Keyword: synchrotron
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MOODS4 Dancing Bunches as van Kampen Modes impedance, damping, injection, proton 94
 
  • A.V. Burov
    Fermilab, Batavia, USA
  
  Theory of van Kampen modes is applied to bunch longitudinal motion. Case of inductive impedance domination is studied in more details. Threshold for loss of Landau damping is found to be very sensitive to fine structure of the distribution function. Good agreement with the Tevatron's "dancing bunches" is obtained.  
slides icon Slides MOODS4 [0.408 MB]  
 
MOP021 The MICE Muon Beamline and Induced Host Accelerator Beam Loss target, factory, injection, emittance 148
 
  • A.J. Dobbs, A. Alekou, K.R. Long
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  Funding: Science and Technology Facilities Council
The international Muon Ionisation Cooling Experiment (MICE) is designed to provide a proof of principle of ionisation cooling to reduce the muon beam phase space at a future Neutrino Factory and Muon Collider. The MICE Muon Beam is generated by the decay of pions produced by dipping a cylindrical titanium target into the proton beam of the 800 MeV ISIS synchrotron at the Rutherford Appleton Laboratory, U.K. Studies of the particle rate in the MICE Muon Beamline and its relationship to induced beam loss in ISIS are presented, using data taken in Summer 2010. Using time-of-flight to perform particle identification estimates of muon rates are presented and related to induced beam loss. 		 
 
MOP043 Simulations of a Muon Linac for a Neutrino Factory linac, simulation, acceleration, factory 181
 
  • K.B. Beard
    Muons, Inc, Batavia, USA
  • S.A. Bogacz, V.S. Morozov, Y. Roblin
    JLAB, Newport News, Virginia, USA
  
  Funding: Supported in part by DOE grant DE-FG-08ER86351
The Neutrino Factory baseline design involves a complex chain of accelerators including a single-pass linac, two recirculating linacs and an FFAG. The first linac follows the capture and bunching section and accelerates the muons from about 244 to 900 MeV. It must accept a high emittance beam about 30 cm wide with a 10% energy spread. This linac uses counterwound, shielded superconducting solenoids and 201 MHz superconducting cavities. Simulations have been carried out using several codes including Zgoubi, OptiM, GPT, and G4beamline, both to determine the optics and to estimate the radiation loads on the elements due to beam loss and muon decay. 		 
 
MOP066 Effects of e-beam Parameters on Coherent Electron Cooling electron, FEL, hadron, ion 232
 
  • S.D. Webb, V. Litvinenko, G. Wang
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent Electron Cooling (CeC) requires detailed con- trol of the phase between the hadron an the FEL-amplified wave packet. This phase depends on local electron beam parameters such as the energy spread and the peak current. In this paper, we examine the effects of local density variations on the cooling rates for CeC. 		 
 
MOP121 Experimental Studies on Coherent Synchrotron Radiation in the Emittance Exchange Line at the Fermilab A0 Photoinjector emittance, radiation, dipole, synchrotron-radiation 322
 
  • J.C.T. Thangaraj, M.D. Church, H.T. Edwards, A.S. Johnson, A.H. Lumpkin, P. Piot, J. Ruan, J.K. Santucci, Y.-E. Sun, R.M. Thurman-Keup
    Fermilab, Batavia, USA
  
  Future accelerators will employ advanced beam conditioning systems such as emittance exchangers to manipulate high brightness beams. Coherent synchrotron radiation (CSR) in the dipoles could limit the performance of the emittance exchanger. In this paper, we report the experimental and simulation studies on measuring coherent synchrotron radiation and its effects on the beam at the A0 photoinjector in the emittance exchange line. We show how CSR can be used to measure bunch length of the beam. We also report on the diagnostic scheme based on a weak skew quad in the emittance exchange line to study the CSR effects on the beam and other beam dynamics.  
 
MOP146 Investigation of Synchro-Betatron Couplings at S-LSR betatron, laser, coupling, solenoid 367
 
  • K. Jimbo
    Kyoto IAE, Kyoto, Japan
  • T. Hiromasa, M. Nakao, A. Noda, H. Souda, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  
  Tune couplings of beam were observed at S-LSR, Kyoto University. Synchrotron oscillation in the longitudinal direction and betatron oscillation in the horizontal direction was intentionally coupled in a drift tube located at the finite dispersive section. Horizontal and vertical coupling of betatron oscillation was also observed. This fact is a good sign of 3-D couplings to achieve a theoretically predicted crystal beam through the resonant coupling method for transverse laser cooling.  
 
MOP169 Optical Beam Diagnostics at ELSA emittance, quadrupole, diagnostics, sextupole 408
 
  • S. Zander, F. Frommberger, P. Haenisch, W. Hillert, S. Patzelt
    ELSA, Bonn, Germany
  
  Funding: Funded by the DFG within the SFB / TR 16.
The Electron Stretcher Facility ELSA consists of several accelerator stages, the last one being a storage ring providing a beam of polarized electrons of up to 3.5 GeV. At ELSA various diagnostic devices based on synchrotron radiation are installed or planned. A new beamline at the storage ring designed for high resolution diagnostics in the transversal plane will be presented. The measurement setup is sensitive at the UV range of the synchrotron light spectrum. Upgrade measures aiming to extend the diagnostic possibilities to the longitudinal direction will be detailed. In the external beamlines beam currents below 1 nA are delivered to photo production experiments. Beam profiles are detected using dedicated synchrotron light monitors optimized for low intensities. The characteristics of the monitors will be described. In addition, beam parameters derived from the measured profiles at different resonance extraction setups will be shown. 		 
 
