Keyword: simulation
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MOCL2 Design of a Novel Cherenkov Detector System for Machine Induced Background Monitoring in the CMS Cavern background, LHC, radiation, shielding 33
 
  • S. Orfanelli, A.E. Dabrowski, M. Giunta
    CERN, Geneva, Switzerland
  • M.J. Ambrose, A. Finkel, R. Rusack
    University of Minnesota, Minneapolis, Minnesota, USA
  • D.P. Stickland
    PU, Princeton, New Jersey, USA
  
  A novel detector system has been designed for an efficient online measurement of the machine induced background in the CMS experimental cavern. The suppression of the CMS cavern background originating from pp collision products and the 25 ns bunch spacing have set the requirements for the detector design. Each detector unit will be a radiation hard, cylindrical Cherenkov radiator optically coupled to an ultra-fast UV-sensitive photomultiplier tube, providing a prompt, directionally sensitive measurement. Simulation and test beam measurements have shown the achievability of the goals that have driven the baseline design. The system will consist of 20 azimuthally distributed detectors per end, installed at a radius of r ~ 180 cm and a distance 20.6 m away from the CMS interaction region. The detector units will enable a measurement of the transverse distribution of the bunch-by-bunch machine induced background flux. This will provide important feedback from the CMS on the beam conditions during the LHC machine setup and comparisons to expectations based on FLUKA simulations.  
slides icon Slides MOCL2 [14.094 MB]  
 
MOPC09 Development of the Sirius RF BPM Electronics BPM, controls, storage-ring, pick-up 63
 
  • D.O. Tavares, R.A. Baron, F.H. Cardoso, S.R. Marques, J.L.B. Neto, L.M. Russo
    LNLS, Campinas, Brazil
  • A.P. Byszuk, G. Kasprowicz, A.J. Wojenski
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  
  A BPM system has been developed for the new low emmitance 3 GeV Brazilian synchrotron light source, Sirius. The Sirius BPM electronics is a modular system based on a PICMG(R) MicroTCA.4 platform using ADC mezzanine cards in ANSI/VITA 57.1 FMC form factor and standalone RF front-end boards. It has been designed under the CERN Open Hardware License (OHL) in a collaboration between Brazilian Synchrotron Light Laboratory (LNLS) and Warsaw University of Technology (WUT). This paper presents: i) overall architecture of the BPM system; ii) performance evaluation of the first prototype of the BPM electronics comprehending beam current, filling pattern and temperature dependencies as well as resolution vs. beam current; and iii) preliminary results with beam at LNLS's UVX storage ring.  
poster icon Poster MOPC09 [1.451 MB]  
 
MOPC14 Beam Position Monitors R&D for keV Ion Beams BPM, pick-up, antiproton, multipole 78
 
  • S. Naveed, A.A. Nosych, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S. Naveed, A.A. Nosych, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • A.A. Nosych, L. Søby
    CERN, Geneva, Switzerland
  
  Funding: Work supported by the EU within the DITANET and oPAC projects under contracts 215080 and 289485, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1.
Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams on the examples of the USR and ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values and describe an experimental setup realized at the Cockcroft Institute for BPM callibration. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably. 		 
 
MOPC19 Status of the Beam Position Monitors for LIPAc pick-up, BPM, beam-position, linac 93
 
  • I. Podadera, F.M. De Aragon, A. Guirao, D. Jimenez, A. Lara, L.M. Martinez, J. Molla
    CIEMAT, Madrid, Spain
  
  Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project AIC10-A-000441 and AIC-A-2011-0654.
The LIPAc accelerator will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology that will be used in the future IFMIF accelerator. Several types of Beam Position Monitors –BPM’s- are placed in each section of the accelerator to ensure a good beam transport and minimize beam losses. Prototypes of almost all the BPM’s have been already fabricated. Acceptance tests have been carried out on each device. The output of the vacuum leak tests and electrical tests will be analyzed in this contribution. In addition, the test bench to characterize the BPM’s has been upgraded and validated using some prototypes in order to obtain a better global measurement accuracy of the electrical center offset. The test bench can be used to crosscheck the simulations with the real response of each BPM. The result of the comparison will be discussed in detail. 		 
 
MOPC24 Design Of The Stripline BPM For The Advanced Photoinjector Experiment BPM, impedance, coupling, diagnostics 108
 
  • S. De Santis, M.J. Chin, D. Filippetto, W.E. Norum, Z. Paret, G.J. Portmann, F. Sannibale, R.P. Wells
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
We describe the design, bench testing, and initial commissioning of the shorted striplines beam position monitors used in the Advanced Photoinjector Experiment (APEX) at Lawrence Berkeley National Laboratory. Our BPM's are characterized by extreme compactness, being designed to fit in the vacuum chamber of the quadrupole magnets, with only a short portion including the RF feedthroughs occupying additional beam pipe length. In this paper we illustrate the design process, which included extensive 3D computer simulations, the bench testing of prototype and final components, and the first measurements with beam. The readout electronics is also described. 		 
 
