• F. Forest, P. Bocher, B. Diougoant, T. Fevrier, J.L. Lancelot, M.J. Leray
  Sigmaphi, Vannes
• D. Einfeld, M. Pont
  CELLS-ALBA Synchrotron, Cerdanyola del Vallès

The paper presents the magnetic measurements of the 32 long dipoles and 8 short dipoles magnet manufactured by Sigmaphi for the ALBA synchrotron booster based in Spain. An extensive set of measurements based on search coils was made by Sigmaphi to characterize the magnetic field at different currents. This paper describes the magnetic measurements results. The measurements show the maximum field integral deviation between the magnets is within ± 3.10^-3 as expected.

• X. Zhao, G. Feng, W. Li, L. Wang, H. Xu, S.C. Zhang
  USTC/NSRL, Hefei, Anhui

HALS(Hefei Advanced Light Source) is the electron storage ring of ultra-low emittance in process of design. Under this design, the quadrupole magnet with sextupole component must be mounted on which the βη is much bigger, to use enough the effect of compersation chromaticity of sextupole magnet field and to use sparingly the space in the same time . So the combined quadrupole and sextupole magnet must be designed, and have more strong sextupole component and restrain the production of high harmonic field. In this paper, the chocie of design scheme is discussed, and the calculation of combined quadrupole and sextupole mangnet design is given.

• A. Sheng, C.K. Kuan
  NSRRC, Hsinchu

National Synchrotron Radiation Research Center (NSRRC) will build a new 3GeV, 400mA synchrotron accelerator machine. Several different IDs have been proposed and the corresponding front ends are designed. Beam lines of IU20, IU28, SW48 and EPU70 will be the phase I requirement. Due to different power load and density flux, fixed masks, photon absorber, slits, photon absorber and photon beam position monitor will all be customized to meet the beam line user requirements as well as the thermomechanical limits. Overall front end layout, analysis results of the high heat load components are illustrated; experiments of photon beam position monitor, front end pressure distribution due to thermal and photon stimulated desorption outgassing analysis, are also presented in this paper.

• L.O. Dallin, M.S. de Jong
  CLS, Saskatoon, Saskatchewan

Coherent Synchrotron Radiation (CSR) is produced when short bunch lengths are set up in the Canadian Light Source storage ring. To achieve short bunches large negative dispersion is introduced into the straight regions of the lattice such that the momentum compaction can be made to approach zero. In this way CSR has been observed using a few single bunches with currents up to 10 mA per bunch at the nominal operating energy of 2.9 GeV. Attempts produce CSR with low bunch currents in many bunches were unsuccessful at 2.9 GeV. At 1.5 GeV, however, it is possible to achieve CSR with a total of 5 mA stored in over 70 bunches. CSR production is enhanced by operating at a horizontal tune where the chromaticity can be kept near zero. Tracking simulations in longitudinal phase space indicate enhanced stability at tunes lower than the nominal tune. The optimum tune does not depend on the fractional tune but rather there is a tune "window" at the center of which stable longitudinal motion can be maximized.

• S. Khan
  DELTA, Dortmund

DELTA is a 1.5-GeV synchrotron radiation source at the TU Dortmund University (Germany) comprising a superconducting wiggler and a storage-ring FEL. Among other activities, it is planned to generate ultrashort and coherent VUV pulses by seeding the FEL in an optical-clystron configuration with femtosecond laser pulses and by producing higher harmonics. In addition to enabling laser-pump/VUV-probe experiments in material sciences with unprecedented time resolution, the seeding process gives rise to coherent and short radiation pulses in the THz regime. The paper reviews the status of DELTA and describes its new projects.

• C. Mitsuda, K. Fukami, M. Masaki, A. Mochihashi, T. Ohshima, M. Oishi, J. Schimizu, Y. Shimosaki, M. Shoji, K. Soutome, K. Tamura, H. Yonehara
  JASRI/SPring-8, Hyogo-ken
• K. Kobayashi, T. Nakanishi
  SES, Hyogo-pref.

