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| THPLS117 | In-vacuum and FEL Undulators at Danfysik | 3553 |
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| Danfysik has recently designed and produced two in-vacuum insertion devices. The first device is a 19 mm period device made for the Swiss Light Source and the second is a 20 mm period device for SOLEIL. Both are hybrid undulators with Samarium Cobalt magnets where the SLS device is made with steel poles while the SOLEIL undulator is optimized for high peak field using Vanadium Permendur poles and relative large magnet blocks. A quasi-periodic undulator has been built for FEL applications at the FOM-Institute for Plasma Physics. The device is based on a standard pure permanent undulator design but then converted into a quasi-periodic device. The magnetic performance of the device was in excellent agreement with theoretical calculations with high suppression of the 3. and 5. harmonics. A conventional undulator has also been built for FEL applications at FZR Rossendorf. A high degree of software assistance and automation has been developed for the magnet mounting, shimming and magnetic testing of the insertion devices. This technique reduces the shimming time significantly, reduces the need for highly trained personnel and results in superior magnetic performance. | ||
| THPLS118 | Status of the SOLEIL Insertion Devices | 3556 |
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| SOLEIL is the French 2.75 GeV synchrotron radiation light source of low emittance under construction near Paris. It will provide high intensity photons covering a wide spectral range from the IR to the hard x-rays. The storage ring commissioning will start in April 2006, and the first photons in the beam lines are expected during summer 2006. The first set of Insertion Devices (ID) will be installed before the commissioning or within the first year of operation of the machine. They consist of one 640 mm period and three 256 mm period electromagnetic helical undulators, three 80 mm period Apple II type undulators, and three 20 mm period in-vacuum undulators. All these ID's make use of a wide panoply of technical solutions for generating various types of magnetic fields. Magnetic and conceptual designs were performed by SOLEIL, and the technical realisation was carried out together with the different manufacturers. The design specificities of the different types of ID's and the magnetic field characterisation and optimisation will be reported. The first commissioning on the beam of these undulators will be described. | ||
| THPLS119 | Development of a Cryogenic Permanent Magnet In-vacuum Undulator at the ESRF | 3559 |
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Lowering the temperature of NdFeB materials increases their field remanence and intrinsic coercivity*. This property is potentially interesting for the construction of cryogenic permanent in-vacuum undulators (CPMU)**. Around 150K, the coercivity is increased to such an extent that the NdFeB material is comparable to the Sm2Co17 as far as resistance to radiation damages is concerned. The improvement in field remanence is less remarkable (15% at 150K) and is dominated by a reversible Spin Reorientation Transition (SRT) occurring around 135K. Below this temperature, the remanence decreases. The complete magnetization curves of NdFeB material measured at different cryogenic temperatures are presented. Non-linear models have been constructed and used in the RADIA code in order to compute the field performance of a hybrid NdFeB in-vacuum undulator. A prototype CPMU is presently under construction at the ESRF. It has a period of 18mm and a magnetic length of 2m. The field integral and local field measurements of the cryogenic device require new systems operated in vacuum. A stretched wire bench and a hall probe bench are under construction; their main characteristics will be presented.