MOP170 Combining Multiturn and Closed-Orbit Methods for Model-Independent and Fast Determination of Optical Functions in Storage Rings closed-orbit, betatron, storage-ring, dipole 411
 
  • B. Riemann, P. Grete, H. Huck, A. Nowaczyk, T. Weis
    DELTA, Dortmund, Germany
  
  Multiturn / turn-by-turn data acquisition is a new source for Twiss parameter determination in storage rings, while closed-orbit measurements are a long-known tool for diagnostics with conventional low-frequency beam position monitor (BPM) systems, being available at almost every storage ring. The presented method aims to join the advantages of multiturn and closed-orbit measurement methods. For uncoupled optics, there are only two correctors per oscillation plane and two multiturn BPMs needed in one drift space in the storage ring for model-independent measurement of beta and betatron phase functions at all BPMs in the ring, including conventional ones. This is a cost-effective alternative to the exclusive usage of multiturn BPMs in a storage ring, resulting in the same amount of information. This method can also be extended to include betatron coupling. In addition, we describe a possible experimental setup needed for multiturn data acquisition using a bunch-by-bunch feedback system. By applying an uncritical coherent excitation to coupled bunch modes, the accuracy of the multiturn data acquisition may be significantly improved, enabling the use of smaller drift spaces.  
 
MOP179 Numerical Study on Zone Plate Imaging electron, radiation, optics 423
 
  • I.S. Ko
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • J.Y. Huang, Y.W. Parc
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Funding: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education, Science and Technology (MEST) (grant No. R0A-2008-000-20013-0).
The X-ray is focused by two zone plates in 1B2 beamline to image electron beam in PLS. From numerical study, we can determine the optical limit of resolution with the same specifications of Fresnel zone plates in 1B2 beamline. The width of Airy pattern and the outmost width of zone plates are turned out to be not good parameters to determine the resolution of the imaging system with a zone plate. The resolution of the entire imaging system 1B2 beamline will be revealed as 682 nm. 		 
 
MOP191 RHIC Spin Flipper Status and Simulation Studies dipole, resonance, betatron, proton 447
 
  • M. Bai, W.C. Dawson, Y. Makdisi, F. Méot, P. Oddo, C. Pai, P.H. Pile, T. Roser
    BNL, Upton, Long Island, New York, USA
  
  Funding: This work was supported by Department of Energy of U.S.A and RIKEN, Japan
The commissioning of the RHIC spin flipper in the RHIC Blue ring during the RHIC polarized proton run in 2009 showed the detrimental effects of global vertical coherent betatron oscillation induced by the 2-AC dipole plus 4-DC dipole configuration *. Additional three AC dipoles were added to the RHIC spin flipper in the RHIC Blue ring during the summer of 2010 to eliminate the vertical coherent betatron oscillations outside the spin flipper [2]. This new design is scheduled to be commissioned during the RHIC polarized proton run in 2011. This paper presents the status of the system as well as latest simulation results.
* M. Bai , T. Roser, C. Dawson, Y. Makdisi, W. Meng, F. Meot, P. Oddo, C. Pai, P. Pile, RHIC Spin Flipper New Design and Commissioning Plan, IPAC10 proceedings, IPAC 2010, Kyoto, Japan, 2010 		 
 
MOP192 NSLS-II BPM System Protection from Rogue Mode Coupling shielding, vacuum, multipole, radiation 450
 
  • A. Blednykh, B. Bacha, A. Borrelli, M.J. Ferreira, C. Hetzel, H.-C. Hseuh, B.N. Kosciuk, S. Krinsky, O. Singh, K. Vetter
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by DOE contract DE-AC02-98CH10886
Rogue mode RF shielding has been successfully designed and implemented into the production multipole vacuum chambers. In order to avoid systematic errors in the NSLS-II BPM system we introduced frequency shift of HOM's by using RF metal shielding located in the antechamber slot of each multipole vacuum chamber. To satisfy the pumping requirement the face of the shielding has been perforated with roughly 50 percent transparency. It stays clear of synchrotron radiation in each chamber. 		 
 
MOP193 Design of Visible Diagnostic Beamline for NSLS2 Storage Ring radiation, diagnostics, electron, storage-ring 453
 
  • W.X. Cheng, H.C. Fernandes, H.-C. Hseuh, B.N. Kosciuk, S. Krinsky, O. Singh
    BNL, Upton, Long Island, New York, USA
  
  A visible synchrotron light monitor (SLM) beam line has been designed at the NSLS2 storage ring, using the bending magnet radiation. A retractable thin absorber will be placed in front of the first mirror to block the central x-rays. The first mirror will reflect the visible light through a vacuum window. The light is guided by three 6" diameter mirrors into the experiment hutch. In this paper, we will describe design work on various optical components in the beamline.  
 
MOP224 A Data Acquisition System for Longitudinal Beam Properties in a Rapid Cycling Synchrotron booster, emittance, acceleration, instrumentation 522
 
  • J. Steimel, C.-Y. Tan
    Fermilab, Batavia, USA
  
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
A longitudinal beam properties, data acquisition system has been commissioned to operate in the Fermilab booster ring. This system captures real time information including beam synchronous phase, bunch length, and coupled bunch instability amplitudes as the beam is accelerated from 400MeV to 8GeV in 33ms. The system uses an off-the-shelf Tektronix oscilloscope running Labview software and a synchronous pulse generator. This paper describes the hardware configuration and the software configuration used to optimize the data processing rate. 		 
 