We have developed a kicker magnet system including a compact power supply to generate short pulse synchrotron radiation in the SPring-8 storage ring. One method to generate the short pulse synchrotron radiation is cutting out a synchrotron radiation coming from an tilted electron bunch with a slit. For this purpose, we induced a head-tail oscillation of an electron bunch due to non-zero vertical chromaticity excited by using a pulsed magnetic field. By using this scheme, the required specification to the magnet system is relaxed which leads to reduction of construction cost. Developed kicker magnet system can generate a short pulsed vertical field of about 3.6 mT within the 3 us to an electron bunch at 1 Hz repeat. With the kicker magnet system, we successfully observed a bunch profile which leans about 2 mm between head and tail position by a streak camera. We will report the detail setup of the kicker magnet system including compact power supply and the measurement system of beam profile, then discuss the comparisons between real beam motion and simulation results.

• H.S. Wang, T.C. Tseng, D.-J. Wang, P.S. Yaw
  NSRRC, Hsinchu

A low run-out rotating sample stage is under development to realize a precise resolution within 30 nm on the horizontal plane for the end-station of transmission X-ray microscope (TXM) at NSRRC. The main assembly consists of a commercial rotation stage with run-out less than 1 μm, six capacitive sensors, one master ball, one flat and a horizontal adjusting stage. Error sources (including the profile of the master ball, run-out of the master ball in horizontal and vertical directions, flat plate) are separated from stage and the sensor readings can be down to the nanometer level. A feedback method is proposed to compensate the systematic errors and keeps the samples with little run-out and axial motion in the level of several tens nanometer. The details and tests of the rotation stage are presented in this paper.

• K.-B. Liu, P.C. Chiu, K.T. Hsu, K.H. Hu, Y.-C. Lin, I. Liu, Z.-D. Tsai, C.Y. Wu
  NSRRC, Hsinchu

Corrector magnets of TLS storage ring are served with linear power supplies (corrector magnet power supplies), with some modifications the long-term output current stability and ripple of these linear power supplies were improved from 500 ppm to 50 ppm. But these linear power supplies are very low efficiency、low power factor and about 20Hz low frequency response bandwidth that waste power、noisy and unable to serve fast orbit correction. MCOR30 is a modular switching power converter with smaller volume、high efficiency and above 100Hz frequency response bandwidth, replacing these linear power supplies with MCOR30s that could save power and increasing orbit correction response.

• A. Sheng
  NSRRC, Hsinchu

Bending Magnet, linear undulator, elliptical polarized undulator and wiggler are all regular synchrotron radiation power profile that accelerator engineers would encounter while they are designing the high heat load components. Due to their characteristic type of power distribution, some temperature solutions are available and can be used as a parametric study, as well as optimized tool applicable on the thermomechanical design such as mask absorber, photon absorber, mirror or other heat load subsystems. The analytical solutions and some interrelation studies are also presented in this paper.

• Y.C. Xu, H. Hao, D.H. He, X.Q. Wang
  USTC/NSRL, Hefei, Anhui

Funding: Work supported by National Natural Science Foundation of China (No.10175062 & 10575100).

The light pulse interval adjustment at Hefei Light Source (HLS) can be realized by using pulsed orbit bump technique, which requires for high-frequency repetitive, high magnetic flux density, short pulse kicker magnet system of which the power supply modulator should be specially designed. The technique of solid state modulator based on MOSFET is being developed in National synchrotron Radiation Laboratory (NSRL). In this paper, the design of a prototype of solid-state modulator with 20 MOSFETs in parallel is introduced, including triggering system, drive circuit, transformer configuration. The oscillation induced by parasitic capacitance and inductance is discussed. This prototype with four stage adder can achieve 100ns width power pulse output with 112A, 2.4 kV to the kicker.