MOPC42 Novel Pickup for Bunch Arrival Time Monitor pick-up, LEFT, transverse, laser 170
 
  • A. Kalinin
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  For an optical-modulator-based BAM, main parameter of the pickup output signal is slope steepness. We suggest a novel pickup with flat thin electrodes in a transverse gap. Increasing the electrode width makes the steepness greater in the same extent as the signal increases. For a given width, reducing the electrode thickness allows to reach ultimate steepness. Wave processes in the pickup were investigated on a large scale model, using the technique described in *. The DESY 40GHz button pickup was used as a reference. It is shown that steepness of the flat electrode pickup can be achieved two times greater. It is also shown that a BAM electrode pickup has a remarkable feature: the steepness does not depend on electrode sizes, if the ratio w/G (a flat electrode pickup, the width and gap length) or d/D (a button pickup, the diameters) is kept constant. This makes pickup bandwidth that is of the order of c over 2G or 2D, a free parameter. For flat electrode pickup, the steepness can be kept as high with transition to a more practical bandwidth 20GHz. The investigation results are the base for a final pickup optimisation using electrodynamic simulation.
* A. Kalinin, “Pickup Electrode Electrodynamics Investigation”, WEPC26, this conference 		 
poster icon Poster MOPC42 [0.549 MB]  
 
MOPC47 Monte Carlo Simulations of Beam Losses in the Test Beam Line of CTF3 beam-losses, quadrupole, electron, CLIC 189
 
  • E. Nebot Del Busto, S. Mallows, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • E. Branger
    Linköping University, Linköping, Sweden
  • S. Döbert, E.B. Holzer, R.L. Lillestøl, S. Mallows, E. Nebot Del Busto
    CERN, Geneva, Switzerland
  • R.L. Lillestøl
    University of Oslo, Oslo, Norway
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  The Test Beam Line (TBL) of the CLIC Test Facility 3 (CTF3) aims to validate the drive beam deceleration concept of CLIC, in which the RF power requested to boost particles to multi-TeV energies is obtained via deceleration of a high current and low energy drive beam (DB). Despite a TBL beam energy (150-80 MeV) significantly lower than the minimum nominal energy of the CLIC DB (250 MeV), the pulse time structure of the TBL provides the opportunity to measure beam losses with CLIC-like DB timing conditions. In this contribution, a simulation study on the detection of beam losses along the TBL for the commissioning of the recently installed beam loss monitoring system is presented. The most likely loss locations during stable beam conditions are studied by considering the beam envelope defined by the FODO lattice as well as the emittance growth due to the deceleration process. Moreover, the optimization of potential detector locations is discussed. Several factors are considered, namely: the distance to the beam, the shielding provided by the different elements of the line, the detector sensitivity and possible saturation effects of both the radiation detectors and electronics.  
 
MOPF04 Results of the High Resolution OTR Measurements at KEK and Comparison with Simulations OTR, radiation, KEK, target 204
 
  • B. Bolzon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.S. Aryshev
    KEK, Ibaraki, Japan
  • B. Bolzon, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • B. Bolzon, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • P. Karataev, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • P. Karataev
    JAI, Egham, Surrey, United Kingdom
  
  Optical Transition Radiation (OTR) is emitted when a charged particle crosses the interface between two media with different dielectric properties. It has become a standard tool for beam imaging and transverse beam size measurements. At the KEK Accelerator Test Facility 2 (ATF2), OTR is used at the beginning of the final focus system to measure a micrometre beam size using the decrease in visibility of the OTR Point Spread Function (PSF). In order to study and improve the resolution of the optical system, a novel simulation tool has been developed in order to characterize the PSF in detail. Based on the physical optic propagation mode of ZEMAX, the propagation of the OTR electric field can be simulated very precisely up to the image plane, taking into account aberrations and diffraction coming through the designed optical system. This contribution will show the results of measurements performed after a first improvement of the ATF2 OTR optical design to confirm the very high resolution of the imaging system and the performance of this simulation tool.  
poster icon Poster MOPF04 [1.590 MB]  
 
MOPF22 The Effect of Space Charge Along the Tomography Section at PITZ space-charge, PITZ, emittance, transverse 255
 
  • G. Kourkafas, M. Khojoyan, M. Krasilnikov, D. Malyutin, B. Marchetti, M. Otevřel, F. Stephan, G. Vashchenko
    DESY Zeuthen, Zeuthen, Germany
  • G. Asova
    INRNE, Sofia, Bulgaria
  
