Measurement of the inelastic x-ray scattering cross section of neon with synchrotron radiation

Thesis/Dissertation · Mon Jan 01 00:00:00 EST 1979

OSTI ID:6090735

Parente, F A.F.C.

Inelastic differential x-ray scattering cross sections are sensitive to electron-electron Coulomb correlation. Until now, this fact has been of little practical importance because in the total (coherent + incoherent) cross section, ordinarily measured, the coherent part vastly dominates (except for the lightest atoms). A new approach is made possible by the high flux and tunability of synchrotron radiation. The incident x-ray energy is chosen so that detection of elastically scattered photons can be suppressed by critical absorption with a suitable filter. The ratio of inelastically to elastically scattered photons reaching the detector can thus be boosted by approximately two orders of magnitude. With a careful measurement of the filter absorption edge, the coherent/inoherent cross-section ratio can then be determined. In the present work, scattering by Ne at incident x-ray energies just above the K edges of Ti, V, Co, Fe, Ni, Cu, and Zn has been measured. Results were compared with theoretical predictions based on the impulse approximation, and on the Waller-Hartree theory with wave functions that include 86% of correlation. New theoretical calculations were performed, based on the excited-state approximation. The various theoretical predictions for neon inelastic x-ray scattering cross sections differ by as much as ca 30% at low momentum transfer, with the impulse approximation leading to higher results than the Waller-Hartree theory; the excited-state approach leads to cross sections that fall between the other two predictions. The experimental data agree with the Waller-Hartree predictions for high momentum transfer. At low momentum transfer, the data tend to favor the excited-state calculations.

• Research Organization: Oregon Univ., Eugene (USA)
• OSTI ID: 6090735
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
NEON
PHOTON-ATOM COLLISIONS
ABSORPTION
DIFFERENTIAL CROSS SECTIONS
EXPERIMENTAL DATA
IMPULSE APPROXIMATION
INELASTIC SCATTERING
MOMENTUM TRANSFER
PHOTONS
SYNCHROTRON RADIATION
WAVE FUNCTIONS
X RADIATION
ATOM COLLISIONS
BREMSSTRAHLUNG
COLLISIONS
CROSS SECTIONS
DATA
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
FLUIDS
FUNCTIONS
GASES
INFORMATION
IONIZING RADIATIONS
MASSLESS PARTICLES
NONMETALS
NUMERICAL DATA
PHOTON COLLISIONS
RADIATIONS
RARE GASES
SCATTERING
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena