| Paper | Title | Page |
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| WEPC053 | An Experimental Study of Radiation-induced Demagnetization of Insertion Device Permanent Magnets | 2112 |
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High brilliance in the 3GeV new light source NSLS II is obtained from the high magnetic fields in insertion devices (ID). The beam lifetime is limited to 3h by single Coulomb scattering in the Bunch (Touschek effect). This effect occurs everywhere around the circumference and there is unavoidable beam loss in the adjacent low-aperture insertion devices. This raises the issue of degradation and damage of the permanent magnetic material by irradiation with high energy electrons and corresponding shower particles. It is expected that IDs, especially those in-vacuum, would experience changes resulting from exposure to gamma rays, x-rays, electrons and neutrons. By expanding an on-going material radiation damage study at BNL the demagnetization effect of irradiation consisting primarily of neutrons, gamma rays and electrons on a set of NdFeB magnets is studied. Integrated doses of several Mrad to a few Grad were achieved at the BNL Isotope Facility with a 112-MeV, 90-uA proton beam. Detailed information on dose distributions and particle energy spectra on the NdFeB magnets was obtained with the MARS15 Monte-Carlo code. This paper summarizes the results of this study.
Work performed under the auspices of the US DOE. |
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| WEPC096 | APPLE Undulator for PETRA III | 2219 |
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| Currently, the storage ring PETRA is being rebuilt to a light source with an ultra low emittance of only 1nm rad. The undulator radiation will take full advantage of this high performance. PETRA III will also provide circularly polarized light and linearly polarized light under arbitrary angles (inclined mode) within the energy range of 250-3000eV. The light will be produced with an APPLE II undulator which is under construction at BESSY at present. The total length of 5m and a minimum gap of only 11mm cause strong 3D forces. Due to the small good field region in an APPLE undulator and a small stay clear between the magnets and the vacuum chamber a sophisticated mechanical layout is required. The design will be presented, the expected residual mechanical deformations will be given and the consequences for the spectral performance will be discussed. | ||
| WEPC097 | Active Shimming of the Dynamic Multipoles of the BESSY UE112 APPLE Undulator | 2222 |
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| APPLE undulators produce strong dynamic multipoles in the elliptical and inclined mode which can significantly reduce the electron beam dynamic aperture. The multipole strength scales with the square of the period length and the inverse of the electron energy. A large horizontal dynamic aperture is essential for top up operation. For the BESSY devices the dynamic multipoles generated in the elliptical mode have efficiently been compensated with iron shims. For the inclined mode no passive compensation scheme is available. In case of the strong BESSY 112mm APPLE device flat current wires have been glued onto the undulator chamber, which permit the cancellation of arbitrary multipoles. The full horizontal dynamic aperture has been recovered in the inclined mode. Tracking simulations and measurements of the electron beam performance for uncompensated and compensated dynamic multipoles will be presented. | ||
| WEPC098 | Development of Cryogenic Undulator CPMU at SOLEIL | 2225 |
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| On SOLEIL at 2.75 GeV, producing hard X rays requires short period and small gap in-vacuum hybrid permanent magnet undulators. Besides, higher achieved peak magnetic field can be while operating at cryogenic temperature Tc (around 140 K). When cooling down the permanent magnets, the remanence Br increases down to a certain temperature at which the process is limited by the appearance of the Spin Reorientation Transition phenomenon. The coercivity is also increased at Tc which improves significantly the resistance to radiation. R&D studies, aims at replacing SmCo by NdFeB permanent magnets whose Br of 1.4 T, could enable to increase at least by 30% the peak magnetic field at Tc. Unfortunately such magnet grade can’t be heated to high temperature without degrading the magnetic properties, which limits the residual pressure that can be achieved. Temperature gradient and mechanical deformation are also technical issues. Different permanent magnet grades at Tc are characterized. Studies are also carried out on a small assembly of four periods. Residual pressures obtained with or without partial baking on standard U20 in-vacuum undulators are compared. | ||
| WEPC099 | A Superconductive Undulator for the Munich Laser-plasma Accelerator | 2228 |