  The Photo Injector Test facility at DESY, Zeuthen site (PITZ) focuses on testing, characterizing and optimizing high brightness electron sources for free electron lasers. Among various diagnostic tools installed at PITZ, the tomography module is used to reconstruct the transverse phase-space distribution of the electron beam by capturing its projections while rotating in the normalized phase space. This technique can resolve the two transverse planes simultaneously with an improved signal-to-noise ratio, allowing measurements of individual bunches within a bunch train with kicker magnets. The low emittance, high charge density and moderate energy of the electron bunch at PITZ contribute to significant space-charge forces which induce mismatches to the reconstruction procedure. This study investigates how the phase-space transformations and thus the reconstruction result are affected when considering linear and non-linear self-fields along the tomography section for the design Twiss parameters. The described analysis proposes a preliminary approach for including the effect of space charge in the tomographic reconstruction at PITZ.  
poster icon Poster MOPF22 [1.312 MB]  
 
MOPF23 Quantifying Dissipated Power From Wake Field Losses in Diagnostics Structures impedance, resonance, single-bunch, DIAMOND 259
 
  • A.F.D. Morgan, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  
  As a charged particle beam passes through structures, wake fields can deposit a fraction of the energy carried by the beam as characterised by the wake loss factor. Some part of the deposited energy will be emitted into the beam pipe, some part can be coupled out of signal ports and some part will be absorbed by the materials of the structures. With increasingly higher stored currents, we require a better understanding of where all the energy deposited by wake losses ends up in order to avoid damaging components. This is of particular concern for diagnostics structures as they are often designed to couple a small fraction of energy from the beam, which makes them susceptible to thermal damage due to increased localised losses. We will detail the simulation and analysis approach which we have developed to quantify power deposition within structures. As an example the analysis of a beam position monitor pickup block of the Diamond storage ring is shown.  
poster icon Poster MOPF23 [0.249 MB]  
 
MOPF30 Novel Diagnostics for Breakdown Studies electron, CLIC, klystron, diagnostics 287
 
  • M. Jacewicz, Ch. Borgmann, M. Olvegård, R.J.M.Y. Ruber, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  • J.W. Kovermann
    CERN, Geneva, Switzerland
  
  The phenomenon that currently prevents achieving high accelerating gradients in high energy accelerators such as the CLIC linear collider is electrical breakdown at very high electrical field. The ongoing experimental work is trying to benchmark the theoretical models focusing on the physics of vacuum breakdown which is responsible for the discharges. The CLIC collaboration has commissioned a dedicated 12 GHz test-stand to validate the feasibility of accelerating structures and observe the characteristics of the RF discharges and their eroding effects on the structure. A versatile system for detection of the dark and breakdown currents and light emission is being developed for the test-stand. It consists of a collimation system with an external magnetic spectrometer for measurement of the spatial and energy distributions of the electrons emitted from the acceleration structure during a single RF pulse. These measurements can be correlated with e.g. the location of the breakdown inside the structure using information from the incident, reflected and transmitted RF powers giving a complete picture of the vacuum breakdown phenomenon.  
 
TUPC11 Beam-Based Measurement of ID Taper Impedance at Diamond impedance, transverse, vacuum, BPM 380
 
  • V.V. Smaluk, R. Bartolini, R.T. Fielder, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  
  New insertion devices (IDs) are being designed now for a Diamond upgrade. One of the important topics of the design is the coupling impedance of the ID vacuum chamber movable tapers. To get a complete and reliable information of the impedance, analytical estimations, numerical simulation and beam-based measurement have been performed. The impedance of an existing ID taper geometrically similar to the new one has been measured using the orbit bump method. It turns out that in spite of the small magnitude (a few um) of orbit distortion to be observed in this case, the BPM resolution is sufficient for this measurement. The measurement results in comparison with simulation data are discussed in this paper.  
 
TUPC14 Development of a Low-Beta Button BPM for PXIE Project BPM, pick-up, beam-position, longitudinal 392
 
  • A. Lunin, N. Eddy, T.N. Khabiboulline, V.A. Lebedev, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  The button BPM is under development for a low beta section of the Project X Injector Experiment (PXIE) at Fermilab. The presented paper includes an analytical estimation of the BPM performance as well a direct wakefield simulation with CST Particle Studio (on a hexahedral mesh). In addition we present a novel approach of a low beta beam interaction with BPM electrodes realized with ANSYS HFSS TD-solver on unstructured tetrahedral mesh. Both methods show a good agreement of BPM output signals for various beam parameters. Finally we describe the signal processing scheme and the electronics we are going to use.  
poster icon Poster TUPC14 [1.051 MB]  
 
TUPC29 Grounded Coplanar Waveguide Transmission Lines as Pickups for Beam Position Monitoring in Particle Accelerators pick-up, XFEL, beam-position, coupling 438
 
