Transverse Profile Monitors
Paper Title Page
TUCLA01 Direct Observation of Ultralow Vertical Emittance Using a Vertical Undulator 1
  • K.P. Wootton
    SLAC, Menlo Park, California, USA
  In recent work, the first quantitative measurements of electron beam vertical emittance using a vertical undulator were presented, with particular emphasis given to ultralow vertical emittances*. Using this apparatus, a geometric vertical emittance of 0.9 ± 0.3 pm rad has been observed. A critical analysis is given of measurement approaches that were attempted, with particular emphasis on systematic and statistical uncertainties. The method used is explained, compared to other techniques and the applicability of these results to other scenarios discussed.
*K.P. Wootton, M.J. Boland and R.P. Rassool (2014) Phys. Rev. ST Accel. Beams, 17, 112802.
slides icon Slides TUCLA01 [6.452 MB]  
TUCLA02 Recent Progress in X-Ray Emittance Diagnostics at SPring-8 1
  • S. Takano, M. Masaki
    JASRI/SPring-8, Hyogo-ken, Japan
  • H. Sumitomo
    SES, Hyogo-pref., Japan
  Synchrotron radiation in the X-ray range is suitable for non-destructive diagnostics of beam emittance *. Both direct imaging and interferometric techniques can resolve the micrometer-order transverse beam size. The beam emittance is obtained from the measured beam size with the knowledge of the betatron and dispersion functions and the beam energy spread. At the SPring-8 storage ring, we have recently developed two X-ray instruments for emittance diagnostics. The one for a bending magnet source is the X-ray pinhole camera which directly images the beam profile. A pinhole in the atmosphere is composed of combined narrow X-Y slits made of tungsten. A scintillator crystal is used to convert the X-ray beam image to a visible image. The spatial resolution is about 7 micrometers. It is operated for continuous emittance diagnostics and coupling correction of user operation of SPring-8. The other for an undulator source is the X-ray Fresnel diffractometry monitor **. Monochromatic X-rays are cut out by a single slit, and the vertical beam size is deduced from the depth of the central dip in a double-lobed diffraction pattern. Resolving beam size less than 5 micrometers is feasible.
* S. Takano, IPAC2010 WEZMH01, p2392. (2010)
** M. Masaki et al., Phys. Rev. ST Accel. Beams 18, 042802 (2015).
slides icon Slides TUCLA02 [6.309 MB]  
TUCLA03 Design of Coronagraph for the Observation of Beam Halo at LHC 1
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  • E. Bravin, O.R. Jones, F. Roncarolo, H. Schmickler, G. Trad
    CERN, Geneva, Switzerland
  In the LHC, the beam halo due to higher beam energy and intensities will increase the impact on LHC machine protection and on luminosity performance. Measurement of the beam halo distribution is therefore important for understanding and controlling the beam halo. A coronagraph was designed for the observation of the beam halo population. A new optical design of the coronagraph is made for the halo observation in the LHC. For convenience of masking the core image, we need a large transverse magnification. For this purpose, a telephoto lens arrangement is applied to the adjective lens to extend the focal length to obtain a large transverse magnification. The result of diffraction analysis, the contrast is estimated better than 106. Since the beam halo is estimated to 104 -105 of the core intensity, the coronagraph is estimated to have enough contrast for the observation of beam halo distribution at LHC. This paper describes the detail study of the coronagraph for the LHC for the observation of transverse profile of the beam halo with a contrast down to a level of 10-6 compared to the peak intensity of the beam core.  
slides icon Slides TUCLA03 [15.520 MB]  
TUPB007 Multifunction Instrument Designs with Low Impedance Structures for Profile, Energy, and Emittance Measurements for LEReC at BNL 1
  • T.A. Miller, M. Blaskiewicz, A.V. Fedotov, D.M. Gassner, D. Kayran, J. Kewisch, M.G. Minty, I. Pinayev, P. Thieberger, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The low energy RHIC electron cooling (LEReC) upgrade project [1], being installed over the next two years will require a low impedance beam line so that the soft 1.6MeV electron beam will not be perturbed by induced electromagnetic fields, especially in the instrumentation chambers. Novel designs of the Profile Monitors, Emittance Slit Scanners and BPMs are presented along with Particle Studio simulations of the electron beam wake-field induced electric potentials. The design of a new instrument incorporating a button beam position monitor (BPM) and YAG screen profile monitor in the same measuring plane is presented as part of a method of measuring beam energy with an accuracy of 10-3.
[1] D. Gassner, et al, TUPF24, proceedings of IBIC2013, Oxford, UK
poster icon Poster TUPB007 [9.428 MB]  
TUPB008 Beam Diagnostics of the LIPAC Injector With a Focus on the Algorithm Developed for Emittance Data Analysis of High Background Including Species Fraction Calculation 1
  • B. Bolzon, N. Chauvin, S. Chel, R. Gobin, F. Senée, M. Valette
    CEA/IRFU, Gif-sur-Yvette, France
  • J. Knaster, Y. Okumura
    IFMIF/EVEDA, Rokkasho, Japan
  • K. Shinto
    Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
  To prove the feasibility of the IFMIF accelerators concept, the EVEDA phase will commission in Japan the LIPAC accelerator, which will deliver a 125 mA/9 MeV CW deuteron beam. LEDA already managed 100 mA in CW at 6.7 MeV in 2000. The different subsystems of LIPAC have been designed and constructed mainly by European labs with the injector developed by CEA-Saclay. This injector must deliver a 140 mA/100 keV CW deuteron beam at 99% D+ ratio, which is produced by a 2.45 GHz ECR ion source. The low energy beam transport line is based on a dual solenoid focusing system to transport the beam and to match it into the RFQ. The normalized RMS target emittance at the RFQ entrance is targeted to be within 0.25π mm·mrad. This article describes the diagnostics installed in the LEBT to measure beam parameters such as intensity, profile, emittance, species fraction and degree of space charge compensation. The article also focuses on the algorithm developed to analyze emittance data of high background from an Allison scanner. Species fractions (D+, D2+, D3+) using mass separation technique were also calculated with the Allison scanner installed between the two solenoids in a first stage.  