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| Laser-plasma accelerators are expected to produce electron beams with bunch charges in the nano-Coulomb range with energies in the GeV range. By employing short-period superconductive undulators this may be utilized for the generation of undulator radiation in the X-ray regime with a compact laboratory-sized set up. In this contribution we report on the project of testing this concept at the Laser-Plasma Accelerator in Munich. A particular aim of this project is to push the superconductive undulator technology to shortest periods and highest on-axis fields at gap widths sufficiently large to reduce the impact of resistive wall wake fields on the electron beam. This might open a path to the generation of coherent radiation via the SASE process. | ||
| WEPC100 | Superconducting Insertion Devices with Variable Period Length | 2231 |
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| 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 | 2234 |
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| 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. | ||
| WEPC102 | Commissioning of the Electromagnetic Insertion Devices at SOLEIL | 2237 |
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| SOLEIL is the French 2.75 GeV third generation synchrotron radiation light source. Eleven undulators are installed yet in the storage ring and nineteen more Insertion Devices (ID) will be installed on the ring by January 2010. Among the installed IDs, there are four electromagnetic undulators of two different designs: one 640 mm period air coils undulator called HU640 and three 256 mm period undulators called HU256, made up of independent H yoke dipoles. The HU640 provides photons in any polarisation from linear to elliptical, in a range extending from 5 to 40 eV, thanks to three different groups of coils powered independently. The HU256, which are subject to hysteresis, provide horizontal and vertical, periodic or quasi-periodic linear polarisations, and also circular polarisation, covering a total range from 10 eV to 1 keV. The effects of each undulator on the closed orbit have been extensive studied, and compensated, using dedicated embedded steering coils. The correction method will be explained and its results will be shown and compared to the magnetic measurements. Finally, the first measurements of the radiation produced will be shown and compared to previsions. | ||
| WEPC103 | Design of a Cold Vacuum Chamber for Diagnostics | 2240 |
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Preliminary studies performed with the cold bore superconducting undulator installed in the ANKA storage ring suggest that the beam heat load is mainly due to the electron wall bombardment. Low energy electrons (few eV) are accelerated by the electric field of the beam to the wall of the vacuum chamber, induce non-thermal outgassing from the cryogenic surface and heat the undulator. In this contribution we report on the design of a cold vacuum chamber for diagnostics to be installed in the ANKA (ANgstrom source KArlsruhe) storage ring and possibly in third generation light sources. The diagnostics implemented are:
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| WEPC105 | Construction of a Cryogenic Permanent Magnet Undulator at ESRF | 2243 |
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| A cryogenic permanent magnet undulator (CPMU) has been constructed at ESRF. The device is a full scale in-vacuum undulator with a magnetic length of 2 metres and a period of 18 mm. This prototype is still compatible with an operation at room temperature, it has been mainly used to investigate the technological issues connected to the operation at low temperature. An important effort has been dedicated to the construction of a complete measuring bench operated in-vacuum with the undulator at cryogenic temperatures around 150 K. The bench includes a stretched wire system for field integral measurement and a local field measurement assembly suitable for the accurate characterization of the optical phase error along the undulator. The main results of the magnetic measurements will be presented , they confirm the simulations performed with RADIA using NdFeB permanent magnet material models at low temperature. The cryogenic system used to cool the undulator is based on a reliable liquid nitrogen closed loop. The heat budget of the device will be discussed. The prototype has been installed on the ESRF ring in December 2007. The first results of operation will be presented. | ||
| WEPC106 | Compensation of Variable Skew- and Normal quadrupole Focusing Effects of APPLE-II Undulators with Computer-aided Shimming | 2246 |
