DOCSLIB.ORG

1 Synchrotron Light Sources

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
1 Synchrotron Light Sources 1 1 Synchrotron Light Sources Zhentang Zhao Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhangheng Road, Pudong New District, Shanghai, 201204, China 1.1 Introduction Synchrotron light sources or storage ring light sources are indispensable large-scale scientific tools for basic and applied frontier research in various fields, ranging from materials science, energy science, life science, environmental science, to archaeological applications. Their development has evolved from the first generation to the third generation in the past five decades, and has now entered into the fourth generation phase with even higher brightness and coherence radiation based on the diffraction limited storage ring concept. Currently, there are over 50 synchrotron light sources in operation in more than 20 countries, and over 15 new synchrotron radiation facilities have been set up worldwide in various stages of commissioning, construction, design, or planning. In this chapter, we will introduce the basics of synchrotron radiation generation, storage ring physics, and radiation characteristics, which are of interest to synchrotron radiation users. We will also present the current status of the storage ring light source development across the world. This chapter is intended to cover only the basic concepts of synchrotron light source and review the current status on its development. For readers who are interested in the detailed physics and related technologies, we recommend the books or monographs in Refs [1–15]. 1.2 Synchrotron Radiation Generation When a relativistic electron moves on a curved path at nearly the speed of light, it emits electromagnetic radiation. This radiation was theoretically predicated and studied by Lienard, Wiechert, and Schott in around 1900, and its visible part was first observed at the 70 MeV GE electron synchrotron in 1947. Since then, this electromagnetic radiation has been called synchrotron radiation. Synchrotron, a kind of circular particle accelerator, can accelerate charged par- ticles from low energy to high energy or keep the particles circulating on the Synchrotron Radiation in Materials Science: Light Sources, Techniques, and Applications, First Edition. Edited by Chunhai Fan and Zhentang Zhao. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2018 by Wiley-VCH Verlag GmbH & Co. KGaA. 2 1 Synchrotron Light Sources 1 γ λ F Bending magnet radiation e– hω >> 1 γ e– F Wiggler radiation λ hω 1 γ N e– F Undulator radiation λ hω Figure 1.1 Synchrotron radiation from bending magnets, wigglers, and undulators [3]. (Cambridge University Press.) circular orbit at a constant energy for hours and days, which is referred to as storage ring. The electron storage ring is the core part of synchrotron light source. Relativistic electrons, circulating in the storage ring, generate synchrotron radia- tion when passing through three on-path major source components: the bending magnet, wiggler, and undulator magnets, as shown in Figure 1.1. This synchrotron radiation is extremely intense over a broad range of wave- lengths from infrared through the visible and ultraviolet range, to the soft and hard X-ray part of the electromagnetic spectrum. Bending magnet radiation has broad spectrum and good photon flux; wiggler radiation provides higher photon energies and more photon flux; and undulator provides brighter radiation with smaller spot size and partial coherence. 1.2.1 Radiation from Bending Magnet A bending magnet, also called a dipole magnet, consists of opposite poles, namely the north and south poles, which are on opposite sides of the magnet providing a homogeneous magnetic field. As shown in Figure 1.2, when a relativistic electron of energy E travels on a circular trajectory in a dipole magnet of main field By = B and bending radius , where G = B = p/e, the ratio of momentum to charge, is often called the magnetic rigidity, it radiates electromagnetic power confined in a cone with ±1/ opening toward its moving direction. Its radiation power can be expressed as, 2 c44 P = r m c2 , s 3 0 0 2 1.2 Synchrotron Radiation Generation 3 y ρ x S Δφ Synchrotron Electron beam radiation Photon N Electron beam z Figure 1.2 Synchrotron radiation from bending magnet. where e is the electron charge, m0 istheelectronrestmass, c is the electron 2 2 2 moving speed, = E/(m0c ) is the Lorentz factor, and r0 = e ∕(4 0m0c ) is the electron classical radius. Integrating the radiated power over an isomagnetic stor- age ring with constant gives an electron energy loss in one turn due to the synchrotron radiation as follows, 4 4 U = r m c23 . 