ELASTIC AND COMPTON-SCATTERING CROSS-SECTIONS IN THE ATOMIC REGION 2-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-82

Coherent and Compton scattering cross sections for the elements Mg, Al , Mn, Ni, Cu, Y, Mo, Pd, Ag, Cd, In, Sn, Sb, Au and Pb have been measu red at 32.06 keV (Ba K alpha) and 33.29 keV (La K alpha) x-ray energie s. Measurements have been performed using an x-ray tube with a seconda ry exciter system as the excitation source instead of radioisotopes. I n order to improve the efficiency of the detection system the excitati on source detector and the sample assembly were placed in a vacuum cha mber and a pressure of 10(-2) mbar was maintained throughout the measu rements. The present system reduced the scattering and background effe cts considerably and improved the monochromaticity. Experimental coher ent scattering cross sections are compared with the normalised integra ted coherent scattering cross sections. Experimental results are highe r around the edges indicating the oscillatory nature of coherent inten sity, resonance behaviour and fine structure effects. Experimental inc oherent scattering cross sections are higher than the theoretical esti mates for low medium Z elements and lower for heavy elements. The latt er is due to the effect of electron binding at low photon energies for heavy elements.