Keyword: optics
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MOPB52 Status and Activities of the SPring-8 Diagnostics Beamlines photon, diagnostics, storage-ring, emittance 186
 
  • S. Takano, M. Masaki, A. Mochihashi, H. Ohkuma, M. Shoji, K. Tamura
    JASRI/SPring-8, Hyogo-ken, Japan
  • H. Sumitomo, M. Yoshioka
    SES, Hyogo-pref., Japan
 
  At SPring-8 synchrotron radiation (SR) in both the X-ray and the visible bands is exploited in the two diagnostics beamlines. The diagnostics I beamline has a dipole magnet source. The beam size is measured by imaging with the zoneplate X-ray optics. Recently, the transfer line of the visible light has been upgraded. The in-vacuum mirror was replaced to increase the acceptance of the visible photons. A new dark room was built and dedicated to the gated photon counting system for bunch purity monitoring. To improve the performance, the input optics of the visible streak camera was replaced by a reflective optics. Study of the power fluctuation of visible SR pulse is in progress to develop a diagnostic method of short bunch length. The diagnostics II has an insertion device (ID). To monitor stabilities of the ID photon beam, a position monitor for the white X-ray beam based on a CVD diamond screen was installed. A turn-by-turn diagnostics system using the monochromatic X-ray beam was developed to observe fast phenomena such as beam oscillation at injection for top-up and beam blowups caused by instabilities. Study of temporal resolution of the X-ray streak camera is also in progress.  
 
MOPB53 Hartmann Screen and Wavefront Sensor System for Extracting Mirror at SSRF synchrotron, synchrotron-radiation, radiation, extraction 191
 
  • J. Chen, Y.B. Leng, K.R. Ye
    SINAP, Shanghai, People's Republic of China
 
  A Be mirror was used to extract visible synchrotron radiation light from bending magnet at SSRF. The surface of mirror was deformed because of X-ray heat. A set of Hartmann Screen Test was used to measure the surface of the mirror. Another equipment named The Shack-Hartmann wavefront sensor system was introduced to get more precision data. The result of two kind of test match each other well.  
 
MOPB67 Development of Offner Relay Optical System for OTR Monitor at 3-50 Beam Transport Line of J-PARC target, proton, radiation, beam-transport 222
 
  • M. Tejima, T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  • Y. Hashimoto, T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • S. Otsu
    Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
 
  An extremely wide aperture relay optical system based on Offner system has been designed and constracted for OTR monitor at 3-50 beam transport line of J-PARC. Diagnostics for beam profile and halo are very important to optimize injection beam from RCS to MR in J-PARC. For this purpose, an OTR monitor is planed to install for an observation of image of the beam and halo after the beam collimators. Since opening of OTR is very wide due to small Gamma; 3.2, extremely wide aperture (500mrad) optics will necessary to extract OTR from file target. We designed Offner type relay optics for the effective extraction of OTR having F=0.83. The clear aperture will cover 100 x 100mm aria on the target screen. Results of optical testing and design of OTR monitor will present in this paper.  
 
MOPB72 First Measurements with Coded Aperture X-ray Monitor at the ATF2 Extraction Line detector, extraction, vacuum, coupling 237
 
  • J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  • G.S. Varner
    University of Hawaii, Honolulu, HI, USA
 
  Funding: Kakenhi
The ATF2 extraction line is used as a test-bed for technologies needed for the ILC final-focus region. An x-ray extraction beam line has been constructed at the final upstream bend before the extraction line straight section, for development and testing of optics and readout systems for a coded aperture-based imaging system. The x-ray monitor is expected to eventually be able to measure single-shot vertical bunch sizes down to a few microns in size at its source location in the ATF2 extraction line. Preliminary scanned measurements have been made with beams in the ~15 micron range, and it is planned to make more measurements with further-tuned beam, and with fast read-out electronics. The details of the layout, expected performance, and preliminary measurement results will be presented.
 
 
TUCC04 Measurement of Nanometer Electron Beam Sizes with Laser Interference using IPBSM laser, detector, alignment, photon 310
 
  • J.N. Yan, S. Komamiya, M. Oroku, T.S. Suehara, Y. Yamaguchi, T. Yamanaka
    University of Tokyo, Tokyo, Japan
  • S. Araki, T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • Y. Kamiya
    ICEPP, Tokyo, Japan
 
