Showing papers on "Synchrotron radiation published in 1971"

Synchrotron Radiation as a Source for X-ray Diffraction

Abstract: Some preliminary results have been obtained with synchrotron radiation from the 7.5 GeV electron synchrotron Deutsches Elektronen - Synchrotron (DESY) in Hamburg as a source for X-ray diffraction.

Far Ultraviolet Spectroscopy of Solids in the Range 6–36 eV Using Synchrotron Radiation from an Electron Storage Ring

Abstract: The 240 MeV electron storage ring at the University of Wisconsin Physical Science Laboratory provides an intense polarized continuum light source in the far ultraviolet. Experimental equipment is described which allows the measurement of optical reflectivity and absorption of solids in the photon energy range 6–36 eV at temperatures between 90 and 500 K with this source. A discussion of the experimental procedures and the performance of the system is presented.

The Trapped Radiation Handbook

Abstract: : The Trapped Radiation Handbook provides useful information and design data for scientists and engineers engaged in the design of spacecraft systems that must operate in the trapped radiation environment. These subjects are discussed: The Magnetosphere; Features and Mathematical Models of the Earth's Magnetic Field; The Motion of Charged Particles in the Field; The Properties of the Particles in the Natural Radiation Belts; Source and Loss Mechanisms; The Artificial Radiation B LTS THAT HAVE RESULTED FROM TESTS OF NUCLEAR DEVICES CONDUCTED AT HIGH ALTITUDES; The Phenomenology of Nuclear Detonations and Beta Injection Processes; The Effects of Trapped Particles--Both Natural and Fission Betas--on Materials and Devices: The Irradiation of Circular Orbit Satellites by Trapped Particles of (1) the natural environment, (2) environments produced by weapon tests at various L-values, and (3) an estimated wartime environment; The Synchrotron Radiation Emitted by the Trapped Electrons; and the Vulnerability of Operational Systems in the Environments (1), (2), and (3) mentioned previously.

Search for optical circular polarization in the Crab Nebula

Abstract: IT has recently been suggested by Gunn and Ostriker1 and by Rees (paper presented at the IAU symposium 46 on the Crab Nebula, Manchester, August 1970) that the magnetic field in the Crab Nebula which causes relativistic particles to emit synchrotron radiation may be an oscillating 30 Hz electromagnetic field from the pulsar rather than a static field. Rees has shown that if this is the case, the nebula should show a component of circular polarization of order a few per cent in visible light. This is predicted to have opposite sense in the NW and SE regions of the nebula, supposing that the spin axis of the pulsar is in the direction of linear polarization.

Soft X-Ray Spectra of Sulfur in Cubic CdS

Abstract: The K β emission spectrum, the L II.III emission spectrum and the L II.III absorption spectrum for sulfur in cubic CdS have been measured with a bent quartz crystal spectrograph or a grazing incidence spectrograph. The light source for measuring the L II.III absorption spectrum was the continuous spectrum of synchrotron radiation. Results are as follows: p -electrons are concentrated near the top of the valence band and s -electrons in the middle part. The states near the bottom of the conduction band are of the s -type. The obtained spectra are compared with the results of the recent band calculation.

Results and Problems of an Investigation of Synchrotron Instability

Abstract: : The article has given the basic results of a study of synchrotron instability in the linear approach The situation essentially reduced to the calculation of reabsorption coefficients of the synchrotron radiation of a system of relativistic electrons(with given distribution function in terms of momentums) and a search for criteria at which these coefficients become negative In the linear theory of synchrotron instability there is still an unclear fundamental area of the conditions of amplification and precise magnetitude of the increments in a strongly rarefied given plasma, when the macroscopic approach to the determination of the nature of normal waves becomes inapplicable Moreover, in linear theory it is advisable to conduct a more thorough consideration of synchrotron instability for different distribution functions of the electrons, especially when the nature of the normal wave polarization is determined by relativistic electrons (Author)

