The goal of this work reported here is to test the limits of the ECPSSR theory in the transition region of the low Z1/Z2.

No description available.

<p> In this thesis, two inner shell excitation spectroscopy techniques, inner shell electron energy loss spectroscopy (ISEELS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy, were used to measure the C ls, N ls and 0 ls spectra of the amino acids, glycine, alanine, cysteine, phenylalanine, proline, threonine, tryptophan and the peptides, Gly-Ala, Lys-Trp-Lys (KWK), and Arg-Gly-Asp (RGD). The spectra are analysed with the aide of ab initio computations using the GSCF3 method. The characteristic spectral features of the specific side chains of amino acids are identified. Differences in the spectra of the gas and solid are related to differences between the neutral gas phase molecule and the zwitterionic solid form. A rationalization of observations of high degree of variability in theN ls spectra of amino acids is proposed. The characteristic spectral signatures of peptide bonds have been identified further by comparing the spectra of small peptides to the spectra of their subunit amino acids. A modified "building block" approach is showed to be very useful in modeling the inner shell excitation spectra of peptides through linear combinations of the spectra of the amino acids residues and peptide bonds. </p> / Thesis / Master of Science (MSc)

In this study, procedures were developed to produce ultra-clean, ultra-thin target foils and to remove x-ray interference from electron bremsstrahlung and low energy K-shell x-rays from contaminant elements.

No description available.

L-shell x-ray production cross sections are presented for Fe, Ni, Cu, Zn, Ga, and Ge by 0.5- to 5.0-MeV protons and by 0.5- to 8.0-MeV helium ions and Ca, Fe, Ni, Cu, and Ge by 0.75- to 4.5-MeV lithium ions. These measurements are compared to the first Born theory and the perturbed-stationary- state theory with energy-loss, Coulomb deflection, and relativistic corrections (ECPSSR). The results are also compared to previous experimental investigations. The high precision x-ray measurements were performed with a windowless Si(Li) detector. The efficiency of the detector was determined by the use of thin target atomic-field bremsstrahlung produced by 66.5 keV electrons. The measured bremsstrahlung spectra were compared to theoretical bremsstrahlung distributions in order to obtain an efficiency versus energy curve. The targets for the measurement were manufactured by the vacuum evaporation of the target element onto thin foils of carbon. Impurities in the carbon caused interferences inthe L-shell x-ray peaks. Special cleansing procedures were developed that reduced the impurity concentrations in the carbon foil, making the use of less than 5 μg/cm^2 targets possible. The first Born theory is seen to greatly overpredict the data at low ion energies. The ECPSSR theory matches the data very well at the high energy region. At low energies, while fitting the data much more closely than the first Born theory, the ECPSSR theory does not accurately predict the trend of the data. This is probably due to the onset of molecular-orbital effects, a mechanism not accounted for in the ECPSSR theory.

L-shell x-ray production cross sections have been measured for thin targets of 29Cu, 32Ge, 37Rb, 38Sr, and 39Y. M-shell x-ray production cross sections have been measured for thin targets of 79Au, 82Pb, 83Bi, 90Th, and 92U. All targets were irradiated with a beam of H+ ions with energies in a range from 70 to 200 keV. Experimental cross sections are compared to other measurements at higher energies and to first Born (Plane Wave Born Approximation for direct ionization and Oppenheimer-Brinkman-Kramers-Nikolaev approximation for electron capture) and the ECPSSR (Energy loss, Coulomb deflection, Perturbed Stationary State calculations with Relativistic effects) theoretical cross sections.