poster icon Poster TUPB008 [1.122 MB]  
TUPB011 Micron-Scale Vertical Beam Size Measurements Based on Transition Radiation Imaging With a Schwarzschild Objective 1
  • G. Kube, S. Bajt
    DESY, Hamburg, Germany
  • I.A. Artyukov
    LPI, Moscow, Russia
  • W. Lauth
    IKP, Mainz, Germany
  • A. Potylitsyn, L.G. Sukhikh, A.V. Vukolov
    TPU, Tomsk, Russia
  Funding: The work was partially supported by the Russian Ministry of Education and Science within the program Nauka Grant No. 3.709.2014/K
Transverse beam profile diagnostics in the case of micron-scale beam sizes from modern electron accelerators are a challenging task. Backward transition radiation (BTR) imaging in the visible spectral region which is usually applied is close to the diffraction limit, i.e. the measured beam image is dominated by the point-spread function (PSF) [*, **]. In order to improve the resolution and to measure sub-micron beam sizes, the influence of the PSF should be decreased which depends not only on the wavelength, but also on optical aberrations. This can be realized by imaging in the EUV spectral region using a multilayer Schwarzschild objective which is free of some types of aberrations [***]. A first test experiment devoted to micron-scale beam size measurements has been carried out at the Mainz Microtron MAMI (Germany), using visible BTR and a Schwarzschild objective. This report summarizes first results of PSF dominated imaging with vertical beam sizes in the order of a few microns. Possibilities to extend the use of a Schwarzschild objective in future experiments with EUV BTR will be discussed.
* P. Karataev et al., PRL 107 (2011) 174801.
** G. Kube et al., proc. of IPAC13 (2013) MOPME010.
*** I.A. Artyukov et al, Opt. Eng. 39 (2000) 2163.
TUPB012 Transverse Beam Profile Imaging of Few-Micrometer Beam Sizes Based on a Scintillator Screen 1
  • G. Kube, S. Bajt
    DESY, Hamburg, Germany
  • I.A. Artyukov
    LPI, Moscow, Russia
  • W. Lauth
    IKP, Mainz, Germany
  • A. Potylitsyn, L.G. Sukhikh, A.V. Vukolov
    TPU, Tomsk, Russia
  Funding: This work was partly supported by the by the Russian Ministry of Education and Science within the program 'Nauka' Grant No. 3.709.2014/K.
Standard beam profile measurements of high-brightness electron beams based on optical transition radiation (OTR) may be hampered by coherence effects induced by the micro-bunching instability which render a direct beam imaging impossible. As consequence, for modern linac based 4th generation light sources as the European XFEL which is currently under construction in Hamburg, transverse beam profile measurements are based on scintillating screen monitors. However, the resolution of a scintillator based monitor is limited due to intrinsic material properties and the observation geometry [*,**]. In this report we present the results of beam size measurements in the order of a few microns using a LYSO:Ce scintillator and discuss the possible achievable resolution.
[*] G. Kube et al., Proc. IPAC'12 (2012) WEOAA02.
[**] B. Walasek-Höhne and G. Kube, Proc. DIPAC'11 (2011) WEOB01.
Simulation of Two-Dimensional PSF-Dominated Beam Profile Images Based on OTR and the Influence of De-Focusing  
  • G. Kube
    DESY, Hamburg, Germany
  • A. Potylitsyn, L.G. Sukhikh
    TPU, Tomsk, Russia
  Funding: This work was partly supported by the by the Russian Ministry of Education and Science within the program 'Nauka' Grant No. 3.709.2014/K.
Transverse beam profile diagnostics in electron accelerators is usually based on direct imaging of a beam spot via visible radiation (transition or synchrotron radiation). In this case, the fundamental resolution limit is determined by radiation diffraction in the optical system. A method to achieve a resolution beyond the diffraction limit is to perform point spread function (PSF) dominated imaging, i.e. the recorded image is dominated by the resolution function of a point source (single electron). With knowledge of the PSF, the true image (beam spot) can be reconstructed. In the case of classical OTR imaging however, the radiation is emitted from a tilted screen surface, and a part of the image will be out of focus. While this de-focusing influence can usually be neglected, it was observed already in the case of sub-micron beam size measurements. This paper presents a model to calculate PSF-dominated beam profile images based on optical transition radiation from a tilted screen surface, taking into account the influence of de-focusing.
