IBIC2018 - Table of Session: WEPB (Wednesday Poster B)

Paper	Title	Page
WEPB01	Photon Beam Imager at SOLEIL	425
	M. Labat, J. Da Silva, N. Hubertpresenter, F. Lepage SOLEIL, Gif-sur-Yvette, France
	In one of the long straight sections of SOLEIL is installed a pair of canted in-vacuum undulators for the ANATOMIX and NANOSCOPIUM beamlines. Since the upstream undulator radiation can potentially damage the downstream undulator magnets, an accurate survey of the respective alignment of the two devices is mandatory. An XBPM has been initially installed for this purpose in the beamline frontend. For redundancy and further analysis, an X-ray imager was then designed and added just downstream the XBPM. It is made of a diamond plate that can be inserted into the upstream beamline frontend at low current. Fluorescence of the Nitrogen impurities in the diamond is imaged on a CCD to check that the upstream radiation is not hitting the downstream insertion device. We present the commissioning of this new device together with its first results in operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB01
About •	paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB02	Development of a a YAG/OTR Monitor	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB02
About •	paper received ※ 04 September 2018 paper accepted ※ 24 September 2018 issue date ※ 29 January 2019
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WEPB03	First Prototype of a Coronagraph-based Halo Monitor for BERLinPro	434
	J.G. Hwang, J. Kuszynski HZB, Berlin, Germany
	Since particle losses by beam halo induced by space charge force and scattering of trapped ions are critical issues for superconducting-linac based high power machines such as BERLinPro, a halo monitor is demanded to monitor and control particle distribution at the level of 10^-4 ~ 10^-5 of the core intensity. A coronagraph-based halo monitor was adopted and the first prototype has been designed as a demonstrator system aimed at resolving a halo-core contrast in the 10^-3 to 10^-4 range. This monitor was tested at BESSY II with various operation modes such as Transverse Resonance Island Buckets (TRIBs) and Pulse-Picking by Resonant Excitation (PPRE). We show our design parameters, experimental criterion, and experimental results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB03
About •	paper received ※ 04 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB04	Comparison of YAG Screens and LYSO Screens at PITZ	438
	R. Niemczyk, P. Boonpornprasert, Y. Chen, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan, Q.T. Zhao DESY Zeuthen, Zeuthen, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The Photo Injector Test facility at DESY in Zeuthen (PITZ) is dedicated to the development of high-brightness electron sources for free-electron lasers. At PITZ, to measure the emittance of space-charge-dominated beams, the slit scan technique is used. For slice emittance measurements a transverse deflecting structure (TDS) is employed. The electron beam distribution is measured by means of scintillator screens. Both the TDS and the slit mask reduce the signal strength, giving stringent requirements on the sensitivity of the screens. At PITZ, high-sensitivity Ce:LYSO screens have been installed at the same screen stations as the standard Ce:YAG screens to solve low-intensity issues. A comparison of both screens is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB04
About •	paper received ※ 03 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPB06	Time-Synchronous Measurements of Transient Beam Dynamics at SPEAR3	441
	Q. Lin, Z.H. Sun Donghua University, Shanghai, People’s Republic of China W.J. Corbett, D.J. Martin, K. Tian SLAC, Menlo Park, California, USA
	Funding: Work supported by the China Scholarship Council and the US Department of Energy Contract DE-AC03-76SF00515, Office of Basic Energy Sciences. Multi-bunch beam instabilities can often be controlled with high-speed digital bunch-by-bunch feedback systems. The detected motion is based on charge centroid measurements that, for short bunches, cannot resolve intrabunch charge dynamics. To compliment the BxB data, we installed a fast-gated camera with a rotating mirror to sweep visible-light synchrotron radiation across the camera CCD. The SR measurements present a complimentary view of the motion. For this work we generated transient beam events in SPEAR3 using the BxB feedback system and synchronously observed the motion on the camera. Results are presented for a high-order multibunch beam instability and for single bunch drive-damp experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB06
About •	paper received ※ 07 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019
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WEPB09	Wire Scanner Measurements at the PAL-XFEL	445
	G. Kim, H.-S. Kang, C. Kim, B.G. Oh, D.C. Shin PAL, Pohang, Kyungbuk, Republic of Korea
