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MPPE044 Damping Wiggler Study at KEK-ATF emittance, damping, power-supply, injection 2809
  • T. Naito, H. Hayano, Y. Honda, K. Kubo, M. Kuriki, S. Kuroda, T. Muto, N. Terunuma, J.U. Urakawa
    KEK, Ibaraki
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  • N. Nakamura, H. Sakai
    ISSP/SRL, Chiba
  • M.C. Ross
    SLAC, Menlo Park, California
  The effects by damping wiggler magnets have been studied at KEK-ATF. The damping ring of the KEK-ATF is a 1.3 GeV storage ring capable of producing ultra-low emittance electron beams. It is significant issue to realize fast damping in the damping ring. The tuning method with 4 sets of wiggler was investigated for the ultra-low emittance beam. The performance on the beam quality, which is related to the transverse (x and y) and the longitudinal (z and dp/p), has been measured by the SR monitor, the laser wire, the streak camera and the energy spread monitor at the extraction line. We report on the operation condition and the measurement results.  
MPPT032 Construction and Performance of Superconducting Magnets for Synchrotron Radiation electron, radiation, multipole, synchrotron 2218
  • C.-S. Hwang, C.-H. Chang, C.-K. Chang, H.-P. Chang, C.-T. Chen, H.-H. Chen, J. Chen, J.-R. Chen, Y.-C. Chien, T.-C. Fan, G.-Y. Hsiung, K.-T. Hsu, S-N. Hsu, M.-H. Huang, C.-C. Kuo, F.-Y. Lin
    NSRRC, Hsinchu
  Two superconducting magnets, one wavelength shifter (SWLS) with a field of 5 T and one wiggler (SW6) with a field of 3.2 T, were constructed and routinely operated at NSRRC for generating synchrotron x-rays. In addition, three multipole wigglers (IASW) with fields of 3.1 T will be constructed and installed each in the three achromatic short straight sections. A warm beam duct of 20 mm inner gap and a 1.5 W GM type cryo-cooler were chosen for the SWLS to achieve cryogen-free operation. For the SW6, a cold beam duct of 11 mm inner gap was kept at 100 K temperature and no trim coil compensation is necessary for its operation. Meanwhile, no beam loss was observed when the SW6 was quenched. A cryogenic plant with cooling power of 450 W was constructed to supply the liquid helium for the four superconducting wigglers. The design concept, magnetic field quality, the commissioning results, and the operation performance of these magnets will be presented.  
MPPT034 Field Modelling for the CESR-c Superconducting Wiggler Magnets damping, quadrupole, emittance, linear-collider 2336
  • J.A. Crittenden, A.A. Mikhailichenko, A. Temnykh
    Cornell University, Department of Physics, Ithaca, New York
  • E.N. Smith, K.W. Smolenski
    Cornell University, Ithaca, New York
  Funding: National Science Foundation.

Superconducting wiggler magnets for operation of the CESR electron-storage ring at energies as low as 1.5 \gev have been designed, built and installed in the years 2000 to 2004. Finite-element models of field quality have been developed, various sources of field errors investigated and compared to field measurements. Minimization algorithms providing accurate analytic representations of the wiggler fields have been established. We present quantitative descriptions of field modelling, of measured field quality and of the accuracy achieved in the analytic functions of the field.

MPPT035 Magnetic Field Analysis of Superconducting Undulators with Variable Field Polarization undulator, polarization, photon 2410
  • S.H. Kim
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy under Contract No. W-31-109-ENG-38.

An undulator with double-helix coils on a cylindrical beam tube is the classical method of producing a helical magnetic field. This type of device, however, can produce only circularly polarized radiation and has limited horizontal aperture for beam injection. A planar superconducting undulator SCU) unit of helical field, which generates horizontal and vertical fields perpendicular to the beam direction, is inserted in between the magnetic poles of a vertical-field unit. This paper analyzes the magnetic fields and a scaling law of the SCU. The angle of the coil windings for the inserted unit is analyzed to maximize the horizontal field Bx. The range of the optimum rotation angle, for the range of gap/period ratio 0.1 - 0.6, is calculated to 30 - 40 degrees.