MOP252 Server Development for NSLS-II Physics Applications and Performance Analysis EPICS, controls, emittance, synchrotron-radiation 585
 
  • G. Shen, M.R. Kraimer
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work performed under auspices of the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 with Brookhaven Science Associates, LLC.
The beam commissioning software framework of NSLS-II project adopts a client/server based architecture to replace the more traditional monolithic high level application approach. The server development is ongoing, and adopts a sourceforge open project so-called epics-pvdata, which consists of pvData, pvAccess, pvEngine, and pvService. Some services have being demonstrated as one service under pvService module such as itemFinder service, gather service, and lattice manager, and each service runs as one standalone server using pvData to store in-memory transient data, pvService to transfer data over network, and pvEngine as service engine. This paper describes a detailed development, latest progress, and performance analysis. 		 
 
MOP263 Fast Orbit Feedback System for the LNLS Storage Ring feedback, controls, storage-ring, injection 597
 
  • L. Sanfelici, F.H. Cardoso, D.D. Felix Ferreira, S.R. Marques, D.O. Tavares
    LNLS, Campinas, Brazil
  
  The Brazilian Synchrotron Light Laboratory (LNLS) is based on a 1.37 GeV storage ring, previously operated by means of a Slow Orbit Feedback System at a maximum rate of 1 correction every 3 seconds. Since photon flux stability is a key issue for light source users, a faster control system was envisaged to provide better beam stability. This work presents an overview of the hardware architecture and the preliminary results achieved with the implementation of a Fast Orbit Feedback System using commercial hardware. BPM signals are acquired in a distributed topology and sent through a deterministic EtherCAT network to a PXI controller, responsible for applying the SVD-based correction matrix multiplication and communicating with the accelerator control system; the calculated current setpoints are sent to the correctors’ power supplies through a second EtherCAT network. FPGA-based acquisition and actuation chassis perform pre-filtering and control on the digitized input and output signals, respectively.  
 
MOP284 A High Performance DAC / DDS Daughter Module for the RHIC LLRF Platform LLRF, controls, luminosity, injection 648
 
  • T. Hayes, M. Harvey, G. Narayan, F. Severino, K.S. Smith, S. Yuan
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The RHIC LLRF upgrade is a flexible, modular system. Output signals are generated by a custom designed XMC card with 4 high speed digital to analog converters interfaced to a high performance field programmable gate array (FPGA). This paper discusses the hardware details of the XMC DAC board as well as the implementation of a low noise rf synthesizer with digital IQ modulation. This synthesizer also provides injection phase cogging and frequency hop rebucketing capabilities. 		 
 
MOP297 A Bunch to Bucket Phase Detector for the RHIC LLRF Upgrade Platform LLRF, feedback, controls, injection 675
 
  • K.S. Smith, M. Harvey, T. Hayes, G. Narayan, S. Polizzo, F. Severino
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
As part of the overall development effort for the RHIC LLRF Upgrade Platform, a 4 channel ADC daughter module was developed to provide high speed, wide dynamic range digitizing and processing of signals from DC to several hundred megahertz. The first operational use of this card was to implement the bunch to bucket phase detector for the RHIC LLRF beam control feedback loops. This paper will describe the design and performance features of this daughter module as a bunch to bucket phase detector, and also provide an overview of its place within the overall LLRF platform architecture as a high performance digitizer and signal processing module suitable to a variety of applications. 		 
 
TUODN1 CSR Fields From Using a Direct Numerical Solution of Maxwell's Equations radiation, vacuum, synchrotron-radiation, dipole 784
 
  • A. Novokhatski
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515.
We discuss the properties of the coherent electromagnetic fields of a very short, ultra-relativistic bunch in a rectangular vacuum chamber inside a bending magnet. The analysis is based on the results of a direct numerical solution of Maxwell’s equations together with Newton’s equations. We use a new dispersion-free time-domain algorithm which employs a more efficient use of finite element mesh techniques and hence produces self-consistent and stable solutions for very short bunches. We investigate the fine structure of the CSR fields including coherent edge radiation. This approach should be useful in the study of existing and future concepts of particle accelerators and ultrafast coherent light sources. 		 
slides icon Slides TUODN1 [8.690 MB]  
 
TUP040 Asset Management Application for a LLRF Control System LLRF, controls, laser, electron 880
 
  • B. Sakowicz, M. Kamiński, D.R. Makowski, P. Mazur, A. Napieralski, A. Piotrowski
    TUL-DMCS, Łódź, Poland
  
  Funding: The research leading to these results has received funding from the Polish National Science Council Grant 642/N-TESLAXFEL/09/2010/0.
In this article an asset management application for a low level radio frequency (LLRF) control system is described. The system was developed to facilitate management of some aspects of controlling a linear accelerator and, among others, provides means to manage and program multiple firmware versions for a large, distributed and frequently changing set of FPGA devices that are present in a control system. The system introduces a multihierarchical tree-based representation of almost all assets involved in accelerator management.*
* Kamiński M., Makowski D., Mazur P., Murlewski J., Sakowicz B.: "Firmware application for LLRF control system based on the Enterprise Service Bus", CADSM 2009, Ukraine, ISBN 978-966-2191-05-9 		 
 
TUP062 Design of Coupler for the NSLS-II Storage Ring Superconducting RF Cavity cavity, coupling, simulation, vacuum 931
 
  • M. Yeddulla, J. Rose
    BNL, Upton, Long Island, New York, USA
  
  NSLS-II requires four superconducting cavities working at 499.68 MHz. These cavities should support a 500 mA beam current. To operate the cavities in over-damped coupling condition, an External Quality Factor (Qext) of ~ 65000 is required. We have modified the existing coupler for the CESR-B cavity which has a Qext of ~ 200,000 to meet the requirements of NSLS-II. CESR-B cavity has an aperture coupler with a coupler "tongue" connecting the cavity to the waveguide. We have optimized the length, width and thickness of the "tongue" as well as the width of the aperture to increase the coupling using the three dimensional electromagnetic field solver, HFSS. Several possible designs will be presented.  
 
