Showing papers on "Synchrotron radiation published in 1980"
01 Jan 1980
TL;DR: One of the most popular books now is the synchrotron radiation research research as discussed by the authors, which is why searching for this popular book in this website will give you benefit, and when you have found the store to buy the book, it will be so hurt when you run out of it.
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669 citations
TL;DR: Experiments on striated muscle have been carried out at the EMBL Outstation at DESY, Hamburg, using the electron–positron storage ring DORIS as a high-intensity X-ray source, and the low-angle reflections from the myosin cross-bridges could be recorded more than 1,000 times more rapidly than with the best conventional X-rays.
Abstract: The use of synchrotron radiation in time-resolved X-ray diffraction studies of myosin layer-line reflections during muscle contraction
148 citations
TL;DR: In this paper, the inner valence shell photoionisation of N2 has been studied using monochromatised synchrotron radiation in the region of 44 to 65 eV.
Abstract: The inner valence shell photoionisation of N2 has been studied using monochromatised synchrotron radiation in the region of 44 to 65 eV. The experimental results are compared with recent theoretical calculations predicting shape resonance features and a breakdown of the independent-particle (MO) picture of ionisation.
102 citations
TL;DR: The properties of zone plates are outlined, along with the microscope systems that employ them, and a number of applications of x-ray microscopes are surveyed, including in biology, environmental science, and materials science.
Abstract: The scope of this article is to describe a transmission X-ray microscope, possible biological applications of soft X-ray microscopy and preliminary results.For soft X-ray microscopy of biological specimens the wavelength range of 1–10 nm is best suited. Microscopy in this wavelength range requires intense X-ray sources as well as high-resolution X-ray lenses. Intense X-radiation is provided by the synchrotron radiation of electron and positron storage rings. Suited X-ray lenses are zone plates.A theoretical treatment of the contrast mechanism and the radiation damage as well as first experiments yield the following results. Firstly, relatively thick (1–10 μm) biological specimens can be investigated. This means that unsectioned dried and even wet cells and cell organelles in a natural state can be examined. Second, it will be possible to resolve cellular aggregates in live cells with a resolution in the region of ≤10nm.
93 citations
TL;DR: In this article, the relative merits of crystals versus moirrors for focusing synchrotron radiation at energies above 10 keV are explored, and the cylindrically curved crystals make the proper Bragg angle for energies above 5 keV and for divergences larger than 10 mrad and to produce X-ray beams which are approximately focused.
93 citations
TL;DR: The assembly of microtubules has been investigated by time-resolved X-ray diffraction using synchrotron radiation and the results suggest that microtubule may be formed from tubulin oligomers smaller than rings.
Abstract: The assembly of microtubules has been investigated by time-resolved X-ray diffraction using synchrotron radiation. The small-angle scattering becomes visible within seconds and thus enables study of the structural transitions of the protein aggregates during assembly from their subunits in solution. The X-ray pattern at 4 °C arises from a mixture of tubulin rings, dimers and some other species. Raising the temperature to 36 °C induces the breakdown of rings, followed by the growth of microtubules. The results suggest that microtubules may be formed from tubulin oligomers smaller than rings.
87 citations
IBM1
TL;DR: In this article, the advantages of the soft x-ray photon in the imaging of biological material, which are not shared by other particles, are discussed, and the status of some of the problems which arise in the use of these photons for this purpose.
Abstract: Our purpose in the first part of this talk is to call attention to certain advantages of the soft (λ = 10-100A) x-ray photon in the imaging of biological material, which are not shared by other particles. The second part will briefly survey the status of some of the problems which arise in the use of these photons for this purpose.
86 citations
CERN1
TL;DR: In this article, a higher harmonic RF system is added to the main system to increase the damping against longitudinal coupled bunch instabilities, and the motion of single particles in this highly non-linear potential is calculated numerically as well as analytically.
