Group of X-ray Spectrometry
Laboratory of Nuclear Instrumentation
Center of Nuclear Energy in Agriculture
University of São Paulo -Brazil
Photons for Agriculture and Environment
Graduate level
CEN-5792
Principles of Electronic and Nuclear Spectroscopy
The present course aims at introducing the principles of several spectroscopic techniques based on electronic transitions and nuclear phenomenon. For that purpose, theoretical and practical lectures will be combined.
1. Electronic structure of atoms and molecules: 1.1 Atomic orbitals // 1.1 Molecular Orbitals // 1.3 Molecular Geometry // 1.4 Structure of solids
2. Nuclear Structure: 2.1 Nuclear Models // 2.2 Nuclear reactions // 2.3 Excited states and relaxation modes // 2.4 Subatomic particles
3. Elements of Symmetry: 3.1 Symmetry operations // 3.2 Polar molecules // 3.3 Building molecular orbitals // 3.4 Ligand field theory
4. Properties of electromagnetic waves : 4.1 Amplitude, wavelength, phase and momentum // 4.2 The relationship between wavelength and frequency // 4.3 Reflection and refraction // 4.4 Interference // 4.5 Polarization
5. Principles of interaction between radiation and matter: 5.1 Elastic scattering // 5.2 Inelastic scattering // 5.3 absorption // 5.4 X-ray fluorescence and photoelectron emission // 5.5 Pair productions
6. Sources of synchrotron radiation: 6.1 Accelerator of particles // 6.2 optical elements // 6.3 beamlines // 6.4 analytical techniques at synchrotron facilities
7. Core level spectroscopy: 7.1 X-ray absorption spectroscopy // 7.2 Photoelectron spectroscopy // 7.3 X-ray fluorescence
8. Valence level spectroscopy: 8.1 Atomic absorption spectroscopy (AAS) // 8.2 Optical emission spectroscopy (AES/OES) // 8.3 UV-Vis spectroscopy
9. Lasers in spectroscopy: 9.1 Mechanism for the generation of lasers // 9.2 Features of Lasers // 9.3 Laser induced breakdown spectroscopy
10. Gamma ray spectroscopy: 10.1 Gamma ray instrumentation // 10.2 Gamma ray decay activated by neutrons // 10.3 Using radioisotopes in agriculture
11. Beta particle spectroscopy: 11.1 Instrumentation for the detection of beta particles // 11.2 Using 14C and 32P in agriculture
Practical and tutorials:
Basic optics // Molecular structure and UV-Vis spectroscopy // X-ray fluorescence spectroscopy // Liquid scintillation counter // Gamma ray detection // Interaction between laser and matter using micro XRF.
CEN-5785
Introduction to X-ray Absorption and Fluorescence Spectroscopy
This course aims to introduce the X-ray absorption (XAS) and X-ray fluorescence (XRF) spectroscopies, with emphasis on the analysis of samples from agronomical, chemical, environmental and mineralogical background.
1. Introduction to XAS and XRF: 1.2 Application of XAS and XRF in chemistry, biology, mineralogy and agronomy// 1.3 Main analytical features of XAS and XRF// 1.4 XAS and XRF spectral regions// 1.5 Historical background of XAS and XRF
2. Basics of Interaction between matter and light: 2.1 Characteristics of X-rays// 2.2 Atomic structure: energy levels and binding energies// 2.3 Fundamentals of X-ray absorption and scattering// 2.3.1 Types of interaction: absorption, scattering and pair production//2.3.2 Absorption: transitions to bound states and photoelectric effect// 2.3.3 Absorption cross section and absorption edges//2.3.4 Elastic and inelastic scattering by free electrons and crystals// 2.4 X-ray emission// 2.4.1 Characteristic X-rays // 2.4.2 Fluorescence lines// 2.4.3 Moseley Law// 2.4.4 X-ray fluorescence versus Auger emission// 2.5 Electronic structure calculation for molecular orbital, clusters and bands.
3. Instrumentation for X-ray absorption fluorescence measurements: 3.1 Overview on the experimental setups: Sources, optics and detection// 3.2 Configurations for X-ray absorption measurements: transmission and fluorescence // 3.3 Configurations for X-ray fluorescence detection: Energy and wavelength dispersive// 3.4 X-ray sources and excitation modes// 3.4.1 X-ray tubes// 3.4.2 Radioactive sources//3.4.3 Proton and electron accelerators// 3.4.4 Synchrotron radiation source: storage ring, bending magnet and insertion devices//3.4.5 Free electron lasers// 3.5 Basic optic elements
3.5.1 mirrors, slits and filters// 3.5.2 Monochromators//3.5.3 X-ray beam features: size, shape, energy resolution, flux and brilliance// 3.6 Detectors// 3.6.1 Ionization chambers, solid state scintillators and semiconductors// 3.7 Basic configurations of X-ray absorption and fluorescence beamlines.
4. Theory of X-ray fluorescence: 4.1 Fundamental equation of energy dispersive XRF// 4.2 Limit cases: thick and thin samples//4.3 Geometric considerations// 4.4 Analysis of a XRF spectrum: Characteristic X-rays, continuum, Compton and Rayleigh peaks, sum and escape peaks// 4.5 Quantitative and qualitative analysis. Empiric and Fundamental methods. Matrix effect correction methods. Empiric methods in quantitative analysis: internal standard, sample and reference compositional matching, Compton correction, multivariate linear regression// 4.6 Calculations of X-ray emission spectra using FEFF code.
5. Variants of XRF: EDXRF, WDXRF and TXRF: 5.1 EDXRF: Geometry, equipment, quantitative and qualitative methods, examples// 5.2 WDXRF: Geometry, equipment, high energy resolution spectra (HERFD), examples// 5.3 TXRF: Geometry. Diffraction, refraction and reflection. Critical angle of total reflection. Fundamental equation of TXRF, examples.
6. Variants of XRF: SEM-EDX, PIXE e µ-XRF: 8.1 SEM-EDX: electron beam probe, peach scattering, sample preparation, advantages and disadvantages compared with X-ray beam excitation. Examples// 8.2 PIXE: Excitation modes, particle sources, advantages and disadvantages compared with X-ray beam excitation. Examples// 8.3 µ-XRF. Micro X-ray beams. Focusing capillaries. X-ray Mapping and space resolved analysis. Examples.
7. Theory of X-ray absorption: XANES and XAFS: 9.1 Analysis of a XAS spectrum: pre-edge, near edged and extended fine structure// 9.2 Transition rate, dipolar electric approximation and selection rules// 9.3 Relationship between wavenumber and the kinetic energy of the photoelectron// 9.4 Calculations of XAS spectra using FEFF (Self consistent field real-space multiple-scattering).
8. Analysis of XANES data: 10.1 Absorption edge features // 10.2 Spectra processing: alignment and normalization// 10.3 Finger print analysis: Comparing experimental data with references// 10.4 Analysis of mixtures by linear combination fitting// 10.5 Analysis of mixtures by PCA.
9. Analysis of XAFS data: 11.1 background subtraction// 11.2 Fourier transform// 11.3 Analysis of the XAFS equation.