	The PAL-XFEL, an X-ray Free electron laser user facility based on a 10 GeV normal conducting linear accelerator, have been operational at Pohang, South Korea. The wire scanners are installed for transverse beam profile measurement of the Linac and the Hard X-ray undulator section. The wire scanner is a useful device for emittance measurements in the Hard X-ray undulator section. In this paper, we describe the details of the wire scanner and the results of the measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB09
About •	paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB10	Grating Scanner for Measurement of Micron-size Beam Profiles	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
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB10
About •	paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB11	Spatial Resolution Improvement of OTR Monitors by Off-axis Light Collection	451
	A. Potylitsyn, A.I. Novokshonov, L.G. Sukhikhpresenter TPU, Tomsk, Russia G. Kube, A.I. Novokshonov 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 The spatial resolution of an OTR monitor for electron beam profile diagnostics is determined by the resolution of the optical system and by the Point Spread Function (PSF) representing the single electron image. In the image plane, the PSF has a typical lobe-shape distribution with an inter-peak distance depending on wavelength and lens aperture ratio []. For a beam with a transverse rms size smaller than the distance, the reconstruction of the beam profile has several difficulties [, *]. We propose to reduce the PSF contribution and to improve the spatial resolution of an OTR monitor simply by rotating the lens optical axis with respect to the specular reflection direction. If the difference between the rotational angle and the lens aperture is much larger than the inverse Lorentz factor, the PSF has a Gaussian-like distribution which matches practically with the Airy distribution. Thus the resolution depends on wavelength and lens aperture. In principle, for lens apertures in the order of 0.1 rad such an approach should allow to measure beam sizes comparable to the wavelength of observation, using a simple deconvolution procedure for the measured image and the PSF. M. Castellano, V.Verzilov, Phys. Rev. ST-AB, 1 (1998). K.Kruchinin, S.T.Boogert, P.Karataev et al., Proc. IBIC 2013 (2013). * L.G. Sukhikh, A.P. Potylitsyn, G. Kube, Phys. Rev. AB 20 (2017).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB11
About •	paper received ※ 04 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPB12	Design and Implementation of Non-Invasive Profile Monitors for the ESS LEBT	455
	C.A. Thomas, T.J. Grandsaert, H. Kocevar, Ø. Midttun, N. Milas, R. Miyamoto, T.J. Shea ESS, Lund, Sweden
	Non-invasive Profile Monitors are designed and distributed along the ESS Linac. In the Low Energy Beam Transport (LEBT), a specific one has been designed to be primarily a beam position monitor. Its main requirement is to measure the beam position with 100µm accuracy, and in addition it provides the beam profile and size. This performance have been shown to be possible and remains to be demonstrated experimentally. The instrument is also potentially capable of measuring the angle of the beam and its divergence. In this paper we will study the accuracy of such a measurement as function of the instrument image quality.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB12
About •	paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB13	Beam-Gas Imaging Measurements at LHCb	459
	G.R. Coombs, M. Ferro-Luzzi, R. Matev CERN, Meyrin, Switzerland
	The LHCb detector is one of the four large particle physics experiments situated around the LHC ring. The excellent spatial resolution of the experiment’s vertex locator (VELO) and tracking system allows the accurate reconstruction of interactions between the LHC beam and either residual or injected gas molecules. These reconstructed beam-gas interactions gives LHCb the ability, unique among experiments, to measure the shape and the longitudinal distribution of the beams. Analysis methods were originally developed for the purpose of absolute luminosity calibration, achieving an unprecedented precision of 1.2% in Run I. They have since been extended and applied for online beam-profile monitoring that is continuously published to the LHC, for dedicated cross-calibration with other LHC beam profile monitors and for studies of the dynamic vacuum effects due to the proximity of the VELO subdetector to the beam. In this talk, we give an overview of the LHCb experience with beam-gas imaging techniques, we present recent results on the outlined topics and we summarise the developments that are being pursued for the ultimate understanding of the Run II measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB13
