Properties of synchrotron radiation

The pronounced forward direction of synchrotron radiation is also called a searchlight effect. Because of this effect, an observer fixed in space can see the synchrotron light only for a short time interval Atobs which can be calculated as 

For K 1 the interference between electromagnetic waves emitted by the same 

According to Liouville s theorem (see Section 10.3.2) the spectral brilliance B cannot be increased further by any optical system, except at the expense of total flux. The brilliance is therefore an important quantity for the design of not only electron storage rings, but also beam lines with their attached monochromators and experimental equipment (see Sections 1.4 and 1.5). 

A further important property of synchrotron radiation concerns its polarization characteristics. The radiation is completely polarized, and the kind of polarization depends on the direction of the circulating electron beam as well as on the direction of photon emission. In order to understand these polarization properties, it is useful to recall the result for the emission of electromagnetic radiation from an electron moving with non-relativistic velocity in a circle the electric field vector follows the same shape and orientation as the projection of the electron s path onto a plane perpendicular to the observation direction. 

The four components of the Stokes vector are determined by four measurements which refer to three different basis systems (ex, ey and, e2 and er, e/5 respectively for more details see Section 9.2)  

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Another very important property of synchrotron radiation is its very high degree of polarization. The radiation is predominantly polarized with the electric field vector parallel to the acceleration... 

Another very important property of synchrotron radiation is its very high degree of polarization. The radiation is predominantly polarized with the electric field vector parallel to the acceleration vector. Thus, in the plane of the orbit, the radiation is 100% plane-polarized. Elliptical polarization can be obtained by going away from the plane however, intensities also decrease significantly. 

Winick H (1980) Properties of Synchrotron Radiation. In Winick H, Doniach S (eds) Synchrotron Radiation Research. Plenum Press, New York... 

Materlik G (1982) Properties of Synchrotron Radiation. In Stuhrmann HB (ed) Uses of Synchrotron Radiation in Biology. Academic Press, London... 

Recent developments in Mossbauer spectroscopy may also lead to interesting high-pressure applications. Many years ago it was proposed that the special properties of synchrotron radiation could be used to provide nuclear excitation without the use of radioactive sources, and recently progress with modern synchrotron-radiation sources could mean that such experiments could be feasible for Fe. Due to the natural high collimation of the most favourable undulator radiation from synchrotron insertion devices, one can expect that high-pressure measurements will be one of the first applications of this technique, which will eventually be applied to isotopes for which no suitable radioactive sources exist. " ... 

Polarization is a very important property of synchrotron radiation. It provides the capability for the study of magnetic and optical circular and linear dichroism, for polarization dependent EXAFS, and a variety of other experiments. On-axis, (in the case of a single electron in the orbit plane, i.e., zero emittance) the photon is 100% polarized with the E vector parallel to the plane. Above and below the plane the radiation is elliptically polarized and the degree of linear polarization is defined as ... 

Most properties of synchrotron radiation may be derived starting from classical electrodynamics, where an oscillating dipole is subjected to a Lorentz transformation. Assuming that relativistic electrons move on curved trajectories in a bending magnet of the radius R, the radiated power... 

The principal properties of synchrotron radiation of interest as a spectroscopic source or excitation source in physicochemistry are as follows (8) ... 

The present article concentrates on atomic physics experiments involving hard synchrotron radiation. Selected experiments are reviewed in order to elucidate basic principles as well as experimental possibilities and achievements. No attempt is made to cover the whole rapidly expanding field or to speculate on future developments. The discussion starts with instrumental details, e.g., the properties of synchrotron radiation, and a brief review of x-ray monochromators and detectors. Thereafter x-ray absorption studies are described that are experimentally very simple (at least in principle). More detailed information on atomic structure may be obtained if one observes not only the x-ray absorption, but additionally the induced fluorescence or emitted electrons. Finally, studies of photon scattering are sketched. 

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