Synchrotron Radiation Storage Ring Research Articles

A review of methods for experimentally determining linear optics in storage rings

In order to maximize the brightness and provide sufficient dynamic aperture in synchrotron radiation storage rings, one must understand and control the linear optics. Control of the horizontal beta function and dispersion is important for minimizing the horizontal beam size. Control of the skew gradient distribution is important for minimizing the vertical size. In this paper, various methods for experimentally determining the optics in a storage ring will be reviewed. Recent work at the National Synchrotron Light Source X-Ray Ring will be presented, as well as work done at laboratories worldwide.

Workshop on performance optimization of synchrotron radiation storage rings (invited)

The purpose of this workshop was to provide a forum, with user participation, for accelerator physicists working in the synchrotron light source field to discuss current and planned state-of-the-art techniques to optimize storage ring performance. The scope of the workshop focused on two areas: lattice characterization and measurement, and fundamental limitations on low frequency beam stability.

Fundamentals of the Synchrotron Radiation Facility Construction

Some fundamental properties of synchrotron radiation and electron beam characteristics in synchrotron radiation storage rings are recapitulated. Then, dicherent design criteria for the construction of synchrotron radiation facilities are discussed as well as some technical solutions to the problem of matching the light and electron beam properties. PACS numbers: 41.60.Ap

Flux and brightness calculations for various synchrotron radiation sources

Abstract Simple expressions for flux, central intensity, vertical opening angle, effective source size (horizontal and vertical), and brightness of bending magnets and ordinary planar insertion devices (undulators and wigglers) on synchrotron radiation (SR) storage rings are compiled. These expressions are evaluated for existing SR sources at the National Synchrotron Light Source (NSLS) and planned SR sources at the Advanced Light Source (ALS) and the Advanced Photon Source (APS). All necessary storage ring and insertion device parameters are listed in tables. The flux, central intensity, and brightness of all of the calculated SR sources are plotted for comparison.

Photon‐beam‐feedback system and mirror‐alignment mechanism

A feedback system is designed and built to automatically correct the long‐term instability of the photon beam generated from the synchrotron radiation storage ring. This feedback system is composed of a stepping motor‐controlled mirror‐alignment mechanism, a photon‐beam‐position monitor, a high precision current amplifier, and a PC‐controlled CAMAC interface system. The details of the system design as well as the motorized mirror‐alignment mechanism are presented in this article.

Projects of SR sources including research and development for insertion devices in the USSR

In this article the technical status and the properties of the already existing electron-positron storage ring synchrotron radiation (SR) sources and those under construction at the Institute of Nuclear Physics (Novosibirsk) are reviewed. The prospects of developing SR sources and the possibilities of new projects, in particular Siberia-3 (based upon the 10 GeV storage ring) and Siberia-4 (based upon the 2.4 GeV storage ring with 6 T superconducting magnets), are discussed. Also considered are various wigglers and undulators (electromagnetic devices, superconducting devices, and devices based on permanent magnets) designed for the INP storage ring. Possible schemes for the arrangement of insertion devices at SR sources and in the FEL optical klystron, which were invented and designed at our Institute, are shown.

X-ray absorption spectroscopy: A fluorescence detection system based on a plastic scintillator

A fluorescence detection system based on a plastic scintillator is presented that can be used for both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Its counting rate is limited by the pulsation frequency of the synchrotron radiation (3.16×10 6 counts s −1), and can be theoretically extended to roughly 5×10 7 counts s −1 if used on a multibunch storage ring synchrotron radiation source. Its physical characteristics (fluorescence decay time and fast electronics) are such that the dead-time correction is entirely defined by the revolution period of the charged particles in the storage ring. It shows a broad spectral response and is particularly well adapted to the measurement of hard X-rays (from 6 to 25 keV). Its volume is small (diameter 60 mm; height 240 mm), and filters of small dimensions are used to preferentially remove the scattered radiation. The entrance window of the detector is placed at 2–3 mm above the top of the sample, and a solid angle of collection of nearly 50% of 2π sr is achieved. The shape of the plastic scintillator can be easily modified to fit various geometries. It operates in both horizontal and vertical planes. It is about ten times less expensive than an energy-dispersive detection system based on a single Ge solid-state detector. The detector presents a high sensitivity. It is possible to obtain the entire EXAFS spectrum of an electrochemically (under potential deposition) deposited monolayer of Cu atoms on gold, with acquisition time of less than one hour (compared to 25 h for a Ge solid-state detector). Orientation-dependent X-ray absorption spectroscopy was performed on thin (800 Å) copper phthalocyanine film, and the spectra of diluted Cu 2+ ions in aqueous solution (18 ppm) and Co atoms in YBa 2Cu 3O 7 powder (230 ppm) were also measured to assess the sensitivity of the detector.

