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wiggler

  
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MOPKF003 Design of 2 T Wiggler Vacuum Chamber for the LNLS Storage Ring vacuum, simulation, insertion, insertion-device 300
 
  • M.J. Ferreira, R.O. Ferraz, H.G. Filho, M.B. Silva
    LNLS, Campinas
  A 2 T wiggler with 2.8 m long and a gap of 22 mm will be installed at LNLS storage ring. The main requirements of the chamber design are short conditioning time and low mechanical deformation. Two different designs in stainless steel are proposed for the prototypes, an elliptical tube and a machined sheet. A pressure profile simulation with and without a NEG coating were made for evaluating the life-time influence and the time necessary for conditioning. A simulation with finite element of mechanical deformation for both case show equivalent results. The first prototype was made with the elliptical tube and a NEG coating deposition will be made at ESRF. The second prototype with machined parts is under construction and will be TIG welded. Descriptions of mounting structure for the prototype are show and the evaluation the dimension tolerance of the chambers.  
 
MOPKF004 Magnet Sorting Algorithm Applied to the LNLS EPU undulator, radiation, polarization, permanent-magnet 303
 
  • X.R. Resende, R.M. Dias
    LNLS, Campinas
  The Brazilian Synchrotron Light Laboratory is about to begin the construction of the first Undulator for its 1.37 GeV electron storage ring. This device will be of the EPU type with a period of 50 milimeters and 22 milimeters minimum magnetic gap. In this work we report on the sorting algorithm applied in the construction of a 10-period undulator prototype.  
 
MOPKF012 A 7T Multipole Wiggler in BESSY II: Implementation and Commissioning Results radiation, vacuum, optics, dynamic-aperture 324
 
  • E. Weihreter, J. Feikes, P. Kuske, R. Müller, G. Wustefeld
    BESSY GmbH, Berlin
  • D. Berger
    HMI, Berlin
  • N.A. Mezentsev, V. Shkaruba
    BINP SB RAS, Novosibirsk
  To generate hard X-ray beams for residual stress analysis and for magnetic scattering with the BESSY II SR source, a 7T wiggler with 17 poles has been implemented. Several problems had to be solved. Wake fields induced by smaller steps in the geometry of the radiation shield inside the beam chamber led to intolerable LHe consumption, which have been analysed numerically and then cured by improving the shield geometry. Much of the routine operation procedures are influenced by the unusually high radiation power level of max. 55 kW. For system protection an interlock system dumps the electron beam automatically in case of relevant error events. This wiggler is by far the strongest perturbation of the linear beam optics, breaking seriously the symmetry of the ring. Beam optical parameters including tune shift and beta beat have been measured to quantify these perturbations and develop efficient cures to limit the negative effects on beam lifetime and dynamic aperture. So far the wiggler is operated at 2.8 T and max. currents up to 250 mA in normal user shifts.  
 
MOPKF039 The ELETTRA Superconducting Wiggler electron, dynamic-aperture, insertion, insertion-device 390
 
  • L. Tosi, C. Knapic, D. Zangrando
    ELETTRA, Basovizza, Trieste
  A 3.5 Tesla 64 mm period superconducting wiggler has been installed in the ELETTRA storage ring as a photon source for a future X-ray diffraction beamline. After several technological upgrades, a series of measurements were carried out to characterize the device and its effects on the electron beam, such as optics distortion and dynamic aperture. A description of the upgrades and measurements are presented.  
 