• R. Müller, A. Bawagan, A. Hoehl, R. Klein, G. Ulm
  PTB, Berlin
• J. Feikes, M.V. Hartrott, U. Schade, G. Wüstefeld
  HZB, Berlin

The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute is operating the low-energy electron storage ring Metrology Light Source (MLS) in Berlin-Adlershof in close cooperation with the BESSY GmbH. The MLS is designed and prepared for a special machine optics mode (low-alpha operation mode) based on a sextupole and octupole correction scheme, for the production of coherent synchrotron radiation in the FIR and THz region. At the MLS two bending magnet beamlines dedicated to the use of IR and THz synchrotron radiation were built. An IR beamline optimized for the MIR to FIR is now in operation. First measurements at this beamline showed the potential of the MLS as a source of THz radiation*. However, the propagation of sub-terahertz electromagnetic waves from the source point to the experiment through such a typical IR beamline is strongly affected by diffraction. This is why we decided to build a dedicated THz beamline with larger extraction optics. We present first results from the commissioning of the dedicated THz beamline.

*R. Müller et al., Proc. of EPAC08, 2058 (2008)

• X. Huang, J.A. Safranek
  SLAC, Menlo Park, California

A preliminary plan for an infrared or terahertz beamline at SSRL is studied. Using chicane in a straight section allows us to redesign a section of the vacuum chamber and extract infrared/terahertz beam with a large acceptance. Under the low alpha operational mode, the terahertz beam power can be greatly enhanced by the coherent synchrotron radiation (CSR) effect. Calculations of photon beam flux and brightness and the shielding and CSR effects are presented.

• A.Y. Murokh, R.B. Agustsson, P. Frigola
  RadiaBeam, Marina del Rey
• V. Solovyov
  BNL, Upton, Long Island, New York

Funding: DOE

A High Temperature Superconducting Dysprosium Pole Undulator (HTS-DPU) is proposed to achieve an ultra-high peak field in a very short period undulator structure. This design utilizes the unique ferromagnetic properties of dysprosium (Dy) at liquid nitrogen temperature. The fabrication of textured Dy fabricated via economic and highly reproducible process is studied experimentally with the goal to achieve sufficient magnetic anisotropy and desired field saturation level at a practical cost. In addition, utilizing the latest capabilities of the 2G HTS wire is investigated. The practical implementation of HTS-DPU would enable the development of short period insertion devices with superior performance.

• Q.K. Jia
  USTC/NSRL, Hefei, Anhui

For planar undulator, the expression of electron trajectory including harmonic motion has been deduced. It were shown that the electrons oscillate at odd harmonics in the transverse direction, and at even harmonics in the axial direction; the amplitude of nth harmonic oscillation is proportional to the nth power of ratio of undulator deflection parameter to the electron energy.

• J. Beebe-Wang
  BNL, Upton, Long Island, New York

Funding: Work performed under the auspices of the US DOE.

A staged approach towards the development of a high energy RHIC-based electron-ion collider has been proposed in BNL*. In the first stage, a medium-energy electron-ion collider (MEeIC) would be constructed. It would utilize a high energy ion beam, accelerated in one of the two existing rings of the RHIC facility, colliding with a medium energy (4GeV) electron beam, generated by a proposed energy-recovery linac. As a part of the design and investigation of the interaction region, it is necessary to estimate the level of background radiation in the physics experiment detector. The primary radiation distribution can be readily calculated by employing electromagnetic theory. However, the secondary radiation is due to a diffuse scattering of soft X-ray off rough surfaces. In this paper, we first calculate the primary radiation spectrum and apply the kinematic Born approximation deduced from the scattering dynamics. Next, the diffuse scattering cross section is calculated as a function of the material and surface properties of the MEeIC vacuum system. Finally, the minimization of the radiation background level by the choices of the material and surface properties is discussed.

*V. Ptitsyn et al., “MEeIC - staging approach to eRHIC”, these proceedings.

• J.-C. Chang, Y.-C. Chung, K.C. Kuo, J.-M. Lee, Y.-C. Lin, C.Y. Liu, A. Sheng, Z.-D. Tsai, T.-S. Ueng
  NSRRC, Hsinchu

To cope with increasing power cost and to confront huge power consumption of the Taiwan Photon Source (TPS) in the future, we have been conducting several power saving schemes since 2006 in the National Synchrotron Radiation Research Center (NSRRC). Those power saving schemes include optimization of chiller operation, air conditioning system improvement, power factor improvement and the lighting system improvement.

