation to on-site installation and alignment. These combined skills allow design optimization for turnkey systems in order to reduce their purchasing and running costs. An example of successful iterative design is presented: a 70 meters beam line designed, manufactured and installed by Sigmaphi for JINR in Dubna, Russia. This design optimization allowed reducing total power consumption of the 14 quadrupoles by 7.5%.

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TUPWI031

Status of the MEIC Ion Collider Ring Design

ion, electron, collider, dipole

2307

V.S. Morozov, Y.S. Derbenev, L. Harwood, A. Hutton, F. Lin, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands
SLAC, Menlo Park, California, USA
J. Gerity, T.L. Mann, P.M. McIntyre, N. Pogue, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported in part by the US DOE Contract No. DE-AC02-76SF00515.
We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated super-conducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.

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TUPWI032

Progress on Optimization of the Nonlinear Beam Dynamics in the MEIC Collider Rings

sextupole, ion, distributed, dynamic-aperture

2311

Y. Nosochkov, Y. Cai, M.K. Sullivan, M.-H. Wang, U. Wienands
SLAC, Menlo Park, California, USA
Y.S. Derbenev, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under US DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported by the US DOE Contract DE-AC02-76SF00515.
One of the key design features of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is a small beta function at the interaction point (IP) allowing one to achieve a high luminosity of up to 10³⁴ cm^-2s^-1. The required strong beam focusing unavoidably causes large chromatic effects such as chromatic tune spread and beam smear at the IP, which need to be compensated. This paper reports recent progress in our development of a chromaticity correction scheme for the ion ring including optimization of dynamic aperture and momentum acceptance.

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TUPWI048

Experimental Demonstration of an Interaction Region Beam Waist Position Knob for Luminosity Leveling

luminosity, controls, detector, experiment

2357

Y. Hao, Y. Luo, A. Marusic, G. Robert-Demolaize, X. Shen
BNL, Upton, Long Island, New York, USA
M. Bai
FZJ, Jülich, Germany
Z. Duan
IHEP, Beijing, People's Republic of China

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this paper, we report on the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at the Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is the only known method to control the luminosity and to reduce the pinch effect of the future eRHIC. We first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by details of the experimental demonstration of such knob in RHIC.

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TUPWI050

Optics Correction for the Multi-pass FFAG ERL Machine eRHIC

simulation, quadrupole, lattice, electron

2363

C. Liu, S.J. Brooks, V. Litvinenko, M.G. Minty, V. Ptitsyn, D. Trbojevic
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Gradient errors in the multi-pass Fixed Field Alternating Gradient (FFAG) Energy Recovery Linac (ERL) machine, eRHIC, distort the beam orbit and therefore cause emittance increase. The localization and correction of gradient errors are essential for an effective orbit correction and emittance preservation. In this report, the methodology and simulation of optics correction for the multi-pass FFAG ERL machine eRHIC will be presented.
The work was performed under Contract No. DE-AC02-98CH10886
with the U.S. Department of Energy.

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TUPWI053

Polarization Simulations in the RHIC Run 15 Lattice

resonance, polarization, simulation, lattice

2372

F. Méot, H. Huang, Y. Luo, V.H. Ranjbar, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA
S.M. White
ESRF, Grenoble, France

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
RHIC polarized proton Run 15 uses a new acceleration ramp optics, compared to RHIC Run~14 and earlier runs, in relation with electron-lens beam-beam compensation developments. The new optics induces different strengths in the depolarizing snake resonance sequence, from injection to top energy. As a consequence, polarization transport along the new ramp has been investigated, based on spin tracking simulations. Sample results are reported and discussed.

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WEBB2

First Considerations on Beam Optics and Lattice Design for the Future Hadron-Hadron Collider FCC-hh

dipole, quadrupole, injection, collider

2466

B. Dalena
CEA/IRFU, Gif-sur-Yvette, France
R. Alemany-Fernández, B.J. Holzer, D. Schulte
CERN, Geneva, Switzerland
A. Chancé, J. Payet
CEA, Gif-sur-Yvette, France

The main emphasis of the Future Circular Collider study is the design of a 100~TeV proton-proton collider in a new tunnel of about 100 km circumference. This paper presents the first optics design of the future hadron collider (FCC-hh). The basic layout follows a quasi-circular geometry ‘‘quasi racetrack'' with 8 arcs and 8 straight sections, four of which designed as interaction points. Assuming 16~T dipole magnets, a first version of the ring geometry and magnet lattice is presented, including the optics of the foreseen high luminosity regions and of the other straight sections dedicated to the installation of injection/extraction lines, beam dump etc., and an arc structure with optimized dipole fill factor to reach the target center-of-mass energy of 100~TeV.

Slides WEBB2 [4.622 MB]

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WEBD1

12 GeV CEBAF Transverse Emittance Evolution

emittance, operation, linac, synchrotron

640

T. Satogata, Y. Roblin, M.G. Tiefenback, D.L. Turner
JLab, Newport News, Virginia, USA

We present commissioning results of measurements of beam phase space evolution of the newly commissioned 12 GeV CEBAF accelerator. These measurements range over two orders of magnitude in energy for a non-equilibrium beam, from near the photocathode to the diamond bremsstrahlung target for the GlueX experiment. We also compare these measurements to modeled beam evolution, and emittance growth expectations driven by synchrotron radiation.