Diagnostics for hot-electron, magnetically confined plasmas

Abstract: Diagnostics have been developed for measuring the temperature, density, velocity distribution, axial and radial profiles, and decay rate, of a hot-electron (te between 20 and 200 kev) plasma confined in a magnetic mirror field. The diagnostics include the measurement of: (1) the magnitude, spectrum, and spatial distribution of the synchrotron radiation, for determining the hot- electron line density, speed distribution, and density profile and angular velocity distribution, respectively; (2) the relativistic X-ray pulse heights, for determining the speed distribution; (3) the relative spatial distribution of visible light, for determining the density profile; and (4) microwave cavity frequency shifts, for determining the electron number. Comparison among these diagnostics is made. It is shown that measurements of temperature, density, and axial profile can be considerably in error if the experimental results are compared with maxwellian velocity distributions, rather than self-consistent, mirror distributions. Theoretical curves of X-ray pulse height distributions and absolute synchrotron radiation spectra are given for a self-consistent velocity distributions applicable to a wide range of hot-electron plasmas.

Radiation from particles falling into black-holes

Abstract: The electromagnetic radiation emitted when a charged particle falls into a neutral Schwarzschild black-hole is calculated. For zero angular momentum fall, a system of N electrons emits 10 times as much electromagnetic radiation as gravitational radiation. This ratio is reduced for particles with a larger mass to charge ratio than the electron. For particles in a spiraling circular orbit the energy emitted is the same in the charged and uncharged cases but the spiral time is much shorter for a charged particle. The linearly falling or orbiting charged particle represents a new radiation mechanism for black-holes. The spiral time for uncharged particles of physical interest emitting gravitational radiation is found to be prohibitively long. Such processes, discussed in the literature, essentially never take place. Key words: black-holes - gravitational radiation - electromagnetic radiation

Production of gamma -rays in the Crab nebula pulsar.

Abstract: The γ-ray flux at energies above 50 MeV from NP 0532 is evaluated for a pulsar model in which the optical and X radiations are produced by the synchrotron effect Synchrotron radiation and inverse Compton scattering are considered as production mechanisms of the γ-rays The theoretical estimates are compared with the experimental values

Synchrotron Radiation From Auroral Electrons

Abstract: The expression for the total power radiated by an electron moving in a helical path was derived from Schwinger's general equation for synchrotron radiation. The equation derived was used to predict the synchrotron radiation from incoming auroral electrons at three different stations, one in the auroral zone and the other two at midlatitudes. The results of the calculations for the station in the auroral zone agree with the data observed by Parthasarathy and Berkey at College, Alaska. The synchrotron radiation from the incoming auroral electrons indeed offers an explanation for the observations of auroral noise observed at College, Alaska.

The Dynamics of Hydromagnetic Bubbles and Double Radio Sources

Abstract: Bubble of energetic charged particles embedded in interstellar or intergalactic magnetic field and in gas, discussing dynamic effects on radio astronomy observation

A "Wavelength Shifter" for the University of Wisconsin Electron Storage Ring

Abstract: In order to enhance the synchrotron radiation experimental program at the University of Wisconsin Physical Sciences Laboratory, a series of three magnets is being designed to be inserted in a long straight section of the 240 MeV electron storage ring. Two of these magnets (each with a 12.5 kG peak field for a 4° bend) will be inverted so as to deflect the equilibrium orbit 1 cm radially away from the ring center. The central magnet will have a maximum field of about 25 kG and will turn the beam through 8°. The synchrotron radiation power spectrum from this central high field magnet will peak at 40 A. Using the Courant and Snyder formalism, tune shifts of ??x = 0.028 and ??z=0.024 have been calculated for an optimum design -- all magnets are to be wedge shaped for normal beam entry and exit at full excitation and each of the magnets will have a constant field gradient of n = 1/3. Stopband widths at nearby resonances have been calculated to be ?0.057 and are considered to be quite tolerable. Calculations have also been carried out to insure that the "wavelength shifter" does not adverseley affect the synchrotron radiation damping rates. For the optimum design, the maximum change to the damping rates will be less than 10%.

Circular Polarization of the Radio Source PKS 1127--14 at 3,240 MHz

Abstract: Observations of circular polarization at 3,240 MHz are presented for the QSO PKS 1127–14. The results are discussed in the light of other observational data and it is concluded that this object contains a component with a magnetic field of at least 6.4 × 10−2 G, provided the mechanism involved is ordinary synchrotron radiation.