*D. Givord et al. Analysis of hysteresis loops in NdFeB sintered magnets, J. Appl. Phys. 60(9) (3263-3265).**T. Hara et al. Cryogenic permanent undulator, Phys.rev. ST AB volume 7 050702 (2004). |
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| THPLS120 | Tracking Simulations and Dynamic Multipole Shimming for Helical Undulators | 3562 |
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| Symplectic and fast tracking simulations of an APPLE type undulator for the BESSY II storage ring are presented. The simulation is based on a multiple harmonic decomposition of the magnetic field and on a generating function approach. Because of the relatively large undulator period length of 112 mm, corrections of the dynamic multipoles are required to achieve a good dynamical aperture. | ||
| THPLS121 | Status of the PETRA III Damping Wigglers | 3565 |
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| After mid-2007, the present PETRA storage ring at DESY will be reconstructed towards a dedicated third generation light source operating at 6 GeV. An emittance reduction down to 1 nm can be achieved by means of damping wigglers. 20 permanent magnet wigglers will be installed in two of the long straights of the machine. The wiggler segments are compact fixed gap devices surrounded by iron enclosures to reduce the leakage flux. Each device will provide a damping integral of 4 T2m per segment and generate a synchrotron radiation power of 42 kW. Every wiggler segment will be followed by an SR-absorber to protect all downstream components, the accumulated on-axis power of about 200 kW will be taken up by a final absorber at the damping section end. The wiggler's magnetic design, field properties and correction schemes have previously been proven by a one period long prototype. At present, the first full length (4m) prototype wiggler has been assembled and characterized magnetically. | ||
| THPLS122 | Investigations of the Thermal Beam Load of a Superconducting In-vacuum Undulator | 3568 |
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| Both the resistive wall effect and the synchrotron radiation~\cite{wallen, casalbuoni, chou} can warm up the cold bore of a superconductive in-vacuum undulator. For the in ANKA installed superconducting undulator measurements showed that the dominant heat load contribution comes from the synchrotron radiation generated in the upstream bending magnet: 1 W per 100 mA stored current at a beam energy of 2.5 GeV and an undulator gap of 8 mm. | ||
| THPLS123 | A Year's Experience with a Superconducting Undulator in the Storage Ring ANKA | 3571 |
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| In ANKA the worldwide first superconducting undulator demonstrator designed for a storage ring was operated during the last year. The undulator has 100 periods and a period length of 14 mm. During the first year the heat transfer from the beam to the cold bore was investigated and the spectra and the electrical tunability together with a monochromator was measured. The results are so encouraging that plans exist to equip ANKA with two more undulators, one with the opportunity to double electrically the period length and one with electrically variable polarization direction. | ||
| THPLS124 | The Second Generation of Superconductive Insertion Devices for ANKA | 3574 |
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| After the superconducting undulator SCU14 was installed and successfully started operation at ANKA in spring 2005, a second generation of superconducting insertion devices for ANKA is under development. The ANKA soft x-ray analytics beamline WERA is planned to be equipped with a superconducting elliptically polarising undulator (SCEPU) with electrically tunable polarisation, and a superconducting combined undulator/wiggler (SCUW) capable of period tripling will serve as the source for the planned ANKA imaging beamline. In this paper the studies on the ANKA superconducting EPU and the status of the SCUW-project will be reviewed. | ||
| THPLS125 | A Concept on Electric Field Error Compensation for the ANKA Superconductive Undulator | 3577 |
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| In April 2005 a superconductive undulator test device, the so-called SCU14 (period length 14 mm, 100 periods) was installed at ANKA. Before installation, the magnetic field was measured and documented. This was the first test of a superconductive undulator in a storage ring and the dominating questions to be answered were related to the interaction of the undulator with the beam. The field quality was of lower importance and will be improved by a modified mechanical fabrication technique at the next superconductive undulators. Nevertheless, after finishing the fundamental beam tests the question was discussed how one would improve the field quality (minimize the phase error) of the existing undulator by local correction devices. The concepts could be used later in a weaker form for local field corrections at future undulators, if necessary. | ||
| THPLS126 | Construction and Testing of a Pair of Focusing Undulators for ALPHA-X | 3580 |