MPPT061 Ideal Wiggler quadrupole, emittance, focusing, dipole 3511
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  Described is the wiggler with reduced nonlinear components for usage in damping ring of Linear Collider. Zigzag field dependence on longitudinal coordinate made by profiling of poles.  
MPPT064 Elements of Magneto-Optics Acting in One Direction octupole, focusing, multipole, quadrupole 3618
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  We describe here the way to use quadrupole, octupole lenses so they are acting in one direction only. The beam is running across the lens in contrast with usual axis running.  
MPPT075 Analysis and Design of Backing Beam for Multipole Wiggler (MPW14) at PLS multipole, synchrotron, synchrotron-radiation, radiation 3940
  • H.-G. Lee, C.W. Chung, H.S. Han, Y.G. Jung, D.E. Kim, W.W. Lee, K.-H. Park, H.S. Suh
    PAL, Pohang, Kyungbuk
  Pohang Accelerator Laboratory (PAL) had developed and installed a Multipole Wiggler (MPW14) to utilize high energy synchrotron radiation at Pohang Light Source (PLS). The MPW14 is a hybrid type device with period of 14 cm, minimum gap of 14 mm, maximum flux density of 2.02 Tesla and total magnetic structure length of 2056 mm. The support locations and structure of an insertion device are optimized to achieve a minimum deflection due to the magnetic loads. A Finite Element Analysis (FEA) is performed to find out the amount of maximum deflection and optimal support positions on the backing beam, the support and drive structures of the MPW14 under expected magnetic load of 14 tons. To reduce the deflection effect further, two springs are designed and installed to compensate the gap dependent magnetic loads. The optimized deflection is estimated to be about 20.6 ? while the deflection before optimization is 238 ?.  
MPPT082 The 8 cm Period Electromagnetic Wiggler Magnet with Coils Made from Sheet Copper power-supply, electron, undulator, klystron 4093
  • G.H. Biallas, S.V. Benson, T. Hiatt, G. Neil, M.D. Snyder
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by the US DOE Contract #DE-AC05-84ER40150, the Office of Naval Research, the Air Force Research Laboratory, the U.S. Army Night Vision Laboratory and the Commonwealth of Virginia.

An electromagnetic wiggler, now lasing at the Jefferson Lab FEL, has 29 eight cm periods with K variable from 0.6 to1.1 and gap of 2.6 cm. The wiggler was made inexpensively in 11 weeks by an industrial machine shop. The conduction cooled coil design uses copper sheet material cut to forms using water jet cutting. The conductor is cut to serpentine shapes and the cooling plates are cut to ladder shape. The sheets are assembled in stacks insulated with polymer film, also cut with water jet. The coil design extends the serpentine conductor design of the Duke OK4 to more and smaller conductors. The wiggler features graded fields in the two poles at each end and trim coils on these poles to eliminate field errors caused by saturation. An added critical feature is mirror plates at the ends with integral trim coils to eliminate three dimensional end field effects and align the entrance and exit orbit with the axis of the wiggler. Details of construction, measurement methods and excellent wiggler performance are presented.

TOAA003 Survey of Superconducting Insertion Devices for Light Sources undulator, multipole, radiation, electron 256
  • N.A. Mezentsev, E. Perevedentsev
    BINP SB RAS, Novosibirsk
  The first Superconducting Insertion devices were designed, fabricated and installed on electron storage rings more than 25 years ago for generation of synchrotron radiation. For these years wide experience of manufacturing and use of such superconducting insertion devices as superconducting wave length shifters, multipolar wigglers and undulators is accumulated. Review of various types of Superconducting Insertion Devices for Light Sources is given in the report. Their basic characteristics as SR sources are discussed.  
TOPB001 Methods of Attosecond X-Ray Pulse Generation electron, laser, undulator, radiation 39
  • A. Zholents
    LBNL, Berkeley, California
  Funding: This work was supported by the Director, Office of Science of the U. S. Department of Energy under Contract No. DE-AC03-76SF00098.

Our attitude towards attosecond x-ray pulses has changed dramatically over the past several years. Not long ago x-ray pulses with a duration of a few hundred attoseconds were just science fiction for most of us, but they are already a tool for some researchers in present days. Breakthrough progress in the generation of solitary soft x-ray pulses of attosecond duration has been made by the laser community. Following this lead, people in the free electron laser community have begun to develop new ideas on how to generate attosecond x-ray pulses in the hard x-ray energy range. In this report I will review some of these ideas.

WPAE007 Commissioning of the LNLS 2 T Hybrid Wiggler storage-ring, vacuum, injection, photon 1072
  • R.H.A. Farias, J.F. Citadini, M.J. Ferreira, J.G.R.S. Franco, A.F.A. Gouveia, L.C. Jahnel, L. Liu, R.T. Neuenschwander, X.R. Resende, P.F. Tavares, G. Tosin
    LNLS, Campinas
  • N.P. Abreu
    UNICAMP, Campinas, São Paulo
  Funding: MCT-CNPq, FAPESP.

We present the results of the commissioning of a 28-pole 2 T Hybrid Wiggler at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. The wiggler will be used mainly for protein crystallography and was optimized for the production of 12 keV photons. The very high field and relatively large gap (22 mm) of this insertion device led to a magnetic design that includes large main and side magnets and heavily saturated poles. We present the results of the commissioning with beam, with special attention to the correction of the large linear tune-shift perturbations produced by the wiggler as well as on the reduction of beam lifetime at full energy. Since the injection at the LNLS storage ring is performed at 500 MeV we also focus on the effects of non-linearities and their impact on injection efficiency.

