Keyword: background
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MOPG35 Single Pulse Sub-Picocoulomb Charge Measured by a Turbo-ICT in a Laser Plasma Accelerator laser, target, plasma, electron 119
  • F. Stulle, J.F. Bergoz
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • W. Leemans, K. Nakamura
    LBNL, Berkeley, California, USA
  Funding: The work by the BELLA Center scientists and staff was supported by Office of Science, Office of HEP, US DOE under Contract DE-AC02-05CH11231 and the National Science Foundation.
Experiments at the Berkeley Lab Laser Accelerator (BELLA) verified that the Turbo-ICT allows high resolution charge measurements even in the presence of strong background signals. For comparison, a Turbo-ICT and a conventional ICT were installed on the BELLA petawatt beamline, both sharing the same vacuum flanges. We report on measurements performed using a gas-jet and a capillary-discharge based laser plasma accelerator. In both setups the Turbo-ICT was able to resolve sub-picocoulomb charges.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG35  
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MOPG40 Performance Studies of a Single Vertical Beam Halo Collimation System at ATF2 collimation, simulation, wakefield, optics 139
  • N. Fuster-Martínez, A. Faus-Golfe
    IFIC, Valencia, Spain
  • P. Bambade, A. Faus-Golfe, S. Wallon, R.J. Yang
    LAL, Orsay, France
  • K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
    Sokendai, Ibaraki, Japan
  • K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  • I. Podadera, F. Toral
    CIEMAT, Madrid, Spain
  Funding: Work supported by IDC-20101074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02
In order to reduce the background that could limit the precision of the diagnostics located in the ATF2 post-IP beamline, a single vertical beam halo collimation system was installed in March 2016. In this paper we present the measurements done in March and May 2016 in order to characterize the collimation system performance. Furthermore, the collimator wakefield impact has also been measured and compared with theoretical calculations and numerical simulations in order to determine the most efficient operation mode of the collimation system in terms of halo cleaning and negligible wakefield impact.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG40  
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MOPG44 SNS RFQ Voltage Measurements Using X-Ray Spectrometer rfq, shielding, radiation, electron 154
  • A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
Absolute measurement of vane voltage is essential to understand RFQ transmission. We used a non-intrusive technique of bremsstrahlung X-ray measurement. Several windows were installed at SNS to allow measurement of the X-ray spectrum in different locations of the RFQ. A CdTe spectrometer was used to estimate spectrum cutoff energy that corresponds to the vane voltage. Different device setups are described as well as measurement accuracy and interpretation of experimental data.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG44  
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MOPG62 Novel Grating Designs for a Single-Shot Smith-Purcell Bunch Profile Monitor radiation, detector, electron, vacuum 213
  • A.J. Lancaster, G. Doucas, H. Harrison, I.V. Konoplev
    JAI, Oxford, United Kingdom
  Funding: This work was supported by the STFC UK (grant ST/M003590/1) and the Leverhulme Trust (International Network Grant IN-2015-012). H. Harrison is supported by STFC UK and the JAI for her DPhil.
Smith-Purcell radiation has been successfully used to perform longitudinal profile measurements of electron bunches with sub-ps lengths. These measurements require radiation to be generated from a series of gratings to cover a sufficient frequency range for accurate profile reconstruction. In past systems the gratings were used sequentially and so several bunches were required to generate a single profile, but modern accelerators would benefit from such measurements being performed on a bunch by bunch basis. To do this the radiation from all three gratings would need to be measured simultaneously, increasing the mechanical complexity of the device as each grating would need to be positioned individually and at a different azimuthal angle around the electron beam. Investigations into gratings designed to displace the radiation azimuthally will be presented. Such gratings could provide an alternative to the rotated-grating approach, and would simplify the design of the single-shot monitor by reducing the number of motors required as all of the gratings could be positioned using a single mount.
