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permanent-magnet

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MOPP015 Continuously Adjustable Permanent Magnet Quadrupole for a Final Focus quadrupole, coupling, multipole, dipole 583
 
  • T. Sugimoto, M. Ichikawa, Y. Iwashita, M. Yamada
    Kyoto ICR, Uji, Kyoto
  • M. Kumada
    NIRS, Chiba-shi
  • S. Kuroda, T. Tauchi
    KEK, Ibaraki
  A permanent magnet quadrupole with continuous strength adjustability has been fabricated. It has a five-ring-singlet structure, which was proposed by R. L.Gluckstern. Its small overall diameter allows an outgoing beamline to pass closeby. Since the permanent magnet pieces do not have any vibration source in themselves, this magnet could be used as a quadrupole in a final focus doublet. Such a quadrupole system is described.  
 
WEPC098 Development of Cryogenic Undulator CPMU at SOLEIL undulator, vacuum, cryogenics, radiation 2225
 
  • C. Benabderrahmane, P. Berteaud, N. Béchu, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, C. A. Kitegi, J. L. Marlats, A. Mary, K. Tavakoli
    SOLEIL, Gif-sur-Yvette
  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.  
 
WEPC101 Improved Homogeneity of Permanent Magnets for Undulators and Wigglers undulator, wiggler, 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.  
 
WEPC129 Undulator Demagnetization due to Radiation Losses at FLASH undulator, radiation, quadrupole, free-electron-laser 2308
 
  • J. Skupin, B. Faatz, Y. Li, J. Pflueger, T. Vielitz
    DESY, Hamburg
  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.  
 
WEPC132 Damping Wigglers at the PETRA III Light Source wiggler, damping, 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.  
 
WEPC135 A New Concept for Reducing Phase Errors in Superconductive Undulators: Induction-shimming undulator, electron, photon, simulation 2323
 
  • D. Wollmann, T. Baumbach, A. Bernhard, P. Peiffer
    University of Karlsruhe, Karlsruhe
  • R. Rossmanith
    FZK, Karlsruhe
  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.  
 
WEPC155 Experimental Characterization of Permanent Magnet Harmonic Corrector Rings quadrupole, dipole, insertion, insertion-device 2371
 
  • A. Madur, S. Marks, S. Prestemon, D. Schlueter
    LBNL, Berkeley, California
  A total of three permanent magnet chicane magnets have been installed at the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory. The magnet design incorporates counter-rotating permanent magnet pairs with trim coils. The purpose is to provide a fixed angular separation between two successive elliptically polarizing undulator (EPU) photon fans and to correct steering perturbation resulting from EPU polarization state and gap changes. This paper presents a method for the determination of the permanent magnets parameters and setting relative orientations of the rotors by performing magnetic measurements with rotating coils. The measurement method will be developed and illustrated with experimental data from the measurement of a 16 cylinder permanent magnet harmonic corrector ring.  
 
WEPC157 A Hybrid Quadrupole Design for the RAL Front End Test Stand (FETS) quadrupole, simulation, proton, beam-losses 2377
 
  • D. C. Plostinar, M. A. Clarke-Gayther
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • P. Davis
    STFC/RAL, Chilton, Didcot, Oxon
  • S. J.S. Jago
    STFC/RAL/ISIS, Chilton, Didcot, Oxon
  The Front End Test Stand project being constructed at Rutherford Appleton Laboratory (RAL) aims to deliver a high current (60 mA) H- chopped ion beam, at 3 MeV and 50 pps. The main components of FETS are the H- ion source, the Low Energy Beam Transport line (LEBT), the Radio Frequency Quadrupole (RFQ) and the Medium Energy Transport (MEBT) line with beam chopper. Space restrictions in the MEBT line place constraints on component length and drive the requirement to identify compact component configurations. A description is given of a novel compact hybrid quadrupole magnet, whose design is based on the concentric combination of a permanent magnet quadrupole (PMQ) and a laminar conductor electromagnetic quadrupole (EMQ). Simulations of magnetic field distribution in 2 and 3D are presented, and possible applications and further developments are discussed.  
 
WEPC164 Development of Modulating Permanent Magnet Sextupole Lens for Focusing of Cold Neutrons sextupole, focusing, dipole, scattering 2392
 
  • M. Yamada, M. Ichikawa, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • T. Ino, S. Muto, H. M. Shimizu
    KEK, Ibaraki
  A modulating permanent magnet sextupole lens that can focus pulsed cold neutrons is under development. It is based on the extended Halbach configuration to generate stronger magnetic field. In order to adjust the strength, the magnet is divided into two co-axial nested rings, where the inner ring is fixed and the outer ring can be rotated. Synchronizing the period of the modulation with that of pulsed neutron beam suppress the chromatic aberration. We have fabricated a half-scale model and studied the strength, the torque and the temperature rise caused by eddy current. Now we are developing the full-scale model improving such problems. These two scale models of magnet are described.  
 
THPC007 Permanent Magnet Skew Quadrupoles for the Low Emittance LER Lattice of PEP-II quadrupole, emittance, lattice, coupling 2987
 
  • F.-J. Decker, S. D. Anderson, D. Kharakh, M. K. Sullivan
    SLAC, Menlo Park, California
  The vertical emittance of the low energy ring (LER) in the PEP-II B-Factory was reduced by using skew quadrupoles consisting of permanent magnet material. The advantages over electric quadrupoles or rotating existing normal quadrupoles are discussed. To assure a high field quality a Biot Savart calculation was used to cancel the natural 12-pole component by using different size poles over a few layers. A magnetic measurement confirmed the high quality of the magnets. After installation and adjusting the original 12 skew and 16 normal quadrupoles the emittance contribution from the region close to the interaction point, which was the biggest part in the original design, was considerably reduced.  
 
THPC146 Beam Halo Monitor Using Diamond Detectors for XFEL/SPring-8 electron, induction, undulator, radiation 3330
 
  • H. Aoyagi, Y. Asano, T. Bizen, K. Fukami, N. Nariyama
    JASRI/SPring-8, Hyogo-ken
  • T. Itoga, H. Kitamura, T. Tanaka
    RIKEN/SPring-8, Hyogo
  The construction of the XFEL facility at SPring-8 has been started. We have been developing a halo monitor as an interlock device for protection of undulator permanent magnets against radiation damage. When permanent magnets are irradiated with a halo part of 8GeV electron beam, magnetic fields are degraded permanently and laser oscillation is weakened. Therefore, the interlock device is required during machine operation. Diamond detector, which operates in photoconductive mode, is good candidate for electron beam sensor. The beam test of the diamond detector head has been carried out at the beam dump of the SPring-8 booster synchrotron. Minimum number of injected electron was about 1·105 /pulse, and we observed the pulse height of 0.1V having the pulse length of 0.6nsec FWHM without a preamplifier. The linearity of output signal on injected beam was also demonstrated. The beam halo monitor equipped with the diamond detectors is under manufacturing. The design and feasibility tests will be presented in this conference.