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| Variable (phase- and gap-dependent) skew- and normal-quadrupole focusing effects of APPLE II undulators on electron beam are reportedly complicating practical use of this type of insertion devices in many synchrotron radiation sources. We show that these undesirable effects, whatever their "origin", can be well controlled and in many cases efficiently compensated during the standard "virtual" shimming of APPLE-II undulators. Our method exploits small variations of the skew- and normal-quadrupole focusing components resulting from extra magnetic interaction, introduced by displacements of permanent magnet blocks during the shimming procedure, at different undulator phase and gap values. These variations can be calculated to a high accuracy, included into the corresponding "shim signatures" of magnetic field integrals, and used, along with undulator magnetic measurements data, for calculation of the most efficient magnet displacements. This approach is well suited for a computer-aided (e.g., genetic optimization based) shimming procedure. Practical results obtained with several APPLE-II undulators, which are currently successfully operating on the SOLEIL storage ring, are presented. | ||
| WEPC107 | Observation and Interpretation of Dynamic Focusing Effects Introduced by APPLE-II Undulators on Electron Beam at SOLEIL | 2249 |
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| The paper presents the results of electron beam closed orbit distortion (COD) and tune shift measurements performed on three different APPLE-II type undulators when making horizontal displacements of the electron beam orbit in those straight sections of the SOLEIL storage ring where these undulators are installed. In agreement with data from other storage rings, our results show that, when APPLE-II undulators are used in elliptical, linear-vertical or linear-tilted polarization modes, the measured tune shifts and the COD can not be explained only by residual first-order focusing effects: taking into account the second-order, or dynamic focusing effects, is necessary. We describe a COD interpretation method allowing for straightforward comparison of the measured effects on electron beam with the corresponding predictions from calculations and magnetic measurements. The observed dynamic effects are in good agreement with calculations performed using RADIA code. We also discuss possible modification of the figures of merit to be used at computer-aided shimming of APPLE-II undulators, which would allow for simultaneous minimization of the first- and second-order focusing effects. | ||
| WEPC108 | Portable Magnetic Field Measurement System | 2252 |
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| This portable magnetic field measurement system is a very sophisticated and sensitive machine for the measurement of magnetic fields in undulators (Planer, EPU, and Apple II), wigglers, and in-vacuum ID units. The magnetic fields are measured using 3 axis hall-effect probes, mounted orthogonally to a thin wand. The wand is mounted to a carriage that rides on vacuum air bearings. The base is granite. A flip coil is provided on two vertical towers with X, Y and Theta axes. Special software is provided to assist in homing, movement, and data collection. | ||
| WEPC109 | Development of an In-vacuum Undulator System for U-SAXS Beamline at PLS | 2255 |
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| The design of a hybrid in-vacuum undulator with 20mm period, effective peak field of 1.05 Tesla, and 1800 mm magnetic length is being 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 in-vacuum undulator (IVUN) is being installed at Pohang Accelerator Laboratory (PAL) for U-SAXS (Ultra Small Angle X-ray Scattering) beamline. The IVUN will generate undulator radiation up to ~14 keV using higher harmonic (upto 9th) undulator radiation with 2.5 GeV PLS electron beam. | ||
| WEPC110 | Development of a Conventional Multipole Wiggler MPW-80 | 2258 |
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| 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. | ||
| WEPC111 | Latest Progress in Insertion Devices at ACCEL Instruments | 2261 |
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| ACCEL Instruments GmbH has designed, manufactured, and tested several insertion devices for synchrotron light sources and free electron lasers around the world. ACCEL has been awarded for the construction of two In – Vacuum – Undulators for the ALBA/CELLS synchrotron light source in Barcelona, Spain. The design originates from the standard ESRF IVU based on the license agreement with their ID group. The status of the design work will be summarized. Also ACCEL is manufacturing two granite measurement benches for the FERMI project at Elettra in Trieste, Italy. Both benches are designed to characterize insertion devices in a fast and accurate way. A summary of the commissioning results will be presented. A full functional prototype Hybrid Undulator for the European X-FEL project in Hamburg was delivered successfully and, as the first device, in full compliance with the technical specification. Also the industrial study requested by DESY for the adaptation of the design towards a large series production of 5m long undulators for the European X-FEL, was completed as the first one in full compliance with the DESY specification and the basic conclusions are presented. | ||