Prospective nonlithographic applications of a synchrotron radiation source for deep-etch lithography

It is pointed out that the performance of superconducting storage ring synchrotron radiation sources designed for deep-etch lithography like the source KSSQ planned at Karlsruhe is much superior to that of typical thin film lithography sources and comes close to that of first and second generation synchrotron radiation sources. Therefore, the range of applications of such machines exceeds the original design goal by far and includes many of the important synchrotron radiation methods based on diffraction, absorption, and fluorescence excitation, as well as foreseeable production methods. Thus, these machines may become a new class of sources of their own.

Storage ring synchrotron radiation sources (December 1988)

Storage ring synchrotron radiation sources (December 1988)

Proposals for Synchrotron Light Sources

Ever since it was first applied in the 1960's synchrotron radiation from an accelerating electron beam has been gaining popularity as a powerful tool for research and development in a wide variety of fields of science and technology. By now there are some 20 facilities operating either parasitically or dedicatedly for synchrotron radiation research in different parts of the world. In addition there are another 20 facilities either in construction or in various stages of proposal and design. The experiences gained from the operating facilities and the recent development of insertion devices such as wigglers and undulators as radiation sources led to a new set of requirements on the design of synchrotron radiation storage rings for optimum utility. The surprisingly uniform applicability and unanimous acceptance of these criteria give assurance that they are indeed valid criteria derived form mature considerations and experiences. Instead of describing the design of each of these new facilities it is, thus, more effective to discuss these desirable design features and indicate how they are incorporated in the design using machines listed as examples. 9 refs., 7 figs., 2 tabs.

Preliminary design of a dedicated 6 GeV synchrotron radiation storage ring

A new magnetic lattice is proposed for a 6 GeV electron storage ring specifically designed for utilization of high brightness undulator and wiggler radiation sources. The basic cell is an achromatic arc with three combined function dipoles, having a vertical focusing gradient. With this arrangement it is possible to achieve an electron beam emittance of ∼ 6 × 10 −9 m·rad at 6 GeV, moderately low chromaticity and good dynamic aperture.

An infrared beam port for the SRS at daresbury

Plans will be presented for the construction and operation of an infrared beam port at the Synchrotron Radiation Storage Ring recently opened at Daresbury, U.K. The beam port incorporates a special metal coated silicon carbide mirror collecting 90 mrad (horizontal) × 100 mrad (vertical) of radiation from an extended source along with focusing and collimating optics which present a parallel beam (7 cm in diameter) to our Martin-Puplett far infrared interferometer. The interferometer will allow radiometric and absorption (or reflection) measurements to be made in the 2–300 cm −1 region with a resolution of ⪖0.1 cm −1. In this region we expect that the SRS will provide at least two orders of magnitude more photon flux than a conventional source lamp with superior noise characteristics and a well-defined time structure. An outline of possible uses of such an IR source will be given, with emphasis on applications in chemical physics, biology and materials science.

Crystallography with synchrotron radiation

There are at least 500 synchrotron radiation storage ring sources (SRS) in operation around the world, but all have been designed with the nuclear physicist in mind and to him the x-and UV radiation they produce is an embarrassment. The newly-completed facility at the SERC Daresbury Laboratory is the first SRS to be dedicated to research using these radiations and, through the high intensity of the beam and the flexibility of control over its wavelength, polarisation state and time structure, it offers the physicist, chemist, metallurgist and biologist exciting, even bewildering, scope for devising experiments.

Current Accelerators for Research and Industry

In this paper we will describe four ongoing accelerator projects at Instrument AB Scanditronix in Uppsala, Sweden. These projects are being pursued in addition to the standard product lines of cyclotrons, microtrons, and magnetic spectrographs of Scanditronix and its U. S. affiliate, Nucletronix, rnc., in Gloucester, Massachusetts. These projects are as follows: 1. The BESSY electron storage ring synchrotron radiation project in Berlin, West Germany 2. The spallation neutron source project at KFA, Julich and KFE, Karlsruhe, West Germany 3. The NT50 clinical neutron therapy project at the University of Washington in Seattle, Washington 4. The RNP16 radionuclide production system at Johns Hopkins University Hospital in Baltimore, Maryland