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| ALPHA-X is a four-year project shared between several research groups in the UK to build a laser-plasma accelerator and produce coherent short-wavelength radiation in an FEL. A pair of undulators for the project have been designed and built by ASTeC at Daresbury Laboratory. The undulators are 1.5m long, 100 period permanent magnet devices with a minimum gap of 3.5mm, a peak field of 0.7T and a two-plane focusing design. The devices were modelled using RADIA, and data from the magnet block manufacturer was used to sort the blocks. To optimise the trajectory in the real devices, magnetic testing (using Hall probe and flipping coil techniques) and block swapping has been performed in Daresbury's dedicated insertion device test facility. The measurements agree well with the models, and the undulators will perform well within specification. | ||
| THPLS127 | Plans for a 2nd Insertion Device in CAMD | 3583 |
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| To allow the possible installation of a 2nd Insertion Device in the CAMD Light Source the lattice optic needs to be changed. The present configuration has a small vertical beta function in the long straight containing the 7T wiggler. The new optic will give small vertical beta at two long straights which are diametrically opposite. Test results with the new optic are presented together with the measured beam parameters. These are used to predict the photon beam performance for several types of Insertion Device which could be installed. | ||
| THPLS128 | Overview of Diamond IDs for Phase 1 | 3586 |
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| Diamond Light Source is a 3GeV synchrotron currently under construction in the UK, which will be operational in early 2007. It is a third generation light source comprising 22 usable straight sections for insertion devices. Phase 1 of beamline construction will include eight Insertion Devices: five PPM in-vacuum undulators, two APPL·10-2 devices to be installed in the same straight, and one 3.5T superconducting wiggler. This paper describes the current status of construction and magnetic measurements for each of the Phase 1 devices. | ||
| THPLS130 | Thermal Neutron Demagnetization of NdFeB Magnets | 3589 |
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| At the Advanced Photon Source at Argonne National Laboratory, NdFeB insertion device magnets have shown losses of magnetization on a few straight sections where the largest electron beam losses occur due to limiting vacuum chamber apertures. In the worst case, these magnetization losses were evident after a three month operational period. To isolate the effect that thermal neutrons have on these magnets, the magnetization and coercivity were studied for two NdFeB grades as a function of dose from 7.5 x 10(12) to 6 x 10(13) neutrons/cm2. After saturation, the remanent magnetization was found to decrease linearly with the logarithm of the dose. At a dose of 7.5 x 10(12) neutrons/cm2.sec, there was already a 43 percent magnetization loss for the N45 grade and a 15 percent loss for the N48 grade. There was no apparent change in coercivity with dose. The change in remanent magnetization is a consequence of boron thermal neutron capture through the 10B(n,alpha)7Li reaction, which generates MeV energy alpha particles and lithium ions. | ||
| THPLS132 | Physics Requirement of a PLS-XFEL Undulator | 3592 |
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| Pohang Accelerator Laboratory(PAL)is planning a 0.3nm SASE (Self Amplification of Spontaneous Emission) XFEL based on a 3.7GeV linear accelerator. For short saturation length, application of the SPring8 type in the vacuum undulator is needed. This reflects the experiences from the Spring8 SCSS project. The end structures were designed to be asymmetric along the beam direction to ensure systematic zero 1st field integral. The thickness of the last magnets was adjusted to minimize the transition distance to the fully developed periodic field. This approach is more convenient to control than adjusting the strength of the end magnets. The final design features 4mm minimum pole gap, 15mm period, and peak effective field of 1.09 Tesla. In this article, the physical design of the undulator, the design of the end structure, and the physics requirements of the undulator system will be presented. | ||
| THPLS133 | Simulations of Electromagnetic Undulator for Far Infrared Coherent Source of TTF at DESY | 3595 |
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| A perspective extension of the VUV FEL user facility at DESY is infrared coherent source on the base of electromagnetic undulator. The undulator consists of 9 periods, period length is 40 cm long, and peak magnetic field is up to 1.2 T. With the energy of electron beam of 500 MeV maximum radiation wavelength is about 200 mkm. An important feature of the beam formation system of the VUV FEL is the possibility to produce ultra-short, down to 50 mkm rms electron bunches. Such short bunches produce powerful coherent radiation with multi-megawatt power level. FIR coherent source operates in a parasitic mode utilizing electron beam passed VUV undulator. Generation of two-colors by a single electron bunch reveals unique possibility to perform pump-probe experiments with VUV and FIR radiation pulses. In this report we present simulations of the undulator magnetic system and beam dynamics. | ||
| THPLS134 | A General View of IDs to be Installed at ALBA on Day One | 3598 |