WPAE015 High Heat-Load Slits for the PLS Multipole Wiggler multipole, storage-ring, synchrotron, synchrotron-radiation 1449
  • K.H. Gil, J.Y. Choi, C.W. Chung, Y.-C. Kim, H.-S. Lee
    PAL, Pohang, Kyungbuk
  The HFMX (High Flux Macromolecular X-ray crystallography) beamline under commissioning at Pohang Accelerator Laboratory uses beam from a multipole wiggler for MAD experiment. Two horizontal and vertical slits relevant to high heat load are installed at its front-end. In order to treat high heat load and to reduce beam scattering, the horizontal slit has two glidcop blocks with 10° of vertical inclination and its tungsten blades defining beam size are bolted on backsides of both blocks. The blocks of the slit are adjusted on fixed slides by two actuating bars, respectively. Water through channels machined along the actuating bars cool down the heat load of both blocks. The vertical slit has the same structure as the horizontal slit except its installation direction and angle of vertical inclination. The installed slits show stable operation performance and no alignment for the blocks is required by virtue of a pair of blocks translating on slides. The cooling performance of two slits is also shown to be acceptable. In this article, the details of the design and manufacture of the two slits are presented and its operation performance is reported.  
WPAE073 3 kA Power Supplies for the Duke OK-5 FEL Wigglers power-supply, feedback, storage-ring, monitoring 3901
  • V. Popov, S.M. Hartman, S. Mikhailov, O. Oakeley, P.W. Wallace, Y.K. Wu
    DU/FEL, Durham, North Carolina
  Funding: U.S. AFOSR MFEL grant F49620-001-0370.

The next generation electromagnetic OK-5/Duke storage ring FEL wigglers require three 3kA/70V power supplies with current stability about 20 ppm and current ripples less than 20ppm in their full operating range. Duke FEL Laboratory acquired three out-of-service thyristor controllable power supplies (Transrex, 5kA/100V) which was built almost 30 years ago. The existing archaic firing circuit, lack of any output voltage filtering and outdated DCCT, would not be able to meet the above requirements.To deliver the desirable high performance with very limited funds, all three T-Rex power supplies have been completely rebuilt in house at DFELL. Modern high stability electronic components and a Danfysik DCCT with a high current stability have been used. New symmetrical firing circuit, efficient passive LC filter and reliable transformer-coupled active filter are used to reduce output current ripples to an appropriate level. At the present time, the first refurbished power supply in operation since August, 2004 with good overall performance. The power supply testing results of this unit will also be presented in this paper.

WOAB010 BUNCH TRACING BY BUNCH BY BUNCH MEASUREMENT SYSTEM IN HLS injection, feedback, simulation, storage-ring 719
  • K. Zheng, W. Li, J.H. Liu, L. Liu, B. Sun, J.H. Wang, Y.L. Yang
    USTC/NSRL, Hefei, Anhui
  Funding: Supported by National Natural Science Project (10175063)

In this paper, we introduce a bunch tracing system which is based on a bunch-by-bunch (BxB) measurement system in Hefei Light Source (HLS), and present the analysis of the experiment results. Using an in-phase gate signal and a double balance mixer to control an external trigger of ADC, we test the reliability of the BxB system. By this system, we can trace all marked bunches in a set time slot or in manual burst mode. We can record all bunches’ data during the injection, ramping, wiggler excitation and normal operation, and provide a powerful facility for machine study.

ROAA002 CESR-c: Performance of a Wiggler-Dominated Storage Ring resonance, luminosity, sextupole, betatron 189
  • A. Temnykh
    Cornell University, Department of Physics, Ithaca, New York
  Funding: Work supported by the U.S. National Science Foundation.

CESR-c operates now as a Wiggler-Dominated Storage Ring extending the lowest operating energy to 1.5GeV/beam. To improve beam stability at low energy, 12 super-ferric wiggler magnets with total length of 15m and 2.1T maximum field were installed in the ring. They cause ~90% of total beam radiation lost and increase radiation damping rate by factor 10 from ~3 to 40 Hz. However, the field of the wiggler magnets not only initiates the radiation, but potentially affects beam dynamics. The latter was an issue of a great concern from the planning the CESR-c project. In this paper we describe general performance of CESR-c and report the results of an experimental study on some aspects of beam dynamics. Comparisons are made between the experimental data and the model prediction. We find that all parameters, which are critically dependent on wigglers, such as beam properties and ring nonlinearity, are in good agreement with those calculated from the model. This validates the ring and wiggler models and justifies our design and production technique of the magnets. The experience we obtained will be extremely useful in future work on linear collider damping rings.