About •	paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB14	Recent Results on Non-invasive Beam Size Measurement Methods Based on Polarization Currents	464
	S. Mazzoni, M. Bergamaschi, O.R. Jones, R. Kieffer, T. Lefèvre, F. Roncarolo CERN, Geneva, Switzerland A. Aryshev, N. Terunuma KEK, Ibaraki, Japan M.G. Billing, J.V. Conway, M.J. Forster, Y.L.P. Fuentes, J.P. Shanks, S. Wang, L.Y. Ying 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB14
About •	paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPB15	A Multipurpose Scintillating Fibre Beam Monitor for the Measurement of Secondary Beams at CERN	468
	I. Ortega Ruiz, L. Fosse, J. Franchi, A. Frassier, J. Fullerton, J. Kral, J. Lauener, T. Schneider, J. Spanggaard, G. Tranquille CERN, Meyrin, Switzerland
	A scintillating fibre beam monitor has been developed at CERN for the measurement of low energy and low intensity secondary beams. This monitor can track the passage of individual particles up to intensities of 10⁷ particles per second per mm², over an active area of 20 cm x 20 cm, and with a spatial resolution of 1 mm. Thanks to an external trigger system, the achieved detection efficiency is 95% and the noise level is kept below 10^-4 events/second. The simple design of this monitor avoids the common production difficulties of scintillating fibre detectors and makes its maintenance easier, when compared to other tracking detectors, due to the absence of gas or cooling. Using special electronics, a version of the monitor can also be used for time-of-flight measurements, achieving a time resolution of 900 ps. Thanks to its versatility, the monitor will perform several functions when measuring the secondary beams of the CERN Neutrino Platform: beam profile, position and intensity measurement, magnetic momentum spectrometry, particle identification through time-of-flight, and trigger generation for the experiments.
	Poster WEPB15 [1.172 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB15
About •	paper received ※ 03 September 2018 paper accepted ※ 14 September 2018 issue date ※ 29 January 2019
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WEPB16	Development of a Beam-Gas Curtain Profile Monitor for the High Luminosity Upgrade of the LHC	472
	R. Veness, M. Ady, N. Chritin, J. Glutting, O.R. Jones, R. Kersevan, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider CERN, Meyrin, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB16
About •	paper received ※ 04 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPB18	Performance of a Reflective Microscope Objective in an X-ray Pinhole Camera	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 WEPB18 [0.751 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB18
About •	paper received ※ 04 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB20	Experimental Setup of Apodization Techniques for Beam Diagnostics Performed at ELBE	482
	B.G. Freeman, J. Gubelipresenter, K. Jordan JLab, Newport News, Virginia, USA P.E. Evtushenko HZDR, Dresden, Germany
	The ELBE (Electron Linac for beams with high Brilliance and low Emittance) facility in Dresden, Germany is a multipurpose user facility, which is also used for accelerator R&D purposes. The beam line was set up for transverse beam profile measurements, where the imaging system includes a series of three apodizers and five circular apertures. During beam operations both of these were changed remotely through automated LabView routines. The bunch structure and charge were varied to collect a series of images that were acquired automatically, and then stored for later analysis. Over 12,000 images were captured and then analyzed using software written at Jefferson Lab that runs ImageJ as it’s main image processing library.
	Poster WEPB20 [0.357 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB20
About •	paper received ※ 06 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPB21	Transverse Beam Emittance Measurements with Multi-Slit and Moving-Slit Devices for LEReC	486
	C. Liu, A.V. Fedotov, D.M. Gassner, X. Gu, D. Kayran, J. Kewisch, T.A. Miller, M.G. Minty, V. Ptitsyn, S. Seletskiy, A. Sukhanov, D. Weiss BNL, Upton, Long Island, New York, USA A. Fuchs Ward Melville High School, Setauket- East Setauket, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Low Energy RHIC electron cooling (LEReC) [1] is the first bunched electron cooler, designed to cool low energy ion beams at RHIC. The beam quality, including the transverse beam emittance, is critical for the success of cooling. The transverse electron beam emittance was characterized with a multi-slit and moving-slit device at various locations in the beamline. The beam emittance measurement and analysis are presented in this report.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB21
About •	paper received ※ 01 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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Paper