  • A. Penirschke, A. Angelovski, R. Jakoby
    TU Darmstadt, Darmstadt, Germany
  • C. Gerth, U. Mavrič, D. Nölle, C. Sydlo, S. Vilcins
    DESY, Hamburg, Germany
  
  Funding: The work was supported by the MSK group at DESY Hamburg. The authors would like to thank the CST AG for providing the CST Software Package.
Energy beam position monitors (EBPM) based on grounded co-planar waveguide (GCPW) transmission lines have been designed for installation in the dispersive sections of the bunch compressor chicanes at the European XFEL. In combination with beam position monitors at the entrance and exit of the bunch compressor chicanes, measurements of the beam energy with single bunch resolution are feasible. The EBPM consists of transversely mounted stripline pickups in a rectangular beam pipe section. The signal detection for the measurement of the phases of the pulses at each end of the pickups is based on the standard down-conversion and phase detection scheme used for the low-level RF-system. A measurement resolution within the lower micrometer range can be achieved for input signal reflections at the pickup of less than -25 dB at 3 GHz. In this paper, simulation results of a novel pickup geometry utilized with GCPW pickup structures and optimized transitions to perpendicular mounted coaxial connectors are presented. The simulation results exhibit small reflection coefficients with reflected signal components having less than 2% of the peak voltage signal. 		 
 
TUPC46 Beam Loss Monitoring Study for SIS100@FAIR beam-losses, ion, GSI, SIS 485
 
  • V.S. Lavrik, L.H.J. Bozyk, O.K. Kester, A. Reiter
    GSI, Darmstadt, Germany
  • O.K. Kester, V.S. Lavrik
    IAP, Frankfurt am Main, Germany
  
  FAIR, the facility for antiproton and ion research, is a multi-disciplinary accelerator facility which will extend the existing GSI complex in Darmstadt, Germany. In the FAIR start version, the new synchrotron SIS100 will provide proton or heavy ion beams for a variety of experiments. The GSI synchrotron SIS18 will operate as injector for SIS100. The current study focuses on beam loss measurements for SIS18 and SIS100. The aim of this study is to find quantitative methods to measure beam losses around the machine, mainly SIS100, on an absolute scale. The contribution will present results of two pilot experiments carried out in the high-energy beam lines and at the SIS18 with Uranium ions in the energy range up to 900 MeV/u. In the first experiment the Uranium beam was totally stopped in a Copper target and the particle shower measured with LHC-type ionization chambers. In the second experiment, the beam was slowly excited in the SIS18 synchrotron to create controlled losses on a scraper which were monitored by the DC current transformer and beam loss monitors. Experimental data are compared against the predictions of Fluka simulations.  
poster icon Poster TUPC46 [5.404 MB]  
 
TUPF05 Particle Tracking for the FETS Laser Wire Emittance Scanner laser, dipole, diagnostics, emittance 503
 
  • J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  
  The Front End Test Stand (FETS) is an R&D project at Rutherford Appleton Laboratory (RAL) with the aim to demonstrate a high power (60 mA, 3 MeV with 50 pps and 10 % duty cycle), fast chopped H− ion beam. The diagnostics of high power particle beams is difficult due to the power deposition on diagnostics elements introduced in the beam so non-invasive instrumentation is highly desirable. The laser wire emittance scanner under construction is based on a photo-detachment process utilizing the neutralized particles produced in the interaction between Laser and H− beam for beam diagnostics purposes. The principle is appropriate to determine the transversal beam density distribution as well as the transversal and longitudinal beam emittance behind the RFQ. The instrument will be located at the end of the MEBT with the detachment taking place inside a dipole field. Extensive particle tracking simulations have been performed for various settings of the MEBT quadrupoles to investigate the best placement and size of the 2D scintillating detector and to determine the range and resolution of the instrument. Additionally the power distribution in the following beam dumps has been determined.  
 
TUPF06 2D Wire Grid Integrated with Faraday Cup for Low Energy H− Beam Analysis at Siemens Novel Electrostatic Accelerator ion, ion-source, electron, plasma 507
 
  • H. von Jagwitz-Biegnitz
    JAI, Oxford, United Kingdom
  • P. Beasley, O. Heid
    Siemens AG, Erlangen, Germany
  • D.C. Faircloth
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • A.J. Holmes
    Marcham Scientific Ltd, Hungerford, United Kingdom
  • R.G. Selway
    Inspired Engineering Ltd, Climping, United Kingdom
  
  A wire grid with 21 wires each vertically and horizontally with a spacing of 1 mm has been developed for beam analysis at Siemens' novel electrostatic accelerator. The wire grid is integrated in a Faraday Cup and profile measurements can therefore be combined with current measurements. The grid is used to analyse the 10 keV H− beam coming from the ion source and the obtained beam parameters will be used as input for simulations of the beam transport in the accelerator. All 42 wires can be read out simultaneously with a multi-channel precision electrometer and the data can be fitted instantly with LabVIEW code that was developed for this purpose. This paper reports on some details of the mechanical design and the data analysis procedure in LabVIEW as well as some results of first measurements at the novel accelerator.  
 
