EPAC08 - List of Keywords (wiggler)

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wiggler

Paper	Title	Other Keywords	Page
MOPP050	Electron Cloud Build Up and Instability in the CLIC Damping Rings	electron, simulation, damping, positron	661
	G. Rumolo, Y. Papaphilippou CERN, Geneva W. Bruns WBFB, Berlin
	Electron cloud can be formed in the CLIC positron damping ring and cause intolerable tune shift and beam instability. 2D and 3D build up simulations with the Faktor2 code, developed at CERN, have been done to predict the cloud formation in the arcs and wigglers of the damping rings. HEADTAIL simulations have been used to study the effect of this electron cloud on the beam and assess the thresholds above which the electron cloud instability would set in.

MOPP060	Parameter Scan for the CLIC Damping Rings	emittance, damping, coupling, target	679
	Y. Papaphilippou, H.-H. Braun, M. Korostelev CERN, Geneva
	Triggered by the RF frequency reduction of the CLIC main linac cavities, the damping ring parameters had to be reevaluated and the rings' performance adapted to the new luminosity requirements. In view of a staged approach for reaching the ultimate energy of the collider, the dependence of the rings output emittances under the influence of Intrabeam Scattering is evaluated with respect to different beam characteristics such as bunch population, beam energy, coupling and longitudinal beam characteristics.

MOPP061	Non Linear Dynamics Study of the CLIC Damping Rings Using Sympletic Integrators	damping, sextupole, resonance, emittance	682
	Y. Papaphilippou CERN, Geneva Ch. Skokos IMCCE, Paris
	A class of symplectic integrators with positive steps (SABA₂) is applied to investigate the non-linear dynamics of the CLIC damping rings. The detrimental effect of the chromaticity sextupoles is studied using frequency and diffusion maps and verified with MADX ptc dynamic aperture tracking. The reduction of the dynamic aperture for off-momentum particles is also investigated.

TUPP024	Electron Cyclotron Resonances in Electron Cloud Dynamics	electron, simulation, resonance, cyclotron	1583
	C. M. Celata, M. A. Furman, J.-L. Vay, J. W. Yu LBNL, Berkeley, California
	We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code “POSINST” was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. At magnetic field values, B, for which the bunch frequency is an integral multiple of the electron cyclotron frequency an enhancement of up to a factor of 3 in the electron cloud equilibrium density was found. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ~ (2πm_e/el_b), with l_b = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. We believe this accounts for the fact that this resonance has not been reported before in the electron cloud literature. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics will be discussed, along with results from 3D simulations.

TUPP031	Electron Cloud Simulations for DAΦNE	electron, simulation, positron, vacuum	1604
	T. Demma, R. Cimino, S. Guiducci, C. Vaccarezza, M. Zobov INFN/LNF, Frascati (Roma)
	After the first experimental observations compatible with the presence of the electron cloud effect in the DAΦNE positron ring, a systematic study has been performed regarding the electron cloud build-up. To assess the effects of the electron cloud, simulations of the cloud build up were carried out using ECLOUD. In particular, we discuss modifications to the secondary emission model, build up for various filling patterns and different wiggler magnetic field models. The obtained numerical results are compared with experimental observations.

WEPC001	Status of PETRA III	damping, vacuum, alignment, quadrupole	1977
	K. Balewski DESY, Hamburg
	PETRA III is a new hard x-ray synchrotron radiation source which will be operated at 6 GeV with a extremely low horizontal emittance of 1nmrad. This new light source will be the result of a conversion of the existing accelerator PETRA II into a light source. The conversion comprises the complete rebuilding of one eighth of the 2304 m long storage ring, which will then house 14 undulator beam lines and the modernisation and refurbishment of the remaining seven eighths. In addition two 100m long damping wiggler section will be installed which are required to achieve the small design emittance. During the last four years extensive design work, construction and production of components have been carried out to prepare for the conversion. Since the 2nd of July the construction activities have started when PETRA II was no longer needed as a pre-accelerator for HERA. At present the project is still on track so that operation with beam is foreseen for January 2009 and first user experiments in the second half of 2009. In this report a brief overview of the project and the status of the constructional work, the different components and the installation in the tunnel will be given.

WEPC026	Laser – Beam Interaction and Calculation of the Sliced Bunch Radiation Spectra for the SLS FEMTO Beam Line	electron, laser, radiation, positron	2040
	D. K. Kalantaryan, G. A. Amatuni, V. M. Tsakanov CANDLE, Yerevan P. Beaud, G. Ingold, A. Streun PSI, Villigen
	The FEMTO insertion at the Swiss Light Source (SLS) produces sub-ps X-ray pulses by modulating the electron energy in a slice of the bunch through interaction with a fs-laser. The electron energy modulation by the laser field in the wiggler magnet is studied analytically to calculate the radiation spectra from a sliced bunch. The analytical expressions for energy modulation and its envelope have been derived. The radiation spectra in the first magnet after the FEMTO insertion have been studied. The spectra of the coherent part of the radiation are determined using a Fourier transformation technique. For a Gaussian bunch the obtained results are compared with the tracking simulation study.