Slides WEBD1 [4.297 MB]

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WEPWA055

Proton Injection into the Fermilab Integrable Optics Test Accelerator (IOTA)

rfq, proton, electron, injection

2627

E. Prebys, S. A. Antipov, H. Piekarz
Fermilab, Batavia, Illinois, USA
S. A. Antipov
University of Chicago, Chicago, Illinois, USA

Funding: This work is supported by the DOE, under Contract No. De-AC02-07CH11359.
The Integrable Optics Test Accelerator (IOTA) is an experimental synchrotron being built at Fermilab to test the concept of non-linear "integrable optics". These optics are based on a lattice including non-linear elements that satisfies particular conditions on the Hamiltonian. The resulting particle motion is predicted to be stable but without a unique tune. The system is therefore insensitive to resonant instabilities and can in principle store very intense beams, with space charge tune shifts larger than those which are possible in conventional linear synchrotrons. The ring will initially be tested with pencil electron beams, but this poster describes the ultimate plan to install a 2.5 MeV RFQ to inject protons, which will produce tune shifts on the order of unity. Technical details will be presented, as well as simulations of protons in the ring.

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THYC2

Recent Trends in Beam Size Measurements using the Spatial Coherence of Visible Synchrotron Radiation

synchrotron, radiation, photon, operation

3662

T.M. Mitsuhashi
KEK, Ibaraki, Japan

The optical method of measuring the transverse beam profile and size using visible synchrotron radiation (SR) began with simple imaging systems. The resolution was limited by both the diffraction and the wavefront error making it difficult to resolve beam sizes less than 50 μm. Instead of imaging, a method for measuring the beam profile and size using the spatial coherence was introduced. The method is based on Van Cittert-Zernike’s theorem, and can resolve 4-5 μm beam sizes with an error of only 0.5 μm. In this presentation, the principle of the measurement, the SR interferometer design, and some resent measurement results are reviewed. The incoherent field depth effect for the horizontal beam size measurement is also described with some results. Design study calculations for the SR interferometer at the LHC will be presented.

Slides THYC2 [2.629 MB]

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THPF050

Applications of Beam Parameter Measurements in Transport Lines at CSNS

linac, beam-transport, DTL, factory

3815

Z.P. Li, L. Huang, Y. Li, J. Peng, S. Wang
IHEP, Beijing, People's Republic of China

Several XAL-based applications for parameter measurements in Medium Energy Beam Transport line (MEBT) and Linac to Ring Beam Transport line (LRBT) at China Spallation Neutron Source (CSNS) have been developed. Algorithms and functions of these applications are introduced in this paper. Real Machine tests are carried out in the MEBT commissioning.

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THPF089

Beam Transfer to the FCC-hh Collider from a 3.3 TeV Booster in the LHC Tunnel

injection, kicker, septum, collider

3901

W. Bartmann, M.J. Barnes, M.A. Fraser, B. Goddard, W. Herr, J. Holma, V. Kain, T. Kramer, M. Meddahi, A. Milanese, R. Ostojić, L.S. Stoel, J.A. Uythoven, F.M. Velotti
CERN, Geneva, Switzerland

Transfer of the high brightness 3.3 TeV proton beams from the High Energy Booster (HEB) to the 100 TeV centre-of-mass proton collider in a new tunnel of 80–100 km circumference will be a major challenge. The extremely high stored beam energy means that machine protection considerations will constrain the functional design of the transfer, for instance in the amount of beam transferred, the kicker rise and fall times and hence the collider filling pattern. In addition the transfer lines may need dedicated insertions for passive protection devices. The requirements and constraints are described, and a first concept for the 3.3 TeV beam transfer between the machines is outlined. The resulting implications on the parameters and design of the various kicker systems are explored, in the context of the available technology. The general features of the transfer lines between the machines are described, with the expected constraints on the collider layout and insertion lengths.

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THPF095

Limits on Failure Scenarios for Crab Cavities in the HL-LHC

simulation, luminosity, collimation, beam-losses

3923

A. Santamaría García, H. Burkhardt, A. Macpherson, K.N. Sjobak, D. Wollmann, B. Yee-Rendón
CERN, Geneva, Switzerland
K. Hernandez-Chahin
DCI-UG, León, Mexico
B. Yee-Rendón
CINVESTAV, Mexico City, Mexico

The High Luminosity (HL) LHC upgrade aims for a tenfold increase in integrated luminosity compared to the nominal LHC, and for operation at a levelled luminosity of 5 10³⁴ cm^-2.s^-1, which is five times higher than the nominal LHC peak luminosity. Crab Cavities (CCs) are planned to compensate the geometric luminosity loss created by the increased crossing angle by rotating the bunch, allowing quasi head-on collisions at the Interaction Points (IP). The CCs work by creating transverse kicks, and their failure may have short time constants comparable to the reaction time of the Machine Protection System (MPS), producing significant coherent betatron oscillations and fast emittance growth. Simulations of CC failure modes have been carried out with the tracking code SIXTRACK, using the newly added functionality called DYNK, which allows to dynamically change the attributes of the CCs. We describe these simulations and discuss early, preliminary results.

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THPF139

Nonlinear Optics of Solenoid Magnets

solenoid, focusing, lattice, factory

4048

S.M. Lund
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and the National Science Foundation under Grant No. PHY-1102511.
Solenoid magnets are often employed for focusing in low energy beam transport lattices in the front-end of a machine. We derive a relatively simple analytic formula for the nonlinear angular focusing kick imparted to particles traversing the solenoid. Few approximations are made. The formula suggests that for beam transport, little can be done to reduce nonlinearities in solenoid-type magnets other than take a simple design without abrupt changes as a function of axial coordinate and appropriately choose the aspect ratio (characteristic bore radius over axial length) of the magnet system and the beam filling factor within the aperture to limit nonlinear effects. Illustrative applications of the formula characterize nonlinear focusing effects in iron-free and iron type solenoid magnets.

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