RPAE006 Feasibility Study on Introducing a Superconducting Wiggler to Saga Light Source lattice, dynamic-aperture, multipole, quadrupole 1021
  • S. Koda, Y. Iwasaki, T. Okajima, H. Setoyama, Y. Takabayashi, T. Tomimasu, K. Yoshida
    Saga Synchrotron Light Source, Industry Promotion Division, Saga City
  • H. Ohgaki
    Kyoto IAE, Kyoto
  • M. Torikoshi
    NIRS, Chiba-shi
  Saga light source (SAGA-LS) is the synchrotron radiation facility, which consists of 250 MeV electron linac and 1.4 GeV storage ring. We have a plan to introduce an existing superconducting wiggler, which has been developed for other project by National Institute of Radiological Sciences. The superconducting wiggler consists of a main pole of 7T and two side poles of 4T. Each pole is composed of a racetrack-shaped coil and an iron core. We have examined the effects of the wiggler on the beam optics when it is introduced into SAGA-LS. The distribution of multipole components in the planes perpendicular to the electron orbit, which is deformed by the wiggler fields, have been calculated using magnetic field calculation code RADIA. Then the lattice function and the dynamic aperture of the ring have been calculated by the lattice calculation code SAD. The results show that the tune shift due to the quadrupole component of the wiggler field is as large as to make horizontal beam orbit unstable. The dynamic aperture after the tune correction becomes small by about 20%. These effects due to multipole field are considered to be tolerable for the SAGA-LS.  
RPAE019 Positron Source from Betatron X-Rays Emitted in a Plasma Wiggler electron, positron, plasma, radiation 1625
  • D.K. Johnson, C.E. Clayton, C. Huang, C. Joshi, W. Lu, K.A. Marsh, W.B. Mori, M. Zhou
    UCLA, Los Angeles, California
  • C.D. Barnes, F.-J. Decker, M.J. Hogan, R.H. Iverson, P. Krejcik, C.L. O'Connell, R. Siemann, D.R. Walz
    SLAC, Menlo Park, California
  • S. Deng, T.C. Katsouleas, P. Muggli, E. Oz
    USC, Los Angeles, California
  In the E-167 plasma wakefield accelerator (PWFA) experiments in the Final Focus Test Beam (FFTB) at the Stanford Linear Accelerator Center (SLAC), an ultra-short, 28.5 GeV electron beam field ionizes a neutral column of Lithium vapor. In the underdense regime, all plasma electrons are expelled creating an ion column. The beam electrons undergo multiple betatron oscillations leading to a large flux of broadband synchrotron radiation. With a plasma density of 3x1017 cm-3, the effective focusing gradient is near 9 MT/m with critical photon energies exceeding 50 MeV for on-axis radiation. A positron source is the initial application being explored for these X-rays, as photo-production of positrons eliminates many of the thermal stress and shock wave issues associated with traditional Bremsstrahlung sources. Photo-production of positrons has been well-studied; however, the brightness of plasma X-ray sources provides certain advantages. In this paper, we present results of the simulated radiation spectra for the E-167 experiments, and compute the expected positron yield.  
RPAE022 Improved Long Radius of Curvature Measurement System for FEL Mirrors laser, electron, optics, radiation 1787
  • J. Li, C. Sun, Y.K. Wu
    DU/FEL, Durham, North Carolina
  Funding: This work is supported by the U.S. AFOSR MFEL grant F49620-001-0370.

The 53.73 meter long Duke free electron laser (FEL) cavity consists of two concave mirrors with radius of curvature longer than 27 meters. A proper radius of curvature is designed to achieve an optimal and stable operation of the FEL. This requires accurate measurements of the cavity mirror's radius of curvature before its initial installation. Subsequent radius of curvature measurements are performed to ensure no significant deformation of the mirror occurs after a period of extensive use. A direct measurement based upon the geometric optics principles has been used at DFELL for years. Recently, we have significantly upgraded this measurement apparatus by utilizing a HeNe laser as the light source and a straight wire with a proper size as the object. In this paper we describe the details of the measurement setup and report the benefits of the recent upgrades. In addition, we report the improved data analysis technique and results of recent long radius of curvature measurements.