WEPC059	Lattice Design of PEP-X as a Light Source Machineat SLAC	emittance, injection, dynamic-aperture, sextupole	2127
	M.-H. Wang, Y. Cai, R. O. Hettel, Y. Nosochkov SLAC, Menlo Park, California
	The lattice study for converting the High Energy Ring (HER) of PEP-II into a light source machine with minimal modifications is reported. In this design, a higher phase advance is used in the HER FODO lattice which reduces the emittance to 5 nm at 4.5 GeV without a damping wiggler, and to 0.4 nm with 116 m damping wiggler included in two straight sections out of six. We also study the possibility of replacing one of the six FODO arcs with eight DBA cells to provide additional dispersion free straight sections for the experimental beam lines. The DBA cells will reuse the existing HER and LER (Low Energy Ring) magnets for a minimal cost of the modification. The main parameters and beam dynamics properties of these lattices are presented.

WEPC062	The SRS at Daresbury Laboratory: a Eulogy to the World's First Dedicated High-energy Synchrotron Radiation Source	storage-ring, synchrotron, lattice, electron	2133
	D. J. Holder, N. G. Wyles STFC/DL/ASTeC, Daresbury, Warrington, Cheshire P. D. Quinn STFC/DL/SRD, Daresbury, Warrington, Cheshire
	2008 marks the last year of operation of the Synchrotron Radiation Source (SRS) at Daresbury Laboratory, which circulated its first 2 GeV beam in 1981. This paper provides a look back at the significant milestones passed on the way and records the achievements of many of those involved in its thirty-year programme. Many of the technologies and techniques developed at the SRS at Daresbury are now standard practice at synchrotron light sources around the world; and there are few light source laboratories that do not benefit from the skills of someone who spent their formative years working on the SRS. The provision of synchrotron light for the UK is now being met by DIAMOND, whose success is a testament to the skills of its designers, honed as they were on the SRS at Daresbury. These skills are now being used to design the UK’s next-generation light source, to provide the pulsed and longer-wavelength light that DIAMOND cannot.

WEPC100	Superconducting Insertion Devices with Variable Period Length	undulator, photon, brilliance, insertion	2231
	A. Bernhard, T. Baumbach, P. Peiffer, D. Wollmann University of Karlsruhe, Karlsruhe R. Rossmanith FZK, Karlsruhe
	The tuning range and functionality of superconducting insertion devices may be significantly enhanced by period length switching. Period length switching can be achieved by employing two or more individually powerable subsets of superconducting coils in such a way that a current reversal in a part of these coil sets results in a period length variation. In this paper the opportunities and restrictions of period length switching in superconducting undulators are discussed from a general point of view. As a particular example, the design of a hybrid superconducting undulator/wiggler (SCUW) for ANKA based upon the period length switching technique is presented.

WEPC101	Improved Homogeneity of Permanent Magnets for Undulators and Wigglers	permanent-magnet, undulator, controls, alignment	2234
	F.-J. Boergermann, R. Blank, G. W. Reppel Vacuumschmelze GmbH & Co. KG, Hanau J. Bahrdt BESSY GmbH, Berlin J. Pflueger DESY, Hamburg
	The homogeneity of permanent magnets for use in undulators and wigglers were significantly improved in close collaboration between industry and scientific institutes throughout the last three years. Magnets with a variation of less than ± 1% in remanence, ± 1° magnetic angle and ± 1% hot/cold-side effect can be produced now - a variation of the magnetic angle of less than ± 0.5 ° is possible for some products. The development was assisted by improved characterization equipment for magnetic dipole moment and magnetic inhomogeneities by the scientific partners, which was made available for industrial application at Vacuumschmelze.

WEPC110	Development of a Conventional Multipole Wiggler MPW-80	multipole, synchrotron, power-supply, electron	2258
	D. J. Waterman, A. Deyhim, J. Kulesza, E. Van Every Advanced Design Consulting, Inc, Lansing, New York K. I. Blomqvist MAX-lab, Lund
	The design for an 80 mm period hybrid wiggler is presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural and finite element analysis, magnetic design, and electrical considerations that influenced the design are then analyzed. This wiggler will be installed at ALBA a new synchrotron radiation source being built at the site of the Centre Direccional in Cerdanyola del Vallès, nearby Barcelona, and will produce ultra-violet and X-ray beams of exceptional brightness. The facility will comprise a 3 GeV electron storage ring, injected from a ~100 MeV linac through a full energy booster synchrotron.