Abstract: The addition of a higher harmonic RF system to the main system allows a control of the synchrotron frequency, the spread in synchrotron frequency and the bunch length. Adjustment of the higher harmonic system so as to reduce the slope of the RF wave to zero at the bunch centre leads to a longer bunch and a greatly increased spread in synchrotron frequency. This increases the Landau damping against: longitudinal coupled bunch instabilities. The motion of single particles in this highly non-linear potential is calculated numerically as well as analytically (by making some approximations). The dependence of the synchrotron frequency on amplitude and the forms of the synchrotron oscillations and the RF bucket are calculated. Finally the bunch shape and the distribution of particles in Qs are calculated for electron bunches.
84 citations
TL;DR: In this article, the decay rate of the lowest 0u+ and 1u states of Xe2*, excited by monochromatized synchrotron radiation from the Stanford storage ring (SPEAR), have been measured in pure xenon and in xenon-argon mixtures over the pressure range 102 to 104 Torr.
Abstract: Formation and decay rates of the lowest 0u+ and 1u states of Xe2*, excited by monochromatized synchrotron radiation from the Stanford storage ring (SPEAR), have been measured in pure xenon and in xenon–argon mixtures over the pressure range 102 to 104 Torr. The results are interpreted to yield radiative lifetimes (4.6±0.3 and 99±2 nsec, respectively, for vibrationally relaxed 0u+ and 1u molecules), vibrational relaxation rates [7×10−11 and 6×10−12 cm3/sec for Xe2* (1u) in collisions with xenon and argon, respectively], the Xe2* (0u+) three‐body formation rate from Xe(3P1) (5.3×10−32 cm3/sec), and rates for 0u+–1u mixing by collisions with xenon and argon.
80 citations
TL;DR: In this paper, the first use of synchrotron radiation for circular dichroism (CD) measurements was described and the measurements were carried out in the wavelength range 1325-2050 A on (+)-3-methylcyclopentanone at the Synchrotrom Radiation Center of the University of Wisconsin-Madison.
76 citations
TL;DR: In this article, it is shown that it is possible to follow changes in X-ray scattering patterns with a time resolution of a few ms, and some examples from recent biological experiments are given.
Abstract: Until recently, time resolved measurements of X-ray scattering patterns have not been feasible because laboratory X-ray sources were too weak and detectors unavailable. Recent developments in both these fields have changed the situation, and it is now possible to follow changes in X-ray scattering patterns with a time resolution of a few ms. The apparatus used to achieve this is described and some examples from recent biological experiments are given.
TL;DR: In this paper, the authors describe a modular computer system which can be used to control the operation of and collect and process spectral data from this spectrometer system, which is suitable for use to wavelengths less than 130 nm.
TL;DR: In this article, it was shown that the very flat radio spectrum of this source results from a superposition of incoherent synchrotron radiation from four distinct, homogeneous components, each with a peaked spectrum, rather than from radiation from a single inhomogeneous component.
Abstract: Multifrequency interferometric and total flux density measurements of the radiation from 0735 plus 178 are discussed. It is shown that it is far more likely that the very flat radio spectrum of this source results from a superposition of incoherent synchrotron radiation from four distinct, homogeneous components, each with a peaked spectrum, than from radiation from a single inhomogeneous component.
TL;DR: In this article, the steady-state features of the free-electron laser oscillator, operating with an electron beam stored in a circular accelerating machine (storage ring), were investigated and the average laser output power was proportional to the power radiated, via synchrotron radiation, in the bending magnets of the storage ring.
Abstract: In this paper we investigate the steady-state features of the free-electron laser oscillator, operating with an electron beam stored in a circular accelerating machine (storage ring). The electron, and laser beam parameters are evaluated. In particular, it comes out that the average laser output power is proportional to the power radiated, via synchrotron radiation, in the bending magnets of the storage ring.
TL;DR: In this article, the general background and theoretical basis of plane grating monochromators (PGMs) is reviewed and the particular case of grazing incidence PGMs suitable for use with synchrotron radiation is considered in detail.