0 3 0 0 In engineering units, E4[GeV] U [keV]=88.5 . 0 [m] For an electron beam traveling through a dipole magnet of bending angle Δ with average current of Ib, the radiated power is, 2 c44 P = r m c2 ΔI . d 3 0 0 e b For an electron beam circulating in storage ring (with average current of Ib and revolution time of T 0), the total radiated power per turn is, I U 4 4 P = b 0 = r m c23 I . 0 e 3 0 0 e b When an electron travels on the circular path in a dipole magnet, its emit- ting radiation on a fixed target outside the orbit circle comes only from a short arc of electron trajectory, this short synchrotron radiation pulse covers a wide continuous spectrum of photon energies from infrared to X-rays depending on the electron energy and the bending magnetic field. A so-called critical photon energy c (or critical frequency c) is defined as the photon energy which divides the synchrotron radiation into two spectral regions with equal radiated power, 3 3 = c , c 2 h 3hc 3 = = . c 2 c 4 In engineering units, 2 . c [keV]=0.665E [GeV]B[T] The significance of the critical photon energy is that it sets up the upper bund for the synchrotron radiation spectrum, and the spectral power falls rapidly for 4 1 Synchrotron Light Sources photon energies above this critical value. The complete spectral distribution of synchrotron radiation can be calculated using the Fourier transform of the radi- ation electric field, ( ) dP P s = s S , d ( ) √c c ∞ 9 3 . S = K5∕3(x)dx 8 ∫ c c ∕ c The K (x)aboveandK (x) below are the modified Bessel functions. The 5/3 2/3̇ on-axis spectral photon flux Nph (defined as the number of photons per unit time) per unit solid angle in a bandwidth Δ / and for a circulating beam current Ib is a more useful parameter. It can be written as, ( ) ( ) ̇ 2 ̇ 2 2 dNph d Nph 3E I Δ = = b K 2 , 2 2 2 2∕3 dΩ d d 4 e(mc ) c 2 c 2 where = e /(2ch 0) is the fine structure constant. In engineering units, and with 0.1% bandwidth, ( ) ( ) ̇ 2 dNph [photons/sec/mrad2]=1.33 × 1013E2 [GeV]I [A] K 2 . b 2∕3 dΩ c 2 c Theon-axisphotonfluxperunitdeflectionangleis, ̇ ( ) dN ph Ps Δ . = S d ch c The photon flux at energy is given by, ( ) √ P 9 3 P ∞ ̇ = s = s ( ) Nph, S 2 K5∕3 x dx 2 2 ∫ c c h c ∕ c and by integrating the photon flux for from zero to infinity, the total number of radiating photons per unit time is, √ +∞ 15 3 P ̇ = ̇ = s . Nph ∫ Nph,d 0 8 c The total photon flux at energy for the storage ring with average beam current Ib is, √ 3 3 r m c234 ∞ ̇ = 0 0 ( ) . Nph, 2 Ib K5∕3 x dx 2 ∫ e c ∕ c The total photon flux √ 5 3 4 ̇ = 23 . Nph r0m0c Ib 2e c 1.2 Synchrotron Radiation Generation 5 1.2.2 Radiation from Undulator Undulator and wiggler, or so-called insertion devices, consisting of a series of alternating magnet poles, deflect the electron periodically in opposite directions. They are installed in the storage ring straight sections and optimized for gener- ating specific synchrotron radiation characteristics. 1.2.2.1 Planar Undulator Radiation The radiation from planar undulator with N u period has the same physical pro- cess as a short bending magnet, but the N u times of oscillations that an elec- tron performs in an undulator transform the radiation into quasi-monochramatic 1∕2 with finite line width and within a cone of 1∕( Nu ). This makes the planar undu- lator radiation intensity effectively enhanced with reasonable radiation power (Figure 1.3). In a planar undulator with period length u and peak field B0, the main mag- netic field is By = B0 sin(2 s/ u), and the average instantaneous radiation power of an electron traveling in planar undulator is, ( ) 2 r cm c22K 2 2 = 0 0 , Pu 3 u where K is the so-called deflection parameter and is defined as, ecB K = 0 u . 2 2 m0c The total energy emitted by an electron from the undulator with a length of Lu = Nu u is, ( ) 2 r m c22K 2L 2 = 0 0 u . Uu 3 u The total average radiated power of an electron beam with current of Ib passing through the undulator is, ( ) 22 2 2 r0m0c K LuIb 2 . Pu, I = 3e u In engineering units, 2 2 . Pu, I [kW]=0.633E [GeV]B0 [T]Lu[m]Ib [A] y x Electron N S N S beam Synchrotron radiation θ S N Photon S N z Figure 1.3 Synchrotron radiation from undulator. 6 1 Synchrotron Light Sources Owing to the cooperative effect of radiation from different periods, the undula- tor radiation has line spectral characteristics. Its radiation wavelength, or photon energy at the nth harmonic, can be expressed as, ( ) 1 = u 1 + K 2 + 22 n 2n2 2 with the line width, Δ n 1 , = n nNu where n = 1, 3, 5, … is the harmonic number of radiation line, n = 2 c/ n, Δ n = −n 1.
