DIFFERENTIAL INCOHERENT-SCATTERING CROSS-SECTIONS IN SOME RARE-EARTH ELEMENTS AT LOW PHOTON ENERGIES

Differential incoherent scattering cross-sections in the elements Sc, Y, La, Ce, Gd, Dy, W, Pt and Pb have been determined in the angular range 30-130--degrees at Photon energies 145 and 320 keV with a 5.1 cm x 5.1 cm NaI(Tl) spectrometer using a ND-60 multichannel analyser. The results are compared with the recent theoretical values to assess the influence of electron binding. The experimental S(X, Z) values are employed to deduce the differential incoherent scattering cross-sections in conjunction with the Klein-Nishina free electron values. The results show a clear deviation from the K-N values at lower angles, the deviations are also seen to increase with increasing Z. A comparison with the data of Hubbell et al. reveals a good correspondence between theory and experiment at all angles except at the lowest.