MOPKF050 Current Heart-like Wiggler undulator, radiation, free-electron-laser, plasma 423
 
  • V.I.R. Niculescu, G.R. Anda, F. Scarlat
    INFLPR, Bucharest - Magurele
  • V. Babin
    INOE, Bucharest
  • C. Stancu, A. Tudorache
    Bucharest University, Faculty of Physics, Bucharest-Magurele
  A new wiggler structure for free electron lasers is presented. Current hart-like wiggler produced magnetic fields which were spatially periodic. The current wiggler structure was in the shape of stacks of modified circle wires. The current had alternating directions. The magnetic field components for each wire present a C2 symmetry (for a model with 3 branches). The wiggler transverse cross - section in arbitrary units was given by the following expressions: x = R(d+sin(3j))cos(j) , y = R(d+sin(3j))sin(j) , z = constant, where d and R are the parameters. In cylindrical coordinates the Biot - Savart law was evaluated numerically. The magnetic field aspect was mainly transversal and also easily adjusted with the current . The versatility of this structure permits new geometrical forms and developments in the wiggler and wiggler design .  
 
MOPKF052 Design of an In Archromatic Superconducting Wiggler at NSRRC vacuum, synchrotron, storage-ring, multipole 425
 
  • C.-H. Chang, H.-H. Chen, T.-C. Fan, G.-Y. Hsiung, M.-H. Huang, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  A 15-pole superconducting wiggler with period length of 6 cm is designed for National Synchrotron Research Center (NSRRC) in Taiwan. The compact superconducting wiggler will be installed near the second bending magnet of the triple bend achromat section in the 1.5 GeV storage ring. This wiggler magnet with maximum peak field of 3.2 T at pole gap width of 19 mm is operated in 4.2 K liquid helium vessel. A 5-pole prototype magnet is tested and measured to verify the magnetic field performance in the testing dewar. Furthermore, the cryogenic considerations and thermal analysis in the 4.2 K wiggler magnet and the 77 K vacuum chamber are also presented in this work.  
 
MOPKF072 Towards Attosecond X-ray Pulses from the FEL electron, laser, radiation, lattice 482
 
  • A. Zholents, J.M. Byrd, W. Fawley, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, M. Venturini, M.S. Zolotorev
    LBNL, Berkeley, California
  The ability to study ultrafast phenomena has been recently advanced by the demonstrated production and measurement of a single, 650-attosecond, soft x-ray pulses precisely synchronized to the pump laser pulse consisted of just few optical cycles. The next frontier is a production of attosecond x-ray pulses at even shorter wavelengths. Here we propose the method of ?seeded attosecond x-ray radiation? where an isolated, attosecond duration, short-wavelength x-ray pulse is radiated by electrons selected by their previous interaction with a few-cycle, intense laser pulse. In principle this method allows excellent synchronization between the attosecond x-ray probe pulse and a pump source that can be the same few-cycle laser pulse or another signal derived from it.  
 
MOPLT091 Accelerator Physics Issues of the VEPP-4M at Low Energy luminosity, electron, polarization, diagnostics 749
 
  • V.V. Smaluk
    BINP SB RAS, Novosibirsk
  The VEPP-4M electron-positron collider is being prepared for a new high-energy physics run in the 1.5 - 2.0 GeV energy range. During the first run (2001-2002), precision mass measurements of the J/psi and psi' mesons using the KEDR detector have been carried out with a record accuracy. To provide high performance, efforts for investigation and further development of the machine have been done. The most important results are described. A record absolute accuracy of energy measurement was achieved using the resonant depolarization method. A possibility to use this method for the absolute energy calibration in tau-lepton mass measurements is studied. For the first time, the Moeller polarimeter based on an internal polarized gas jet target has been developed and successfully used at the VEPP-3 booster storage ring. A system of energy measurement using Compton back-scattering has been put into operation. To increase the machine luminosity, operation with dipole wigglers is studied, and a project of turn-by-turn feedback system to suppress beam instabilities has been started. For beam diagnostics, a multi-anode photomultiplier tube and a white light coronograph were installed. The VEPP-4M operation experience with the longitudinal magnetic field within the KEDR detector is also described.  
 