Load more

Recommended publications
  • Undulator Radiation & FEL
    U.S. Particle Accelerator School January 25 – February 19, 2021 VUV and X-ray Free-Electron Lasers Introduction, Electron Motions in an Undulator, Undulator Radiation & FEL Dinh C. Nguyen,1 Petr Anisimov,2 Nicole Neveu1 1 SLAC National Accelerator Laboratory 2 Los Alamos National Laboratory LA-UR-21-20610 Monday (Jan 25) Lecture Outline Time • VUV and X-ray FELs in the World 10:00 – 10:30 • Properties of electromagnetic radiation 10:30 – 10:50 • Break 10:50 – 11:00 • Electron motions in an undulator 11:00 – 11:20 • Undulator radiation 11:20 – 11:40 • Introduction to FELs 11:40 – Noon 2 VUV and X-ray FELs in the World 3 World Map of VUV and X-ray FELs FLASH FERMI European XFEL Italy Germany SPARC LCLS Italy SwissFEL POLFEL LCLS-II & LCLS-II-HE Switzerland Poland USA PAL XFEL S. Korea SACLA Japan SDUV-SXFEL SHINE China Blue=VUV to Soft X-ray 4 Purple=Soft to Hard X-ray Sub-systems of an RF Linac Driven X-ray FEL An RF-linac driven XFEL has the following sub-systems in order to produce Low-emittance • PHOTOINJECTOR to generate low-emittance electrons in ps bunches electron beams • RF LINAC to accelerate the electron beams to GeV energy • BUNCH COMPRESSORS to shorten the bunches and produce kA current High peak current • LASER HEATER to reduce the microbunching instabilities • BEAM OPTICS to transport the electron beams to the undulators • UNDULATORS to generate and amplify the radiation in a single pass Single-pass, high- gain X-ray FEL • DIAGNOSTICS to characterize the electron & FEL beams Laser Photoinjector heater L2 BC2 L1 L3 Optics
    [Show full text]
  • FEL Physics Summary
    VUV and X-Ray Free Electron Lasers: The Technology and Its Scientific Promise William Barletta and Carlo Rizzuto Sections I & III – Motivations & FEL Physics List of symbols fine structure constant dimensionless vector potential aw horizontal Twiss x bunching parameter b mean resolution error of BPMs BPMres position error of BPMs BPMpos remanent field BR undulator magnetic field strength Bw horizontal Twiss x speed of light c mean phase error in undulator penetration depth δp horizontal dispersion Dx derivative of Dx D´x FEL beam diameter on optic Dw energy chirp from CSR E/E beam emittance electron charge e beam energy E peak electric field in gun Eo normalized emittance n energy in the FEL pulse EPulse longitudinal space charge force Fsc angle of incidence j i 1 2 relativistic factor (E/ me c ) optical function in transport H magnetic coercivity HC Alfven current at =1 IAo beam current Ib BBU threshold current IBBU undulator parameter K mean undulator strength Krms undulator spatial frequency kw gain length LG th m harmonic wavelength m plasma wavelength P radiation wavelength r undulator wavelength w root of gain equation harmonic number m electron mass me number of electrons Ne electron density ne number of undulator periods Nu radiation power P input laser power Plaser noise power Pn pole roll angle error BNP (or Pierce) parameter quantum FEL parameter ´ atom density A quality factor Q dipole quality factor Qdipole FEL energy constraint ratio r1 FEL emittance constraint ratio r2 FEL diffraction constraint ratio r3 classical radius of electron re bend angle in undulator bend angle in achromat 2 th phase of i electron i kick relative to each pole error j mean energy spread of electrons e bunch length z relativistic plasma frequency p distance along undulator z mean longitudinal velocity <vz> impedance of free space Zo Rayleigh range ZR 3 I.