Upgrade of the Beam Profile Monitoring System in the Injection Beam Line of COSY  
  • K. Reimers, C. Böhme, V. Kamerdzhiev
    FZJ, Jülich, Germany
  • J.L. Conradie, M.A. Crombie, H.W. Mostert
    iThemba LABS, Somerset West, South Africa
  The 183 m long synchrotron and storage ring COSY is fed by the cyclotron Julic. The 95 m long injection beam line (IBL) transports H-/D- ions which are injected into the ring via a multi-turn stripping injection. 8 profile monitoring stations are installed in the IBL. Each station contains two harps having 39 wires at 1mm spacing. Each harp is read out by a multichannel pico-amperemeter electronics designed by iThemba LABS, South Africa, delivering profile data to the COSY control system. The technical details of the upgrade are described and first results are presented.  
TUPB021 Characterization of the SR Visible Beam Polarization State at SPEAR3 1
  • C.L. Li
    East China University of Science and Technology, Shanghai, People's Republic of China
  • W.J. Corbett
    SLAC, Menlo Park, California, USA
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  Synchrotron radiation has the well-known property of horizontal field polarization in the midplane with increasingly elliptical polarization in the vertical plane. By measuring the beam intensity transmitted through a linear polarizer, it is possible to characterize the beam polarization state, determine the Stokes' parameters and solve for the beam polarization ellipse in the visible portion of the SR spectrum. The results can be compared with Schwinger's equations for synchrotron radiation taking into account the effect of extraction mirrors.  
poster icon Poster TUPB021 [1.493 MB]  
TUPB024 Beam Halo Measurement Utilizing YAG:Ce Screen 1
  • T. Naito, T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  Funding: Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
At the ATF2 project, we are aiming to produce an extremely small beam having a vertical beam size of 37 nm. The beam halo surrounding of beam core will make a background for the beam size measurement using the Laser interferometer beam size monitor. The understanding of beam halo distribution is important for measurement of the beam size at the final focus point of ATF2. In order to measure the beam halo distribution, we developed a beam halo monitor based on fluorescence screen. A YAG:Ce screen, which has 1 mm slit in the center is set in the beam line. The image on fluorescence screen is observed by imaging lens system and CCD camera. In this configuration, the beam in the core will pass through the slit. The beam in the surrounding halo will hit the fluorescence screen, and we can observe the distribution of beam halo. The intensity contrast of beam halo to the beam core is measured by scanning the beam position for the fixed fluorescence screen position. The results of observation of beam halo are presented.
TUPB025 Design of Coded Aperture Optical Elements for SuperKEKB X-ray Beam Size Monitors 1
  • E. Mulyani
    Sokendai, Ibaraki, Japan
  • J.W. Flanagan
    KEK, Ibaraki, Japan
  We describe the design of coded aperture optical elements for the SuperKEKB x-ray beam size monitors. X-ray beam profile monitor are being installed in each ring of SuperKEKB (LER and HER) to provide high resolution bunch-by-bunch, turn-by-turn measurement capability for low emittance tuning, collision tuning and instability measurements. We use two types of optical elements, single-slit (pinhole) and multi-slit optical elements (coded apertures, CA). CA imaging offers greater open aperture than a single pinhole, for greater photon throughput and better statistical resolution for single-shot measurements. X-rays produced by a hard-bend magnet pass through a pinhole or CA optical element onto a detector. The resolution is obtained by calculating the differences between the images recorded by the detector for various simulated beam sizes, for a given number of photons. The CA elements that we have designed for use at SuperKEKB are estimated to provide 1.25-2.25 microns resolution for 10-25 microns of vertical beam sizes at 1 mA bunches. We present the design principle and optimizing process used to optimize the resolution at various beam sizes for SuperKEKB.  
poster icon Poster TUPB025 [6.145 MB]  
TUPB027 Bunch Length Analysis of Negative Hydrogen Ion Beam in J-PARC Linac 1
  • A. Miura, N. Hayashi
    JAEA/J-PARC, Tokai-mura, Japan
  • S. Fukuoka
    University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan
  • Y. Liu
    KEK/JAEA, Ibaraki-Ken, Japan
  • T. Maruta
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • T. Miyao
    KEK, Ibaraki, Japan
  We used bunch shape monitors (BSMs) to measure the longitudinal bunch length of a negative hydrogen ion beam in the J-PARC linac. Because we experienced a vacuum degradation to suspend a beam operation during the BSM operations, BSMs were once dismounted for vacuum conditioning. We installed one BSM again in the beam line with additional vacuum equipment. We stared to measure the 191-MeV beam again to tune the buncher amplitude after checking a functioning BSM by comparing its results with those of a simulation. To evaluate the measurement errors with peak beam current increasing, we observed waveforms with various beam currents. Therefore, the RMS bunch length depends on the peak beam current and the bending at the pulse head grows with the peak beam current. Furthermore, to avoid the thermal stress, we compared the data taken at an off-center beam with the ones taken at an on-center beam, because a target wire will be exposed to a higher peak beam current. In this study, we introduced the peak beam current dependence of the bunch length waveforms, and an effect of on-/off-centering of the wire position. Finally, the new buncher tuning method using one BSM is discussed.  