RPAE036 Damping Wigglers for the PETRA III Light Source damping, emittance, radiation, synchrotron 2446
  • M. Tischer, K. Balewski, W. Decking, M. Seidel, L. Yongjun
    DESY, Hamburg
  • V. Kuzminykh, E. Levichev, P. Vobly, K. Zolotariov
    BINP SB RAS, Novosibirsk
  Within the reconstruction of the PETRA booster ring at DESY towards a third generation light source after 2007, damping wigglers will be installed to reduce the emittance to a value of 1 nmrad. Two damping sections in the long straights of PETRA have been assigned to accommodate 20 wigglers in total. The wigglers will be permanent magnet devices with a fixed gap which are surrounded by an iron enclosure to reduce the leakage flux. Each wiggler will provide a damping integral of 4 T2m per segment and generate a synchrotron radiation power of 42 kW. A short one period long prototype has recently been built to prove the magnetic design and study the correction scheme for tuning the pole strength. The wiggler segments will be followed by an SR absorber shading the downstream quadrupole and successive wiggler segment, the accumulated on-axis power of about 200 kW will be taken up by the final absorber at the damping section end.  
RPAE050 Status of the CAMD Light Source quadrupole, lattice, emittance, diagnostics 3103
  • V.P. Suller
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • E.J. Anzalone, M.G. Fedurin, P. Jines, D.J. Launey, T.A. Miller, Y. Wang
    LSU/CAMD, Baton Rouge, Louisiana
  With the increasing diversity of its research program, the CAMD Light Source has improved its beam brightness and quality. Using a well calibrated model of the lattice, the ring optic has been refined to generate a lower beam emittance of 150 nm.rad and this has been confirmed by measuring the beta values with the modulated quadrupole shunt system. The beam sizes have also been measured with an X-ray pinhole camera and compared to the calculated emittance. The beam orbit is corrected to a standard position referenced to the quadrupole centers to a precision better than 0.5 mm, using a suite of well localized bumps which can also flexibly steer the user photon beams to their requirements. Beam reliability has been improved by bringing into use a VME control system for the energy ramp.  
RPAE074 Recommissioning of Duke Storage Ring with a HOM-Damped RF Cavity and a New Straight Section Lattice for FELs storage-ring, lattice, vacuum, injection 3934
  • Y.K. Wu, M.D. Busch, M. Emamian, J.F. Faircloth, J. Gustavsson, S.M. Hartman, C. Howell, M. Johnson, J. Li, S. Mikhailov, O. Oakeley, J. Patterson, M. Pentico, V. Popov, V. Rathbone, G. Swift, P.W. Wallace, P. Wang
    DU/FEL, Durham, North Carolina
  Funding: This work is supported by the U.S. AFOSR MFEL grant F49620-001-0370 and by U.S. DoE grant DE-FG02-01ER41175.

The Duke FEL lab operates a unique UV/VUV storage ring FEL and an FEL driven, nearly monochromatic, highly polarized, high intensity Compton gamma-ray source. The Duke storage ring light source is undergoing several phases of upgrade in order to significantly improve light source capabilities and performance. The 2004 phase included an upgrade of the RF system with a high-order mode damped RF cavity and a new 34 meter long straight section lattice to host new FEL wigglers in the next phase. This upgrade was completed in August 2004 and storage ring and light source commissioning were completed in November 2004. This paper will provide an overview of this upgrade project and report our commissioning experience of the storage ring and light sources.

RPAE077 A Magnetic Field Model for the Undulator in HLS undulator, storage-ring, insertion, insertion-device 3994
  • H. Zhang, L. Wang
    USTC/NSRL, Hefei, Anhui
  • Y.L. Li
    DESY, Hamburg
  It is important to understand the influence of wigglers and undulators on the beam dynamics in design and optimization of a storage ring, especially when the storage ring runs on a low emittance mode. We present an analytic model of the undulator field in HLS, which can be used in the tracking study to evaluate the effects of it. Coefficients needed by the model are generated by fitting to the results of a numerical field caculation. Fringe fields are included in this model. Then we use three different methods to track particles through the undulator, and compare the results.  
RPAE082 The New Undulator Based fs-Slicing Beamline at the ALS undulator, insertion, insertion-device, laser 4096
  • C. Steier, D. Robin, F. Sannibale, R.W. Schoenlein, W. Wan, W. Wittmer, A. Zholents
    LBNL, Berkeley, California
  Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098.

The existing Femtoslicing beamline at the ALS employs a femtosecond laser beam interacting resonantly with the electron beam in a wiggler (modulator). The induced energy spread over the femtosecond duration is converted to a transverse displacement by exploiting the storage ring dispersion. The displaced femtosecond pulse radiates and produces femtosecond synchrotron radiation. Up to now a regular bending magnet was used as radiator. To improve the flux, a significant upgrade was implemented, replacing the modulator, installing an in-vacuum undulator as new radiator, and installing a higher repeptition rate laser system. The new beamline will provide 100-200 fs long pulses of soft and hard x-rays with moderate flux and with a repetion rate of 10-40 kHz for experiments concerning ultrafast dynamics in solid state physics, chemistry and biology. To achieve the necessary spatial separation of the energy modulated slice from the rest of the bunch, a sizeable local vertical dispersion bump in the radiator is required. All accelerator physics aspects of the upgrade including challenging issues like the impact on the transverse single particle dynamics will be discussed together with initial results of the commissioning.