    [Show full text]
  • Chapter 3: Front Ends and Insertion Devices
    Advanced Photon Source Upgrade Project Final Design Report May 2019 Chapter 3: Front Ends and Insertion Devices Document Number : APSU-2.01-RPT-003 ICMS Content ID : APSU_2032071 Advanced Photon Source Upgrade Project 3–ii • Table of Contents Table of Contents 3 Front Ends and Insertion Devices 1 3-1 Introduction . 1 3-2 Front Ends . 2 3-2.1 High Heat Load Front End . 6 3-2.2 Canted Undulator Front End . 11 3-2.3 Bending Magnet Front End . 16 3-3 Insertion Devices . 20 3-3.1 Storage Ring Requirements . 22 3-3.2 Overview of Insertion Device Straight Sections . 23 3-3.3 Permanent Magnet Undulators . 24 3-3.4 Superconducting Undulators . 30 3-3.5 Insertion Device Vacuum Chamber . 33 3-4 Bending Magnet Sources . 36 References 39 Advanced Photon Source Upgrade Project List of Figures • 3–iii List of Figures Figure 3.1: Overview of ID and BM front ends in relation to the storage ring components. 2 Figure 3.2: Layout of High Heat Load Front End for APS-U. 6 Figure 3.3: Model of the GRID XBPM for the HHL front end. 8 Figure 3.4: Layout of Canted Undulator Front End for APS-U. 11 Figure 3.5: Model of the GRID XBPM for the CU front end. 13 Figure 3.6: Horizontal fan of radiation from different dipoles for bending magnet beamlines. 16 Figure 3.7: Layout of Original APS Bending Magnet Front End in current APS. 17 Figure 3.8: Layout of modified APSU Bending Magnet Front End to be installed in APSU.
    [Show full text]
  • Colliding a Linear Electron Beam with a Storage Ring Beam* ABSTRACT
    SLAC i PUB - 4545 February 1988 WA) Colliding a Linear Electron Beam with a Storage Ring Beam* P. GROSSE- WIESMANN Stanford Linear Accelerator Center Stanford University, Stanford, California 94305 ABSTRACT We investigate the possibility of colliding a linear accelerator electron beam with a particle beam stored in a circular storage ring. Such a scheme allows e+e- colliders with a center-of-mass energy of a few hundred GeV and eP colliders with a center-of-mass energy of several TeV. High luminosities are possible for both colliders. Submitted to Nuclear Instruments & Methods * W&k supported by the Department of Energy, contract DE - A C 0 3 - 76 SF 00 5 15. 1. Introduction In order to get a better understanding of the standard model of particle physics, higher energies and higher luminosities in particle collisions are desir- able. It is generally recognized that particle collisions involving leptons have a considerable advantage for experimental studies over purely hadronic interac- tions. The initial state is better defined and cleaner event samples are achieved. Unfortunately, the center-of-mass energy and the luminosity achievable in an electron storage ring are limited. The energy losses from synchrotron radiation increase rapidly with the beam energy. Even with the largest storage rings un- der construction or under discussion the beam energy cannot be extended far beyond 100 GeV [l]. I n addition, the luminosity in a storage ring is strongly limited by the beam-beam interaction. Event rates desirable to investigate the known particles are not even available at existing storage rings. One way out of this problem is the linear collider scheme [2,3].