TUPB030 Measurements of Beam Halo by Wire Scanner Monitor 1
  • H. Jiang
    TUB, Beijing, People's Republic of China
  • P. Li, T.G. Xu
    IHEP, Beijing, People's Republic of China
  A wire scanner is used in the beam halo experiment at the Institute of High Energy Physics (IHEP) to measure the beam halo for the study of beam halo dynamics. The beam energy in the FODO transport line is 3.5 MeV and the peak current is 24 mA. Firstly we get the emittance value for the vertical and the horizontal plane respectively by measuring the matched beam. Then we measure the beam halo of the mismatched beam.  
poster icon Poster TUPB030 [0.344 MB]  
Beam Profile Detector Measurements with a Non-Destructive Ionization Position Monitor (IPM) at IMP  
  • H.M. Xie
    IMP/CAS, Lanzhou, People's Republic of China
  An accelerator-driven subcritical system (ADS) project was launched in China in 2011. The driver linac is designed to produce a 10 mA beam current of high energy protons at 1.5 GeV in continuous wave operation mode. To meet the extremely high power and intense beam requirements of the accelerator, non-destructive monitors for the beam transverse profile are required for this proton linac. Taking advantage of the residual gas as active material, the Ionization Position Monitor (IPM) produces charged ions from the interaction between incident ions and gas molecules for transverse profile measurements. The components of this non-destructive method are a metal electrostatic field plate, aμchannel plate and a phosphor coated screen and CCD camera. The spatial resolution can be optimized to 0.1 mm with a CCD while the time resolution is poorer than with a photodiode as signal collector. The profile detection experiments with the IPM were done in the synchrotron of Heavy Ion Research Facility of Lanzhou (HIRFL), later the IPM will be installed in ADS linac. The experimental results and details will be presented in this paper.  
poster icon Poster TUPB032 [1.280 MB]  
Construction and Measurement of the Emittance System and the Profile System  
  • Z. Xue
    IMP/CAS, Lanzhou, People's Republic of China
  The software part of the Emittance System and the Profile System mainly use NI CRIO equipment. It is made of a Crio chassis (such as 9024), a data acquisition card (for example 9223,9215) and an encoder card (9411). The system uses the electric machinery from Kollmorgen to move the hardware. At the same time, we use NI equipment to provide software control. The probe was designed in-house and constructed by an external company. This system has been used to measure the beam profile at IMP.  
TUPB037 Interferometer Data Analyzing Using the PCA Method at SSRF 1
  • Y.B. Leng, H.J. Chen, J. Chen, Z.C. Chen, Y.B. Yan
    SSRF, Shanghai, People's Republic of China
  An SR interferometer, which was used to monitor the transverse beam size in the SSRF ring, had been implemented and put into operation since 2009. The direct projection and curve fitting was adopted for raw image data processing. Any CCD alignment error could introduce some beam size measurement error in this case. Using primary component analyzing (PCA) method to process raw image data, the horizontal and vertical distribution information can be decoupled and the misalignment information of CCD can be derived. Beam experiment results will be discussed in this paper.  
TUPB043 Development of a Scintillation Screen Monitor for Transverse Ion Beam Profile Measurment at the Khima Project 1
  • S.Y. Noh, S.D. Chang, J.G. Hwang
    KIRAMS/KHIMA, Seoul, Republic of Korea
  • G. Hahn, T.K. Yang
    KIRAMS, Seoul, Republic of Korea
  The scintillation screen monitor measures transverse profile of ion beam in beam transport line. The Korea Heavy Ion Medical Accelerator Project (KHIMA) has developed a scintillation screen monitor in the high energy beam transport (HEBT) line. The images of each beam pulse were recorded by CCD camera and evaluated the beam properties by the LabVIEW-based in-house program in real time. We designed a scintillation screen monitor using phosphor screen, P43. In order to investigate the limits of scintillating screen during beam profile monitoring at low intensity, we designed a remote control device of iris for the incoming light adjustment to the CCD camera. In this paper, we present details of the image processing system using the LabVIEW and the beam profile measurement results from the in-beam test.  
Using Incoherent and Coherent Polarization Radiation as a Diagnostic of the Transverse Beam Size  
  • D.Yu. Sergeeva, A.A. Tishchenko
    MEPhI, Moscow, Russia
  Polarization radiation (diffraction radiation, Smith-Purcell radiation, transition radiation) can be a good diagnostic for sub-micron beam measurements. It is the so-called 'form-factor' of the beam that contains information about beam size. It represents the sum of two parts corresponding to the coherent and incoherent radiation [1]. Contrary to general opinion the incoherent part does not always equal unity [1]. It was mentioned in Ref. [2]. We give a theoretical description of the incoherent and coherent parts of the form-factor both for Gaussian and uniform distribution of ultra-relativistic particles in the bunch [1,3]. We show that the incoherent part depends on the transverse size of the beam, and dependence is not the same for different distributions. The possible role of the incoherent part of the form-factor of the bunch for different parameter is discussed.