| WEPC112 | The Acceptance and Photon Beam Formation in SLS FEMTO Beamline | 2264 |
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| 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 radiation from the sliced bunch in the FEMTO undulator of the SLS storage ring has been studied. Only photons passing all apertures of the beam line arrive at the experiment. We derive the transverse phase space distribution of these photons, the radiation spectra, and the spatial and angular distribution. Transmission of the radiated photons through the FEMTO beamline is calculated using the SRW simulation code in order to evaluate the acceptance of the beamline and the photon beam phase space distribution at the experimental station. | ||
| WEPC113 | Heat Load Issues of Superconducting Undulator Operated at TPS Storage Ring | 2267 |
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| The superconducting undulator with periodic length of 1.5 cm and magnet gap of 5.6 mm has been studied. The magnetic flux density of 1.4 T has been achieved. However, the heat loads from image current of the electron in the storage ring and the synchrotron radiation from bending magnet are the critical issues. The calculated power from the image current and the synchrotron radiation of bending magnet are about 3.5 W/m and 1.7 W, respectively. The superconducting undulator will be operated at the 3 GeV TPS storage ring that the operation current and the magnet flux density of dipole magnet is 400 mA and 1.19 T, respectively. The superconducting RF cavity will be installed in the TPS such that the bunch length is only 2.8 mm. Hence, the superconducting Landau cavity is necessary to extend the bunch length for reducing the heat load on the beam duct. In addition, some strategies are needed to be studied to avoid the synchrotron radiation heating on the 4.2 K vacuum chamber. The soft-end dipole design and the chicane mechanism are studied to solve the issue herein. | ||
| WEPC115 | Development of IVUN at Pohang Accelerator Laboratory | 2273 |
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| Pohang Accelerator Laboratory (PAL) is developing In Vacuum Undulator (IVUN). A short magnetic length (about 1.0 m) IVUN with 24 mm magnetic period will be developed first and a longer IVUN with 1.8 m magnetic length which will be installed in the PLS storage ring will follow. The IVUN will be equipped with built-in magnetic measurement system to ensure the accuracy of the assembly, any degradation coming from the radiation damage or high temperature. Basically, a hall probe system will be installed with linear guide to translate the measurement assembly. In this report, the design issues related to the vacuum system, measurement system, and other engineering problems of the IVUN will be discussed. | ||
| WEPC116 | FERMI@Elettra Undulator Frame Study | 2276 |
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| The FERMI@Elettra project foresees installation of both linear (LPU) and elliptical polarization undulators (EPU). Following the girder study presented last year, a detailed design of the undulator frame has been now carried out. The aim of this work was to find out a mechanical structure that guarantees minimum displacement of the girders supporting the magnet arrays. At the same time the undulator overall dimensions have been taken into account and the mechanical structure mass minimized. In this paper topology optimization result, finite element simulation and multi-objective optimization analysis are presented. | ||
| WEPC117 | Influence of Insertion Devices on the ALBA Dynamic Aperture | 2279 |
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| 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. | ||
| WEPC118 | Study of Controllable Polarization SASE FEL by a Crossed-planar Undulator | 2282 |
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| A potential and economical access to generate arbitrary polarized XFEL is to utilize crossed-undulator scheme instead of helical undulators. In this paper, the polarization of x-ray radiation for the European XFEL is investigated. The degree of polarization and the Stokes parameters are calculated for different configurations. The shot-to-shot fluctuation of polarization and the degree of polarization distribution over the transverse plane are also studied. | ||
| WEPC119 | First Year's Experience of Diamond Insertion Devices | 2285 |
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| 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 | 2288 |
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| 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. | ||
| WEPC121 | Magnetic Measurement Device for Superconductive Undulator Mock-up Coils at ANKA | 2291 |