    [Show full text]
  • Insertion Devices Lecture 4 Undulator Magnet Designs
    Insertion Devices Lecture 4 Undulator Magnet Designs Jim Clarke ASTeC Daresbury Laboratory Hybrid Insertion Devices – Inclusion of Iron Simple hybrid example Top Array e- Bottom Array 2 Lines of Magnetic Flux Including a non-linear material like iron means that simple analytical formulae can no longer be derived – linear superposition no longer works! Accurate predictions for particular designs can only be made using special magnetostatic software in either 2D (fast) or 3D (slow) e- 3 Field Levels for Hybrid and PPM Insertion Devices Assuming Br = 1.1T and gap of 20 mm When g/u is small the impact of the iron is very significant 4 Introduction We now have an understanding for how we can use Permanent Magnets to create the sinusoidal fields required by Insertion Devices Next we will look at creating more complex field shapes, such as those required for variable polarisation Later we will look at other technical issues such as the challenge of in-vacuum undulators, dealing with the large magnetic forces involved, correcting field errors, and also how and why we might cool undulators to ~150K Finally, electromagnetic alternatives will be considered 5 Helical (or Elliptical) Undulators for Variable Polarisation We need to include a finite horizontal field of the same period so the electron takes an elliptical path when it is viewed head on We want two orthogonal fields of equal period but of different amplitude and phase 3 independent variables Three independent variables are required for the arbitrary selection of any polarisation state
    [Show full text]
  • Persis S. Drell Stanford Helmut Dosch DESY
    Persis S. Drell Helmut Dosch Stanford DESY Outline • Introduction • BESAC Contributions & Impact – John Hemminger’s Leadership – Most recent recommendations on future BES light source facilities • Americas Perspective – Science Results & Drivers – New Rings & FELs • Asia & Europe Perspective – Science Results & Drivers – New Rings & FELs • Concluding Remarks 2 BESAC Contributions & Impact to BES Facilities • Dr. John Hemminger: 13 years as BESAC Chairperson – Key BESAC & SC Strategic Planning Reports (See Below) – New Facilities: SNS, 5 NSRCs, LCLS, NSLS-II, LCLS-II, APS-U, … 20000 Near Doubling of BES User Community 8.8K → 16.3K since 2004! 15000 10000 5000 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 NSLS II NSLS SSRL ALS APS LCLS HFBR IPNS SNS HFIR LS Users: 7.7K → 11K Lujan EMC NCEM ShaRE CNMS MF CINT CNM CFN Basic Energy Sciences Report of the BESAC Report Facilities Prioritization BESAC Subcommittee on on Future X-ray Light Facility Upgrades Co-Chaired by : Sources John C. Hemminger, Chair Univ ersity of California, Irv ine & William Barletta Approv ed by the Approv ed by the Basic Energy MIT Basic Energy Sciences Sciences Adv isory Committee Adv isory Committee on February 26-27, 2013 on July 25, 2013 June 9, 2016 3 Motivation: Desire to Probe Nature at Atomic Length (Å) & Time (fs) Scales Seeing the Invisible in Real Materials Where are the Atoms? Compositional Newly discovered heterogeneity in a structure of a LiNi1/3Co1/3Mn1/3O2 hydrogen-stuffed, battery hundreds quartz-like form of of hours after ice charging
    [Show full text]
  • Vacuum Ultraviolet Photoabsorption Spectroscopy of Space-Related Ices: 1 Kev Electron Irradiation of Nitrogen- and Oxygen-Rich Ices S
    A&A 641, A154 (2020) Astronomy https://doi.org/10.1051/0004-6361/201935477 & © ESO 2020 Astrophysics Vacuum ultraviolet photoabsorption spectroscopy of space-related ices: 1 keV electron irradiation of nitrogen- and oxygen-rich ices S. Ioppolo1, Z. Kanuchovᡠ2, R. L. James3, A. Dawes3, N. C. Jones4, S. V. Hoffmann4, N. J. Mason5, and G. Strazzulla6 1 School of Electronic Engineering and Computer Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK e-mail: [email protected] 2 Astronomical Institute of Slovak Academy of Sciences, 059 60 Tatranská Lomnica, Slovakia 3 School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK 4 ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark 5 School of Physical Sciences, University of Kent, Park Wood Rd, Canterbury CT2 7NH, UK 6 INAF – Osservatorio Astrofisico di Catania, Via Santa Sofia 78, Catania 95123, Italy Received 15 March 2019 / Accepted 24 July 2020 ABSTRACT Context. Molecular oxygen, nitrogen, and ozone have been detected on some satellites of Saturn and Jupiter, as well as on comets. They are also expected to be present in ice-grain mantles within star-forming regions. The continuous energetic processing of icy objects in the Solar System induces physical and chemical changes within the ice. Laboratory experiments that simulate energetic processing (ions, photons, and electrons) of ices are therefore essential for interpreting and directing future astronomical observations. Aims. We provide vacuum ultraviolet (VUV) photoabsorption spectroscopic data of energetically processed nitrogen- and oxygen-rich ices that will help to identify absorption bands and/or spectral slopes observed on icy objects in the Solar System and on ice-grain mantles of the interstellar medium.