1.D.Yu.Sergeeva, A.A.Tishchenko et al., NIM B (2013)
2.J.H. Brownell et al., PRE (1998); G. Doucas et al., PR STAB (2002)
3.D.Yu.Sergeeva et al., Proc. of FEL 2014, TUP013
EUV, X-ray Diffraction and Smith-Purcell Radiation as a Base for Non-Invasive Sub-Micron Beam Diagnostics  
  • A.A. Tishchenko, D.Yu. Sergeeva
    MEPhI, Moscow, Russia
  Developing sub-micron beam diagnostics is a vital problem for modern accelerators and colliders like CLIC, ILC, SLAC, DESY. High energy of the particles leads to requirement of the non-invasive diagnostics; because of small beam size the high resolution is required. The accuracy of resolution is limited to the wavelength because of the diffraction (Rayleigh) limit. All these problems can be solved with help of diagnostics based on incoherent and short-wavelength diffraction radiation (DR). We suggest DR and Smith-Purcell radiation of EUV and X-ray ranges as an instrument for submicron non-invasive beam diagnostics, proceeding from the developed theoretical description [1]. We construct theory of EUV and X-ray DR and SPR from ultra-relativistic beams for both uniform and Gaussian distributions of the particles [2]. The theory contains the case of beam skimming the target [2], which leads to mixing DR and transition radiation; the case of oblique incidence of the beam to the target [3], which leads to the conical effect in spatial distribution of DR and allows counting the divergence of the beam. Also, we describe analytically and analyse the incoherent form-factor of the beam.
1.A.A.Tishchenko et al.,PRE (2004); D.Yu.Sergeeva, A.A.Tishchenko et al., NIM B (2013)
2.D.Yu.Sergeeva, A.A.Tishchenko, Proc.of FEL 2014, TUP013
3.D.Yu.Sergeeva, A.A.Tishchenko et al., PR STAB (2015)
TUPB049 Limitations and Solutions of Beam Size Measurements via Interferometry at ALBA 1
  • L. Torino, U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  The interferometry beamline at ALBA had several limitations which have been overcome over the past years until currently, beam size measurements are successfully performed using this technique. The main limitation has been related to vibrations in the light wavefront transportation along the beamline. Several counter-measures have been taken to overcome these limitations, related both to the software analysis and the mechanical setup, where the conventional double slit system is substituted by a double pinhole in order to obtain more light and a better interferogram. This report describes the current interferometry setup at ALBA, and show some results.  
poster icon Poster TUPB049 [1.073 MB]  
TUPB052 Wire Scanners and Vibrations - Models and Measurements 1
  • J. Herranz, B. Dehning, E. Effinger, J. Emery, A. Guerrero, C. Pereira
    CERN, Geneva, Switzerland
  • A. Barjau, J. Herranz
    Universitat Politécnica de Catalunya, Barcelona, Spain
  • J. Herranz
    Proactive Research and Development, Barcelona, Spain
  The new fast wire scanner foreseen to measure small emittance beams throughout the LHC injector chain will have a wire travelling at a speed of up to 20 m.s−1, with a requested wire position measurement accuracy of the order of a few microns. The vibration of the thin carbon wires used has been identified as one of the major error sources on the wire position accuracy. In this project the most challenging and innovative development has been the wire vibrations measurement strategy based on the piezo resistive effect of the wire itself, while the deflection of the fork supporting the wire has been measured by semiconductor strain gauges. Dynamic models of the wire and fork have been created to predict the behaviour of the fork-wire assembly. This model, validated by the measurements, has then been used for optimisation of the wire-fork assembly. The contribution will discuss the measurement setup and the model development as well as their comparison. In addition it will show that this technology can easily be implemented in current operating devices without major modifications. For the first time the piezo resistive effect is used for wire vibrations measurements during the scan.  
poster icon Poster TUPB052 [2.371 MB]  
TUPB053 A High Dynamic Range Diamond Detector Readout System for the CERN Beam Wire Scanners Program 1
  • J.L. Sirvent Blasco, B. Dehning, J. Emery
    CERN, Geneva, Switzerland
  • A. Dieguez
    UB, Barcelona, Spain
  A secondary particle shower acquisition system is under design for the upgrade of CERN's beam wire scanners. The system needs to be capable of performing bunch-by-bunch synchronous measurements with an integration time of 25 ns and to cope with signal variations of up to 6 orders of magnitude. The whole dynamic range should be covered by the acquisition system with a single configuration and should have no tuneable parameters. The secondary particles are detected using a polycrystalline diamond detector with the signal digitization performed nearby with a custom front-end system, designed to resist a total ionising radiation dose up to 1 kGy in 10 years. The digital data transmission, front-end synchronization and control are performed through a bi-directional optical link operating at 4.8 Gbps using CERN's GBT protocol. For the digitization, two radiation tolerant integrator ASICs (ICECAL and QIE10) are under study.  
poster icon Poster TUPB053 [1.319 MB]  
TUPB055 Design of a Laser-based Profile Monitor for LINAC4 Commissioning at 50 MeV and 100 MeV 1
  • T. Hofmann, E. Bravin, U. Raich, F. Roncarolo
    CERN, Geneva, Switzerland
  • G.E. Boorman, A. Bosco, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • E. Griesmayer
    CIVIDEC Instrumentation, Wien, Austria
  Funding: Marie Curie Network LA3NET which is funded by the European Commission under Grant Agreement Number GA-ITN-2011-289191.