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| A device for precise magnetic measurements of superconductive coils was designed, built and installed at the synchrotron radiation source ANKA, Forschungszentrum Karlsruhe. Accurate magnetic field measurements are a prerequisite for the characterization and optimization of insertion devices. The new device allows measuring the magnetic field magnitude of test coils with a longitudinal precision of 10 μm using a 2D Hall probe bench. The cylindrical liquid He cryostat allows mounting coils of maximum dimensions 50 cm in length and 30 cm in diameter. The set-up is computer controlled. The contribution will present the new device as well as the results obtained. | ||
| WEPC122 | Magnetic Characterization of an APPLE-II Undulator Prototype for FERMI@Elettra | 2294 |
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| The FERMI@Elettra free electron lasers will use APPLE-II undulators in the radiating sections to provide variably polarized photon beams. In preparation of the manufacturing of the final devices a prototype has been developed in order to test different methods of magnetic field optimization. For this purpose, an existing variable-gap support structure was equipped with a new mechanical interface providing the required longitudinal shifting of the magnetic arrays. Permanent magnet blocks were mounted on short modules and their field integrals measured using a stretched wire system. Field optimization was iteratively performed by proper selection of the modules to be mounted based on measurements of the partially assembled undulator structure. The results of the final magnetic field characterization are presented showing the achieved trajectory, phase and multipole errors. These results are compared with those of a previous assembly where the same modules were mounted in random order. Further improvements obtained by shimming and application of “magic fingers” are finally described. | ||
| WEPC124 | Magnetic Measurement System for the SPARC Insertion Devices | 2297 |
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| The characteristics and performances of the magnetic measurement system for the SPARC insertion devices are presented. A typical configuration formed by a a Hall probe mounted on a cart sliding on a granite beam was adopted to measure the properties of the six SPARC undulator sections. This approach has been adopted usually for rapid local field measurements. In this contribution we show that precision levels comparable to those of other well established techniques can be achieved also for critical issues like alignments, field integrals, phase errors etc. A new device purposedly designed to identify the reading area of the Hall probe with respect to bench coordinate system is presented and discussed. | ||
| WEPC125 | Development of Three New Superconducting Insertion Devices for the ANKA Storage Ring | 2300 |
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| 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 | 2303 |
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| 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. | ||
| WEPC128 | SPUR: A New Code for the Calculation of Synchrotron Radiation from Very Long Undulator Systems | 2305 |
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| The accurate calculation of synchrotron radiation from an undulator is a common problem and numerous codes have been developed that describe analytic and measured fields. However, for very long undulator systems, comprising of many individual modules and total lengths in excess of 100s of meters, for example as found in the LCLS, X-FEL, the ILC positron source undulator systems, there is not a suitable code that can handle the amount of data in a convenient manner and which runs in a practically realisable time limit. The development of a new code, SPontaneous Undulator Radiation, SPUR, is presented which computes the spontaneous radiation from electron beams passing through a system of undulators. The code supports parallel architecture, and uses the HDF5 technology to efficiently handle the multi-dimensional data. The latest results developments and benchmarking are presented. | ||
| WEPC129 | Undulator Demagnetization due to Radiation Losses at FLASH | 2308 |
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| The free-electron laser FLASH was set up at DESY Hamburg in 2004. It is a high-gain, single pass FEL which operates in the VUV and soft X-ray wavelength regime. To monitor the demagnetization of the undulator structures due to radiation losses a small test undulator was installed. This dosimetric undulator (DU) consists of a short piece of magnetic undulator structure with only 3 pole pairs and corresponding magnets. It is positioned in front of the first undulator module where a high dose rate is to be expected. The accumulated dose of DU and undulator system is derived by weekly measurements with thermoluminescence dosimeters (TLDs). The DU is dismounted and magnetically measured regularly. Based on these measurements a (maximal) relative demagnetization rate of about 5*10-4/kGy was derived. In view of this result magnetic measurements on one of the undulators from TTF1 (the predecessor of FLASH) were reviewed. They show a relative demagnetization rate of about 2*10-4/kGy which is lower but still in the same range as the result from FLASH. FEL simulations to analyse the influence of the demagnetization on the SASE process are in progress. | ||
