Keyword: impedance
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MOPG01 Design, Production and Tests of Button Type BPM for TAC-TARLA IR FEL Facility electron, simulation, FEL, radiation 27
  • M.T. Gundogan, O. Yavaş
    Ankara University, Faculty of Engineering, Tandogan, Ankara, Turkey
  • A.A. Aydin, E. Kasap
    Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara, Turkey
  • Ç. Kaya
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  Funding: Ankara University
Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility is proposed as an IR FEL and Bremsstrahlung facility as the first facility of Turkish Accelerator Center (TAC) in Golbasi Campus of Ankara University. TARLA is proposed to generate oscillator mode FEL in 3-250 microns wavelengths range and Bremsstrahlung radiation. It will consist of normal conducting injector system with 250 keV beam energy and two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. The electron beam will be in both continuous wave (CW) and macro pulse (MP) modes. The bunch charge will be limited by 77pC and the average beam current will be 1 mA. To detect electron beam position inside beam line, BPM (Beam Position Monitor) has to use through beam line. Wall current monitor based systems button type TARLA BPM are briefly mentioned. In this study, simulation results of the calculations in CST, production and test studies for button type TARLA BPMs are presented. Mechanical and electronic designs, antenna simulations, and the latest testing procedures are determined for button type BPMs.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG01  
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MOPG05 Transient Studies of the Stripline Kicker for Beam Extraction from CLIC Damping Rings flattop, extraction, kicker, simulation 35
  • C. Belver-Aguilar, M.J. Barnes
    CERN, Geneva, Switzerland
  Stripline kickers are generally assumed to have equal contributions from the electric and magnetic field to the total deflection angle, for ultra-relativistic beams. Hence parameters of the striplines, such as the characteristic impedance, the field homogeneity and the deflection angle are typically determined by simulating the striplines from an electrostatic perspective. However recent studies show that, when exciting the striplines with a trapezoidal current pulse, the magnetic field changes during the flat-top of the pulse, and this can have a significant effect upon the striplines performances. The transient solver of Opera2D has been used to study the magnetic field, for the striplines to be used for beam extraction from the CLIC damping rings, when exciting the electrodes with a pulse of 1 us flat-top and 100 ns rise and fall times. The time dependence of the characteristic impedance, field homogeneity and deflection angle are presented in this paper. In addition, two solutions are proposed to improve the flatness of the magnitude of the magnetic field throughout the flat-top of the pulse, and the predicted results are reported.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG05  
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MOPG37 Comparative Study of Magnetic Properties for CERN Beam Current Transformers electron, radiation, monitoring, solenoid 127
  • S. Aguilera, H. Hofmann, P. Odier
    CERN, Geneva, Switzerland
  • S. Aguilera, H. Hofmann
    EPFL, Lausanne, Switzerland
  At CERN, the circulating beam current measurement is provided by two types of transformer, the Direct Current Current Transformer and the Fast Beam Current Transformer. Each transformer is built based on toroidal cores made from a soft magnetic material. Depending on the type of measurement to be performed these cores require different magnetic characteristics for parameters such as permeability, coercivity and the shape of the magnetisation curve. In order to study the effect of changes in these parameters on the current transformers, several interesting raw materials based on their as-cast properties were selected. The materials have been characterised to determine their crystallisation, melting and Curie Temperatures in order to determine suitable annealing processes to tailor their properties. They have been analysed by several techniques including Electron Microscopy and X-ray Diffraction. As-cast magnetic properties such as the permeability, the B-H curve and Barkhausen noise have also been measured to enable the study of the effect of thermal treatment in the microstructure of the alloys, and the correlation of this with the change in the magnetic properties.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG37  
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MOPG41 A New Wall Current Monitor for the CERN Proton Synchrotron vacuum, proton, synchrotron, simulation 143
  • J.M. Belleman, W. Andreazza
    CERN, Geneva, Switzerland
  • A.A. Nosych
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  Wall Current Monitors are the devices of choice to observe the instantaneous beam current in proton accelerators. These entirely passive transformers deliver a high-fidelity image of the beam intensity in a bandwidth spanning from about 100kHz up to several GHz. They serve as a signal source for a diverse set of applications including Low Level RF feedback and longitudinal diagnostics such as bunch shape measurements and phase-space tomography. They are appreciated for their excellent reliability, large bandwidth and unsurpassed dynamic range. We describe the design of a new Wall Current Monitor for the CERN Proton Synchrotron with a useful bandwidth of 100kHz to 4GHz. Two such devices have been installed in the PS machine and are now used in regular operation. Some usage examples will be shown.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG41  
