Keyword: photon
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MOPA17 Momentum Compaction Measurement Using Synchrotron Radiation SRF, radiation, electron, experiment 66
  • L. Torino, N. Carmignani, A. Franchi
    ESRF, Grenoble, France
  The momentum compaction factor of a storage ring can be obtained by measuring how the beam energy changes with the RF frequency. Direct measurement of the beam energy can be difficult, long or even not possible with acceptable accuracy and precision in some machines such as ESRF. Since the energy spectrum of the Synchrotron Radiation (SR) depends on the beam energy, it is indeed possible to relate the variation of the beam energy with a variation of the produced SR flux. In this proceeding, we will present how we obtain a measurement of the momentum compaction using this dependence.  
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TUOB04 A Vertical Phase Space Beam Position and Emittance Monitor for Synchrotron Radiation synchrotron, electron, experiment, detector 186
  • N. Samadi
    University of Saskatchewan, Saskatoon, Canada
  • L.D. Chapman, L.O. Dallin
    CLS, Saskatoon, Saskatchewan, Canada
  We report on a system (ps-BPM) that can measure the electron source position and angular motion at a single location in a synchrotron bend magnet beamline using a combination of a monochromator and an absorber with a K-edge to which the monochromator was tuned in energy. The vertical distribution of the beam was visualized with an imaging detector where horizontally one part of the beam was with the absorber and the other part with no absorber. The small range of angles from the source onto the monochromator crystals creates an energy range that allows part of the beam to be below the K-edge and the other part above. Measurement of the beam vertical location without the absorber and edge vertical location with the absorber gives the source position and angle. Measurements were made to investigate the possibility of using the ps-BPM to correct experimental imaging data. We have introduced periodic electron beam motion using a correction coil in the storage ring lattice. The measured and predicted motions compared well for two different frequencies. We then show that measurement of the beam width and edge width gives information about the vertical electron source size and angular distribution.
[1] A phase-space beam position monitor for synchrotron radiation. J Synchrotron Radiat, 2015. 22(4): p. 946-55.
slides icon Slides TUOB04 [9.532 MB]  
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TUPA02 A Micromegas Based Neutron Detector for the ESS Beam Loss Monitoring neutron, detector, simulation, proton 211
  • L. Segui, D. Desforge, F. Gougnaud, T.J. Joannem, C. Lahonde-Hamdoun, Ph. Legou, J. Marroncle, V. Nadot, T. Papaevangelou, G. Tsiledakis
    CEA/IRFU, Gif-sur-Yvette, France
  • H. Alves, S. Aune, J. Beltramelli, Q. Bertrand, T. Bey, M. Combet, M. Kebbiri, P. Le Bourlout, O. Maillard
    IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France
  • I. Dolenc Kittelmann, T.J. Shea
    ESS, Lund, Sweden
  • Y. Mariette
    CEA/DSM/IRFU, France
  Beam loss monitors are of high importance in high-intensity hadron facilities where any energy loss can produce damage or/and activation of materials. A new type of neutron BLM have been developed for hadron accelerators aiming to cover the low energy part. In this region typical BLMs based on charged particle detection are not appropriate because the expected particle fields will be dominated by neutrons and photons. Moreover, the photon background due to the RF cavities can produce false beam loss signals. The BLM proposed is based on gaseous Micromegas detectors, designed to be sensitive to fast neutrons and insensitive to photons (X and gamma). In addition, the detectors will be insensitive to thermal neutrons, since part of them will not be directly correlated to beam loss location. The appropriate configuration of the Micromegas operating conditions will allow excellent timing, intrinsic photon background suppression and individual neutron counting, extending thus the dynamic range to very low particle fluxes. The concept of the detectors and the first results from tests in several facilities will be presented. Moreover, their use in the nBLM ESS system will be also discussed  
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TUPA09 The Monte Carlo Simulation for the Radiation Protection in a Nozzle of HUST-PTF neutron, proton, radiation, shielding 232
  • Y.C. Yu, H.D. Guo, Y.Y. Hu, X.Y. Li, Y.J. Lin, P. Tan, L.G. Zhang
    HUST, Wuhan, People's Republic of China
  Nozzle is the core component in proton therapy machine, which is closest to the patient and is necessary to consider the radiation impacts on patients and machine. The ionization chamber and the range shifter in active scanning nozzle are the main devices in the beam path that affect the proton beam and produce secondary particles during the collision, causing damage to the patients and machine. In this paper, the spatial distribution of energy deposited in all regions, the distribution of the secondary particles of 70-250MeV proton beam in the nozzle in Huazhong University of Science and Technology Proton Therapy Facility(HUST-PTF) are studied with Monte Carlo software FLUKA in order to provide reference for radiation shielding design. Six types of materials commonly used today as range shifters are analyzed in terms of the influence on radiation, so that the most suitable material will be selected.  