  At ATF2, the Local Chromaticity Correction focusing scheme is to be verified through realizing its design vertical e- beam size (σy ) of 37 nm. The 'IPBSM', installed at ATF2's virtual IP, is the only existing beam size monitor capable of measuring σy < 100 nm, making it indispensable for ATF's goals and R&D at future LCs. This owes to a novel technique of colliding e- beam against laser interference fringes. σy is derived from the modulation depth of resulting Compton photons, which is large for small σy. The measurable range from O(10) nm ~ a few μm, is controlled by switching between laser crossing angles θ = 174° , 30°, and 2° - 8° . In early 2011, measuring σy < 300 nm was hindered by an immense earthquake and heavy signal jitters. The ensuing recovery and upgrades stabilized the laser system and improved resolution to 5%. In spring 2012, we commissioned advanced crossing angle modes by consistently measuring σy ≥ 150 nm. Our goals for the autumn 2012 run is to stably measure σy < 50 nm. Major hardware upgrades during the summer aim at more reliable alignment and optimization of specialized functions to suppress bias factors.  
slides icon Slides TUCC04 [10.535 MB]  
 
TUPA42 Diagnostics Beamline Optimisation and Image Processing for Sub-ps Streak Camera Bunch Length Measurement synchrotron, synchrotron-radiation, radiation, controls 445
 
  • C.A. Thomas, I.P.S. Martin, G. Rehm
    Diamond, Oxfordshire, United Kingdom
 
  Low alpha beam lattice at Diamond can generate bunch length as small as 0.6ps. In order to be able to measure reliably such a short bunch, we have been optimising the optical design of the visible Diagnostics beamline, and we have implemented image processing, taking into account the point spread function of the streak camera. The beamline optical design has removed a large chirp of 15ps/150nm bandwidth to 2ps /200nmbandwidth. It has also permit the transport of almost all the available power, increasing the power by a factor 20, yet maintaining the possibility to focus the beam down to less than 20um into the streak camera for the best static streak camera point spread function. The deconvolution technique implemented extends the performance of the streak camera to bunch length measurement much smaller than the 1ps PSF of the streak camera. In this paper we present these two essential features required to measure sub-ps bunched with a streak camera.  
 
TUPA47 Middle-infrared Prism Spectrometer for Single-shot Bunch Length Diagnostics at the LCLS detector, laser, diagnostics, radiation 463
 
  • T.J. Maxwell, Y. Ding, A.S. Fisher, J.C. Frisch, H. Loos
    SLAC, Menlo Park, California, USA
  • C. Behrens
    DESY, Hamburg, Germany
 
  Funding: Work supported in part by US Department of Energy contract number DE-AC02-76SF00515.
Modern high-brightness accelerators such as laser plasma wakefield and free-electron lasers continue the drive to ever-shorter bunches. At low-charge (< 20 pC), bunches as short as 10 fs are reported at the Linac Coherent Light Source (LCLS). Advanced time-resolved diagnostics approaching the fs-level have been proposed requiring the support of rf-deflectors, modern laser systems, or other complex systems. Though suffering from a loss of phase information, spectral diagnostics remain appealing by comparison as compact, low-cost systems suitable for deployment in beam dynamics studies and operations instrumentation. Progress in mid-IR imaging and detection of the corresponding micrometer-range power spectrum has led to the continuing development of a single-shot, 1.2 - 40 micrometer prism spectrometer for ultra-short bunch length monitoring. In this paper we report further analysis and experimental progress on the spectrometer installation at LCLS.
 
 
WEIC02 Recent Progress in SR Interferometer photon, experiment, factory, detector 576
 
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
 
  Beam size measurement in accelerator is very important to evaluate beam emittance. SR interferometer has been used as one of powerful tools for measurement of small beam size through special coherence of visible SR. Recent progresses in this technique improve measurable range for smaller beam size less than 10μm. An application of reflective optics to eliminate chromatic aberration in focus system of SR interferometer makes it possible to measure the beam size down to 5μm range. The unbalanced input technique is developed in recent few years, and this technique magnifies beam size 2-3 times, and observation range is improved down to 2-3μm range. These progresses on SR interferometer will introduce in this talk.  
slides icon Slides WEIC02 [1.687 MB]  
 
WECD01 Operation of a Single Pass, Bunch-by-bunch x-ray Beam Size Monitor for the CESR Test Accelerator Research Program detector, positron, electron, vacuum 585
 
  • N.T. Rider, M.G. Billing, M. P. Ehrlichman, M.A. Palmer, D.P. Peterson, D. L. Rubin, J.P. Shanks, K.G. Sonnad
    CLASSE, Ithaca, New York, USA
  • J.W. Flanagan
    KEK, Ibaraki, Japan
 
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings and other low emittance storage rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the design, commissioning and operation of an x-ray beam size monitor capable, on a turn by turn basis, of collecting single pass measurements of each individual bunch in a train over many thousands of turns. This new instrument utilizes custom, high bandwidth amplifiers and digitization hardware and firmware to collect signals from a linear InGaAs diode array. The instrument has been optimized to allow measurements with 3x109 to 1x1011 particles per bunch. This paper reports on the operational capabilities of this instrument, improvements for its performance, and the methods utilized in data analysis. Examples of key measurements which illustrate the instrument's performance are presented. This device demonstrates measurement capabilities applicable to future high energy physics accelerators and light sources.
 
slides icon Slides WECD01 [3.480 MB]