• C.E. Mayes, G.H. Hoffstaetter
  CLASSE, Ithaca, New York

Funding: NSF PHY-0131508

The forces from Coherent Synchrotron Radiation (CSR) on the particle bunch can be computed exactly for a line charge. Modeling a finite bunch by a line charge often produces a very good model of the CSR forces, and the full bunch can then be propagated under these forces. This 1-D model of CSR has often been used with a small angle approximation, an ultra relativistic approximation, and the approximation that radiation originating in one dipole can be neglected in the next dipole. Here we use Jefimenko's forms of Maxwell's equations, without such approximations, to calculate the wake-fields due to the longitudinal CSR force in multiple bends and drifts. Several interesting observations are presented, including multiple bend effects, shielding by conducting parallel plates, and bunch compression.

• S.P. Weathersby, A. Novokhatski, M.K. Sullivan
  SLAC, Menlo Park, California

Funding: Work supported by Department of Energy Contract DE-AC02-76SF00515

Synchrotron radiation is the main source of vacuum chamber heating in the PEP-II storage ring collider. This heating is reduced substantially as lattice energy is lowered. Energy scans over Υ energy states were performed by varying the high energy ring (HER) lattice energy at constant gap voltage and frequency. We observed unexpected temperature rise at particular locations when HER lattice energy was lowered from 8.6 GeV (Υ(3S)) to 8.0 GeV (Υ(2S)) while most other temperatures decreased. Bunch length measurements reveal a shorter bunch at the lower energy. The shortened bunch overheated a beam position monitoring electrode causing a vacuum breach. We explain the unexpected heating as a consequence of increased higher order mode (HOM) power generated by a shortened bunch. In this case, temperature rise helps to identify HOM sources and HOM sensitive vacuum chamber elements. Reduction of gap voltage helps to reduce this unexpected heating.

• K.G. Sonnad, I. Birkel, S. Casalbuoni, E. Huttel, D. Saez de Jauregui, N.J. Smale
  FZK, Karlsruhe
• F. Caspers
  CERN, Geneva
• A.-S. Müller, K.G. Sonnad
  KIT, Karlsruhe
• R. Weigel
  Max-Planck Institute for Metal Research, Stuttgart

Funding: This work has partly been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320.

A superconducting undulator is installed in the ANKA electron storage ring. Electron clouds could potentially contribute to the heat load of this device. A microwave transmission type electron cloud diagnostic has been installed for the undulator section of the ANKA machine. We present the system layout with particular emphasis on the electron machine aspects. Hardware transfer function results and e-cloud data for different machine settings are discussed. Special care has been taken for front end filter design both on the microwave injection and pick-up side.

• A. Bocci, A. Drago, A. Marcelli
  INFN/LNF, Frascati (Roma)
• C. Li, Z. Qi, B. Sun, B.Y. Wang, J.G. Wang, Z.Y. Wu
  USTC/NSRL, Hefei, Anhui
• J.P. Piotrowski
  VIGO System S.A., Ozarow Maz.

Real time diagnostics is a fundamental tool for accelerator physics, particularly important to improve performances of existing synchrotron radiation sources, colliders and a key issue for 4th generation sources and FELs. We report the first measurements in the time and frequency domain performed at Hefei Light Source (HLS), the SR facility of the National Synchrotron Radiation Laboratory (NSRL), of the longitudinal bunch lengths. A fast uncooled HgCdTe photodiode optimized in the mid-IR range has been used to record at the IR port the length of the e^- bunches. IR devices are compact and low cost detectors suitable for a bunch-by-bunch longitudinal diagnostics. The data are useful to investigate longitudinal oscillations and characterize the bunch length. The IR signal has been used to measure the synchrotron oscillation frequency, its harmonics in the multi-bunch mode and the bunch lengths in multi-bunch mode at different beam currents. For the first time, simultaneously, data have been collected at visible wavelengths using a fast photodiode at the diagnostics beamline of HLS. A comparison between IR data and diagnostics realized in the visible will be presented and discussed.