TUPF08 Characterization of Compressed Bunches in the SwissFEL Injector Test Facility longitudinal, electron, transverse, acceleration 515
 
  • G.L. Orlandi, M. Aiba, F. Baerenbold, S. Bettoni, B. Beutner, H. Brands, P. Craievich, F. Frei, R. Ischebeck, E. Prat, T. Schietinger, V. Schlott
    PSI, Villigen PSI, Switzerland
  
  The quality of the beam transverse emittance at the cathode and the uniformity of the longitudinal compression of the electron bunch are essential for the lasing efficiency of a Free Electron Laser. In SwissFEL the longitudinal compression of the electron beam is performed by means of two magnetic chicanes and an off-crest acceleration scheme. The curvature induced on the beam longitudinal phase-space during the compression can be compensated by means of an X-band cavity. The beam longitudinal phase-space can be experimentally characterized by means of a Transverse Deflecting Cavity (TDC) and a profile monitor in a dispersive section. Longitudinal phase-space measurements at the SwissFEL Injector Test Facility under compression with and without X-band linearizer are presented. In addition, energy spread measurements done by monitoring the Synchrotron Radiation (SR) emitted by the electron beam in the dispersive section of the chicane are shown. A comparison with numerical simulations is presented.  
 
TUPF16 Analysis of Measurement Errors of INR Linac Ionization Beam Cross Section Monitor ion, linac, space-charge, proton 535
 
  • S.A. Gavrilov, A. Feschenko, P.I. Reinhardt-Nickoulin, I.V. Vasilyev
    RAS/INR, Moscow, Russia
  • A. Feschenko, S.A. Gavrilov
    MIPT, Dolgoprudniy, Moscow Region, Russia
  
  Residual gas ionization beam cross section monitors (BCSM) are installed at LEBT and HEBT of INR RAS proton linac to measure cross section, profiles and position of the beam. BCSMs provide two-dimensional non-destructive real-time beam diagnostics at LINAC operation with repetition frequency from 1 to 50 Hz, pulses duration from 0.3 to 170 μs and wide range of amplitudes, particle energy 400 keV and 209 MeV. The analysis of systematic measurements errors (accuracy) because of nonuniform electrostatic fields, determined by BCSM design features, is presented. New detector model, minimizing these nonuniformities, is shown. Besides that, the analysis of statistical errors (precision) due to the method features, in particular, ions thermal motion and a beam space charge, is done. The simulation results make it possible to estimate measured cross sections size, profiles and beam positions and to draw conclusions about the reliability of BCSM results for beams with various parameters.  
 
TUPF31 Intensity Control in GANIL’s Experimental Rooms diagnostics, controls, instrumentation, pick-up 587
 
  • C. Courtois, C. Doutresssoulles, B. Ducoudret, C. Jamet, W. Le Coz, G. Ledu, C. Potier de courcy
    GANIL, Caen, France
  
  The safety re-examination of existing GANIL facilities requires the implementation of a safety system which makes a control of beam intensities sent in the experimental rooms possible. The aim is to demonstrate that beam intensities are below the authorized limits. The required characteristics should enable the measurement, by a non-interceptive method, of beam intensities from 5 nA to 5μA with a maximum uncertainty of 5%, independently of the frequency and the beam energy. After a comparative study, two types of high frequency diagnostics were selected, the capacitive peak-up and the Fast current transformer. This paper presents the signal simulations from diagnostics with different beam energies, the uncertainty calculations and the results of the first tests with beam.  
poster icon Poster TUPF31 [2.086 MB]  
 
TUPF34 Resonant TE Wave Measurement of Electron Cloud Density Using Multiple Sidebands resonance, electron, positron, pick-up 597
 
  • J.P. Sikora, J.A. Crittenden
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • S. De Santis
    LBNL, Berkeley, California, USA
  • A.J. Tencate
    ISU, Pocatello, Idaho, USA
  
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
A change in electron cloud (EC) density will change the resonant frequency of a section of beam-pipe. With a fixed drive frequency, the resulting dynamic phase shift across the resonant section will include the convolution of the frequency shift with the impulse response of the resonance. The effect of the convolution on the calculated modulation sidebands is in agreement with measured data, including the absolute value of the EC density obtained from ECLOUD simulations. These measurements were made at the Cornell Electron Storage Ring (CESR) which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV. 		 
poster icon Poster TUPF34 [2.423 MB]  
 
WEPC09 Performance of NSLS2 Button BPM BPM, storage-ring, booster, vacuum 678
 
  • W.X. Cheng, B. Bacha, B.N. Kosciuk, S. Krinsky, O. Singh
    BNL, Upton, Long Island, New York, USA
  
  Several types of button BPMs are used in NSLS2 complex. Coaxial vacuum feedthroughs are used to couple the beam induced signal out. The feedthroughs are designed to match the external transmission line and electronics with characteristic impedance of 50 Ohm. Performances of these BPM feedthroughs are presented in this paper.  
 
