Experimental ionization cross-sections of phosphorus and calcium by electron spectroscopic imaging.
The absolute partial electron scattering cross-section for the phosphorus L2,3-shell ionization was measured by electron spectroscopic imaging using poliovirus as a primary standard. The equivalent calcium cross-section was obtained in relation to phosphorus using the stoichiometric ratio for these two elements in hydroxyapatite, Ca10(PO4)6(OH)2. At 80 keV, the partial cross-section of phosphorus was 2.26 x 10(-20) and 2.68 x 10(-20) cm2/atom for poliovirus and hydroxyapatite, respectively, at 150 eV loss for a 15-eV energy window and an acceptance angle of 15 mrad. Under the same conditions the calcium cross-section was 0.49 x 10(-20) cm2/atom at 360 eV loss. The experimental values are slightly higher than the theoretical cross-sections calculated either by hydrogenic or Hartree-Slater approaches.
Heng
Y M
YM
Electron Microscopy Facility, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada.
Simon
G T
GT
Boublik
M
M
Ottensmeyer
F P
FP
D002118:Calcium / Q000737:chemistry*; D017886:Durapatite; D004577:Electron Probe Microanalysis; D006882:Hydroxyapatites / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*; D017955:Poliovirus / Q000648:ultrastructure*; D012015:Reference Standards
D006882:Hydroxyapatites; D010758:Phosphorus; D017886:Durapatite; D002118:Calcium