Measurements of shock wave flight times in long pipes

In order to determine the time interval between the catastrophic failure of a vacuum component and the arrival of the resulting shock wave at some critical point in the rest of a long vacuum pipe, e.g. the beam line system at a synchrotron radiation storage ring, experiments were performed with various entrance geometries and pipe diameters. Perhaps the most salient conclusion that can be drawn from these experiments is that a slit, e.g. the exit slit of a monochromator, serves very effectively to slow the shock wave. Thus if accidents can be restricted to the experimental chambers employed on beam line systems behind a monochromator, shock wave flight times of greater than 30 ms can be easily reached in a length of 3 m.

Some Aspects on Linear and Non-Linear Orbit Motion in Storage Rings

Our purpose is the development of a general analytical theory which describes the orbit motion of particles in a storage ring, including the effect of the acceleration, analogous as done for cyclotrons. We only present here the start, neglecting the effect of the RF system. We will use a Hamilton formalism with action and angle variables and show that this leads, after several correct transformations, to expressions for the off-energy function , tunes and chromaticities. This theory can be extended to the influence of non-linear elements as sextupoles and octupoles and long straight sections on the orbit motion. Our treatment only needs direct field quantities in the form of Fourier components of the guide field elements. No a priori information about the lattice functions (η,ß etc.) is required, whereas normally one uses the behaviour of these functions as provided by lattice designing matrix codes. The results of the analytical theory as given here will be compared with numerical results applied on the lattice of the proposed Dutch dedicated synchrotron radiation storage ring PAMPUS.

Measurements on the efficiency of acoustic delay lines in view of beam lines for synchrotron radiation

Tests were run to study the propagation of a pressure wave as originated by the rupture of a beam exit foil window in the beam line of a synchrotron radiation storage ring. The measured velocities were approximately 1000 m/s for air and 2000 m/s for helium. The influence of various acoustic delay lines on the propagation of such waves was studied in detail by measuring the local dependence of the velocity in the pressure range of 10−6 to 10−3 mbar. It was found that the use of acoustic delay lines results in a drastic reduction of propagation velocity remaining at the same low level even in the part of the beam line behind the delay line. The efficiency of a delay line as defined by the ratio of inlet versus outlet velocity is determined mainly by its geometry and changes little with type of gas.

Thin windowed gas absorption apparatus for use with storage ring synchrotron radiation sources

A thin window gas absorption apparatus suitable for experiments with a storage ring synchrotron radiation source is described. The apparatus has been used with the grazing incidence monochromator on the 4° beam line at the Stanford Synchrotron Radiation Laboratory in experiments studying K-edge absorption in small molecules containing carbon and nitrogen.

Utilization of synchrotron radiation: current status and prospects

The review discusses the research and technological potential of contemporary sources of synchrotron radiation. A comparison is made of various sources of ultraviolet and x radiation. Characteristics are given of present electron storage rings—the principal sources of synchrotron radiation, and the means and limits of their further refinement are discussed. The features of performing experiments with synchrotron radiation in storage rings are considered. The main formulas characterizing the properties of synchrotron radiation are presented in a form convenient for practical calculations. The regions of application of synchrotron radiation are discussed (x-ray microscopy, x-ray structural analysis, and molecular, atomic, and nuclear spectroscopy). The principal attention is given to those questions in which the use of synchrotron radiation opens new possibilities. The prospects for practical application of synchrotron radiation are discussed (metrology, medicine, materials science, radiation technology).

The Use of Synchrotron Radiation as an Absolute Source of VUV Radiation.

Synchrotron radiation has been used as a standard source to calibrate spectrographic instruments at the National Bureau of Standards (NBS). Conceptually it is straightforward to apply the calculable continuum distribution of synchrotron radiation to problems requiring a source of known irradiance if the electron energy, the radius of the electron orbit, and the beam current are known. In practice many factors affect the accuracy of such a calibration, such as temporal and spatial variations in the electron beam, uncertainties in the orbital radius and maximum energy of the orbiting electron beam. These sources of error are discussed and the method of calibration on SURF-I is specified. A storage ring synchrotron radiation facility (SURF-II) is now operational at NBS. The calibration techniques developed for SURF-I are applied to SURF-II with anticipated improvements in calibration accuracy. For SURF-I the incident flux was determined with an accuracy of 15 percent while for SURF-II we anticipate accuracies of about 7 percent.