RPPE077 A Complete System for Operation of a Superconducting Magnet power-supply, superconducting-magnet, controls, monitoring 4003
  • G.W. Codner, M.W. Comfort, D.M. Sabol, T.F. VanDerMark, D.W. Widger, R.J. Yaeger
    CESR-LEPP, Ithaca, New York
  Funding: National Science Foundation.

A complete system for operating, protecting and monitoring a superconducting magnet is described. This system is used in CESR (Cornell Electron Storage Ring) at Cornell University's Laboratory for Elementary Particle Physics (LEPP) for the CESR superconducting wigglers, part of the accelerator upgrade in pursuit of the CESR charm physics program known as CESR-c.

RPPP005 Simulation Study of a Dogbone Damping Ring space-charge, damping, emittance, simulation 928
  • Y. Ohnishi, K. Oide
    KEK, Ibaraki
  Damping ring is one of the major issues in the future linear collider (ILC). We discuss the design of the dogbone damping ring and the performance that includes dynamic apertures, space charge effects, and optics corrections.  
RPPP007 CLIC Damping Ring Optics Design Studies damping, emittance, dynamic-aperture, sextupole 1060
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  In this paper the nonlinearities induced by the short period NbFeB permanent wiggler optimized for the CLIC damping ring and their influence to the beam dynamics are studied.  
RPPP008 The Short Circumference Damping Ring Design for the ILC damping, emittance, scattering, dynamic-aperture 1126
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  • K. Kubo, M. Kuriki, S. Kuroda, T. Naito, J.U. Urakawa
    KEK, Ibaraki
  • M.C. Ross
    SLAC, Menlo Park, California
  The ILC damping ring tentative design is driven by the operational scenario of the main linac, the beam-dynamics demand of producing a stable and high-quality beam, the injection/extraction scheme and the kicker performance. In this paper, a short circumference damping ring design based on TME cells is described. The ring accommodates injection kickers which provide a flat top of 280 nsec and a 60 nsec rise and fall time and very fast strip-line kickers for beam extraction with a 2 nsec rise and fall time for 3-MHz operation. The potential impact of collective effects and the possible degradation of the dynamic aperture by nonlinear-wiggler fields are estimated.  
RPPP012 Collective Effects in the CLIC Damping Rings damping, ion, emittance, radiation 1312
  • F. Zimmermann, M. Korostelev, D. Schulte
    CERN, Geneva
  • T.A. Agoh, K. Yokoya
    KEK, Ibaraki
  The small emittance, short bunch length, and high current in the CLIC damping ring could give rise to collective effects which degrade the quality of the extracted beam. In this paper, we survey a number of possible instabilities and estimate their impact on the ring performance. The effects considered include fast beam-ion instability, coherent synchrotron radiation, and electron cloud, in addition to conventional single and multi-bunch instabilities.  
RPPP020 Linear Damping Systems for the International Linear Collider damping, emittance, positron, radiation 1689
  • G. Dugan
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: Supported by the National Science Foundation

The International Linear Collider requires very low transverse emittance beams in order to realize the specified high luminosity. These beams are conventionally produced using radiation damping in specially designed damping rings. A linear damping system, consisting of alternating wigglers and accelerating structures arranged in a straight line, can be considered to replace, or to augment, conventional damping rings. In this paper, the basic features, feasibility, advantages, and disadvantages, of such systems, as applied to the International Linear Collider, will be discussed.

RPPP025 CESR-c Wiggler Studies in the Context of the International Linear Collider Damping Rings damping, dynamic-aperture, emittance, linear-collider 1880
  • J.T. Urban, G. Dugan
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: Work supported by the NSF.

We present a picture of the International Linear Collider (ILC) damping ring wiggler dynamics using the experience gained from the experimental and simulation-based research studying the wigglers used in the current configuration of the Cornell Electron Storage Ring (CESR). CESR is currently running at 1.8 GeV with 12 superconducting wigglers that have been designed, fabricated, tested, and simulated on-site. We will present results which include frequency map analyses and conventional dynamic aperture studies of CESR-c and the ILC damping rings. We will also provide results from an initial look at physical limitations in the design of the ILC damping ring wigglers.