WEPC17 Design and Simulation of Beam Position Monitor for the CADS Injector I Proton Linac BPM, pick-up, linac, impedance 710
 
  • Y.F. Sui, J.S. Cao, H.Z. Ma, Q. Ye, J. Yue
    IHEP, People's Republic of China
  
  Funding: Work supported by the National Natural Science Foundation of China (NO. 11205172)
Beam Position Monitors (BPM) based on both capacitive and stripline pick-ups are designed for the China Accelerator Driven Subcritical system (C-ADS) Injector I proton LINAC. The BPM will be installed to measure the transverse beam position in the LINAC, of which the beam parameters are listed as current 10mA, energy 10MeV and the repetition frequency 325MHz. This contribution presents the status of the BPM design development and focuses on the design of the pick-ups and CST Particle Studio simulation results, including impedance, sensitivity, time domain, frequency domain response, etc. The main goal of the simulation is optimization of the mechanical design. 		 
 
WEPC22 First Steps Towards a Fast Orbit Feedback at ALBA feedback, DIAMOND, ESRF, brilliance 727
 
  • A. Olmos, S. Blanch-Torné, Z. Martí, J. Moldes, M. Muñoz, R. Petrocelli, X. Serra-Gallifa
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
  • A. Gutierrez-Milla
    UAB, Barcelona, Spain
  
  An optimum performance of the ALBA facility requires a beam orbit stability on the sub-micron level up to frequencies in the 100 Hz range. The Fast Orbit FeedBack system (FOFB) is designed to achieve such a stability. After investigation of possible system architecture, a decision has been taken that exploits the available in-house hardware. This “low-cost” first stage FOFB will be an ideal test-bench to learn about beam stabilization and find possible problems and improvements on it. This report explains the current lay-out and status of the FOFB at ALBA.  
poster icon Poster WEPC22 [3.107 MB]  
 
WEPC25 Optimisation of a Split Plate Position Monitor for the ISIS Proton Synchrotron beam-position, coupling, BPM, proton 739
 
  • C.C. Wilcox, J.C. Medland, S.J. Payne, A. Pertica, M.A. Probert
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  A new Beam Position Monitor (BPM) has been designed for the ISIS proton accelerator facility at the Rutherford Appleton Laboratory in the UK. The new monitor, which will be installed in the beam line to Target 1, is of a ‘split plate’ design which utilises two pairs of electrodes to allow the beam position to be measured simultaneously in the horizontal and vertical planes. Simulations carried out using the CST low frequency solver have highlighted the inaccuracies in the measured beam position caused by strong inter-electrode coupling in such a monitor. This coupling, along with imbalanced electrode capacitances, leads to reduced sensitivity to changes in beam position as well as producing a positional offset error. This paper describes how the problems associated with inter-electrode coupling have been removed with the addition of grounded rings placed between each of the four electrodes. The design and positioning of the rings also ensured that the four electrode capacitances were matched. The results are presented both as CST simulations of ‘thin wire’ beam position measurements and results from bench measurements of a prototype dual plane BPM.  
 
WEPC40 Pickup Signal Improvement for High Bandwidth BAMs for FLASH and European - XFEL pick-up, DESY, laser, resonance 778
 
  • A. Angelovski, R. Jakoby, A. Penirschke
    TU Darmstadt, Darmstadt, Germany
  • M.K. Czwalinna, H. Schlarb, C. Sydlo
    DESY, Hamburg, Germany
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  In order to measure the arrival time of the electron bunches in low (20 pC) and high (1 nC) charge operation mode, new high bandwidth pickups were developed as a part of the Bunch Arrival-time Monitors (BAMs) for FLASH at DESY *. The pickup signal is transported via radiation resistant coaxial cables to the electro-optic modulator (EOM) **. Due to the high losses of the 40 GHz RF front-end the signal in the RF path is attenuated well below the optimal operation voltage of the EOM. To improve the overall performance, the signal strength of the induced pickup signal needs to be increased and at the same time the losses in the RF front-end significantly reduced. In this paper, the analysis towards improving the induced pickup signal strength is presented. Simulations are performed with the CST STUDIO SUITE package and the results are compared with the state of the art high bandwidth pickups.
* A. Angelovski et al., Phys. Rev. ST Accel. Beams 15, 112803 (2012)
** A. Penirschke et al., Proc. of IBIC2012, Tsukuba, Japan (2012) 		 
 
WEPC45 Beam Loss Monitoring at the European Spallation Source beam-losses, ESS, LHC, XFEL 795
 