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WEPA02 Recent Progress of Bunch Resolved Beam Diagnostics for BESSY VSR diagnostics, cavity, beam-diagnostic, operation 379
  • J.G. Hwang, T. Atkinson, P. Goslawski, A. Jankowiak, M. Koopmans, M. Ries, A. Schälicke, G. Schiwietz
    HZB, Berlin, Germany
  • T. Mertens
    Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany
  BESSY VSR is an upgrade project of the existing storage ring BESSY II to create long and short photon pulses simultaneously for all beam lines by installing additional superconducting cavities with harmonic frequencies of 1.5 GHz and 1.75 GHz. The storage-ring operation will be influenced by a transient beam-loading effect of all cavities and by the complex filling pattern due to the disparity in the current of long and short bunches. This, in turn, could introduce a variation of beam trajectory, transverse profile, and length for the different bunches. This stimulates the development of bunch-resolved monitors for bunch length, beam size, filling pattern and beam trajectory displacement. In this paper, we show new developments of crucial beam diagnostics including measurements of the bunch-resolved temporal profile with a resolution of less than 1 ps FWHM and bunch-resolved profile with a resolution of less than 10 um rms. The upgrade of the booster beam-diagnostics will be discussed as well.  
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WEPB02 Development of a a YAG/OTR Monitor diagnostics, background, detector, target 429
  • R.J. Yang, P. Bambade, S. Wallon
    LAL, Orsay, France
  • A. Aryshev, T. Naito, N. Terunuma
    KEK, Ibaraki, Japan
  • M. Bergamaschi
    CERN, Geneva, Switzerland
  To study the mechanisms of beam halo formation and its dynamics, a YAG/OTR monitor has been developed and tested at the KEK-ATF. The monitor has four ceramic Ce:YAG screens for the visualization of the beam core and beam halo and an OTR target to provide complementary measurements of beam core. A high dynamic range (DNR>105) and a high resolution (<10 um) have been demonstrated through the optimization of light detection, reduction of background and suppression of scintillation saturation. Measurements using this monitor are consistent with previous results and theoretical modeling of beam halo at ATF, and have allowed further progress in the characterization of the driving mechanisms.  
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WEPB10 Grating Scanner for Measurement of Micron-size Beam Profiles electron, simulation, collider, positron 448
  • L.G. Sukhikh, A. Potylitsyn, S.A. Strokov
    TPU, Tomsk, Russia
  • G. Kube, K. Wittenburg
    DESY, Hamburg, Germany
  Funding: The work was partly supported by the program ‘‘Nauka' of the Russian Ministry of Education and Science, grant # 3.1903.2017
Wire scanners are widely used for transverse beam size diagnostics. The minimum detectable beam size is affected by the diameter of a single wire. The smallest carbon or tungsten wires used so far have diameters of about 4 microns. With the development of modern electron accelerators and the demands from future linear electron-positron colliders, sub-micron beam sizes have to be resolved. In order to increase the resolution, the decrease of the wire diameter is required. The authors of Ref. * proposed to manufacture thin gold stripes of rectangular shape (widths are equal to 1 µm or 2 µm and height is equal to 3 µm) on Si3N4 membrane. We propose to use another arrangement of gold stripes with varying period on a Si substrate. A set of 11 stripes with 1 µm width and 10 micron height with varying gap width in the range 3-0.25 µm ("grating scanner") was simulated by using an analytical model and by the Geant4 code. By moving this scanner across the beam one could measure the Bremsstrahlung yield vs. the coordinate, resulting in an oscillating dependence. The visibility of the resulting image allows defining the beam sizes in the range of 0.5-1.5 µm for the proposed scanner parameters.
* S. Borrelli et al., "Generation and Measurement of Sub-Micrometer Relativistic Electron Beams", arXiv:1804.04252v1 [physics.acc-ph] 11 Apr 2018
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WEPB14 Recent Results on Non-invasive Beam Size Measurement Methods Based on Polarization Currents radiation, target, experiment, polarization 464
  • S. Mazzoni, M. Bergamaschi, O.R. Jones, R. Kieffer, T. Lefèvre, F. Roncarolo
    CERN, Geneva, Switzerland
  • A. Aryshev, N. Terunuma
    KEK, Ibaraki, Japan
  • L.Y. Bartnik, M.G. Billing, J.V. Conway, M.J. Forster, Y.L.P. Fuentes, J.P. Shanks, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V.V. Bleko, A.S. Konkov, A. Potylitsyn
    TPU, Tomsk, Russia
  • L. Bobb
    DLS, Oxfordshire, United Kingdom
  • P. Karataev, K. Lekomtsev
    JAI, Egham, Surrey, United Kingdom
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  We present recent results on non-invasive beam profile measurement techniques based on Diffraction Radiation (DR) and Cherenkov Diffraction Radiation (ChDR). Both methods exploit the analysis of broadband electromagnetic radiation resulting from polarization currents produced in, or at the boundary of, a medium in close proximity of a charged particle beam. To increase the resolution of DR, measurements were performed in the UV range at a wavelength of 250 nm. With such configurations, sensitivity to the beam size of a 1.2 GeV electron beam below 10 um was observed at the Accelerator Test Facility (ATF) at KEK, Japan. In the case of the ChDR, a proof of principle study was carried out at the Cornell Electron Storage Ring (CESR) where beam profiles were measured in 2017 on a 5.3 GeV positron beam. At the time of writing an experiment to measure the resolution limit of ChDR has been launched at ATF where smaller beam sizes are available. We will present experimental results and discuss the application of such techniques for future accelerators.  