    [Show full text]
  • A Review of High-Gain Free-Electron Laser Theory
    atoms Review A Review of High-Gain Free-Electron Laser Theory Nicola Piovella 1,* and Luca Volpe 2 1 Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy 2 Centro de Laseres Pulsados (CLPU), Parque Cientifico, 37185 Salamanca, Spain; [email protected] * Correspondence: [email protected] Abstract: High-gain free-electron lasers, conceived in the 1980s, are nowadays the only bright sources of coherent X-ray radiation available. In this article, we review the theory developed by R. Bonifacio and coworkers, who have been some of the first scientists envisaging its operation as a single-pass amplifier starting from incoherent undulator radiation, in the so called self-amplified spontaneous emission (SASE) regime. We review the FEL theory, discussing how the FEL parameters emerge from it, which are fundamental for describing, designing and understanding all FEL experiments in the high-gain, single-pass operation. Keywords: free-electron laser; X-ray emission; collective effects 1. Basic Concepts The free-electron laser is essentially a device that transforms the kinetic energy of a relativistic electron beam (e-beam) into e.m. radiation [1–4]. The e-beam passing through a transverse periodic magnetic field oscillates in a direction perpendicular to the magnetic Citation: Piovella, N.; Volpe, L. field and the propagation axis, and emits radiation confined in a narrow cone along the A Review of High-Gain Free-Electron propagation direction. The periodic magnetic field is provided by the so-called undulator, an Laser Theory. Atoms 2021, 9, 28. insertion device usually realized with two arrays of permanent magnets with alternating https://doi.org/10.3390/atoms9020028 polarities (see Figure1) or with two helical coils with current circulating in opposite directions.
    [Show full text]
  • Third-Generation Synchrotron X-Ray Diffraction of 6- M Crystal of Raite, Na
    Proc. Natl. Acad. Sci. USA Vol. 94, pp. 12263–12267, November 1997 Geology Third-generation synchrotron x-ray diffraction of 6-mm crystal of raite, 'Na3Mn3Ti0.25Si8O20(OH)2z10H2O, opens up new chemistry and physics of low-temperature minerals (crystal structureymicrocrystalyphyllosilicate) JOSEPH J. PLUTH*, JOSEPH V. SMITH*†,DMITRY Y. PUSHCHAROVSKY‡,EUGENII I. SEMENOV§,ANDREAS BRAM¶, CHRISTIAN RIEKEL¶,HANS-PETER WEBER¶, AND ROBERT W. BROACHi *Department of Geophysical Sciences, Center for Advanced Radiation Sources, GeologicalySoilyEnvironmental, and Materials Research Science and Engineering Center, 5734 South Ellis Avenue, University of Chicago, Chicago, IL 60637; ‡Department of Geology, Moscow State University, Moscow, 119899, Russia; §Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, 117071, Russia; ¶European Synchrotron Radiation Facility, BP 220, 38043, Grenoble, France; and UOP Research Center, Des Plaines, IL 60017 Contributed by Joseph V. Smith, September 3, 1997 ABSTRACT The crystal structure of raite was solved and the energy and metal industries, hydrology, and geobiology. refined from data collected at Beamline Insertion Device 13 at Raite lies in the chemical cooling sequence of exotic hyperal- the European Synchrotron Radiation Facility, using a 3 3 3 3 kaline rocks of the Kola Peninsula, Russia, and the 65 mm single crystal. The refined lattice constants of the Monteregian Hills, Canada (2). This hydrated sodium- monoclinic unit cell are a 5 15.1(1) Å; b 5 17.6(1) Å; c 5 manganese silicate extends the already wide range of manga- 5.290(4) Å; b 5 100.5(2)°; space group C2ym. The structure, nese crystal chemistry (3), which includes various complex including all reflections, refined to a final R 5 0.07.