  • L. Tchelidze, H. Hassanzadegan, A. Jansson, M. Jarosz
    ESS, Lund, Sweden
  
  At the European Spallation Source proton linear accelerator will generate 5 MW protons to be delivered to a target. This high power accelerator will require significant amount of beam instrumentation, among which the beam loss monitoring system is one of the most important for operation. An LHC type ionization chamber will be used with ~54 uC/Gy sensitivity. At most 1.5 mGy/sec radiation levels are expected close to the beam pipe during normal operation, resulting in up to 80 nA current signal in detectors. Loss monitor electronics is designed to be able to measure currents as little as 1% of the expected current up to as much as 1% of the total beam loss, thus ~800 pA – few mA. In order to study beam loss pattern along the accelerator a coherent model of the whole machine is created for the purposes of Monte Carlo particle transport simulations. Data obtained using the model will be stored in a database together with the initial beam loss conditions. The contents of the database will then be processed using custom neural network algorithms to optimize number and position of the loss monitors and to provide reference on the beam loss localization during operation of the machine.  
poster icon Poster WEPC45 [1.784 MB]  
 
WEPC46 Beam Delivery Simulation (BDSIM): A Geant4 Based Toolkit for Diagnostics and Loss Simulation LHC, CLIC, lattice, background 799
 
  • S.T. Boogert
    Royal Holloway, University of London, Surrey, United Kingdom
  • S.T. Boogert, S.M. Gibson, R. Kwee-Hinzmann, L.J. Nevay, J. Snuverink
    JAI, Egham, Surrey, United Kingdom
  • L.C. Deacon
    CERN, Geneva, Switzerland
  
  BDSIM is a Geant4 and C++ based particle tracking code which seamlessly tracks particles in accelerators and particle detectors, including the full range of particle interaction physics processes in Geant4. The code has been used to model the backgrounds in the International Linear Collider (ILC), Compact Linear Collider (CLIC), Accelerator Test Facility 2 (ATF2) and more recently the Large Hadron Collider (LHC). This paper outlines the current code and possible example applications and presents a roadmap for future developments.  
 
WEPF04 A New Compact Design of a Three-Dimensional Ionization Profile Monitor (IPM) IPM, laser, DESY, beam-position 811
 
  • H.F. Breede, H.-J. Grabosch, M. Sachwitz, L.V. Vu
    DESY Zeuthen, Zeuthen, Germany
  
  FLASH at DESY in Hamburg is a linear accelerator, which uses superconducting technology to produce soft x-ray laser light ranging from 4.1 to 45 nm. To ensure the operation stability of FLASH, monitoring of the beam is mandatory. Two Ionization Profile Monitors (IPM) detect the lateral x and y position changes. The functional principle of the IPM is based on the detection of particles, generated by interaction of the beam with the residual gas in the beam line. The newly designed IPM enables the combined determination of the horizontal and vertical position as well as the profile. This is made possible by a compact monitor, consisting of a cage in a vacuum chamber, two micro-channel plates (MCP) and two repeller plates with toggled electric fields at the opposite sides of the MCPs. The particles created by the FEL beam, drift in a homogenous electrical field towards the respective MCP, which produces an image of the beam profile on an attached phosphor screen. A camera for each MCP is used for evaluation. This indirect detection scheme operates over a wide dynamic range and allows the detection of the center of gravity and the shape of the beam. The final design is presented.  
poster icon Poster WEPF04 [3.643 MB]  
 
WEPF14 A New Low Intensity Beam Profile Monitor for SPIRAL2 electron, MCP, SPIRAL2, permanent-magnet 841
 
  • J.L. Vignet, P. Gangnant, E. Guéroult, J. Pancin
    GANIL, Caen, France
  
  In order to obtain profiles of SPIRAL 2 ion beams, several beam profile monitors are presently being developed at GANIL. One of them is a low-intensity beam-profile monitor (EFM). This Emission-Foil Monitor (EFM) will be used in the radioactive beam lines of SPIRAL2 and in the experimental rooms of this new facility. The ions produce secondary electrons when they are stopped in an aluminium emissive foil. The electrons are then guided in an electric field placed parallel to a magnetic field in a double-stage microchannel plate (MCP). A 2D pixelated pad plane placed below the MCP is then used to collect the signal. The magnetic field created by permanent magnets in a closed magnetic circuit configuration permits the beam-profile reconstruction to be achieved with good resolution. The EFM can visualize beam-profile intensities between only a few pps to as much as 109 pps and with energies as low as several keV. This profiler has been under development since 2011 and is actually manufactured. For the signal acquisition, a new dedicated electronics system will be employed. Recent results of this monitor and its associated electronics will be presented here.  
 
