International Henry Moseley School and Workshop on X-ray Science (original) (raw)
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Analytical Chemistry, 2004
T17) Bendall, M. R.; Pege, D. T. J. Magn. Reson. 1986, 68, 252. (TIE) Hetherington, H. P.; Wlshart, D.; Fkpatrlck, S. M.; Cole, P.; Shulman, R. G. J. &gn. Reson. 1986, 66, 313. (Tl9) Bendall, M. R.; Pegg, D. T. J. Magn. Reson. 1986, 67, 376. (T20) W e l l , D. M.; Bulsing, J. M.; Galloway, G. J.; Brooks, W. M.; Fleld, J.; Irving, M.; Baddeley, H. J. Magn. Reson. 1986, 70, 319. F21) Doddrell, D. M.; Field, J.; Brereton, I. M.; Galloway, G. J.; Brooks, W. M.; Irving, M. G. J. Mgn. Reson. 1987, 73, 159. (T22) Galloway, G. J.; Brooks, W. M.; Bulsing, J. M.; Brereton, I. M.; Fekl, J.; Irving, M.; Baddeley, H.; Doddrell, D. M.
Physics of X-Ray , Lectures No,1 of X-Ray , Lectures of Clinical and Physics of Imaging , LinkedIn , Physics of Diagnostic Radiology , X-Ray Scans, 2024
- In 1895Wilhelm Conrad Röntgen discovered a new type of radiation, which he called x-rays. He was uncertain what they were, but he noticed that they were able to penetrate opaque matter. To demonstrate this he took x-ray images of his wife’s hand, the first x-ray images ever, which made him and the new method instantly famous worldwide. Since then x-rays have been known to the general public mainly for their medical use. Röntgen was the first awardee of the Physics Nobel Prize in 1901. However, medical x-ray imaging is only one of many other uses of x-rays, the others include x-ray scattering, x-ray spectroscopy, and x-ray microscopy in all fields of science and technology. X-rays from low energies to high energies are so omnipresent that a world without x-rays is hard to imagine. Without x-rays we probably would not know about the helical structure of DNA, the complex folding of proteins such as myoglobin and hemoglobin, the rich structure and functionality of ribonucleic acid (RNA), and many others. - X-rays are electromagnetic (EM) waves with energies ranging from 50 eV up to several MeV, corresponding to wavelengths λ from 25nm (50 eV) down to 0.0012nm (1MeV). The conversion factor derived from the equation for the energy of photons E = hf = hc/λ is: λ(nm) = 1240 eVnm/E(eV). , where h = 6.623 × 10−34 Js is the Planck constant, c = 299792458m/s ≈ 3 × 10^8 m/s^−1 is the vacuum velocity of EM waves, and f is the frequency. - At the lower energy end x-rays overlap with far ultraviolet radiation. At the upper energy scale they overlap with γ-radiation. It is not primarily the energy or the respective wavelength that characterizes x-rays; it is the method by which x-rays are produced. Three kinds of x-ray production can be distinguished: 1. bremsstrahlung, radiation produced by deacceleration of high energy electrons; 2. characteristic radiation, occurring after excitation of core shell electrons of atoms; 3. synchrotron radiation emitted by radial acceleration of electrons in high energy storage rings. - For medical x-ray diagnostics (radiography) and for x-ray cancer treatment (radiotherapy) only bremsstrahlung is used. Their specifications are, however, very different. Hence the same x-ray equipment cannot be employed for both applications. X-ray diagnostics requires bremsstrahlung up to about 150 keV, whereas x-ray radiotherapy entails x-ray energies up to 25 MeV.
This chapter contains sections titled: Introduction Experimental methods Results Conclusion Acknowledgements Bibliography
Journal of Electron Spectroscopy and Related Phenomena, 2013
This essay sketches the development of X-ray Absorption Fine Spectroscopy (XAFS) ever since the second half of 20 th century. At that time, synchrotrons started competing with X-ray discharge tubes as the sources of the excitation able to show the pre-and near-edge structures (XANES) and extended oscillations (EXAFS) that characterize the X-ray absorption edge of solid matter. Actually, modern XAFS began after 1975, when the hard-X-ray synchrotron radiation derived from storage rings took over. Ever since, XAFS greatly contributed to both technical refinement and to theoretical development of Materials Science. Although a unified theory of X-ray fine absorption has not been reached yet, many XAFS advancements benefited of theoretical models and complex calculations made possible by the continuous growth of the computing power, while contributing to developing new or previously never used materials.
The X-Ray Facility of the Physics Department of the Ferrara University
Experimental Astronomy, 2004
We will report on the equipment and performance of the X-ray facility of the University of Ferrara. Initially developed to test the PDS (Phoswich Detection System) instrument aboard the BeppoSAX satellite and to perform reflectivity measurements of mosaic crystal samples of HOPG (Highly Oriented Pyrolytic Graphite), with time the facility has been improved and its applications extended. Now these applications include test and calibration of hard X-ray (>10 keV) detectors, reflectivity measurements of hard X-ray mirrors, reflectivity tests of crystals and X-ray transparency measurements. The facility is being further improved in order to determine the optical axis mosaic crystals in Laue configuration within a project devoted to develop a hard X-ray (>60 keV) focusing optics (Pisa, A. et al.: in press, Feasibility study of a Laue lens for hard X-rays for space astronomy, SPIE Proc., 5536).