Title

Page

Photon Beam Imager at SOLEIL

425

M. Labat, J. Da Silva, N. Hubertpresenter, F. Lepage
SOLEIL, Gif-sur-Yvette, France

In one of the long straight sections of SOLEIL is installed a pair of canted in-vacuum undulators for the ANATOMIX and NANOSCOPIUM beamlines. Since the upstream undulator radiation can potentially damage the downstream undulator magnets, an accurate survey of the respective alignment of the two devices is mandatory. An XBPM has been initially installed for this purpose in the beamline frontend. For redundancy and further analysis, an X-ray imager was then designed and added just downstream the XBPM. It is made of a diamond plate that can be inserted into the upstream beamline frontend at low current. Fluorescence of the Nitrogen impurities in the diamond is imaged on a CCD to check that the upstream radiation is not hitting the downstream insertion device. We present the commissioning of this new device together with its first results in operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB01

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paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB02

Development of a a YAG/OTR Monitor

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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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB02

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paper received ※ 04 September 2018 paper accepted ※ 24 September 2018 issue date ※ 29 January 2019

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WEPB03

First Prototype of a Coronagraph-based Halo Monitor for BERLinPro

434

J.G. Hwang, J. Kuszynski
HZB, Berlin, Germany

Since particle losses by beam halo induced by space charge force and scattering of trapped ions are critical issues for superconducting-linac based high power machines such as BERLinPro, a halo monitor is demanded to monitor and control particle distribution at the level of 10^-4 ~ 10^-5 of the core intensity. A coronagraph-based halo monitor was adopted and the first prototype has been designed as a demonstrator system aimed at resolving a halo-core contrast in the 10^-3 to 10^-4 range. This monitor was tested at BESSY II with various operation modes such as Transverse Resonance Island Buckets (TRIBs) and Pulse-Picking by Resonant Excitation (PPRE). We show our design parameters, experimental criterion, and experimental results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB03

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paper received ※ 04 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB04

Comparison of YAG Screens and LYSO Screens at PITZ

438

R. Niemczyk, P. Boonpornprasert, Y. Chen, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan, Q.T. Zhao
DESY Zeuthen, Zeuthen, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The Photo Injector Test facility at DESY in Zeuthen (PITZ) is dedicated to the development of high-brightness electron sources for free-electron lasers. At PITZ, to measure the emittance of space-charge-dominated beams, the slit scan technique is used. For slice emittance measurements a transverse deflecting structure (TDS) is employed. The electron beam distribution is measured by means of scintillator screens. Both the TDS and the slit mask reduce the signal strength, giving stringent requirements on the sensitivity of the screens. At PITZ, high-sensitivity Ce:LYSO screens have been installed at the same screen stations as the standard Ce:YAG screens to solve low-intensity issues. A comparison of both screens is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB04

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paper received ※ 03 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPB06

Time-Synchronous Measurements of Transient Beam Dynamics at SPEAR3

441

Q. Lin, Z.H. Sun
Donghua University, Shanghai, People’s Republic of China
W.J. Corbett, D.J. Martin, K. Tian
SLAC, Menlo Park, California, USA

Funding: Work supported by the China Scholarship Council and the US Department of Energy Contract DE-AC03-76SF00515, Office of Basic Energy Sciences.
Multi-bunch beam instabilities can often be controlled with high-speed digital bunch-by-bunch feedback systems. The detected motion is based on charge centroid measurements that, for short bunches, cannot resolve intrabunch charge dynamics. To compliment the BxB data, we installed a fast-gated camera with a rotating mirror to sweep visible-light synchrotron radiation across the camera CCD. The SR measurements present a complimentary view of the motion. For this work we generated transient beam events in SPEAR3 using the BxB feedback system and synchronously observed the motion on the camera. Results are presented for a high-order multibunch beam instability and for single bunch drive-damp experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB06

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paper received ※ 07 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019