WEPF15 High-Power Tests at CesrTA of X-ray Optics Elements for SuperKEKB DIAMOND, optics, factory, LEFT 844
 
  • J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda
    KEK, Ibaraki, Japan
  • A. Lyndaker, D.P. Peterson, N.T. Rider
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  X-ray beam size monitors at SuperKEKB must withstand high, sustained incident power loads. Two prototype optics elements were fabricated and tested at CesrTA, using incident X-ray power densities comparable to those expected at the SuperKEKB LER. One element was based on a silicon substrate, the other a CVD diamond substrate, with each substrate supporting a coded aperture mask pattern in gold on its surface. The diamond substrate mask showed superior performance to the silicon substrate mask, with the the mask pattern on the silicon substrate melting at the highest incident power level tested, where the diamond-substrate mask survived. We will present here the high-power test results, along with analysis of X-ray power absorption and heat transfer in the two prototype elements, and the resulting implications for the design of the optics, beam line and heat sink for SuperKEKB.  
 
WEPF18 Zemax Simulations of Diffraction and Transition Radiation OTR, radiation, target, electron 852
 
  • T. Aumeyr, P. Karataev
    JAI, Egham, Surrey, United Kingdom
  • M.G. Billing
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • L.M. Bobb, B. Bolzon, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  
  Diffraction Radiation (DR) and Transition Radiation (TR) are produced when a relativistic charged particle moves in the vicinity of a medium or through a medium respectively. The target atoms are polarised by the electric field of the charged particle, which then oscillate thus emitting radiation with a very broad spectrum. The spatial-spectral properties of DR/TR are sensitive to various electron beam parameters. Several projects aim to measure the transverse (vertical) beam size using DR or TR. This paper reports on how numerical simulations using Zemax can be used to study such a system.  
poster icon Poster WEPF18 [0.573 MB]  
 
WEPF23 Beam Diagnostics R&D within oPAC radiation, diagnostics, OTR, transverse 864
 
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: oPAC is funded by the European Commission under Grant Agreement Number 289485.
Optimization of particle accelerators by combining research into beam physics, beam instrumentation, accelerator control systems and numerical simulation studies is the goal of the oPAC project. Supported with 6 Million Euros by the European Union, the network is one of the largest-ever Initial Training Networks. During the project's four year duration 22 fellows will be trained and a very broad international training program, consisting of schools, topical workshops and conferences will be organized by a consortium of currently more than 30 partner institutions. In this contribution, we will give an overview of oPAC's broad beam diagnostics R&D program, comprising absolute beam intensity measurements for low energy beams, beam diagnostics for synchrotron light sources, cyrogenic beam loss monitors, beam halo monitoring and 3D dose measurements as part of intensity modulated radiotherapy treatment. We will also summarize past oPAC events and give an outlook on future events. 		 
 
WEPF35 Current Status of the Schottky Cavity Sensor for the CR at FAIR coupling, dipole, shielding, vacuum 907
 
  • M. Hansli, R. Jakoby, A. Penirschke
    TU Darmstadt, Darmstadt, Germany
  • P. Hülsmann, W. Kaufmann
    GSI, Darmstadt, Germany
  
  Funding: This work was supported by the GSI. The author would like to thank the CST AG for providing CST Studio Suite.
In this paper the current status of the Schottky Cavity Sensor development for the Collector Ring at FAIR, a dedicated storage ring for secondary particles, rare isotopes, and antiprotons, is presented. Designed for longitudinal and transversal Schottky signals, the Sensor features a pillbox cavity with attached waveguide filters utilizing the Monopole mode at 200 MHz for longitudinal and the Dipole mode at around 330 MHz for transversal Schottky measurements. Separated coupling structures allow for mode-selective coupling to measure the different Schottky planes independently. A ceramic vacuum shielding inside the pillbox is implemented to enable non-hermetic adjustable coupling, tuning devices and waveguide structures. Simulations of the structure with focus on the impact of the coupling structures and the ceramic vacuum shielding on the R-over-Q values and the coupling are presented as well as measurements of a scaled demonstrator including comparisons with the simulations. 		 
 
THBL1 RF Heating from Wake Losses in Diagnostics Structures resonance, longitudinal, LHC, impedance 929
 
  • E. Métral
    CERN, Geneva, Switzerland
  
  Heating of diagnostics structures (striplines, buttons, screen vessels, wire scanners etc) has been observed at many facilities with higher stored currents*. Simulations of wake losses using 3D EM codes are regularly used to estimate the amount of power lost from the bunched beam but on its own this does not tell how much is radiated back into the beam pipe or transmitted into external ports and how much is actually being dissipated in the structure and where. This talk should introduce into the matter, summarise some of the observations at various facilities and illustrate what approaches of detailed simulations have been taken.
* summarizing a workshop at DLS (see http://tinyurl.com/wakeloss ) 		 
slides icon Slides THBL1 [9.078 MB]