| WEPC130 | Shimming Correction of Dynamic Multipole Effects on Apple-II Type EPUs at the ALS | 2311 |
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| Elliptically Polarizing Undulators that provide full photon polarization control also have fast, intrinsic transverse roll-off of the magnetic field. The roll-off is particularly fast for vertical polarization settings, and can have big detrimental effects on the nonlinear single particle dynamics. Particularly low and medium energy light sources and long period EPUs are prone to those effects. The three existing 50mm period EPUs at the ALS have been retrofitted with shims to correct for these dynamic multipole effects and a new 90mm period device which otherwise would have caused a huge reduction in dynamic aperture has been shimmed before installation. Simulations and beam measurements will be presented, including frequency map measurements. | ||
| WEPC131 | Insertion Devices for NSLS-II Baseline and Future | 2314 |
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| 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 | 2317 |
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| 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. | ||
| WEPC133 | Status of the PETRA III Insertion Devices | 2320 |
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| The PETRA storage ring is presently reconstructed towards a third generation light source. In total, 14 undulator beamlines will be available in the new octant of the machine. We report on the status of Petra III undulators. Three prototypes with 29mm period length, two 2m and one 5m long device have been investigated by mechanical and magnetic measurements. The prototype results are the basis for the refined design of the remaining 8 planar devices which are in the procurement phase. We present preliminary magnetic results of the prototypes and also report on the APPLE–2 and the in-vacuum undulator for PETRA III. | ||
| WEPC135 | A New Concept for Reducing Phase Errors in Superconductive Undulators: Induction-shimming | 2323 |
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| Undulators are the most advanced sources for the generation of synchrotron radiation. The photons generated by a single electron add up coherently along the electron trajectory. In order to do so the oscillatory motion of the electron has to be in phase with the emitted photons along the whole undulator. Small magnetic errors can cause unwanted destructive interferences. In standard permanent magnet undulators the magnetic errors are reduced by applying shimming techniques. Superconductive undulators have higher magnetic fields than permanent magnet undulators but shimming is more complex. In this paper it is shown that coupled superconductive loops installed along the surface of the superconductive undulator coil can significantly reduce the destructive effect of the field errors. This new idea might allow the building of undulators with a superior field quality. | ||
| WEPC136 | Waveguide Structures for RF Undulators with Applications to FELs and Storage Rings | 2326 |
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| RF undulators, suggested long time ago, has the advantage of fast dynamic control of polarization, undulator strength and wavelength. However, RF undulators require very strong RF fields in order to produce radiation of the same order as conventional static devices. Very high power RF energy confined inside a waveguide or a cavity can provide the necessary RF fields to undulate the electron beam. However, the wall losses in the waveguide should be low enough to make it practically feasible as a CW or quasi CW undulator and, hence, competitive with static devices for applications to storage rings and FELs. Here we present various waveguide structures such as smooth walled and corrugated walled waveguides and various RF modes. We will show that there are some advantages in operating with higher order modes and also with hybrid modes in the corrugated guide. We will show that the RF power requirement for some of these modes will permit a quasi CW operation of the undulator, thus permitting its operation in a storage ring. | ||
| WEPC137 | Design of Two Variable Polarization Undulators for the ALBA Project | 2329 |
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| This paper summarizes the main aspects of the magnetic, mechanical and control system design of two APPLE-II type undulators presently under construction in the framework of a collaboration between CELLS and Sincrotrone Trieste. | ||
| WEPP156 | Spherical Aberrations-free Wiggler | 2853 |
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| 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. |