Journal of X-Ray Science and Technology - Volume 6, issue 3
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Journal of X-Ray Science and Technology is an international journal designed for the diverse community (biomedical, industrial and academic) of users and developers of novel x-ray imaging techniques. The purpose of the journal is to provide clear and full coverage of new developments and applications in the field.
Areas such as x-ray microlithography, x-ray astronomy and medical x-ray imaging as well as new technologies arising from fields traditionally considered unrelated to x rays (semiconductor processing, accelerator technology, ionizing and non-ionizing medical diagnostic and therapeutic modalities, etc.) present opportunities for research that can meet new challenges as they arise.
Abstract: The influence of smooth (not step-like) variation of the dielectric function near a surface on the reflectivity and scattering of x rays is investigated theoretically with the model function ε(z) = 1 − 0.5(1 − ε+ )(l + tanh(z/(2L))) taken as an example. It is shown that the presence of the transition layer can essentially change the shape of the differential scattering intensity diagram, especially when the incidence angle of the x-ray beam is greater than the critical angle of the total external reflection (TER). The results of measurements of the x-ray reflection coefficient and the differential scattered intensity are…discussed. The model of the near-surface transition layer is shown to describe quantitatively the specific features of experimental curves for the incident beam beyond the TER region, whereas these experimental data cannot be explained in the framework of a step-like model of the dielectric function, taking into account the scattering from surface roughness.
Abstract: This work is devoted to the experimental investigation of incoherent soft x-ray radiation from an electron cyclotron resonance discharge with pumping by a millimeter-wave beam from a gyrotron. The basic contribution to the x-ray spectrum was shown to be produced by a plasma emission in the wavelength region 4.5–12 nm. The power of the x-ray emission from the ECR discharge was about 35 kW, and the efficiency of conversion of the gyrotron radiation into an x-ray emission exceeded 25%.
Abstract: The effects appearing in a crystal microstructuring by reactive ion etching on diffraction properties of Bragg-Fresnel lenses were studied. Possible deviations of the real zone structures from ideal ones were considered. The influence of the Fresnel zone displacements due to sidewall undercutting effects and due to a mask erosion was analyzed. Technological tolerances for a different zone profile shape were defined.
Abstract: The analysis of bremsstrahlung events presented in this paper is based on conservation of energy. It develops an action constant that applies to any nucleus. The constant differs from Planck’s constant; it is needed to obtain a relation for the bremsstrahlung power radiated from a plasma per unit volume. The equation agrees with experimental tests and leads to the conclusion that magnetically confined plasmas cannot produce self-sustaining fusion power.
Abstract: The charge coupled devices (CCDs) developed for the Joint European X-ray Telescope (JET-X) are described in detail. A history of the development program and device performance is given. We present results from a comprehensive study to characterize the x-ray response of the flight model focal plane detectors. The goal of the program is to calibrate the efficiency, energy resolution, gain, etc. down to a precision of ~1%. Final calibration data sets will be based on combinations of measurements and calculations. For example, the CCD quantum efficiency will be composed of discrete line measurements made at the University of Leicester test…facility and calculation and synchrotron measurements from the Daresbury Synchrotron Radiation Source (SRS). The absolute normalizations will be provided by x-ray long beam pipe measurements at the Max Planck Institut für Extraterrestrische Physik (MPE) Panter test facility in Munich. Using the available data, it is shown that it is possible to calibrate the quantum efficiency, the FWHM energy resolution, and the system gain of the flight devices to better than 1%.
Abstract: Directional-spin-dependent Compton profiles of ferromagnetic hexagonal close packed cobalt metal have been measured with 117 keV and 167 keV circularly polarized synchrotron radiation at the new ESRF high energy beamline. Significantly improved resolution was achieved at the higher energy. The results have been compared with the profile predicted from an augmented plane wave (APW) calculation of the electron momentum density in the hexagonal phase. No significant difference was found between the c-axis and the basal plane magnetic profiles. The experiments show that there is substantially more 3d spin density at high momentum than in the model calculation. After correcting for…this deficiency we find that the 4s−p component of the momentum density remains significantly different than predicted.