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MOPG49 A Precise Pulsed Current Source for Absolute Calibration of Current Measurement Systems With No DC Response operation, power-supply, hardware, instrumentation 165
  • M. Krupa, M. Gąsior
    CERN, Geneva, Switzerland
  • M. Krupa
    TUL-DMCS, Łódź, Poland
  Absolute calibration of systems with no DC response requires pulsed calibration circuits. This paper presents a precise pulsed current source designed primarily for remote calibration of a beam intensity measurement system. However, due to its simple and flexible design, it might also prove interesting for other applications. The circuit was designed to drive a load of 10 Ω with current pulses lasting a few hundred microseconds with an amplitude of 1 A and precision in the order of 0.01%. The circuit is equipped with a half-bridge for precise determination of the absolute output current using the 0 V method. This paper presents the circuit topology and discusses in detail the choice of the critical components along with their influence on the final achieved accuracy. The performance of the built prototype of the current source is presented with laboratory measurements.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG49  
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MOPG55 Streak Camera Calibration Using RF Switches synchrotron, cavity, injection, storage-ring 186
  • U. Iriso, M. Alvarez, A.A. Nosych
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • A. Molas
    UAB, Barcelona, Spain
  The streak camera has been used to measure the bunch length since the ALBA storage ring commissioning in 2011. Previously, we developed an optical calibration system based on the Michelson interferometry. Similar to the work at the DLS*, in this report we show the calibration kit based on the different electrical delays which can be used via rf switches. We compare both calibration systems and we show measurements of the longitudinal impedance obtained with the new calibration.
*L. Bobb, A. Morgan, and G. Rehm, "Streak Camera PSF optimisation and udal sweep calibration for sub-ps bunch length measurements", Proc. of IBIC2015 (Australia)
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG55  
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TUCL02 Novel Accelerator Physics Measurements Enabled by NSLS-II RF BPM Receivers vacuum, closed-orbit, factory, feedback 294
  • B. Podobedov, W.X. Cheng, Y. Hidaka
    BNL, Upton, Long Island, New York, USA
  • D. Teytelman
    Dimtel, San Jose, USA
  NSLS-II light source has state of the art RF BPM receivers that were designed and built in-house incorporating the latest technology available in the RF, digital, and software domains. The recently added capability to resolve the orbits of multiple bunches within a turn as well as further improvement in transverse positional resolution for single- and few-bunch fills [*] allowed us to perform a number of novel beam dynamics measurements. These include measuring small impedances of vacuum chamber components, and of extremely small (~10-5) current-dependent tune shifts (transverse and synchrotron), as well as obtaining an amplitude-dependent tune shift curve from a single kicker pulse. We are also effectively utilizing our BPMs to decipher the lifetimes of individual bunches and to visualize single bunch instability dynamics. In this paper we review the unique capabilities of NSLS-II BPMs and present examples of beam physics measurements that greatly benefit from them.
* B. Podobedov, W. Cheng, K. Ha, Y. Hidaka, J. Mead, O. Singh, K. Vetter "Single Micron Single-Bunch Turn-by-Turn BPM Resolution Achieved at NSLS-II", in Proc. IPAC'16, Busan, Korea, May 2016, WEOBB01
slides icon Slides TUCL02 [5.788 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUCL02  
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TUPG04 CERN PS Booster Transverse Damper: 10 kHz - 200 MHz Radiation Tolerant Amplifier for Capacitive PU Signal Conditioning radiation, pick-up, linac, electronics 315
  • A. Meoli, A. Blas, R. Louwerse
    CERN, Geneva, Switzerland
  After connection to the LINAC4, the beam intensity in the PSBooster is expected to double and thus, an upgrade of the head electronics of the transverse feedback BPM is necessary. In order to cover the beam spectrum for an effective transverse damping, the pickup (PU) signal should have a large bandwidth on both the low and high frequency sides. Furthermore, in order to extend the natural low frequency cut-off from 6MHz (50' load) down to the required 10kHz, with no modification of the existing PUs, a high impedance signal treatment is required. The electronic parts should withstand the radiation dose received during at least a year of service. This constraint implies the installation of the amplifier at a remote location. A solution was found inspired by the technique of oscilloscopes' high impedance probes that mitigates the effect of transmission line mismatch using a lossy coaxial cable with an appropriate passive circuitry. A new large bandwidth, radiation tolerant amplifier has been designed. The system requirements, the analysis, the measurements with the present PUs, the design of the amplifier and the experimental results are described in this contribution.  