A laser-based profile monitor has been designed for commissioning of CERN's LINAC4 accelerator at 50 MeV and 100 MeV, as part of the development of a non-destructive profile and emittance monitor foreseen for the final 160 MeV beam. The system is based on a low power laser which is scanned through the H beam. Electrons, which are photo-detached from the ions by the laser, are deflected by a steerer magnet and measured by a diamond detector. The custom designed diamond detector is tailored to minimize the disturbance due to the electromagnetic field of the passing main beam. The laser source will be installed in the LINAC4 Klystron gallery located 75 m away from the profile station and an optical fiber will transport the laser to the tunnel. The laser propagation for different pulse length and peak power values was characterized with laboratory tests with such a long fiber. In this paper we describe the overall design, focusing on key elements such as the fiber-based laser transport and the electron detection with the diamond detector.
poster icon Poster TUPB055 [1.647 MB]  
TUPB057 Development of a Versatile OTR-ODR Station for Future Linear Colliders. 1
  • R. Kieffer, M. Bergamaschi, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • T. Aumeyr, P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • M.G. Billing, J.V. Conway, J.P. Shanks
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • L.M. Bobb
    DLS, Oxfordshire, United Kingdom
  • N. Terunuma
    KEK, Ibaraki, Japan
  In order to study the feasibility of Optical Transition (OTR) and Diffraction (ODR) Radiation based profile measurement for the future electron-positron linear colliders (ILC, CLIC) a new dedicated instrument is under development at CERN to be installed in KEK-ATF2 beam line in fall 2015. To optimize sensitivity to micron and sub-micron beam sizes, we plan to observe ODR/OTR in the visible-UV wavelength range, down to approximately 150 nm. ODR light will be produced by narrow (25-500 μm) slits with non-uniform reflectivity. To improve our knowledge on the complex pattern produced by ODR, a preparatory experiment is being conducted on the CTF3 CALIFES beam line (CERN). This device produces interferences between two OTR screens in the visible optical range with the possibility to control the distance between them, i.e. to probe the shadowing region. The new results of this OTR interference measurement will be presented, together with the latest results from the ODR run in CesrTA (Wilson lab-Cornell).  
TUPB059 Development of an Ionization Profile Monitor Based on a Pixel Detector for the CERN Proton Synchrotron 1
  • J.W. Storey, D. Bodart, B. Dehning, S. Levasseur, P. Pacholek, A. Rakai, M. Sapinski, G. Schneider, D. Steyart
    CERN, Geneva, Switzerland
  • K. Satou
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  The transverse emittance measurement in the CERN Proton Synchrotron is currently performed using fast rotational wire scanners. These scanners cannot provide continuous bunch-by-bunch measurements and the expected future increase of the beam brightness will lead to an accelerated sublimation of the wire. A novel Ionization Profile Monitor is being constructed to cope with these challenges. The readout of this device will be based on a hybrid silicon pixel detector with a Timepix3 chip. Pixel detectors are sensitive to single electrons therefore eliminating the need for traditional Multi-Channel Plates, which suffer from ageing phenomena. The early digitization of the signal will reduce the susceptibility of the readout system to electromagnetic interference, while the time resolution of the chip allows the required bunch-by-bunch measurement. Due to the small length of the detector a new, simplified ion trap has been designed. Resistive glass plates are used to provide maximum uniformity of the electric field and to simplify construction. The guiding field will be provided by a new, self-compensating magnet. It is foreseen to have the device ready for testing with beam in 2016.  
TUPB061 Experience From the Construction of a New Fast Wire Scanner Prototype for the CERN- SPS and its Optimisation for Installation in the CERN-PS Booster 1
  • R. Veness, W. Andreazza, N. Chritin, B. Dehning, J. Emery, D. Gudkov, J. Herranz, P. Magagnin, E. Piselli, S. Samuelsson
    CERN, Geneva, Switzerland
  A new design of wire scanner is under development for the LHC Injector Upgrade project at CERN. A prototype has been designed, built and installed in the SPS accelerator to test the concept in an operational accelerator environment. New technology has been developed and qualified for in-vacuum motor and structural components using 3D metal additive machining. This paper will describe the technology developed for this scanner and the test results to date. This prototype has recently been re-optimised to fit in the limited space available in the PS Booster rings. This design will also be presented.  
poster icon Poster TUPB061 [0.866 MB]  
TUPB067 Synchrotron Radiation Measurement at Taiwan Photon Source 1
  • C.Y. Liao, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, S.Y. Hsu, H.P. Hsueh, K.H. Hu, C.K. Kuan, C.Y. Wu
    NSRRC, Hsinchu, Taiwan
  The synchrotron radiation light produced from a dipole magnet is widely used to characterize beam parameters in synchrotron light source (photon synchrotron). The synchrotron radiation monitor (SRM) systems were implemented for the booster synchrotron and the storage ring at Taiwan Photon Source (TPS). The beam parameters of the booster were recorded during the energy ramping process through the CCD camera and streak camera. The beam size measurement and beam behavior observed of the storage ring were performed by X-ray pinhole camera and streak camera respectability. The results are summarized in this report.  
TUPB071 Simulations of the FETS Laser Diagnostic 1
  • A. Kurup, J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • S.M. Gibson, K.O. Kruchinin
    JAI, Egham, Surrey, United Kingdom
  • S.M. Gibson, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  The Front-End Test Stand (FETS) aims to demonstrate clean chopping of a 60mA, 3MeV H ion beam. Such high beam intensities require unconventional emittance and profile measuring devices such as the laserwire system that will be used on FETS. A laser is used to neutralise part of the H ion beam. The main beam is then separated from the stripped beam by using a dipole magnet. This paper presents tracking results of the laser diagnostic lattice using a simulated field map of an existing dipole magnet and investigates the possibility of laser stripping upstream of the dipole.  