RPPP036 A Test Facility for the International Linear Collider at SLAC End Station A for Prototypes of Beam Delivery and IR Components insertion, synchrotron, linear-collider, collider 2461
  • M. Woods, R.A. Erickson, J.C. Frisch, C. Hast, R.K. Jobe, L. Keller, T.W. Markiewicz, T.V.M. Maruyama, D.J. McCormick, J. Nelson, N. Phinney, T.O. Raubenheimer, M.C. Ross, A. Seryi, S. Smith, Z. Szalata, P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  • D.A.-K. Angal-Kalinin, C.D. Beard, F.J. Jackson, A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Arnold
    University of Massachusetts, Amherst
  • D. Bailey
  • R.J. Barlow, G.Yu. Kourevlev, A. Mercer
    UMAN, Manchester
  • S.T. Boogert, A. Liapine, S. Malton, D.J. Miller, M.W. Wing
    UCL, London
  • P. Burrows, G.B. Christian, C.C. Clarke, A.F. Hartin, S. Molloy, G.R. White
    Queen Mary University of London, London
  • D. Burton, N. Shales, J. Smith, A. Sopczak, R. Tucker
    Microwave Research Group, Lancaster University, Lancaster
  • D. Cussans
    University of Bristol, Bristol
  • C. Densham, J. Greenhalgh
    CCLRC/DL, Daresbury, Warrington, Cheshire
  • M.H. Hildreth
    Notre Dame University, Notre Dame, Iowa
  • Y.K. Kolomensky
    UCB, Berkeley, California
  • W.F.O. Müller, T. Weiland
    TEMF, Darmstadt
  • N. Sinev, E.T. Torrence
    University of Oregon, Eugene, Oregon
  • M.S. Slater, M.T. Thomson, D.R. Ward
    University of Cambridge, Cambridge
  • Y. Sugimoto
    KEK, Ibaraki
  • S.W. Walston
    LLNL, Livermore, California
  • N.K. Watson
    Birmingham University, Birmingham
  • I. Zagorodnov
    DESY, Hamburg
  • F. Zimmermann
    CERN, Geneva
  Funding: U.S. Department of Energy.

The SLAC Linac can deliver damped bunches with ILC parameters for bunch charge and bunch length to End Station A (ESA). A 10Hz beam at 28.5 GeV energy can be delivered to ESA, parasitic with PEP-II operation. During the engineering design phase for the ILC over the next 5 years, we plan to use this facility to prototype and test key components of the Beam Delivery System (BDS) and Interaction Region (IR). We discuss our plans for this ILC Test Facility and preparations for carrying out experiments related to Collimator Wakefields, Materials Damage Tests and Energy Spectrometers. We also plan an IR Mockup of the region within 5 meters of the ILC Interaction Point to investigate effects from backgrounds and beam rf higher-order modes (HOMs).

RPPP047 Global Optimization of Damping Ring Designs Using a Multi-Objective Evolutionary Algorithm damping, sextupole, lattice, optics 2962
  • L. Emery
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Several damping ring designs for the International Linear Collider have been proposed recently. Some of the specifications, such as circumference and bunch train, are not fixed yet. Designers must make a choice anyway, select a geometry type (dog-bone or circular), an arc cell type (TME or FODO), and optimize linear and nonlinear part of the optics. The design process include straightforward steps (usually the linear optics), and some steps not so straightforward (when nonlinear optics optimization is affected by the linear optics). A first attempt at automating this process for the linear optics is reported. We first recognize that the optics is defined by just a few primary parameters (e.g., phase advance per cell) that determine the rest (e.g., quadrupole strength). In addition to the exact specification of circumference, equilibrium emittance and damping time there are some other quantities which could be optimized that may conflict with each other. A multiobjective genetic optimizer solves this problem by producing a population of best-ranked solutions on a multi-dimensional surface from which one solution can be chosen by the designer. The application of the NSGA-II optimizer to a damping ring of FODO cells is presented.

RPPP051 Characterization of a 6-km Damping Ring for the International Linear Collider lattice, dynamic-aperture, damping, emittance 3147
  • A. Xiao
    Fermilab, Batavia, Illinois
  • L. Emery
    ANL, Argonne, Illinois
  Several damping ring designs for the International Linear Collider have been proposed recently. One particular design has a circumference of 6 km (hoping to take advantage of future kicker technology advances), TME arc cells, and 77 m of 2 T wigglers. Several beam dynamics characterizations and optimizations are reported. We used the accelerator code elegant for matching and tracking, and a 100-CPU linux cluster to provide high throughput.  
RPPT019 Start to End Simulations of the ERL Prototype at Daresbury Laboratory simulation, linac, electron, booster 1643
  • C. Gerth, M.A. Bowler, B.D. Muratori, H.L. Owen, N. Thompson
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • B. Faatz
    DESY, Hamburg
  • B.W.J. McNeil
    Strathclyde University, Glasgow
  Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will serve as a research and development facility for the study of beam dynamics and accelerator technology important to the design and construction of the proposed 4th Generation Light Source (4GLS) project. Two major objectives of the ERLP are the demonstration of energy recovery and of energy recovery from a beam disrupted by an FEL interaction as supplied by an infrared oscillator system. In this paper we present start-to-end simulations of the ERLP including such an FEL interaction. The beam dynamics in the high-brightness injector, which consists of a DC photocathode gun and a superconducting booster, have been modelled using the particle tracking code ASTRA. After the booster the particles have been tracked with the code GPT which includes space charge in the injector line at 8.3 MeV. The 3D code GENESIS 1.3 was used to model the FEL interaction with the electron beam at 35 MeV.  
RPPT024 Doubling the Intensity of an ERL Based Light Source linac, undulator, electron, synchrotron 1862
  • A. Hutton
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by the U.S. DOE under Contract No. DE-AC05-84ER40150.