MOPLT122 Dynamical Aperture Study for the NLC Main Damping Rings damping, dynamic-aperture, lattice, octupole 824
 
  • M. Venturini, S. Marks, A. Wolski
    LBNL, Berkeley, California
  A sufficiently large acceptance is critical for the NLC Main Damping Rings (MDR) as the high power carried by the beams demands very high injection efficiency. Both chromatic sextupoles and wiggler insertions, needed for damping, are substantial sources of nonlinearities limiting the dynamical aperture. We report on our latest studies on single particle dynamics for the MDR current lattice with and without inclusion of lattice errors and with attention paid to working point optimization. The possibility to use octupole magnets for compensation is also explored.  
 
MOPLT123 A Reduced Emittance Lattice for the NLC Positron Pre-damping Ring lattice, damping, emittance, injection 827
 
  • I. Reichel, A. Wolski
    LBNL, Berkeley, California
  The Pre-Damping Ring of the Next Linear Collider has to accept a large positron beam from the positron production target, and reduce the emittance and energy spread to low enough values for injection into the Main Damping Ring. A previous version of the lattice yielded an emittance of the extracted beam which was about 20% too large. In order to get the emittance down to the required value the quadrupole magnets in the dispersive regions in the ring were moved horizontally; this modifies the damping partition numbers. In addition, the model of the wigglers has been modified to reflect more closely the magnetic field map. The new lattice design meets damping and emittance requirements. The lattice and dynamic aperture studies are presented.  
 
TUPLT036 Optimization of Low Emittance Lattices for PETRA III lattice, damping, sextupole, emittance 1225
 
  • W. Decking, K. Balewski
    DESY, Hamburg
  The reconstruction of the existing 2.3 km long storage ring PETRA II into a 3rd generation synchrotron light source (PETRA III) calls for an horizontal emittance of 1 nm rad. In addition the on- and off-momentum dynamic acceptance should be large to ensure sufficient injection efficiency and beam lifetime. We present three different types of lattices for the arcs of PETRA: a so-called TME lattice and a FODO lattice which both are newly designed to reach the specified emittance and the present FODO lattice with damping wigglers. The different lattice types have been compared through tracking calculations, including wiggler nonlinearities. Only the relaxed FODO lattice with damping wigglers meets the acceptance goals.  
 
WEPKF034 The Modified DAFNE Wigglers sextupole, collider, betatron, octupole 1678
 
  • S. Guiducci, S. Bertolucci, M. Incurvati, M.A. Preger, P. Raimondi, C. Sanelli, F. Sgamma
    INFN/LNF, Frascati (Roma)
  Modifications to the pole shape of a spare wiggler have been tested to increase the width of the good field region, with the aim of reducing the effect of nonlinearities affecting the dynamic aperture and the beam-beam interaction. Additional plates realized with the same material of the pole have been machined in several shapes and glued on the poles. Accurate measurements of the vertical field component on the horizontal symmetry plane of the magnet have been performed to find the best profile. The particle motion inside the measured field has been simulated to minimize the field integral on the trajectory, to determine the wiggler transfer matrix and to estimate the amount of non linear contributions. All wigglers in the collider have been modified to the optimized pole shape. Measurements with beam performed with the modified wigglers show a significant reduction of nonlinearities.  
 
WEPKF054 Auto-filling Cryogenic System for Superconducting Wiggler radiation, synchrotron, synchrotron-radiation, superconducting-RF 1726
 
  • F.-Y. Lin, C.-H. Chang, H.-H. Chen, T.-C. Fan, M.-H. Huang, C.-S. Hwang
    NSRRC, Hsinchu
  A 3.2 Tesla superconducting wiggler with period length of 6.0 cm (SW6) was installed in January of 2004 at the National Synchrotron Radiation Research Center (NSRRC). A cryogenic plant for superconducting rf cavity will also provide liquid helium and liquid nitrogen for SW6 by using an independent automatic filling system. To facilitate a stable and precise auto-filling process, a PID controller, the kernel of the auto-filling system, will control the valves of liquid helium and liquid nitrogen, respectively. The authors shall present the control algorithm of different operation modes, namely the pre-cooling mode and normal auto-filling mode. The boil off rate of liquid helium and liquid nitrogen will be discussed.  
 