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WEPB09

Wire Scanner Measurements at the PAL-XFEL

445

G. Kim, H.-S. Kang, C. Kim, B.G. Oh, D.C. Shin
PAL, Pohang, Kyungbuk, Republic of Korea

The PAL-XFEL, an X-ray Free electron laser user facility based on a 10 GeV normal conducting linear accelerator, have been operational at Pohang, South Korea. The wire scanners are installed for transverse beam profile measurement of the Linac and the Hard X-ray undulator section. The wire scanner is a useful device for emittance measurements in the Hard X-ray undulator section. In this paper, we describe the details of the wire scanner and the results of the measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB09

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paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB10

Grating Scanner for Measurement of Micron-size Beam Profiles

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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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB10

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paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB11

Spatial Resolution Improvement of OTR Monitors by Off-axis Light Collection

451

A. Potylitsyn, A.I. Novokshonov, L.G. Sukhikhpresenter
TPU, Tomsk, Russia
G. Kube, A.I. Novokshonov
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
The spatial resolution of an OTR monitor for electron beam profile diagnostics is determined by the resolution of the optical system and by the Point Spread Function (PSF) representing the single electron image. In the image plane, the PSF has a typical lobe-shape distribution with an inter-peak distance depending on wavelength and lens aperture ratio [*]. For a beam with a transverse rms size smaller than the distance, the reconstruction of the beam profile has several difficulties [**, ***]. We propose to reduce the PSF contribution and to improve the spatial resolution of an OTR monitor simply by rotating the lens optical axis with respect to the specular reflection direction. If the difference between the rotational angle and the lens aperture is much larger than the inverse Lorentz factor, the PSF has a Gaussian-like distribution which matches practically with the Airy distribution. Thus the resolution depends on wavelength and lens aperture. In principle, for lens apertures in the order of 0.1 rad such an approach should allow to measure beam sizes comparable to the wavelength of observation, using a simple deconvolution procedure for the measured image and the PSF.
* M. Castellano, V.Verzilov, Phys. Rev. ST-AB, 1 (1998).
** K.Kruchinin, S.T.Boogert, P.Karataev et al., Proc. IBIC 2013 (2013).
*** L.G. Sukhikh, A.P. Potylitsyn, G. Kube, Phys. Rev. AB 20 (2017).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB11

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paper received ※ 04 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPB12

Design and Implementation of Non-Invasive Profile Monitors for the ESS LEBT

455

C.A. Thomas, T.J. Grandsaert, H. Kocevar, Ø. Midttun, N. Milas, R. Miyamoto, T.J. Shea
ESS, Lund, Sweden

Non-invasive Profile Monitors are designed and distributed along the ESS Linac. In the Low Energy Beam Transport (LEBT), a specific one has been designed to be primarily a beam position monitor. Its main requirement is to measure the beam position with 100µm accuracy, and in addition it provides the beam profile and size. This performance have been shown to be possible and remains to be demonstrated experimentally. The instrument is also potentially capable of measuring the angle of the beam and its divergence. In this paper we will study the accuracy of such a measurement as function of the instrument image quality.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB12

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paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB13

Beam-Gas Imaging Measurements at LHCb

459

G.R. Coombs, M. Ferro-Luzzi, R. Matev
CERN, Meyrin, Switzerland

The LHCb detector is one of the four large particle physics experiments situated around the LHC ring. The excellent spatial resolution of the experiment’s vertex locator (VELO) and tracking system allows the accurate reconstruction of interactions between the LHC beam and either residual or injected gas molecules. These reconstructed beam-gas interactions gives LHCb the ability, unique among experiments, to measure the shape and the longitudinal distribution of the beams. Analysis methods were originally developed for the purpose of absolute luminosity calibration, achieving an unprecedented precision of 1.2% in Run I. They have since been extended and applied for online beam-profile monitoring that is continuously published to the LHC, for dedicated cross-calibration with other LHC beam profile monitors and for studies of the dynamic vacuum effects due to the proximity of the VELO subdetector to the beam. In this talk, we give an overview of the LHCb experience with beam-gas imaging techniques, we present recent results on the outlined topics and we summarise the developments that are being pursued for the ultimate understanding of the Run II measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB13

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paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB14

Recent Results on Non-invasive Beam Size Measurement Methods Based on Polarization Currents