Measurement of Cross Section of a High-Energy Electron Beam by Means of the X-Ray Portion of the Synchrotron Radiation

Abstract: Synchrotron light is routinely used in measuring the cross-section of a high-energy, orbiting, electron beam. The resolution of the height measurement is limited by the small vertical opening angle of this light. Because the angle decreases as a fractional power of decreasing wavelength, it is advantgeous to use a shorter wavelength portion of the synchrotron radiation, i.e., the x-ray portion. Accurate measurement of beam height is especially important to the CEA colliding beam program. A pinhole was installed in one of the tangential beam runs and the x-radiation image of the crosssection was recorded with a Polaroid x-ray cassette. A resolution of about 0.1 mm in beam height was obtained. The measured height of the stored beam was in agreement with expectation.

Fluorescence excitation of ultra-soft x-ray emission spectra using synchrotron radiation.

Abstract: Attemps have been made to use the synchrotron radiation of the 7.5 GeV electron synchrotron DESY for the fluorescence excitation of ultra-soft X-ray emission spectra. The very intense background produced by the scattered radiation of short wavelengths could be reduced so that it was possible to observe the K emission bands of carbon (45 A), boron (67 A) and beryllium (114 A). The results are compared with data obtained by electron excitation.

A Far Infrared Spectroscopic System Used in Fusion Plasma Diagnostics

Abstract: A far infrared spectroscopic system, covering the wavelength region between 50 ?m and capable of variable spectral resolution between 100 and 1000, has been built. The spectroscopic system is described in some detail. It is comprised of a monochromator, which utilizes five different echelette gratings, each of which covers one octave, of a radiometric system for absolute power calibration, and of various cryogenic and room temperature detectors. The system works in two modes: a continuous mode using the absolute power calibration, the radiometer, and continuous standard radiation sources, and a pulsed mode without the radiometer for plasma radiation studies. In this manner the power spectrum of the observed pulsed plasma radiation is absolutely calibrated. A rather new method in monochromator design utilizing ray transfer matrix method and phase space diagrams is discussed, and various optical errors in the system are evaluated. The method of performing and the evaluation of radiation studies utilizing this system is presented. The system will be used in the very near future to measure the far infrared radiation from several of our fusion experiments: from Texas Tokamak, a large experimental fusion device; from a small, adiabatically heated, symmetric, hot electron stellarator; and from some other hot plasma devices. These experiments have strong magnetic fields, ranging between 30 to 5OkG. Moreover, high electron temperatures--between 1 to 20 keV--are expected, so that the synchrotron radiation in the far infrared will be appreciable. Synchrotron radiation from Tokamak as a function of the electron temperature and density is discussed.

Exact derivation of the synchrotron-radiation equation

Abstract: The energy radiated by a charge moving along a circle or a helix is calculated exactly (i.e., without an expansion in terms of some parameter). The method used seems extremely promising for analyzing macroscopic systems for the case in which the observer may be much closer to the source than the wave zone. These equations can be used to analyze the coherent radiation of several electrons.

Synchrotron Radiation in High Magnetic Fields

Abstract: We suggest that if there exist within the Crab Nebula localised condensations of material containing high magnetic fields, (» 1 G), the rapidly evolving synchrotron radiation power spectrum emitted by a single electron can give a radiation continuum with a spectral index having a unique value similar to that observed in the optical and low-energy X-ray regions. One implication of this result is that a simple comparison between the observed fluxes of optical and gamma radiation emitted by the Nebula is no longer meaningful, so that one cannot draw any immediate conclusion regarding the fundamental mechanism of electron and gamma ray production.

A mechanism for pulsar radiation

Abstract: It is shown that the low frequency radiation emitted by a magnetic neutron star with the axis of its dipole field at an angle to the rotation axis, is periodic. This low frequency radiation accelerates electrons and protons to high energies. The synchrotron radiation emitted by the high energy particles in the ambient magnetic field is shown to be the pulsar radiation.

Low-Mode Coherent Synchrotron Radiation and Pulsar Models

Abstract: The radio pulses from pulsars are considered to be formed from the beamed radiation from relativistic electrons. This radiation is in low order harmonics of the gyro frequency, giving pulse shapes and polarisations which agree with observation.