TUP145 Introduction to HLSII Storage Ring Conventional Magnets quadrupole, dipole, sextupole, storage-ring 1100
 
  • H. Zhang, G. Feng, W.W. Li, W. Li, J.J. Liang, L. Wang, S.C. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  HLS (Hefei Light Source) is a dedicated synchrotron radiation research facility, whose emittance is relatively large. In order to improve the performance of HLS, especially getting higher brilliance synchrotron radiation and increasing the number of straight section for insertion devices, an upgrade project named HLSII will be proceeded soon. The storage ring lattice comprises 8 dipoles, 32 quadrupoles and 32 combined function sextupoles. Design and analysis of the magnets are showed in the paper. the multipurpose combined function magnet is the first one designed and used in China. Mechanical design and fabrication procedures for the magnets are presented also.  
 
TUP149 Magnetic Field Mapping and Integral Transfer Function Matching of the Prototype Dipoles for the NSLS-II at BNL dipole, electron, storage-ring, quadrupole 1112
 
  • P. He, M. Anerella, G. Ganetis, R.C. Gupta, A.K. Jain, P.N. Joshi, J. Skaritka, C.J. Spataro, P. Wanderer
    BNL, Upton, Long Island, New York, USA
  
  The National Synchrotron Light Source-II (NSLS-II) storage ring at Brookhaven National Laboratory (BNL) will be equipped with 54 dipole magnets having a gap of 35 mm, and 6 dipoles having a gap of 90 mm. The large aperture magnets are necessary to allow the extraction of long-wavelength light from the dipole magnet to serve a growing number of users of low energy radiation. The dipoles must not only have good field homogeneity (0.015% over a 40 mm x 20 mm region), but the integral transfer functions and integral end harmonics of the two types of magnets must also be matched. The 35 mm aperture dipole has a novel design where the yoke ends are extended up to the outside dimension of the coil using magnetic steel nose pieces. A Hall probe mapping system has been built with three Group 3 Hall probes mounted on a 2-D translation stage. The probes are arranged with one probe in the midplane of the magnet and the others vertically offset by ±10 mm. The field is mapped along a nominal 25 m radius beam trajectory. The results of measurements in the as-received magnets, and with modifications made to the nose pieces will be presented.  
 
TUP152 Dipole Corrector Magnets for the LBNE Beam Line dipole, simulation, quadrupole, target 1115
 
  • M. Yu, D.J. Harding, G. Velev
    Fermilab, Batavia, USA
  
  The conceptual design of a new dipole corrector magnet has been thoroughly studied. The planned Long-Baseline Neutrino Experiment (LBNE) beam line will require correctors capable of greater range and linearity than existing correctors, so a new design is proposed based on the horizontal trim dipole correctors built for the Main Injector synchrotron at Fermilab. The gap, pole shape, length, and number of conductor turns remain the same. To allow operation over a wider range of excitations without overheating, the conductor size is increased, and to maintain better linearity, the back leg thickness is increased. The magnetic simulation was done using ANSYS to optimize the shape and the size of the yoke. The thermal performance was also modeled and analyzed.  
 
TUP190 Upgrade of the APS Booster Synchrotron Magnet Ramp booster, dipole, controls, injection 1181
 
  • C. Yao, B. Deriy, G. Feng, H. Shang, J. Wang
    ANL, Argonne, USA
  
  Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06-CH11357
The APS booster is a 7-GeV electron synchrotron with 0.5-second cycle time. Both voltage and current ramp modes were in the original design but only the voltage ramp has been commissioned. Two software-based ramp control programs are used to regulate the current waveform to a linear ramp. The system has been operated for user beam operations for many years. Some instability exists in the ramp correction that requires manual intervention from time to time by the operators. Sensitivity of magnet currents to external changes, such as AC line voltage, harmonic interference from the high-power rf system, etc., has been observed. In order to meet the increased single-bunch-charge requirement of the APS upgrade we need more flexible current ramps such as flat porches for injection and extraction and smooth transitions. Recent efforts to develop an energy-saving operation mode also call for ramp improvement. This paper presents test results of a workstation-based current regulation program and an FPGA-based implementation as a future upgrade. 		 
 
TUP202 Non-Scaling FFAG Proton Driver for Project X proton, linac, injection, focusing 1199
 
  • C. Johnstone, D.V. Neuffer
    Fermilab, Batavia, USA
  • M. Berz, K. Makino
    MSU, East Lansing, Michigan, USA
  • L.J. Jenner, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • P. Snopok
    IIT, Chicago, Illinois, USA
  
  The next generation of high-energy physics experiments requires high intensity protons at multi-GeV energies. Fermilab’s HEP program, for example, requires an 8-GeV proton source to feed the Main Injector to create a 2 MW neutrino beams in the near term and would require a 4 MW pulsed proton beam for a potential Neutrino Factory or Muon Collider in the future. High intensity GeV proton drivers are difficult at best with conventional re-circulating accelerators, encountering duty cycle and space-charge limits in the synchrotron and machine size and stability concerns in the weaker-focusing cyclotrons. Only an SRF linac, which has the highest associated cost and footprint, has been considered. Recent innovations in FFAG design, however, have promoted another re-circulating candidate, the Fixed-field Alternating Gradient accelerator (FFAG), as an attractive, but as yet unexplored, alternative. Its strong focusing optics coupled to large transverse and longitudinal acceptances would serve to alleviate space charge effects and achieve higher bunch charges than possible in a synchrotron and presents an upgradeable option from the 2 MW to the 4 MW program.  
 