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG62  
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MOPG74 Design and Performance of Coronagraph for Beam Halo Measurements in the LHC injection, vacuum, scattering, synchrotron 253
  • A. Goldblatt, E. Bravin, F. Roncarolo, G. Trad
    CERN, Geneva, Switzerland
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  The CERN Large Hadron Collider is equipped with two Beam Synchrotron Radiation (BSR) systems, one per beam, used to monitor the transverse distribution of the beam, its longitudinal distribution and the abort gap population. During the 2015-2016 winter shut-down period, one of the two BSR systems was equipped with a prototype beam halo monitor, based on the coronagraph technique, classically used in astrophysics telescopes to measure the sun corona. The system design, as well as its optics, was inherited from the coronagraph used in the KEK Photon Factory with some modifications made in order to satisfy the LHC BSR source constraints. This project is in the framework of the HL-LHC project, for which there is the requirement to monitor the beam halo at the level of 10-6 of the core intensity. This first prototype has been designed as a demonstrator system aimed at resolving a halo-core contrast in the 10-3 to 10-4 range. After discussing the design of the LHC coronagraph and its technical implementation, this contribution presents the result of the first tests with beam and the planned system upgrades for 2017.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG74  
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MOPG75 Single Shot Transversal Profile Monitoring of Ultra Low Charge Relativistic Electron Bunches at REGAE electron, coupling, photon, detector 257
  • H. Delsim-Hashemi
    DESY, Hamburg, Germany
  Relativistic electron microscopes are increasingly under consideration in dream experiments of observing atomic scale motions as they occur. Compared to ordinary electron microscopes with energies limited to few tens of keV, relativistic electrons reduce strongly the space-charge effects. This enables packing more electrons in shorter bunches and thereby capturing atomic scale ultra-fast dynamics in single shot. A typical relativistic-electron-microscope, based on an RF-gun, can provide experiments with couple of thousands to millions of electrons bunched in a few μm length and a transversal dimension of a fraction of a mm. After scattering from a sample and at the position of detector, electrons are distributed over transversal dimensions typically two orders of magnitude larger. For transversal diagnostics before scattering a cost effective solution is implemented while for diffraction pattern detection objective is single-electron imaging with good signal to noise ratio in single shot. In this contribution the implementations and results at REGAE will be presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG75  
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TUPG20 The CMS Beam Halo Monitor at the LHC: Implementation and First Measurements detector, experiment, vacuum, luminosity 364
  • N. Tosi
    INFN-Bologna, Bologna, Italy
  A Cherenkov based detector system has been installed at the Large Hadron Collider (LHC), in order to measure the Machine Induced Background (MIB) for the Compact Muon Solenoid (CMS) experiment. The system is composed of forty identical detector units formed by a cylindrical Quartz radiator directly coupled to a Photomultiplier. These units are installed at a radius of 1.8m and a distance of 20.6 m from the CMS interaction point. The fast and direction-sensitive signal allows to measure incoming MIB particles while suppressing the much more abundant collision products and albedo particles, which reach the detector at a different time and from a different direction. The system readout electronics is based on the QIE10 ASIC and a uTCA based back-end, and it allows a continuous online measurement of the background rate separately per each bunch. The detector has been installed in 2015 and is now fully commissioned. Measurements demonstrating the capability of detecting anomalous beam conditions will be presented.
on behalf of the CMS collaboration
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG20  
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TUPG54 Novel Approach to the Elimination of Background Radiation in a Single-Shot Longitudinal Beam Profile Monitor radiation, detector, polarization, electron 471
  • H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster, H. Zhang
    JAI, Oxford, United Kingdom
  • A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  It is proposed to use the polarization of coherent Smith-Purcell radiation (cSPr) to distinguish between the cSPr signal and background radiation in a single-shot longitudinal bunch profile monitor. A preliminary measurement of the polarization has been carried out using a 1mm periodic metallic grating installed at the 8MeV electron accelerator LUCX, KEK (Japan). The measured degree of polarization at '=90° (300GHz) is 72.6 ±%. To make a thorough test of the theoretical model, measurements of the degree of polarization must be taken at more emission angles - equivalent to more frequencies.
This work was supported (in parts) by the: STFC UK, the Leverhulme Trust, JAI University of Oxford and the Photon and Quantum Basic Research Coordinated Development (Japan).