    [Show full text]
  • Beam Dynamics of the Superconducting Wiggler on the Ssrf Storage Ring
    Submitted to ‘Chinese Physics C’ BEAM DYNAMICS OF THE SUPERCONDUCTING WIGGLER ON THE SSRF STORAGE RING * ZHANG Qing-Lei(张庆磊)1,2 TIAN Shun-Qiang(田顺强)1 JIANG Bo-Cheng(姜伯承)1 XU Jie-Ping(许皆平) 1 ZHAO Zhen-Tang(赵振堂)1;1) 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P.R. China 2 University of Chinese Academy of Sciences, Beijing 100049, P.R. China * Supported by National Natural Science Foundation of China (11105214) 1) E-mail: [email protected] Abstract In the SSRF Phase-II beamline project, a Superconducting Wiggler (SW) will be installed in the electron storage ring. It may greatly impact on the beam dynamics due to the very high magnetic field. The emittance growth becomes a main problem, even after a well correction of the beam optics. A local achromatic lattice is studied, in order to combat the emittance growth and keep the good performance of the SSRF storage ring, as well as possible. Other effects of the SW are simulated and optimized as well, including the beta beating, the tune shift, the dynamic aperture, and the field error effects. Key word SSRF storage ring, superconducting wiggler, beam dynamics, Accelerator Toolbox PACS 29.20.db, 41.85.-p INTRODUCTION Shanghai Synchrotron Radiation Facility (SSRF) is a third generation light source with the beam energy of 3.5GeV [1-3]. It has been operated for users’ experiments since 2009. There are 20 straight sections in the storage ring of SSRF, including 4 long straight sections (LSSs) and 16 standard straight sections (SSSs).
    [Show full text]
  • Synchrotron Light Source
    Synchrotron Light Source The evolution of light sources echoes the progress of civilization in technology, and carries with it mankind's hopes to make life's dreams come true. The synchrotron light source is one of the most influential light sources in scientific research in our times. Bright light generated by ultra-rapidly orbiting electrons leads human beings to explore the microscopic world. Located in Hsinchu Science Park, the NSRRC operates a high-performance synchrotron, providing X-rays of great brightness that is unattainable in conventional laboratories and that draws NSRRC users from academic and technological communities worldwide. Each year, scientists and students have been paying over ten thousand visits to the NSRRC to perform experiments day and night in various scientific fields, using cutting-edge technologies and apparatus. These endeavors aim to explore the vast universe, scrutinize the complicated structures of life, discover novel nanomaterials, create a sustainable environment of green energy, unveil living things in the distant past, and deliver better and richer material and spiritual lives to mankind. Synchrotron Light Source Light, also known as electromagnetic waves, has always been an important means for humans to observe and study the natural world. The electromagnetic spectrum includes not only visible light, which can be seen with a naked human eye, but also radiowaves, microwaves, infrared light, ultraviolet light, X-rays, and gamma rays, classified according to their wave lengths. Light of Trajectory of the electron beam varied kind, based on its varied energetic characteristics, plays varied roles in the daily lives of human beings. The synchrotron light source, accidentally discovered at the synchrotron accelerator of General Electric Company in the U.S.
    [Show full text]
  • CERN Intersecting Storage Rings (ISR)
    Proc. Nat. Acad. Sci. USA Vol. 70, No. 2, pp. 619-626, February 1973 CERN Intersecting Storage Rings (ISR) K. JOHNSEN CERN It has been realized for many years that it would be possible to beams of protons collide with sufficiently high interaction obtain a glimpse into a much higher energy region for ele- rates for feasible experimentation in an energy range otherwise mentary-particle research if particle beams could be persuaded unattainable by known techniques except at enormous cost. to collide head-on. A group at CERN started investigating this possibility in To explain why this is so, let us consider what happens in a 1957, first studying a special two-way fixed-field alternating conventional accelerator experiment. When accelerated gradient (FFAG) accelerator and then, in 1960, turning to the particles have reached the required energy they are directed idea of two intersecting storage rings that could be fed by the onto a target and collide with the stationary particles of the CERN 28 GeV proton synchrotron (CERN-PS). This change target. Most of the energy given to the accelerated particles in concept for these initial studies was stimulated by the then goes into keeping the particles that result from the promising performance of the CERN-PS from the very start collision moving in the direction of the incident particles (to of its operation in 1959. conserve momentum). Only a quite modest fraction is "useful After an extensive study that included building an electron energy" for the real purpose of the experiment-the trans- storage ring (CESAR) to investigate many of the associated formation of particles, the creation of new particles.
    [Show full text]