WEPC117	Influence of Insertion Devices on the ALBA Dynamic Aperture	undulator, lattice, dynamic-aperture, betatron	2279
	E. B. Levichev, P. A. Piminov BINP SB RAS, Novosibirsk D. Einfeld ALBA, Bellaterra
	Insertion devices can produce effects reducing the dynamic aperture in a storage ring. To study these effects for the ALBA light source the following insertion devices were inserted in the ALBA lattice: a superconducting wiggler SC-W31 with 31-mm-period and 2.1-T-field amplitude, and two Apple-II type PMM NdFeB undulators with periods of 62 mm (HU62) and 71 mm (HU71). Results of numerical study of the nonlinear beam dynamics by a 6D computer code are presented.

WEPC119	First Year's Experience of Diamond Insertion Devices	injection, undulator, photon, insertion	2285
	E. C. Longhi, R. T. Fielder, I. P.S. Martin, J. C. Schouten, B. Singh Diamond, Oxfordshire R. Bartolini JAI, Oxford
	Diamond was commissioned at 3GeV with seven insertion devices (IDs) already installed. The phase 1 IDs include five in-vacuum permanent magnet undulators, an APPLE–2 variable polarization device, and a superconducting wiggler. Since initial commissioning of the ring, three more in-vacuum undulators have been installed, and another three devices will be installed in the coming year. In this paper, we describe commissioning, characterizing, and operating with these IDs.

WEPC120	An In Vacuum Wiggler WSV50 for Producing Hard X-rays at SOLEIL	vacuum, photon, insertion, insertion-device	2288
	O. Marcouillé, P. Brunelle, O. V. Chubar, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, J. L. Marlats, A. Mary, K. Tavakoli SOLEIL, Gif-sur-Yvette
	SOLEIL is a medium energy storage ring (2.75 GeV) operating since 2006. The production of intense high energy photon beams requires insertion devices with high magnetic field and large number of periods. To cover the 20 keV-50 keV Photon Energy range, an in vacuum wiggler has been preferred to a superconducting wiggler. This choice results from a compromise between photon flux, investment and running cost. Deep studies have been performed to find the optimum magnetic field and period producing the maximum flux in the dedicated spectral range (20-50 keV). The wiggler is composed of 38 periods of 50 mm producing a 2.1 T magnetic field at a minimum gap of 5.5 mm. To minimize the high magnetic forces acting between the magnet arrays (10 tons), two compensation systems, composed of either springs or magnet blocks, have been designed. This paper presents the spectral performances of the wiggler compared with an optimized superconducting wiggler, the mechanical and magnetic design of the wiggler and the first tests of the compensation system.

WEPC125	Development of Three New Superconducting Insertion Devices for the ANKA Storage Ring	undulator, synchrotron, insertion, insertion-device	2300
	R. Rossmanith, S. Casalbuoni, A. W. Grau, M. Hagelstein FZK, Karlsruhe T. Baumbach, A. Bernhard, P. Peiffer, D. Wollmann University of Karlsruhe, Karlsruhe C. Boffo, M. Borlein, W. Walter BNG, Würzburg B. K. Kostka, E. M. Mashkina, E. Steffens University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
	After a first successful test of a superconductive cold bore undulator in ANKA a new generation of superconductive insertion devices is under construction or in a detailed planning phase. The first one, referred to as as SCU14 and now under construction, is an improved version of the existing undulator (14 mm period length, 100 periods long) with a new cooling scheme for small gap operation and a reduced field error. The period length of the second device called SCUW can be switched electrically between 15 and 45 mm. The third one is a superconductive undulator which can tolerate a beam heat load of several Watts in combination with a small field error named SCU2. It is designed for third generation light sources with a heat load of up to 6 Watt from the beam to the cold bore.

WEPC126	On a Biscuit Current Undulator	undulator, electron, laser, radiation	2303
	S. Sandru UPG, Ploiesti V. Babin INOE, Bucharest M. R. Leonovici Bucharest University, Faculty of Physics, Bucharest-Magurele V. I.R. Niculescu INFLPR, Bucharest - Magurele
	A new undulator structure for free electron lasers was presented. Current BISCUIT devices produce magnetic fields which are spatially periodic. The current structure was in the shape of wires stacks . The current has alternating directions. The magnetic field components for each wire presents symmetry with two axis. The BISCUIT undulator transverse cross-section (in arbitrary units) is a function depending directly on cosine (for x component) and sine (for y component) and inverse on the square root of the sum of forth power of sine and cosine. The z component is a constant. The Biot - Savart law was numerically evaluated. The magnetic field is longitudinal and easily adjustable with the current. The versatility of the constant parameter covers longitudinal undulator or wiggler design for one or two beams devices with transverse momenta.