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WEPB16 Development of a Beam-Gas Curtain Profile Monitor for the High Luminosity Upgrade of the LHC electron, proton, simulation, vacuum 472
  • R. Veness, M. Ady, N. Chritin, J. Glutting, O.R. Jones, R. Kersevan, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider
    CERN, Geneva, Switzerland
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • A. Salehilashkajani
    The University of Liverpool, Liverpool, United Kingdom
  • P. Smakulski
    WRUT, Wroclaw, Poland
  • C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  High luminosity upgrades to the LHC at CERN and future energy frontier machines will require a new generation of minimally invasive profile measurement instruments. Production of a dense, focussed gas target allows beam-gas fluorescence to be exploited as an observable, giving an instrument suitable for installation even in regions of high magnetic field. This paper describes the development of a device based on these principles that would be suitable for operation in the LHC. It focusses on mechanisms for the production of a homogeneous gas curtain, the selection of an appropriate working gas and the optical fluorescence detection system.  
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WEPB18 Performance of a Reflective Microscope Objective in an X-ray Pinhole Camera target, electron, emittance, storage-ring 477
  • L. Bobb, G. Rehm
    DLS, Oxfordshire, United Kingdom
  X-ray pinhole cameras are used to measure the transverse beam profile of the electron beam in the storage ring from which the emittance is calculated. As improvements to the accelerator lattice reduce the beam emittance, e.g. with upgrades to fourth generation synchrotron light sources, likewise the beam size will be reduced such that micron and sub-micron scale resolution is required for beam size measurement. Therefore the spatial resolution of the pinhole camera imaging system must be improved accordingly. Here, the performance of a reflective microscope objective is compared to the high quality refractive lens which is currently in use to image the scintillator screen to the camera. The modulation transfer functions for each system have been assessed and will be discussed.  
poster icon Poster WEPB18 [0.751 MB]  
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WEPC08 Optical System of Beam Induced Fluorescence Monitor Toward MW Beam Power at the J-PARC Neutrino Beamline proton, operation, simulation, radiation 505
  • S.V. Cao, M.L. Friend, K. Sakashita
    KEK, Tsukuba, Japan
  • M. Hartz
    Kavli IPMU, Kashiwa, Japan
  • A. Nakamura
    Okayama University, Okayama, Japan
  A Beam Induced Fluorescence (BIF) monitor is being developed as an essential part of the monitor update toward MW beam power operation at the J-PARC neutrino beamline. By measuring the fluorescence light from proton-gas interactions, the BIF monitor will be used as a continuous and non-destructive diagnostic tool for monitoring the proton beam profile spill-by-spill, with position and width precision on the order of 200 µm. The main challenge lies in collecting a sufficient amount of fluorescence light for the beam profile reconstruction while controlling the beam-induced noise with the current beamline configuration. A study is presented with a particular focus on the optical system under development, which allows us to transport fluorescence light away from the high radiation environment near the proton beamline and detect the optical signal with a Multi-Pixel Photon-Counter-based fast readout.  
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WEPC16 Design and Radiation Simulation of the Scintillating Screen Detector for Proton Therapy Facility radiation, proton, simulation, electron 516
  • P. Tian, Q.S. Chen, K. Fan, J.Q. Li, K. Tang
    HUST, Wuhan, People's Republic of China
  A proton therapy facility based on a superconducting cyclotron is under construction in Huazhong University of Science and Technology (HUST). In order to achieve precise treatment or dose distribution, the beam current would vary from 0.4 nA to 500 nA, in which case conventional non-intercepting instruments would fail due to their low sensitivity. So we propose to use a retractable scintillating screen to measure beam position and beam profile. In this paper, a comprehensive description of our new designed screen monitor is presented, including the choice of material of the screen, optical calibration and simulation of radiation protection. According to the off-line test, the resolution of the screen monitor can reach 0.13 mm/pixel.  
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WEPC17 X-ray Pinhole Camera in the Diagnostics Beamlime BL7B at PLS-II electron, radiation, diagnostics, beam-diagnostic 519
  • J.J. Ko, J.Y. Huang, D. Kim, D.W. Lee, B.H. Oh, S. Shin, J. U. Yu
    PAL, Pohang, Kyungbuk, Republic of Korea
  • M. Yoon
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  The beam diagnostics beamline BL7B using synchrotron radiation with 8.6 keV critical photon energy from bending magnet has been used to measure the electron-beam size and photon-beam profile on real-time basis. After the completion of the PLS-II, the Compound Refractive Lens (CRL) system was implemented in the optical hutch at BL7B to measure the electron-beam size from X-ray imaging. But we could not have a good image due to short focal length caused by limited space of the optical hutch. To solve this problem a Pinole Camera is implemented in the front-end of BL7B in return for the beamline extension. The progresses on the new x-ray imaging system is introduced in this presentation.  
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