poster icon Poster TUPG04 [1.030 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG04  
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TUPG08 Design of the Transverse Feedback Kicker for ThomX kicker, simulation, feedback, dipole 329
  • M. El Ajjouri, N. Hubert, A. Loulergue, R. Sreedharan
    SOLEIL, Gif-sur-Yvette, France
  • D. Douillet, A.R. Gamelin, D. Le Guidec
    LAL, Orsay, France
  ThomX is a Compton source project in the range of the hard X rays to be installed in 2017. The machine is composed of an injector Linac and a storage ring where an electron bunch collides with a laser pulse accumulated in a FabryPerot resonator. The final goal is to provide an X-rays average flux of 1011÷1013 ph/s. To achieve this target, it is required to install a transverse feedback system to suppress instabilities generated by injection position jitter sources, resistive wall impedance or collective effects. This paper describes the design and simulation studies of the stripline kicker that will be used for the transverse feedback system.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG08  
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TUPG12 Design for the Diamond Longitudinal Bunch-by-Bunch Feedback Cavity cavity, resonance, HOM, coupling 340
  • A.F.D. Morgan, G. Rehm
    DLS, Oxfordshire, United Kingdom
  In 2017 it is planned to install some additional normal conducting cavities into the Diamond storage ring. In order to deal with the potential higher order modes in these we are designing a longitudinal bunch-by-bunch feedback system. This paper will focus on the design of the overloaded cavity kicker, adapted to the Diamond beam pipe cross section. The design has evolved in order to reduce the strong 3rd harmonic resonance seen on the introduction of the racetrack beam pipe. Through a combination of geometry optimisation and the addition of integrated taper transitions this harmonic has been greatly reduced while also minimising sharp resonances below 15GHz. The major features will be described, as well as the expected performance parameters.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG12  
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TUPG13 A New Stripline Kicker for PF-AR Transverse Feedback Damper kicker, feedback, damping, operation 344
  • R. Takai, T. Honda, T. Nogami, T. Obina, Y. Tanimoto, M. Tobiyama
    KEK, Ibaraki, Japan
  A feedback damper equipped with a long stripline kicker was used to damp transverse beam oscillation at the Photon Factory Advanced Ring (PF-AR), which is a 6.5-GeV synchrotron radiation source of KEK. Recently, the stripline kicker was renewed to one having shorter electrodes and a smaller loss factor because its insulating support was broken by the beam-induced thermal stress and caused frequent electric discharges inducing dust trapping phenomena. In this paper, we present details of the new stripline kicker, from design to installation, as well as demonstrate results of beam oscillation damping obtained with the new kicker.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG13  
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TUPG18 Design Optimization of Button-Type BPM Electrode for the SPring-8 Upgrade resonance, simulation, storage-ring, vacuum 360
  • M. Masaki, H. Dewa, T. Fujita, S. Takano
    JASRI, Hyogo, Japan
  • H. Maesaka, S. Takano
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  The requirements for a BPM system for the SPring-8 upgrade are long-term stability, sufficient signal intensity and high accuracy*. The design of a button-type electrode for the BPM has been optimized from the perspectives of 1) mechanical structure, 2) rf characteristics, 3) thermal issue. We have adopted the electrode structure without a sleeve enclosing the button to maximize the button diameter for the narrow aperture of the vacuum chamber. The absence of an annular slot around the sleeve in a lodging hole for the electrode eliminates the associated beam impedance. To minimize the beam impedance and the trapped mode heating of the electrode, the rf structure has been optimized by 3D electro-magnetic simulations. To suppress the ohmic loss on the button and center pin thermally isolated from the water cooled BPM block, we have selected molybdenum as a material with high electric and thermal conductivities. The reduction of the heating suppresses thermal deformation of the electrode and the BPM block, and improves thermal stability of the BPM system. The mechanical tolerance of the electrode was defined to fit the error budget for the total BPM offset error of 0.1 mm rms.
* H. Maesaka et al., in this conference.
poster icon Poster TUPG18 [1.104 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG18  
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TUPG32 Blip Scanning System Power Supply Control feedback, target, controls, software 406
  • Z. Altinbas, R.F. Lambiase, C. Theisen
    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. Dept. of Energy.