WEPC131	Insertion Devices for NSLS-II Baseline and Future	undulator, insertion, insertion-device, electron	2314
	T. Tanabe RIKEN/RARF/CC, Saitama J. Bengtsson, D. A. Harder, S. L. Kramer, G. Rakowsky, J. Rank BNL, Upton, New York
	NSLS-II is going to employ Damping Wigglers not only for emittance reduction but also as broadband hard X-ray source. In-Vacuum Undulators with minimum RMS phase error (< 2 degree) and possible cryo-capability are planned for X-ray planar device, and Elliptically Polarized Undulators are utilized for polarization controls. Due to lack of hard X-ray flux from weak dipole field (0.4 Tesla), three pole wigglers of peak field over 1 Tesla will be mainly used by NSLS bending magnet beam line users. Magnetic designs and kick maps for dynamic aperture surveys were created using the latest version of Radia for Mathematica 6 which we supported the development. There are other devices planned for later stage of the project, such as quasi-periodic EPU, superconducting wiggler/undulator, and Cryo-Permanent Magnet Undulator with Praseodymium Iron Boron (PrFeB) magnets and textured Dysprosium poles. For R&D, Hybrid PrFeB arrays were assembled and field measured at room temperature, liquid nitrogen and liquid helium temperature using our vertical test facility. We have also developed a specialized power supply for pulsed wire measurement.

WEPC132	Damping Wigglers at the PETRA III Light Source	damping, permanent-magnet, emittance, storage-ring	2317
	M. Tischer, K. Balewski DESY, Hamburg A. M. Batrakov, I. V. Ilyin, D. Shichkov, A. V. Utkin, P. V. Vagin, P. Vobly BINP SB RAS, Novosibirsk
	We report on the progress in construction of the PETRA III damping sections. A series of 10 permanent magnet wigglers followed by SR-absorbers will be installed in each of the two damping sections. Thereby, the emittance of the 6 GeV storage ring will be reduced down to 1 nmrad. Prototypes of all major components have meanwhile been characterized and a test assembly of one complete wiggler cell has been performed successfully. The wigglers have a period length of 200 mm and provide a peak field of 1.5 T. Most of the 4 m long devices have been fabricated and assembled. We present results of magnetic measurements and tuning.

WEPP156	Spherical Aberrations-free Wiggler	sextupole, quadrupole, multipole, octupole	2853
	A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York
	We represented details of design of a wiggler with linear piecewise longitudinal field dependence. This type of field distribution eliminates spherical aberrations in wiggler. This wiggler can be recommended for usage in cooler rings including ILC ones.

THPC032	Vertical Beam Size Reduction via Compensation of Residual Transverse Coupling	coupling, optics, simulation, closed-orbit	3047
	T. F. Roque, X. R. Resende, P. F. Tavares LNLS, Campinas
	The Brazilian Synchrotron Light Source (LNLS) is currently constructing a beamline which will make use of the radiation produced by the EPU installed in the storage ring (SR) in 2007. Various force tasks have been triggered by this new beamline in order to achieve required beam properties and stability. One of these tasks has to do with reducing the SR's vertical beam size at the straight section where the EPU is located, hence improving the radiation brilliance from the EPU. This report will describe our recent efforts in understanding and controlling what residual effects there are in the ring that dominate the ring's vertical beam size. In particular, we study the effects of residual coupling perturbations on the beam size through the transfer matrix formalism which, we argue, is the most appropriate. A beam model including transverse linear coupling is validated with measured closed orbit response functions. By Analyzing this model we are able to propose new skew quadrupole elements to the SR that might reduce the vertical beam size at the EPU section and we can infer the validity of results with a pinhole beam imaging system which we have available in our diagnostic beamline.

THPC055	Dynamic Aperture Studies for PETRA III Including Magnet Imperfections	multipole, dynamic-aperture, lattice, damping	3107
	A. Kling, K. Balewski, W. Decking DESY, Hamburg Y. J. Li BNL, Upton, New York
	PETRA III is a 3rd generation synchrotron radiation light source. Efficient injection in the top up mode requires a dynamic aperture of 30 mmmrad or larger, while a 2 hour Touschek lifetime needs an average momentum aperture of around 1.5 %. We present studies on the impact of recently measured magnet imperfections on the available dynamic aperture. To this end, tracking simulations have been performed including the effects of measured multipole errors of lattice magnets and of 20 four-meters-long damping wigglers.