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG54  
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TUPG76 Performance Studies of Industrial CCD Cameras Based on Signal-To-Noise and Photon Transfer Measurements photon, electron, diagnostics, detector 540
  • G. Kube
    DESY, Hamburg, Germany
  Taking advantage of the rapid development and the huge market for commercial available optical sensors, in the past years optical measuring techniques took on greater significance. Nowadays, area scan CCD or CMOS sensors are widely used for beam profile diagnostics. They provide the full two-dimensional information about the particle beam distribution, allowing in principle to investigate shot-to-shot profile fluctuations at moderate repetition rates. In order to study the performance and to characterize these cameras, photon transfer is a widely applied popular and valuable testing methodology. In this contribution, studies based on signal-to-noise and photon transfer measurements are presented for CCD cameras which are in use for beam profile diagnostics at different DESY accelerators.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG76  
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WEPG54 Bunch Shape Measurements at the National Superconducting Cyclotron Laboratory ReAccelerator (ReA3) cavity, timing, electron, bunching 771
  • R. Shane, S.M. Lidia, Z. Liu, S. Nash, A.C.C. Villari, O. Yair
    FRIB, East Lansing, USA
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
The longitudinal bunch shape of a reaccelerated heavy-ion beam at the National Superconducting Cyclo-tron Laboratory's (NSCL) ReA3 beamline was measured using an Ostrumov-type bunch-shape monitor. The phase of the last accelerating cavity was varied to change the bunch length, while the energy was kept constant by adjusting the amplitude of the voltage on the cavity. Two peaks were observed in the longitudinal projection of the bunch shape distribution. The widths of the two peaks did not vary much when the cavity phase was changed, while the peak separation decreased to the point that the two peaks became unresolvable as the bunching was increased. The relative amplitudes of the two peaks was very sensitive to tuning parameters. This, coupled with a lack of information about the transverse profile of the bunch, complicated the analysis and made a simple width assignment difficult. Measurements were also made with an MCP timing grid for comparison. The general shape and trend of the two data sets were similar; however, the widths measured by the timing grid were about 30-50% smaller.
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG54  
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WEPG67 Non-Invasive Beam Profile Measurement for High Intensity Electron Beams electron, laser, photon, detector 803
  • T. Weilbach, K. Aulenbacher, M.W. Bruker
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  Beam profile measurements of high intensity electron beams below 10 MeV, e.g. in energy recovery linacs or magnetized high energy electron coolers, have to fulfill special demands. Commonly used diagnostic tools like synchrotron radiation and scintillation screens are ineffective or not able to withstand the beam power without being damaged. Non-invasive methods with comparable resolution are needed. Hence, a beam profile measurement system based on beam-induced fluorescence (BIF) was built. This quite simple system images the light generated by the interaction of the beam with the residual gas onto a PMT. A more elaborated system, the Thomson Laser Scanner (TLS) - the non-relativistic version of the Laser Wire Scanner - is proposed as a method for non-invasive measurement of all phase space components, especially in the injector and merger parts of an ERL. Since this measurement suffers from low count rates, special attention has to be given to the background. Beam profile measurements with the BIF system will be presented as well as a comparison with YAG screen measurements. The recent status of the TLS system will be presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG67  
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WEPG80 Optical Effects in High Resolution and High Dynamic Range Beam Imaging Systems electron, optics, diagnostics, radiation 844
  • J. Wolfenden, R.B. Fiorito, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • P. Karataev, K.O. Kruchinin
    JAI, Egham, Surrey, United Kingdom
  Optical systems are used to transfer light in beam diagnostics for a variety of imaging applications. The effect of the point spread function (PSF) of these optical systems on the resulting measurements is often approximated or misunderstood. It is imperative that the optical PSF is independently characterised, as this can severely impede the attainable resolution of a diagnostic measurement. A high quality laser and specially chosen optics have been used to generate an intense optical point source in order to accomplish such a characterisation. The point source was used to measure the PSFs of various electron-beam imaging systems. These systems incorporate a digital micro-mirror array, which was used to produce very high (>105) dynamic range images. The PSF was measured at each intermediary image plane of the optical system; enabling the origin of any perturbations to the PSF to be isolated and potentially mitigated. One of the characterised systems has been used for optical transition radiation (OTR) measurements of an electron beam at KEK-ATF2 (Tsukuba, Japan).  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG80  
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