• M. Micheler, G.A. Blair, G.E. Boorman, V. Karataev
  JAI, Egham, Surrey
• R. Corsini, T. Lefèvre
  CERN, Geneva

The diagnostics of a 6D phase space distribution is a crucial and a challenging task, which is required for modern and future installations such as light sources or linear colliders, like CLIC. The longitudinal profile is one of the parameters which needs to be monitored. A setup for the investigation of coherent diffraction radiation from a conducting screen as a tool for non-invasive longitudinal electron beam profile diagnostics has been designed and installed in the CRM line of the CLIC Test Facility (CTF3) at CERN. This setup also allows the measurements of Coherent Synchrotron Radiation from the last bending magnet. In this report we present the status of the experiment and show some preliminary results on coherent synchrotron radiation and coherent diffraction radiation studies. The plans for interferometric measurements of coherent radiation are also presented.

• S. De Santis, J.M. Byrd, R.B. Wilcox
  LBNL, Berkeley, California
• Y. Yin
  Y.Y. Labs, Inc., Fremont, California

Funding: Work supported by the U.S. Department of Energy under Contract No.

By coupling the emitted synchrotron light into an optical fiber, it is possible to transmit the signal at substantial distances from the light port, without the need to use expensive beamlines. This would be especially beneficial in all those cases when the synchrotron is situated in areas not easily access because of their location, or due to high radiation levels. Furthermore, the fiber output can be easily switched, or even shared, between different diagnostic instruments. We present the latest results on the coupling and dispersion measurements performed at the Advanced Light Source in Berkeley.

• Z.-D. Tsai, J.-C. Chang, J.-R. Chen, H.S. Wang
  NSRRC, Hsinchu

The vibration issue is significant issue about the accelerator commission. The utility system has many mechanical parts and induces severe vibrations. For the purpose of tracing vibration source and preventing facility failure, the on-line vibration measurement and trace system has been developed. The system adopt programmable automation controller with FPGA function to conduct a series of data acquisition and algorithm. The system including specific analysis of time and frequency domain has also been integrated into the previous monitor and archive system. The user friendly interface may provide on-line analysis and trace vibration source via network anywhere and anytime.

• B. Dalena, D. Schulte, R. Tomás
  CERN, Geneva
• D. Angal-Kalinin
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

The emission of Synchrotron Radiation in the CLIC BDS is one of the major limitations of the machine performance. An extensive revision of this phenomenon is presented with special emphasis on the IP solenoid.

• D. Newton
  The University of Liverpool, Liverpool
• D. Newton, A. Wolski
  Cockcroft Institute, Warrington, Cheshire

Analytic descriptions of arbitrary magnetic fields can be calculated from the generalised gradients* of the on-axis field. Using magnetic field data, measured or computed on the surface of a cylinder, the generalised gradients can be calculated by solving Laplace's equation to find the three-dimensional multipole expansion of the field within the cylinder. After a suitable transformation, this description can be combined with a symplectic integrator allowing the transfer map to be calculated. A new tracking code is under development in C++, which makes use of a differential algebra class to calculate the transfer map. The code has been heavily optimised to give a fast, accurate calculation of the transfer map for an arbitrary field. The multipole nature of the field description gives additional insights into fringe-field and pseudo-multipole effects and allows a deeper understanding of the beam dynamics.

*Venturini M. and Dragt A., NIM Phys. Res. Sect. A, 427, 387 (1999)

• C. Liu
  PKU/IHIP, Beijing
• P. Evtushenko, A. Freyberger, C. Liu
  JLAB, Newport News, Virginia
• A.H. Lumpkin
  Fermilab, Batavia

Funding: DOE Contract DE-AC05-060R23177 China Scholarship Council

Beam size measurement with near-field optical diffraction radiation (ODR) has been carried out successfully at CEBAF. The ODR station is installed on the Hall-A beam line after eight bending magnets. The ODR images were affected by an unexpected radiation. Some calculations for analyzing the source of the radiation will be presented. Furthermore, two schemes will be proposed to alleviate the contamination.