TL;DR: Excitation energies, oscillator strengths, and line shapes for valence excitons in rare gas solids are presented and discussed in the light of recent theoretical approaches.
Abstract: Excitation energies, oscillator strengths, and line shapes for valence excitons in rare gas solids are presented and discussed in the light of recent theoretical approaches. In a second section, first results are reported for solid Kr obtained in a two-photon photoemission experiment combining synchrotron radiation and a laser.
01 Jan 1980
TL;DR: Synchrotron radiation produced by storage rings (rather than synchrotrons) offers several important properties including high intensity, high polarization, high intensity and high intensity properties.
Abstract: Synchrotron radiation has several important properties including:
1
High intensity
2
Broad spectral range
3
High polarization
4
Pulsed time structure
5
Natural collimation
In addition, synchrotron radiation produced by storage rings (rather than synchrotrons) offers:
6
High-vacuum environment
7
Small-source-spot size
8
Stability
TL;DR: In this paper, the anomalous X-ray scattering was measured by single-crystal diffraction experiments with synchrotron radiation at wavelengths through the region of the three L absorption edges of cesium, the first such experiment for any element at the L edges.
Abstract: Both real and imaginary components of the anomalous X-ray scattering were measured by single-crystal diffraction experiments with synchrotron radiation at wavelengths through the region of the three L absorption edges of cesium, the first such experiment for any element at the L edges. Near the L3 edge f' varies between -26.7 and -13.9 and f" between 4.0 and 16.1 electrons in a wavelength interval of 0.008 A. Similar but smaller changes occur near the L2 edge, and still smaller ones at L1. Fine structure in the f" curve corresponds to that observed in an absorption curve and also, by a dispersion relation, to fine structure in the f' curve. These effects offer promise as a substitute for isomorphous replacement for solving the phase problem for macromolecular crystal structure. Similar experiments with cobalt near the K edge give f' values in agreement with measurements by other workers for nickel and copper by different methods at corresponding wavelengths; the lowest value observed is f' = -7.5 electrons.
TL;DR: In this paper, the solid state spectrometer on the Einstein Observatory and the GSFC cosmic X-ray spectrometers on OSO 8 have observed the spectrum of SN 1006 and the data can be well represented by a power-law model with alpha = 1.2.
Abstract: The solid-state spectrometer on the Einstein Observatory and the GSFC cosmic X-ray spectrometer on OSO 8 have observed the X-ray spectrum of SN 1006. The data can be well represented by a power-law model with alpha = 1.2, similar to the spectrum of the Crab Nebula. This is in contrast to the radio and X-ray maps of SN 1006 which show a shell structure more typical of SNR with thermal X-ray emission. The X-ray spectrum is suggestive of nonthermal synchrotron emission, raising the possibility that the remnant of SN 1006 contains a source of relativistic electrons.
TL;DR: In this article, two novel types of x-ray monochromators which eliminate unwanted higher orders usually present in crystal Monochromatized synchrotron radiation beams have been used successfully in spectroscopic studies.
Abstract: Two novel types of x‐ray monochromators which eliminate unwanted higher orders usually present in crystal monochromatized synchrotron radiation beams have been used successfully in spectroscopic studies. The design of the monochromators is based on the refractive index correction’s dependence on wavelength and relative orientation of crystal surface to reflecting Bragg planes. In addition to the order sorting property, both types of monochromators can be used to decrease or increase the reflected beam cross section by Bragg focusing, and in one type, to determine the polarization state of the diffracted beam.
TL;DR: Angle resolved photoemission from solids can be used to study band structures and surface states and some examples are given for the (110) and (111) orientations of Cu.
Abstract: Angle resolved photoemission from solids can be used to study band structures and surface states Some examples are given for the (110) and (111) orientations of Cu
TL;DR: In this article, the lifetime and rates for formation, vibrational relaxation and collisional mixing of the lowest Ou+ and lu states of Kr2 were determined by time-resolved fluorescence spectroscopy following excitation by monochromatized synchrotron radiation.