TUPB075 Development of a Supersonic Gas Jet Beam Profile Monitor 1
  • H.D. Zhang, A. Jeff, V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Jeff
    CERN, Geneva, Switzerland
  • A. Jeff, V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • V. Tzoganis
    RIKEN, Saitama, Japan
  • V. Tzoganis
    RIKEN Nishina Center, Wako, Japan
  A supersonic gas jet beam profile monitor has been developed by the QUASAR Group at the Cockcroft Institute, UK. It creates a supersonic gas curtain which interacts with the primary beam, and then images the beam cross-section by collecting the generated ions. The gas curtain is inclined at 45 degrees to the beam and functions as a minimally intercepting screen, which allows it to be used in high energy and high power beams without worrying about material damage. An accurate profile measurement requires homogeneous gas density across the curtain, while high resolution measurement requires a very thin jet. In order to characterize the gas curtain density distribution and understand the jet better, a new movable gauge module has been installed in the gas jet test stand. In this contribution, we discuss the monitor design and the characterization of the gas curtain with the newly installed movable gauge module. In addition, we present a new method for the generation of a very narrow pencil jet using deBroglie wave focusing. Such a narrow jet could be used as a non-invasive counterpart to wire scanners in high-intensity beams where the latter cannot be used.  
TUPB077 Installation Status of the Electron Beam Profiler for the Fermilab Main Injector 1
  • R.M. Thurman-Keup, M.L. Alvarez, J. Fitzgerald, C.E. Lundberg, P.S. Prieto, M. Roberts, J.R. Zagel
    Fermilab, Batavia, Illinois, USA
  • W. Blokland
    ORNL, Oak Ridge, Tennessee, USA
  The planned neutrino program at Fermilab requires large proton beam intensities in excess of 2 MW. Measuring the transverse profiles of these high intensity beams is challenging and often depends on non-invasive techniques. One such technique involves measuring the deflection of a probe beam of electrons with a trajectory perpendicular to the proton beam. A device such as this is already in use at the Spallation Neutron Source at ORNL and the installation of a similar device is underway in the Main Injector at Fermilab. The present installation status of the electron beam profiler for the Main Injector will be discussed together with some simulations and test stand results.  
poster icon Poster TUPB077 [2.490 MB]  
TUPB081 LANSCE 1L Harp Data Acquisition System Upgrade: First Results 1
  • J.D. Sedillo, D. Martinez, J.D. Nguyen
    LANL, Los Alamos, New Mexico, USA
  Funding: U.S. Department of Energy under contract no. DE-AC52-06NA25396
Efforts applied toward the upgrade of the LANSCE 1L harp beam diagnostic data acquisition system have completed with the system's successful deployment in late December 2014. Leveraging the principle of secondary electron emission, the data acquisition system measures the particle beam-induced, negative charge-loss response of a statically-located, harp-style, beam diagnostic sensor. The harp's sense wires span two orthogonal planes, transversely oriented with the beam's direction of travel resulting in two orthogonal profiles. The profile data provided by this beam diagnostic system allows LANSCE operators to measure the particle beam's transverse properties prior to reaching its final destination: the 1L target. Details will be provided with respect to the system's final hardware architecture, the system's theoretical beam response model, and the system's measured beam response.
Performance of the New Fast Wire Scanner at the LCLS  
  • P. Krejcik, M.L. Campell, J.M. D'Ewart, H. Loos
    SLAC, Menlo Park, California, USA
  Funding: This work was supported by Department of Energy Contract No. DE-AC0276SF00515.
A new fast wire scanner based on a linear DC servo motor acting through dual bellows has been developed at SLAC. After successful beam testing at LCLS we are now replacing all the old style stepping motor driven scanners with the new type. The fast scanner design allows full emittance scans to be completed in seconds rather than minutes as before, facilitating speedier tuning of the accelerator. The low vibration design allows for wire speeds up to 1 m/s, making it also suitable for use in the new LCLS-II machine where high wire speeds are essential to prevent wire breakage from the high power electron beam with a 1 MHz repetition rate. The wire scanner design is presented along with beam measurements demonstrating its performance.
TUPB084 Cherenkov Converter for Large Dynamic Range, High Sensitivity Detectors for Use on Wire-Scanners 1
  • J. Gubeli, P.E. Evtushenko
    JLab, Newport News, Virginia, USA
  We are developing a wire-scanner with a dynamic range of 10+6 or larger. In addition to the large dynamic range (LDR), high sensitivity is very desirable so that measurements can be made with a small amount of beam or small duty cycle beam. This high sensitivity requirement makes photo multiplier tubes (PMT) the preferred detector. Low dark current PMTs have maximum quantum efficiency in the visible wavelength range. We describe a converter where Cherenkov radiation (CR) is used to generate visible photons from electrons and positrons that are present due to wire-beam interaction. Also described is an optical system that collects and couples the CR into an optical fiber that delivers the visible photons to the PMT outside of the accelerator area, reducing background. The directional nature of the CR is used in a way that, when CR in the radiating medium is generated by particles not directed from the wire-beam interaction point to the converter, the CR is not coupled into the optical fiber and therefore does not create background for the wire-scanner measurements. Sensitivities to the refractive index of the radiating medium, alignment and mechanical tolerances are also presented.