WEPLT066 Beam Dynamics Study for PETRA III Including Damping Wigglers damping, undulator, lattice, dynamic-aperture 1999
 
  • Y.L. Li, K. Balewski, W. Decking
    DESY, Hamburg
  Damping wigglers will be installed in the storage ring PETRA III to control the beam emittance to 1 nmrad. These wigglers will produce linear and nonlinear perturbations on beam dynamics. A new expanded transport matrix method is developed to solve linear dynamics, and used to match linear lattice functions. The symplectic method is adopted to track particle through the whole ring including the damping wigglers. Halbach?s formulae are used to describe the wiggler field. The main parameters of the wigglers are derived from field calculations. In order to avoid dangerous resonances, tune scanning is implemented to find suitable working points. According to presently known field quality, the nonlinear effects of damping wigglers will not degrade the performance of PETRA III and the dynamic aperture is still larger than the physical aperture.  
 
WEPLT098 Experience with Long Term Operation with Demineralized Water Systems at DAFNE ion, synchrotron, vacuum, booster 2080
 
  • L. Pellegrino
    INFN/LNF, Frascati (Roma)
  During eight years operation of the Dafne water cooling system we coped with several critical situations and managed successfully specific upgrades to the demineralized water system. Here we revise critically the collected data and the experience gained in the field of copper corrosion and related water treatment.  
 
WEPLT120 Control Environment for the Superconducting Insertion Devices at NSRRC power-supply, insertion, insertion-device, storage-ring 2134
 
  • J. Chen, C.-K. Chang, K.-T. Hsu, K.H. Hu, C.H. Kuo, C.-J. Wang
    NSRRC, Hsinchu
  To enhance hard X-ray capability in the 1.5 GeV storage ring of NSRRC to serve the rapidly growing X-ray user community in Taiwan, the storage ring was installed two superconducting insertion devices. Three more superconducting insertion devices are in planning. A 6 Tesla superconducting wavelength shifter was installed in mid-2002. A 3.2 Tesla superconducting multi-pole wiggler was installed in December of 2003. Control system and operation environment have been set up to support the operation of the superconducting insertion devices. The implementation and operation experiences will be summarized in this report.  
 
THOBCH02 DAFNE Operation with the FINUDA Experiment quadrupole, luminosity, coupling, collider 233
 
  • C. Milardi, D. Alesini, G. Benedetti, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, A. Clozza, G.O. Delle Monache, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, G. Mazzitelli, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, U. Rotundo, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, C. Vaccarezza, M. Vescovi, M. Zobov
    INFN/LNF, Frascati (Roma)
  DAFNE operation restarted in September 2003, after a six months shut-down for the installation of FINUDA, a magnetic detector dedicated to the study of hypernuclear Physics. FINUDA is the third experiment running, in sequence, at DAFNE and operates while keeping on place the other detector KLOE. During the shut-down both the Interaction Regions have been equipped with remotely controlled rotating quadrupoles in order to operate at different solenoid fields. Among many other hardware upgrades one of the most significant is the reshaping of the wiggler pole profile to improve the field quality and the machine dynamic aperture. Commissioning of the collider in the new configuration has been completed in short time. The peak luminosity delivered to FINUDA has reached 6 1031 s-1 cm-2, with a daily integrated value exceeding 3 pb-1.

Work presented by C. Milardi on behalf of the DAFNE Team

 
Video of talk
Transparencies
 
THPKF014 Status of the BESSY II Femtosecond X-ray Source laser, electron, radiation, storage-ring 2287
 