• C. Kim, H. J. Choi, Y.J. Han, J.Y. Huang, S.N. Kim
  PAL, Pohang, Kyungbuk

A photon-beam-position-monitor (PBPM) is installed in a diagnostic beamline of the Pohang Light Source (PLS). From experience of existing PBPMs, we enriched our understanding of the synchrotron radiation and this understanding is fully considered for physical design of the new PBPM. The newly built PBPM is tested by using a high-power ultraviolet laser and its performance is checked before installation. Measurement results of beam position shows that the current (thermal) effect is reduced significantly and they also shows good agreement with results from a beam position monitor inside the PLS storage ring.

• L.M. Gu, S.F. Lin, P. Lu, C.B. Shen, B. Sun
  USTC/NSRL, Hefei, Anhui

The stability of synchrotron radiation source is of great significance for users, and an accurate and reliable photon beam position monitor (PBPM) is essential for success of synchrotron radiation experiments. Recently, we development a new PBPM called staggered pair photon beam position monitor for photon beam position measurement in Hefei Light Source (HLS). Its main advantage is to reduce the influence of bunch size. Usually, difference over sum (Δ/Σ) method is used to process the photon beam signal. Two new methods are put forward, which are a ratio method and a log-ratio method. For photon beam with Gaussian distribution, differences among methods of Δ/Σ, ratio and log-ratio are introduced. Some calculating results are given for three signal processing methods. Comparing those three methods of position signal processing, log-ratio method is found to have the widest range of linearity, and can obtain identical beam position with different bunch size. Based on that, we also compare staggered pair monitor with double-blade monitor. The staggered pair monitor is found to have higher sensitivity, as well it can ignore the influence of bunch size.

• R. Li
  JLAB, Newport News, Virginia

Funding: This work is supported under U.S. DOE Contract No. DE-AC05-06OR23177.

When an electron bunch with initial linear energy chirp traversing a bunch compression chicane, the bunch interacts with itself via coherent synchrotron radiation (CSR) and space charge force. The effective longitudinal CSR force for a 2D energy-chirped gaussian bunch on a circular orbit has been analyzed earlier*. In this paper, we present our analytical results of the effective longitudinal CSR force for such a bunch going through a general orbit, which includes the entrance and exit of a circular orbit.

*R. Li, Phys. Rev. ST Accel. Beams 11, 024401 (2008).

• D. Newton
  The University of Liverpool, Liverpool
• D. Newton, A. Wolski
  Cockcroft Institute, Warrington, Cheshire

An analytic tracking code has been developed to describe an arbitrary magnetic field in terms of its generalised gradients* and multipole expansion, which is used with a 2nd-order symplectic integrator** to calculate dynamical maps for particle tracking. The modular nature of the code permits a high degree of flexibility and allows customised modules to be integrated within the code framework. Several different applications are presented, and the speed, accuracy and flexibility of the algorithms are demonstrated. A module to simulate synchrotron emission is described and its application to an 'ILC-type' undulator system is demonstrated.

*Venturini M. and Dragt A., NIM Phys. Res. Sect. A, 427, 387 (1999)
**Wu Y., Forest E., Robin D.S., Physical Review E,68, 4, Part 2, 046502 (2003)

• M. Klein, T. Bückle, M. Fitterer, A. Hofmann, A.-S. Müller, K.G. Sonnad
  KIT, Karlsruhe
• I. Birkel, E. Huttel, Y.-L. Mathis
  FZK, Karlsruhe

Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320.

In synchrotron light sources, coherent synchrotron radiation (CSR) is emitted at wavelengths comparable to and longer than the bunch length. One effect of the CSR wake field is the distortion of the bunch distribution, which increases with higher currents. In the theoretical calculations, a threshold exists beyond which the solutions begin to diverge. On the other hand, the CSR wake can also excite a micorbunching instability which prevents stable emission of CSR for high currents and leads to highly intense bursts of radiation. In this paper the development of the calculated bunch shapes and the corresponding moments of the current distribution for varying bunch currents are studied. It can be shown that the numerical threshold beyond which the solutions diverge, does not coincide with the observed bursting-stable-threshold at the ANKA storage ring, which agrees well with theory.