TUP216 Design of a Helium Phase Separator with Condenser cryogenics, radiation, vacuum, synchrotron-radiation 1214
 
  • F. Z. Hsiao, T.Y. Huang, C.P. Liu, H.H. Tsai
    NSRRC, Hsinchu, Taiwan
  
  This paper presents the design of a helium phase separator with volume of 100 litres. A condenser using a cryocooler for cooling is built into the phase separator to save liquid helium consumption during the test period. The heat loss to the 4.2 K inner vessel is confined within 1W due to the limited 1.5W cooling capacity from the cryocooler. Analysis of mechanical strength and heat load is illustrated.  
 
TUP217 The Application of 400KW DC Bank for Cryogenic System at NSRRC cryogenics, booster, controls, superconducting-magnet 1217
 
  • H.C. Li, S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, T.F. Lin, H.H. Tsai
    NSRRC, Hsinchu, Taiwan
  
  There will be a power sag (>50% drop) several times and annual maintenance of power company every year that course cryogenic system shutdown and take hours to recover. We install the AC UPS to maintain a steady power supply to the control circuit and low power devices to avoid such incidences. However, the AC UPS is not suitable for the 315-kW compressor with inverter due to the harmonic distortion effect and low power factor. We built two sets of 400-kW DC UPS (also called DC Bank system) to keep two 315-kW compressor in full load operation at least 3 minutes when power sag or power cut-off in 2010. The DC Bank was parallel connect to the inverter, thus, will not affect the inverter operation when DC Bank need to maintenance or failure. This paper presents the configuration of DC Bank and the test of the system. Results show that when the inverter is operated at 242KW with main power cut off, the helium compressor is keeping stable operation for 257 seconds by DC Bank support.  
 
TUP239 Development of a Super-Mini Undulator undulator, power-supply, electron, photon 1274
 
  • A. Deyhim, J.D. Kulesza
    Advanced Design Consulting, Inc, Lansing, New York, USA
  • C. Diao, H.O. Moser
    SSLS, Singapore, Singapore
  
  This paper describes development and initial results for a small prototype of a superconducting undulator with a period less than 1 cm, referred to here as a “super-mini” undulator. The development of superconducting mini-undulators started in the early 1990s with work at BNL and KIT (Germany). In 1998, KIT demonstrated the first photon production with a super-mini of 3.8 mm period length *. This super-mini consisted of two coils wound bi-filarly in analogy to a solenoid. If such coils are arranged alongside each other, separated only by a small gap of the order of a couple of millimeters, a spatially alternating magnetic field is produced that makes a passing electron beam undulate and emit undulator radiation. Owing to the short period length, the photon energy is much higher than with conventional undulators at the same electron energy. Likewise, for a given photon energy, the electron energy can be much smaller entailing considerable cost savings of accelerator, building, and operations.
* T. Hezel, B. Krevet, H.O. Moser, J.A. Rossmanith, R. Rossmanith, and Th. Schneider, A superconductive undulator with a period length of 3.8 mm, J. Synchrotron Rad. 5(1998) pp. 448-450. 		 
 
WEOCN5 Beam Halo Measurements at UMER and the JLAB FEL Using an Adaptive Masking Method FEL, quadrupole, electron, radiation 1449
 
  • H.D. Zhang, S. Bernal, R.B. Fiorito, R.A. Kishek, P.G. O'Shea, A.G. Shkvarunets
    UMD, College Park, Maryland, USA
  • S.V. Benson, D. Douglas, F.G. Wilson, S. Zhang
    JLAB, Newport News, Virginia, USA
  
  Funding: US Dept. of Energy Offices of High Energy Physics and Fusion Energy Sciences and by the Dept. of Defense Office of Naval Research and Joint Technology Office.
Beam halo is a challenging issue for intense beams since it can cause beam loss, emittance growth, nuclear activation and secondary electron emission. Because of the potentially low number of particles in the halo compared with beam core, traditional imaging methods may not have sufficient contrast to detect faint halos. We have developed a high dynamic range, adaptive masking method to measure halo using a digital micro-mirror array device and demonstrated its effectiveness experimentally on the University of Maryland Electron Ring (UMER). We also report on similar experiments currently in progress at the Jefferson Lab Free Electron Laser (FEL) using this method. 		 
slides icon Slides WEOCN5 [1.287 MB]  
 
WEODN3 Performance Optimization for the LNLS Fast Orbit Feedback System feedback, controls, power-supply, storage-ring 1485
 
  • D.O. Tavares, S.R. Marques
    LNLS, Campinas, Brazil
  
  The Brazilian Synchrotron Light Laboratory (LNLS) has recently commissioned a Fast Orbit Feedback System for its 1.37 GeV third-generation UVX Storage Ring. This paper presents the optimization work which was carried out using the new hardware capabilities. Well known strategies such as singular values conditioning for correction matrix, dynamic control by means of PID or IMC controllers and EVC (Eigenvector constrained) method for minimizing position error in source points were explored. The problem of actuator limitations (saturation and slew rate) was also investigated, providing a new front line for improving orbit stability through feedback.  
slides icon Slides WEODN3 [1.114 MB]  
 
WEP005 Modeling the Low-Alpha-Mode at ANKA with the Accelerator Toolbox quadrupole, optics, sextupole, dipole 1510
 
  • M. Klein, N. Hiller, A. Hofmann, E. Huttel, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller
    KIT, Karlsruhe, Germany
  • K.G. Sonnad
    CLASSE, Ithaca, New York, USA
  
  The ANKA storage ring is operated frequently with low momentum compaction lattices to produce short bunches for the generation of coherent synchrotron radiation in the THz range. The bunch length can be varied in steps from one centimeter down to the sub millimeter level. These low alpha optics are modeled by using the Matlab based tools, Accelerator Toolbox (AT) and LOCO. The results are compared with measurements such as orbit response matrices, dispersion and chromaticity. This paper provides results of a study on the feasibilities as well as limitations of the measurements and calculations.  
 