*Work supported by US DOE office of Basic Energy Sciences under the early career program; DOE award number FWP#JLAB-BES11-05
poster icon Poster TUPB084 [1.383 MB]  
TUPB085 Multi-Diagnostic Transverse Profile Monitor Chamber for Extreme Ultraviolet Lithography 1
  • T.J. Campese, R.B. Agustsson, M.A. Harrison, B.T. Jacobson, A.Y. Murokh, A.G. Ovodenko, M. Ruelas, H.L. To
    RadiaBeam, Santa Monica, California, USA
  • M.G. Fedurin, I. Pogorelsky, T.V. Shaftan
    BNL, Upton, Long Island, New York, USA
  Funding: DOE SBIR Grant No DE-SC0007703
RadiaBeam Technologies has developed a compact transverse beam profile measurement system for the Extreme Ultraviolet Lithography (EUL) experiment at the Brookhaven National Laboratory-Accelerator Test Facility (BNL-ATF). The EUL experiment requires fine e-beam and laser alignment across multiple passes. To accomplish this, the system consists of four profile monitor diagnostics: Interaction Point (IP), upstream, downstream, and a sub-micron resolution diagnostic 11.5 mm downstream of the IP. Care was taken in the design to minimize footprint, avoid possible diagnostic collisions, and maximize ease of assembly and alignment. This paper will review the requirements for the dimensional and optical constraints and solutions for this experiment.
poster icon Poster TUPB085 [0.571 MB]  
Magnet Edge Radiation for Non-Destructive Emittance Measurements  
  • M.G. Fedurin, M. Babzien, O.V. Chubar, C. Swinson
    BNL, Upton, Long Island, New York, USA
  • V. Yakimenko
    SLAC, Menlo Park, California, USA
  A non-destructive emittance measurement technique is presently under development at Brookhaven National Laboratory Accelerator Test Facility (BNL ATF). The properties of magnet edge radiation produced by an electron beam may be used for this purpose. The interference pattern of radiation, produced at two magnet edges, at a certain wavelength depends on transverse beam size. Magnets configuration setup, observation diagnostics and measurement results will be discussed in this report.  
WEALA02 First LHC Emittance Measurements at 6.5 TeV 1
  • M. Kuhn, F. Antoniou, E. Bravin, B. Dehning, J. Emery, V. Kain, A. Langner, Y. Papaphilippou, E. Piselli, G. Trad
    CERN, Geneva, Switzerland
  During LHC Run 1 significant transverse emittance growth through the LHC cycle was observed. Measurements indicated most of the blow-up to occur during the injection plateau and the ramp. Intra beam scattering was one of the main drivers of emittance growth. However, finding a good wire scanner working point was difficult. Photomultiplier saturation added uncertainty on all measurements. A large discrepancy between emittances from wire scanners and luminosity was discovered but not solved. During Long Shutdown 1 the wire scanner system was upgraded with new photomultipliers. In April 2015 the LHC re-started with collision energy of 6.5 TeV per beam. This paper presents the first transverse emittance measurements through the LHC Run 2 cycle with low beam intensity. Comparisons with data from the synchrotron light monitors and the LHC experiments will be discussed and results summarized. In addition, a thorough study of wire scanner photomultiplier saturation will be presented. Finally, the emittance growth results will be compared to intra beam scattering simulations.  
slides icon Slides WEALA02 [6.747 MB]  
WEDLA03 Beam Profile Monitor at the 1 MW Spallation Neutron Source 1
  • S.I. Meigo, A. Akutsu, K. Ikezaki, M. Nishikawa, M. Ooi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • S.F. Fukuta
    KEK/JAEA, Ibaraki-Ken, Japan
  At the Japanese Spallation Neutron Source (JSNS) using a mercury target, the transverse beam profile of 3 GeV beam having the power of 1 MW is measured by a multi-wire profile monitor (MWPM) placed at the proton beam window (PBW) being the separator between vacuum and helium area at the target station. The profile monitor is crucial because the beam peak current density should be kept as low as possible to mitigate the damage at the mercury target vessel due to the pitting erosion caused by the high power proton beam. Simple beam expantion at the target is useless because it simply increases the heat load and the radiation dose at the entrance of the target. To mitigate damage, a beam flattening system using non-linear optics with octupole magnets has been developed. It was confirmed the beam shape was controlled as designed using calculations. In order to obtain a 2D profile, we have begun using the profile monitor by observing the infrared from the target by imaging a capillary tube. At JSNS the life time of the PBW is important. To improve the lifetime of the PBW, we measure the gas production rate by using a beam dump.  
slides icon Slides WEDLA03 [9.556 MB]  
THBLA01 Summary of the 2014 Beam-Halo Monitoring Workshop 1
  • A.S. Fisher
    SLAC, Menlo Park, California, USA
  Understanding and controlling beam halo is important for high-intensity hadron accelerators, for high-brightness electron linacs, and for low-emittance light sources. This can only be achieved by developing suitable diagnostics. The main challenge faced by such instrumentation is the high dynamic range needed to observe the halo in the presence of an intense core. In addition, measurements must often be made non-invasively. This talk summarizes the one-day workshop on Beam Halo Monitoring that was held at SLAC on September 19 last year, immediately following IBIC 2014 in Monterey. Workshop presentations described invasive techniques using wires, screens, or crystal collimators, and non-invasive measurements with gas or scattered electrons. Talks on optical methods showed the close links between observing halo and astronomical problems like observing the solar corona or directly observing a planet orbiting another star.  
slides icon Slides THBLA01 [195.460 MB]