X-ray cross-section

In the one-electron transition model it is assumed that only one core electron is excited to an unfilled state present in the initial, unperturbed solid. The remaining electrons are assumed to be unaffected, remaining frozen in their original states. In essence the one-electron model describes the potential seen by the final-state electrons as nonoverlapping spherically symmetric spin-independent potentials (muffin-tin scatterers) centered around an atom from which the X-ray cross section from a deep core level of an atom to final states above the Fermi level can in principle be calculated for any energy above threshold. 

An X-ray tube rotates helically around the subject while an array of detectors opposite the tube measures the residual radiation that has passed through the body according to the density of local tissues to X-rays. Cross-sectional images are constructed using mathematical algorithms... 

Historically, it was controversial to recognise the local nature of the XAFS techniques (see Lytle for a recent discussion)39 but now the theoretical description of the techniques is reasonably well-settled.36,37 The absorption of X-ray by matter is described in many text books.40 The treatment of the radiation as an electric field without practical spatial variation on a molecular/local scale and eliminating magnetic parts leads to the Fermi Golden Rule for the X-ray cross section ... 

McMaster, W.H., N. Nerr del Grande, and J.H. Mallett. 1969. Compilation of x-ray cross sections. Rep. UCRL-50174. Sect. 2. Rev. 1. Lawerence Radiat. Lab., Univ. California, Livermore, CA. 

Calculated with p from McMaster WH, Kerr Del Grande N, Mallet JH, Hubbell JH Compilation of X-Ray Cross Sections Nat Techn. Inform Serv, Springfield, VA, and a density of 0.693 for... 

McMaster WH, Kerr Del Grande N, Mallett JH, Hubbell JH (1969) Compilation of X-ray Cross Sections. 

X-RAY CROSS SECTIONS (Continued) TaMe II. Total Cross Section in ctn g (Continued)... 

W. H. McMaster, N. Kerr Del Grande, J. H. Mallet, and J. H. Hubell, Compilation of X-Ray Cross Sections. Lawrence Radiation Laboratory, Livermore, California, 1969. 

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