WEP109 Simulations of Electron Cloud Induced Instabilities and Emittance Growth for CesrTA emittance, simulation, electron, positron 1683
 
  • K.G. Sonnad, K.R. Butler
    Cornell University, Ithaca, New York, USA
  • G. Dugan, M.A. Palmer
    CLASSE, Ithaca, New York, USA
  • M.T.F. Pivi
    SLAC, Menlo Park, California, USA
  
  Funding: US Department of Energy DE-FC02-08ER41538, National Science Foundation PHY-0734867
We present results of a series of studies obtained using the simulation code CMAD to study how electron clouds affect the dynamics of positron beams in CesrTA. The study complements ongoing experiments dedicated for studying the same phenomena. The simulation involves tracking positrons through the CesrTA lattice and simultaneously computing the force exerted due to space charge of the electrons on each of the tracked positrons. The electrons themselves are allowed to evolve under the influence of the positrons. Several results bear a close resemblance to what has been observed experimentally. 		 
 
WEP116 Bucket Shaking Stops Bunch Dancing in Tevatron simulation, impedance, dipole, damping 1704
 
  • A.V. Burov, C.-Y. Tan
    Fermilab, Batavia, USA
  
  Bunches in Tevatron are known to be longitudinally unstable: their collective oscillations stay without any sign of decay. Typically, a feedback damper is used to stop these oscillations. Recently, it was theoretically predicted that the oscillations can be stabilized by means of small bucket shaking*. Detailed measurements in Tevatron have shown that this method does work. In this paper, an essential theory and specific observations of the related process are presented.
* A. Burov, “Dancing Bunches as van Kampen Modes”, this conference. 		 
 
WEP119 Coherent Radiation in Whispering Gallery Modes vacuum, resonance, radiation, impedance 1710
 
  • R.L. Warnock
    SLAC, Menlo Park, California, USA
  • J.C. Bergstrom
    CLS, Saskatoon, Saskatchewan, Canada
  
  Funding: Work at SLAC: U.S. Department of Energy Contract No. DE-AC03-76SF00515 Work at CLS: NSERC, NRC, Province of Saskatchewan, U. of Saskatchewan.
Theory predicts that CSR in storage rings should appear in whispering gallery modes *, which are resonances of the entire vacuum chamber and are characterized by their high frequencies and concentration of the field near the outer wall of the chamber. The theory assumes that the chamber is a smooth circular torus. We observe that a power spectrum from the NSLS-VUV ring **, which has a vacuum chamber in bends like that of the model, shows a series of sharp peaks with frequencies close to those of the theory. Sharp peaks are also seen in highly resolved spectra at the Canadian Light Source***, and those are invariant in position under large changes in the machine setup (energy, fill pattern, bunch length, CSR bursting or steady, optical beam line, etc.). Invariance of the spectrum suggests that it is due to resonances like whispering gallery modes, but they must be strongly perturbed from the circular case because of large outer wall excursions at the two IR ports.
* R. L. Warnock and P. Morton, Part. Accel. 25, 113 (1990).
** G. L. Carr et al., Proc. PAC 2001, Chicago.
*** T. May et al., IEEE 33rd Intl. Conf. IR Millimeter and THz Waves, 2008. 		 
 
WEP139 Comparison of 1D and 2D CSR Models with Application to the Fermi@Elettra Bunch Compressors emittance, dipole, electron, synchrotron-radiation 1743
 
  • G. Bassi
    BNL, Upton, New York, USA
  • J.A. Ellison, K.A. Heinemann
    UNM, Albuquerque, New Mexico, USA
  
  Funding: Work partially supported by DOE grant DE-FG02-99ER41104
We compare our 2D mean field (Vlasov-Maxwell) treatment of coherent synchrotron radiation (CSR) effects with 1D approximations of the CSR force which are commonly implemented in CSR codes. In our model we track particles in 4D phase space and calculate 2D forces*. The major cost in our calculation is the computation of the 2D force. To speed up the computation and improve 1D models we also investigate approximations to our exact 2D force. Preliminary results are encouraging**. As an application, we present numerical results for the LCLS bunch compressors, where recently detailed measurements of the CSR-induced energy loss and transverse emittance growth have been performed and compared with numerical calculations***.
* Phys. Rev. ST Accel. Beams 12, 080704 (2009)
** http://www.lnf.infn.it/conference/uBI10/
*** Phys. Rev. ST Accel. Beams 12, 030704 (2009)
 
 
WEP140 Benchmarking Stepwise Ray-Tracing in Rings in Presence of Radiation Damping damping, emittance, radiation, lattice 1746
 
  • F. Méot
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A number of recent machine designs, including ‘‘nano-beams'', sub-millimeter ‘‘low-beta'' IRs, etc., require high accuracy on beam orbit and beam size, reliable evaluation of machine parameters, dynamic apertures, etc. This can only be achieved using high precision simulation tools. Stepwise ray-tracing methods are in this category of tools, stochastic synchrotron radiation and its effects on an electron beam in a storage ring are simulated here in that manner. Benchmarking of the method against analytical model expectations, using a Chasman-Green cell, is presented. 		 
 