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| The new 3rd generation synchrotron radiation source ALBA to be built nearby Barcelona is planned to start operation in 2009 with several different insertion devices installed in the storage ring either from "day one" or within the first year of operation. The list of high-priority insertion devices includes: 2 planar PPM SmCo in-vacuum undulators with the period of 21.3 mm; 2 Apple-II type PPM NdFeB undulators with the period of 71 mm; 1 superconducting planar wiggler with the period of 30 mm and a maximum field of 2 T, and a 1 conventional wiggler with the period of 65 mm and a maximum field of 1.55 T. The emission of these undulators covers wide spectral range extending from hard X-rays to UV. Pre-design of the IDs was done by ALBA. The construction will be done by industrial companies and institutions with production capabilities. ALBA will set up a magnetic measurement laboratory for the acceptance tests. The paper will present peculiarities of the magnetic design, calculated maximum-flux spectra and associated heat load in various modes of operation. | ||
| THPLS135 | The Study of Errors of ALBA Fixed Stretched Wire Bench | 3601 |
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| The new synchrotron radiation source ALBA to be built nearby Barcelona is planned to start operation in 2009. The facility includes a laboratory for magnetic measurements laboratory devoted to IDs. The stretched wire measurement technique is widely used to obtain magnetic field integrals. This technique is based upon the displacement of a stretched wire relative to the magnetic structure to be measured. In the most usual configuration, the magnets are kept fixed while the wire is moved. This arrangement is especially well suited for measuring big structures such as full undulators or its jaws. In contrast, in the fixed stretched wire configuration the magnetic structure is moved relative to a stationary pick-up coil with a straight segment. This layout is convenient for the measurement of small units, such as individual magnet blocks or magnetic modules. These measurements allow characterising the inhomogeneities of the building blocks of an undulator. In this paper we present an exhaustive analysis of error sources and tolerance requirements for a particular design of a fixed stretched wire bench made at ALBA, based both in the ESRF, SOLEIL and BESSY previous existing designs. | ||
| THPLS136 | Magnetic Field Multipole Measurement with Hall Probe | 3604 |
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| When assembling an insertion device before shimming, sorting algorithms are used to reduce the field errors by choosing the best arrangement of magnetic blocks. In order to carry it out, magnets to be placed in the array are measured with the Helmholtz coil. This yields the magnetic dipolar moment of each one. In fact, Helmholtz coil measurements assume a dipolar filed for each block. The development of narrow gap insertion devices yields a growing interest in the effect of magnetic inhomogeneities. Magnetic inhomogeneities introduce multipolar terms that are added to those corresponding to the multipole development of an ideal magnetic source. However, magnetic inhomogeneities are not measured so far with the Helmholtz coil, because it evaluates the magnetic field far from the magnet, and the multipolar terms decay faster than the dipolar with distance. In order to take into account inhomogeneities, a new approach could be used, based on the measurement of multipoles corresponding to each block. In this paper we propose a method for the fast measurement of the multipoles corresponding to an arbitrary magnetic block, using a Hall probe scanning along a single straight line. | ||
| THPLS137 | Insertion Devices for the MAX IV Light Source | 3607 |
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| The foreseen insertion devices and expected brilliance for the MAX IV light source are presented. The planned MAX IV light source consists of three low emittance storage rings and a 3 GeV linac. The linac is used as a full energy injector. The three storage rings will be operated at 700 MeV, 1.5 GeV, and 3.0 GeV, which makes it possible to cover a large spectral range from IR to hard X-rays with insertion devices optimised for each storage ring. | ||
| THPLS138 | Fast Polarization Switching at the SLS Microspectroscopy Beamline POLLUX | 3610 |
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| POLLUX is a new microspectroscopy facility which will be operated at a bending magnet at the Swiss Light Source (SLS). It offers spectroscopy with sub-micrometer spatial resolution for polymer science and magnetism. First user operation is scheduled for summer 2006. One of the novel envisaged options of the beamline is the usage of circular polarized light. The circular polarization will be generated by a localized angular steering of the electron beam within the bending magnet. This is accomplished by means of the global fast orbit feedback system of the SLS which allows to stabilize the electron beam to the sub-micrometer level up to frequencies of ~100 Hz. Due to the adapting coupling compensation involving dedicated adjacent skew quadrupoles, this steering becomes practically transparent to the other beamlines. Polarization switching rates of a few Hz are within reach. | ||
| THPLS139 | In-Achromatic Superconducting Wiggler in Taiwan Light Source: Installation and Test Results | 3613 |
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| In order to increase more high flux x-ray photon beams for the Taiwan Light Source, the achromatic superconducting wiggler has been installed and tested in a 1.5 GeV storage ring. The 3.1 Tesla superconducting wiggler will be operated in a 4.5 K liquid helium cryogenic system. In this work, the operation experience and test results of the achromatic superconducting wiggler are described. |