464

S. Mazzoni, M. Bergamaschi, O.R. Jones, R. Kieffer, T. Lefèvre, F. Roncarolo
CERN, Geneva, Switzerland
A. Aryshev, N. Terunuma
KEK, Ibaraki, Japan
M.G. Billing, J.V. Conway, M.J. Forster, Y.L.P. Fuentes, J.P. Shanks, S. Wang, L.Y. Ying
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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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB14

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paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPB15

A Multipurpose Scintillating Fibre Beam Monitor for the Measurement of Secondary Beams at CERN

468

I. Ortega Ruiz, L. Fosse, J. Franchi, A. Frassier, J. Fullerton, J. Kral, J. Lauener, T. Schneider, J. Spanggaard, G. Tranquille
CERN, Meyrin, Switzerland

A scintillating fibre beam monitor has been developed at CERN for the measurement of low energy and low intensity secondary beams. This monitor can track the passage of individual particles up to intensities of 10⁷ particles per second per mm², over an active area of 20 cm x 20 cm, and with a spatial resolution of 1 mm. Thanks to an external trigger system, the achieved detection efficiency is 95% and the noise level is kept below 10^-4 events/second. The simple design of this monitor avoids the common production difficulties of scintillating fibre detectors and makes its maintenance easier, when compared to other tracking detectors, due to the absence of gas or cooling. Using special electronics, a version of the monitor can also be used for time-of-flight measurements, achieving a time resolution of 900 ps. Thanks to its versatility, the monitor will perform several functions when measuring the secondary beams of the CERN Neutrino Platform: beam profile, position and intensity measurement, magnetic momentum spectrometry, particle identification through time-of-flight, and trigger generation for the experiments.

Poster WEPB15 [1.172 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB15

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paper received ※ 03 September 2018 paper accepted ※ 14 September 2018 issue date ※ 29 January 2019

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WEPB16

Development of a Beam-Gas Curtain Profile Monitor for the High Luminosity Upgrade of the LHC

472

R. Veness, M. Ady, N. Chritin, J. Glutting, O.R. Jones, R. Kersevan, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider
CERN, Meyrin, 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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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB16

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paper received ※ 04 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPB18

Performance of a Reflective Microscope Objective in an X-ray Pinhole Camera

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 WEPB18 [0.751 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB18

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paper received ※ 04 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB20

Experimental Setup of Apodization Techniques for Beam Diagnostics Performed at ELBE

482

B.G. Freeman, J. Gubelipresenter, K. Jordan
JLab, Newport News, Virginia, USA
P.E. Evtushenko
HZDR, Dresden, Germany

The ELBE (Electron Linac for beams with high Brilliance and low Emittance) facility in Dresden, Germany is a multipurpose user facility, which is also used for accelerator R&D purposes. The beam line was set up for transverse beam profile measurements, where the imaging system includes a series of three apodizers and five circular apertures. During beam operations both of these were changed remotely through automated LabView routines. The bunch structure and charge were varied to collect a series of images that were acquired automatically, and then stored for later analysis. Over 12,000 images were captured and then analyzed using software written at Jefferson Lab that runs ImageJ as it’s main image processing library.

Poster WEPB20 [0.357 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB20

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paper received ※ 06 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPB21

Transverse Beam Emittance Measurements with Multi-Slit and Moving-Slit Devices for LEReC

486

C. Liu, A.V. Fedotov, D.M. Gassner, X. Gu, D. Kayran, J. Kewisch, T.A. Miller, M.G. Minty, V. Ptitsyn, S. Seletskiy, A. Sukhanov, D. Weiss
BNL, Upton, Long Island, New York, USA
A. Fuchs
Ward Melville High School, Setauket- East Setauket, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Low Energy RHIC electron cooling (LEReC) [1] is the first bunched electron cooler, designed to cool low energy ion beams at RHIC. The beam quality, including the transverse beam emittance, is critical for the success of cooling. The transverse electron beam emittance was characterized with a multi-slit and moving-slit device at various locations in the beamline. The beam emittance measurement and analysis are presented in this report.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB21

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paper received ※ 01 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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