WEP151 HPC Cloud Applied to Lattice Optimization lattice, storage-ring, synchrotron-radiation, quadrupole 1767
 
  • C. Sun, S. James, K. Muriki, H. Nishimura, Y. Qin, K. Song
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
As Cloud services gain in popularity for enterprise use, vendors are now turning their focus towards providing cloud services suitable for scientific computing. Recently, Amazon Elastic Compute Cloud (EC2) introduced the new Cluster Compute Instances (CCI), a new instance type specifically designed for High Performance Computing (HPC) applications. At Berkeley Lab, the physicists at the Advanced Light Source (ALS) have been running Lattice Optimization on a local cluster, but the queue wait time and the flexibility to request compute resources when needed are not ideal for rapid development work. To explore alternatives, for the first time we investigate running the Lattice Optimization application on Amazon’s new CCI to demonstrate the feasibility and trade-offs of using public cloud services for science.

 
 
WEP173 Numerical Calculations for the SR Characteristics Described in Terms of Quantum Theory: The Case of Weakly Excited Particles. radiation, polarization, electron, synchrotron-radiation 1810
 
  • A.N. Bourimova
    Tomsk State University, Tomsk, Russia
  • V.G. Bagrov
    Institute of High Current Electronics, Tomsk, Russia
  
  We present the numerical calculations based on the theoretical research of SR characteristics for the weakly excited particles. For a spinless and spinor particle the exploration of effective angles and deviation angles is to be conducted. Comparing the data obtained with its classical analogue , one shows that the quantum theory gives a number of unpredictable results.  
 
WEP185 Properties of Longitudinally Uniform Beam Waveguides factory, undulator, resonance, synchrotron-radiation 1834
 
  • Y.W. Kang
    ORNL, Oak Ridge, Tennessee, USA
  • R. Kustom, R. Nassiri
    ANL, Argonne, USA
  
  Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Beam waveguide (BWG) geometry with two longitudinally uniform concave reflectors can support quasi-optical transverse resonances of electromagnetic waves and longitudinal power transmission. The quasi-optical resonance in BWG can be treated as a Gaussian beam. The BWG are often known to have high Q-factors while operating in higher order modes. The latest interests on these beam waveguides are the application for microwave or millimeter wave undulators for synchrotron radiation. The general properties of the BWG are discussed with the field solutions and dispersion properties derived with elliptical beam waveguides approximation. Potential applications of BWG for supporting circularly polarized wave are discussed. 		 
 
WEP199 Estimation of Ecloud and TMCI Driven Vertical Instability Dynamics from SPS MD Measurements - Implications for Feedback Control feedback, controls, simulation, injection 1861
 
  • O. Turgut, A. Bullitt, J.D. Fox, G. Ndabashimiye, C.H. Rivetta, M. Swiatlowski
    SLAC, Menlo Park, California, USA
  • W. Höfle, B. Salvant
    CERN, Geneva, Switzerland
  • R. Secondo
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
We present analysis of beam motion data obtained in high intensity SPS MD studies in 2009 and 2010. The single-bunch vertical E-cloud motion seen in parts of the bunch train after injection shows large tune shifts (roughly 0.02 above the 0.185 tune) developing between tail and head of unstable bunches. The unstable vertical motion has spectral content up to roughly 1.2 GHz and a quasi-periodic growth and decoherence relaxation oscillation effect is seen with time scales of hundred turns. Beam slice FFT and RMS techniques are illustrated to extract parameters important for the design of wide-band vertical feedback system, such as a growth rates of unstable motion, tune shifts within a single bunch and characterization of the bandwidth of the unstable structures within a bunch. We highlight the impact of synchrotron motion and injection transients on a proposed vertical processing channel. We present our MD plans including the beam driving process, developments in reduced model / identification techniques to extract dynamics from experimental and simulation data.
*J. Fox et al., ‘‘SPS Ecloud Instabilities - Analysis Of Machine Studies And Implications For Ecloud Feedback,'' IPAC'10, WEPEB052 		 
 
THOAS2 Solid State RF Power - The route to 1W per Euro Cent electron, klystron, radiation, linac 2047
 
  • O. Heid
    Siemens AG, Healthcare Technology and Concepts, Erlangen, Germany
  • T.J.S. Hughes
    Siemens AG, Erlangen, Germany
  
  In most particle accelerators RF power is a decisive design constraint due to high costs and relative inflexibility of power sources based on electron beams i.e. Klystrons, Magnetrons, Tetrodes etc. At VHF/UHF frequencies the transition to solid state devices promises to fundamentally change the situation. Recent progress brings 1 Watt per Euro cent installed cost within reach. We present a Silicon Carbide semiconductor solution utilising the Solid State Direct Drive technology [*,**,***] at unprecedented efficiency, power levels and power densities. The proposed solutions allows retrofitting of existing RF solutions and opens the route to novel accelerator designs.
* Heid O., Hughes T. THPD002, IPAC10, Kyoto, Japan
** Hergt M et al, 2010 IEEE International Power Modulator and High Voltage Conf., Atlanta GA, USA
*** Heid O., Hughes T. THP068, LINAC10, Tsukuba, Japan 		 
slides icon Slides THOAS2 [1.776 MB]  
 
THOBS5 Extruded Aluminum Vacuum Chambers for Insertion Devices vacuum, undulator, insertion, insertion-device 2093
 