  • S. Khan, H.-J. Baecker, J. Bahrdt, H.A. Duerr, V. Duerr, W. Eberhardt, A. Gaupp, K. Godehusen, K. Holldack, E. Jaeschke, T. Kachel, D. Krämer, R. Mitzner, M. Neeb, W.B. Peatman, T. Quast, G. Reichardt, M.-M. Richter, M. Scheer, O. Schwarzkopf, F. Senf, G. Wustefeld
    BESSY GmbH, Berlin
  • I. Hertel, F. Noack, W. Sandner, I. Will, N. Zhavarnokov
    MBI, Berlin
  At the BESSY II storage ring, work is in progress to produce X-ray pulses with 50 fs (fwhm) duration and tunable energy and polarization by "femtoslicing" [*].This work includes extensive alterations to the storage ring (one new and one modified undulator, both in the same straight section, three additional dipole magnets, a new IR beamline, and nine meters of new vacuum vessels) and to two beamlines (relocation and new optical designs), as well as the installation of a femtosecond Ti:sapphire laser system. Commissioning is planned for May 2004. This paper reviews the principles and technical implementation of the new femtosecond X-ray source, and reports the status of the project.

* A. Zholentz, M. Zoloterev, Phys.Rev.Lett. 76 (1996), 912

 
 
THPKF019 PETRA III: A New High Brilliance Synchrotron Radiation Source at DESY undulator, damping, emittance, insertion 2302
 
  • K. Balewski, W. Brefeld, W. Decking, Y.L. Li, G.K. Sahoo, R. Wanzenberg
    DESY, Hamburg
  DESY has decided to rebuild its 2304 m long accelerator PETRA II into a dedicated light source called PETRA III. The reconstruction is planned to start mid of 2007.The new light source will operate at an energy of 6 GeV, a current of 100 mA, a horizontal emittance of 1 nmrad and an emittance coupling of 1%. In the first phase thirteen insertion devices are foreseen. In this paper the principle layout of the machine will be presented. The structure of the new machine combines properties of conventional storage rings and light sources and is therefore quite unconventional. One of the major challenges of the project is to achieve the small emittances. The basic idea is to use so called damping wigglers with a total length of 80 m to reduce the horizontal emittance to the desired level. To obtain and maintain the small emittances imposes tight tolerances on spurious dispersion and orbit quality and stability. These limits will be given and discussed.  
 
THPKF069 Improvements to, and Current Status of, the CAMD Light Source power-supply, injection, lattice, diagnostics 2424
 
  • V.P. Suller, M.G. Fedurin, P. Jines, D.J. Launey, T.A. Miller, Y. Wang
    LSU/CAMD, Baton Rouge, Louisiana
  Throughout 2003 a sustained program of modifications and improvements has been applied to the CAMD light source. These affected the 7 Tesla wiggler, the RF system, the magnet power supplies, the control system, the diagnostics and the injector linac. These modifications and their impact on the storage ring performance are described, together with an analysis of where future improvements should be directed. The present performance and limitations of CAMD are described.  
 
THPKF078 Coherent Infrared Radiation from the ALS Generated via Femtosecond Laser Modulation of the Electron Beam electron, laser, radiation, lattice 2448
 
  • A. Zholents, J.M. Byrd, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, M. Venturini, M.S. Zolotorev
    LBNL, Berkeley, California
  Interaction of an electron beam with a femtosecond laser pulse co-propagating through a wiggler at the ALS produces significant modulation of the electron energies within a short ~100 fs slice of the electron bunch. Subsequent propagation of the energy-modulated bunch around the storage ring results in an appearance of a local temporal modulation of the electron density (micro-bunching) due to the dispersion of electron trajectories. The temporal width of this perturbation evolves as the electron bunch propagates around the ring. The shortest modulation, ~50 microns, appears in the ALS sector immediately following the wiggler magnet, and stretches to ~ 500 microns following propagation over 2/3 of a storage ring orbit. The modulated electron bunch emits single-cycle pulses of temporally and spatially coherent infrared light which are automatically synchronized to the laser pulses. The intensity and spectra of the infrared light were measured in two locations in the ring indicated above and were found to be in good agreement with analytical calculations. Ultra-short pulses of coherent infrared radiation are presently used for a fine tuning the laser ? electron beam interaction for generating femtosecond x-ray pulses.