TL;DR: Theoretical expressions for the angular and spectral distributions of synchrotron radiation involve modified Bessel functions of fractional order and the integral ʃ x ∞ K ν (η) d η as discussed by the authors.
TL;DR: In this paper, the spatial distributions of photoelectrons from the molecules N2 and O2 were determined over a photon energy range of 16 to 25 eV using a Seya monochromator.
Abstract: Radiation from the 25 GeV electron synchrotron at the Bonn Physikalisch Institut has been used to measure the spatial distributions of photoelectrons from the molecules N2 and O2 Values of the asymmetry parameter beta of various ionic states have been determined over a photon energy range of 16 to 25 eV using a Seya monochromator to produce plane polarised radiation to a bandwidth of 500 mV Good agreement with He I and Ne I resonance line measurements by other workers is observed and a comparison with theoretical studies is given Additional measurements on N2 and C0 which complement the published date of Marr et al (1979 , 1980) using the Synchrotron Radiation Facility at the Daresbury Laboratory are provided in tabular form
TL;DR: In this paper, the satellite's ionisation energy in the photo-electron spectrum of acetylene has been studied as a function of photon energy using synchrotron radiation.
TL;DR: In this paper, photoelectron spectra of the methoxy species formed by the decomposition of methanol on nickel(111) indicate that the C-O-nickel bond is normal or nearly normal to the metal surface.
TL;DR: In this article, the use of multilayer interference coatings with enhanced, wavelength selective, reflectivity was proposed to extend the application of these mirrors down to X = 50 A and to profit from the advantages of normal incidence mirrors: smaller aberrations and larger apertures.
Abstract: Microscopic imaging with soft x-rays is, in principle, possible by shadow casting,',* Fresnel zone plates,' a pinhole in combination with a scanning drive: hol~graphy,~ and grazing incidence mirror!!" Since the reflectivities of mirror coating materials at wavelengths below 100 A are smaller than a tenth of a percent for normal incidence mirrors, these mirrors have not been considered so far. By the use of multilayer interference coatings'. lo with enhanced, wavelength selective, reflectivity, it seems possible to extend the application of these mirrors down to X = 50 A and to profit, thereby, from the advantages of normal incidence mirrors: smaller aberrations and larger apertures. A Schwarzschild type objective, for example, with two spherical concentric mirrors, under certain geometrical conditions, is almost free from aberrations and can be produced with good accuracy because of the spherical shape of the mirrors. Since, however, two reflections are necessary, the efficiency of such an objective will be small in any case. If used for direct imaging, the specimen would be irradiated by a number of photons two or three orders of magnitude larger than the number contributing to the formation of the image. Therefore, we prefer a scanning version of such a microscope and use the objective to form a highly demagnified image of the source. In the next section, the experimental setup is outlined; in the two sections following, details about multilayer interference coatings and the Schwarzschild type objective are given; and, in the penultimate section, the prototype of a microscope presently under construction at the Deutsches Elektronen-Synchrotron (DESY) is descn bed.
TL;DR: In this article, the performances of various optical elements are presented for ideally monochromatic X-rays in terms of position-angle space, which is used in the phase-space method.
Abstract: The performances of various optical elements are presented for ideally monochromatic X-rays in terms of position–angle space, which is used in the phase-space method. The optical elements discussed are a synchrotron radiation source, flat perfect crystals (reflection and transmission geometries), mosaic crystals, curved crystals of reflection (Johansson, Johann and logarithmic spiral types) and transmission geometries, and an elliptic total reflection mirror. The angular widths of acceptance and emergence for diffraction are properly taken into account in both the flat and curved crystals. It is shown that focusing optical elements such as a curved crystal and an elliptical mirror should not be treated simply as lenses.