  • E. Trakhtenberg, P.K. Den Hartog, G.E. Wiemerslage
    ANL, Argonne, USA
  
  Funding: Work is supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Science under Contract No. DE-AC02-06CH 11357.
Extruded aluminum vacuum chambers are commonly used in the storage rings of synchrotron facilities. For 18 years the APS has designed and fabricated vacuum chambers made from extruded aluminum for use with insertion devices at the APS and for use at other facilities including BESSY II, the Swiss Light Source (SLS), the Canadian Light Source (CLS), the TESLA Test Facility (TTF), and the European Synchrotron Radiation Facility (ESRF). Most recently extruded aluminum chambers were developed for LCLS with a 0.5-mm wall thickness along the entire 3.8-meter length. Surface roughness for the LCLS vacuum chamber interior was reduced, on average, to less than 300 nm through an abrasive flow polishing technique. Currently under development is an extruded aluminum chamber for the superconducting undulator at the APS. So far, 120 vacuum chambers have been produced with these methods. Results of the development, construction, and manufacturing of extruded aluminum vacuum chambers with small vertical apertures and thin walls are presented. The design, technological challenges, and positive and negative experiences are discussed. 		 
slides icon Slides THOBS5 [7.855 MB]  
 
THP039 Development of a High-power THz-TDS System on the Basis of a Compact Electron Linac electron, laser, linac, synchrotron-radiation 2190
 
  • M. Kumaki, K. Sakaue, M. Washio
    RISE, Tokyo, Japan
  • R. Kuroda, H. Toyokawa, K. Yamada
    AIST, Tsukuba, Ibaraki, Japan
  
  The high-power terahertz time-domain spectroscopy (THz-TDS) system has been developed on the basis of a compact S-band electron linac at AIST, Japan. The linac whose injector is a photocathode rf gun generates about a 40 MeV, 1 nC electron bunch. The bunch is compressed into less than 1ps with a magnetic compressor. It is bended by a 90-degree bending magnet, which causes generation of the THz coherent synchrotron radiation (CSR). It has useful characteristics such as high power, a short pulse and continuous spectrum. In particular, peak power of THz-CSR is estimated to be about 106 times larger than that of the conventional THz source on the basis of the mode-locked fs laser. The THz-TDS is based on the EO sampling methods with the pump-probe technique. The frequency spectrum is obtained by Fourier transform of the measured temporal THz waveform. In addition, it is applied to the ultra-short bunch length monitor by analysing the THz spectrum. In this paper, we will describe details of our system and preliminary experimental results.  
 
THP103 Spin Code Benchmarking at RHIC resonance, closed-orbit, simulation, status 2318
 
  • F. Méot, M. Bai, V. Ptitsyn
    BNL, Upton, Long Island, New York, USA
  • V.H. Ranjbar
    Tech-X, Boulder, Colorado, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Stepwise ray-tracing methods are being developed at C-AD, BNL, in view of benchmarking of existing spin codes and of spin dynamics simulations at RHIC. A status of that work is reported here. 		 
 
THP127 Analysis of NSLS-II Touschek Lifetime betatron, simulation, closed-orbit, longitudinal-dynamics 2360
 
  • J. Choi, S.L. Kramer
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by DOE contract DE-AC02-98CH10886
As scrapers are adopted for the loss control of NSLS-II storage ring, Touschek lifetime estimations for various cases are required to assure the stable operation. However, to estimate the Touschek lifetime, momentum apertures should be measured all along the ring and, if we want to estimate the lifetime in various situations, it can take extremely long time. Thus, rather than simulating for each case, semi-analytic methods with the interpolations are used for the measurements of the momentum apertures. In this paper, we described the methods and showed the results. 		 
 
THP140 Synchrotron Light Options at Super-B brightness, photon, radiation, undulator 2384
 
  • W. Wittmer, Y. Nosochkov, A. Novokhatski, J.T. Seeman, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • M.E. Biagini, P. Raimondi
    INFN/LNF, Frascati (Roma), Italy
  
  The Super-B facility will collide electron and positron beams with different characteristics as done in the past at PEP-II and KEKB. The ring and electron (positron) beam characteristic of both high and low energy rings of the Super-B are comparable to NSLS-II and other state of the art synchrotron light sources. This suggests the use of this facility, either parasitically or in dedicated runs, as light source. In this paper we compare the characteristics of the synchrotron light generated at Super-B with existing, in construction and proposed facilities. We investigate different schemes to incorporate the generation of synchrotron radiation in the collider lattice design and look at different beam line layouts for users.  
 
THP213 Traveling Wave Electron Linac for Synchrotron Injector linac, electron, simulation, injection 2519
 
  • S.V. Kutsaev, K.I. Nikolskiy, N.P. Sobenin
    MEPhI, Moscow, Russia
  
  In this paper the project design of a travelling wave electron linac used as an injector to synchrotron in Lebedev Physical Institute of the Russian Academy of Sciences (LPI RAS) is presented. The injected beam to the synchrotron should have very small emittance and energy spectrum. Thus, the buncher design is an essential question in this problem. One of the best output beam parameters can be achieved by using a waveguide buncher with the non-uniform parameters. The proposals of optimal buncher design and beam dynamics calculation results are presented.  
 
FROCB2 Science with Light and Neutron Sources neutron, scattering, electron, photon 2596
 
  • S.K. Sinha
    UCSD, La Jolla, California, USA
  
  In recent years there has been great progress in the development of accelerator-based light and neutron sources. The speaker will give an overview of the exciting new opportunities provided by the enhanced source capabilities available at present and future facilities.
Speaker Sunhil Sinha, a professor in the Physics Department of the University of California at San Diego 		 
slides icon Slides FROCB2 [26.588 MB]