In the Brookhaven LINAC Isotope Producer (BLIP) facility, a fixed target is bombarded by proton beam to produce isotopes for medical research and cancer treatment. This bombardment process causes spot heating on the target and reduces its lifetime. To mitigate this problem, an upgrade to the beamline has been made by spreading the beam on the target in a circular pattern, which allows the target to heat more uniformly. The beam is steered in a circular pattern by a magnet with orthogonal (X and Y) windings. Each of these two windings is independently powered as part of a resonant circuit driven by a power amplifier. This paper describes the hardware platform used as well as the software implementation of the resonant circuit design and its feedback loops.
poster icon Poster TUPG32 [9.262 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG32  
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WEAL02 The Wall Current Transformer - a New Sensor for Precise Bunch-by-Bunch Intensity Measurements in the LHC vacuum, instrumentation, network, operation 568
  • M. Krupa, M. Gąsior
    CERN, Geneva, Switzerland
  The Wall Current Transformer (WCT) is a new bunch-by-bunch intensity monitor developed by the CERN Beam Instrumentation Group to overcome the performance issues of commercial Fast Beam Current Transformers (FBCT) observed during Run 1 of the LHC. In the WCT the large magnetic cores commonly used in FBCTs are replaced with small RF transformers distributed around the beam pipe. Rather than directly measuring the beam current, the WCT measures the image current induced by the beam on the walls of the vacuum chamber. The image current is forced to flow through a number of screws which form the single-turn primary windings of the RF transformers. The signals of the secondary windings are combined and the resulting pulse is filtered, amplified and sent to the acquisition system. This paper presents the principle of operation of the WCT and its performance based on laboratory and beam measurements.  
slides icon Slides WEAL02 [13.114 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEAL02  
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WEPG05 Design of Stripline Beam Position Monitors for the ESS MEBT electronics, quadrupole, simulation, coupling 620
  • S. Varnasseri, I. Bustinduy, A. Ortega, I. Rueda, A. Zugazaga
    ESS Bilbao, Zamudio, Spain
  • R.A. Baron, H. Hassanzadegan, A. Jansson, T.J. Shea
    ESS, Lund, Sweden
  There will be overall 8 Beam Position Monitors (BPM) installed in MEBT of ESS. Seven of them will be used for the measurement of beam position, phase and intensity. One BPM will be used for the fast timing characterization of the chopped beam. The design is based on shortened stripline to accommodate the signal level for low velocity proton beam within MEBT read by electronics. Due to mechanical space limits, all the BPMs are embedded inside quadrupoles; which requires special care on the magnetic properties of the materials within BPM sets and in particular the feedthroughs. The prototype electromagnetic and mechanical design is finished and its fabrication is underway. This paper gives an overview of the electromagnetic and mechanical design and related analysis including position signal sensitivity of the BPMs.  
poster icon Poster WEPG05 [1.107 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG05  
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WEPG41 Measurement of Coupling Impedances using a Goubau Line simulation, resonance, coupling, scattering 719
  • F. Stulle, J.F. Bergoz
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • H.-W. Glock
    HZB, Berlin, Germany
  Longitudinal coupling impedances can be deduced from S-Parameter measurements performed on a Goubau Line. The Goubau Line, also known as single wire line, is a variant of the coaxial wire method. Both setups use a wire for mimicking the particle beam. Coaxial tapers at the wire ends adapt wave impedance to the 50ohm impedance of coaxial cables, sources and receivers. But for guiding the electromagnetic wave, the Goubau Line relies on the realistic boundary conditions imposed by an insulated wire instead of using a coaxial shield. Equations for the deduction of longitudinal coupling impedances are reviewed and applied to Goubau Line measurements. Goubau Line measurements and CST Studio simulations are compared, showing good agreement.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG41  
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WEPG56 Single-Shot THz Spectroscopy for the Characterization of Single-Bunch Bursting CSR detector, radiation, electron, operation 778
  • J. Raasch, M. Arndt, J. Hänisch, K.S. Ilin, K. Kuzmin, A.-S. Müller, A. Schmid, M. Siegel, J.L. Steinmann, S. Wuensch
    KIT, Karlsruhe, Germany
  • G. Cinque, M. Frogley
    DLS, Oxfordshire, United Kingdom
  • B. Holzapfel
    Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
  Funding: The work was supported by the BMBF (05K13VK4), the Helmholtz International Research School for Teratronics & the Karlsruhe School of Elementary Particle and Astroparticle Physics.
An integrated array of narrow-band high-Tc YBa2Cu3O7-x (YBCO) detectors embedded in broad-band readout was developed for the future use at synchrotron light sources as a single-shot terahertz (THz) spectrometer. The detection system consists of up to four thin-film YBCO nanobridges fed by planar double-slit antennas covering the frequency range from 140 GHz up to 1 THz. We present first results obtained at the ANKA storage ring and at Diamond Light Source during operation of two and four frequency-selective YBCO detectors, respectively.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG56  
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