A light source based on an Energy Recovered Linac (ERL)* consists of a superconducting linac and a transfer line that includes wigglers and undulators to produce the synchrotron light. The transfer line brings the electrons bunches back to the beginning of the linac so that their energy can be recovered when they traverse the linac a second time, ????out of phase. There is another interesting condition when the length of the transfer line is (n±1/4) ?. In this case, the electrons drift through on the zero RF crossing, and make a further pass around the transfer line, effectively doubling the circulating current in the wigglers and undulators. On the third pass through the linac, they will be decelerated and their energy recovered. The longitudinal focusing at the zero crossing is a problem, but it can be canceled if the drifting beam sees a positive energy gradient for the first half of the linac and a negative gradient for the second half (or vice versa). This paper presents a proposal to use a double chicane at the center of the linac to provide this focusing inversion for the drifting beam while leaving the accelerating and decelerating beams on crest.

*G. R. Neil et al., Phys. Rev. Let. 84, 662 2000.

RPPT044 Design, Construction and Commissioning of a NEG Coated Wiggler Vacuum Chamber for the LNLS Storage Ring vacuum, photon, insertion, insertion-device 2807
  • M.J. Ferreira, R.O. Ferraz, H.G. Filho, M.B. Silva
    LNLS, Campinas
  Funding: MCT - CNPQ - FAPESP

We present the design of the vacuum chamber for the LNLS 2 T Hybrid Wiggler. The chamber is a 3 m long, 1.2 mm thick 316 SS tube, which was mechanically pressed into an elliptical shape from an originally round tube. In order to provide the necessary mechanical tolerances, the rather flexible tube is welded to lateral supports that run the complete length of the chamber. Special care has been given to the mechanical and magnetic characterization of the chamber and the inner surface of the chamber was NEG-coated at the ESRF. We present the installation procedure as well the vacuum conditioning charge evolution.

RPPT049 Linear Optics Compensation of the Superconducting Wiggler in HLS quadrupole, storage-ring, optics, focusing 3037
  • L. Wang, G. Feng, W. Li, H. Xu, H. Zhang
    USTC/NSRL, Hefei, Anhui
  Hefei Light Source is a dedicated VUV light source. A superconducting wiggler magnet with 6 Tesla magnetic field was installed on the storage ring to generate hard X-ray radiation. With the compensation of tune shift due to insertion device, beam was successfully stored, but the beam lifetime was decreased much. In order to cure the lifetime, a simple hard-edge model of the wiggler was constructed in lattice simulation code and the compensation scheme was extensively studied again. Calculation showed that it is difficulty to localize the strong focusing effects from wiggler magnet. Then, a new scheme was brought forward and experimental result showed that it can restore the beam lifetime largely. As the application of LOCO method in HLS, a new compensation scheme was calculated by response matrix fitting, and the experimental result also presented in this paper.  
FPAP001 Electron Cloud Build-Up Study for DAFNE positron, electron, vacuum, simulation 779
  • C. Vaccarezza, R. Cimino, A. Drago, M. Zobov
    INFN/LNF, Frascati (Roma)
  • G. Bellodi
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • K. Ohmi
    KEK, Ibaraki
  • M.T.F. Pivi
    SLAC, Menlo Park, California
  • G. Rumolo
    GSI, Darmstadt
  • D. Schulte, F. Zimmermann
    CERN, Geneva
  After the first experimental observations compatible with the presence of the electron cloud effect in the DAFNE positron ring, a more systematic study has been performed regarding the e-cloud build-up and related instability. The measured field map of the magnetic field has been taken into account in the simulation for elements present in the four 10 m long bending sections, representing 40% of the whole positron ring. The simulation results obtained with different codes are presented and compared with the recent experimental observations performed on the beam instabilities and the vacuum behavior of the positron ring.  
FPAT070 Performance of COTS I/O Modules in an Accelerator Control System power-supply, monitoring, impedance, storage-ring 3822
  • S.M. Hartman
    DU/FEL, Durham, North Carolina
  Funding: This work is supported by U.S. AFOSR MFEL grant F49620-001-0370 and by U.S. Department of Energy grant DE-FG02-01ER41175.

We analyze some recent experiences with commercial off the shelf (COTS) I/O hardware modules, comparing manufacturer specifications with our in-house measurements. Discrepancies between quoted specifications and measured performance under accelerator laboratory conditions have been observed. In some cases, design or manufacturing faults have been found which could have impact on the overall performance of the accelerator.