Influence of solid state environment effects on measured elastic scattering cross sections in the X-ray regime and the associated anomalous dispersion

Experimental elastic scattering cross sections in the atomic region 21 less than or equal to Z less than or equal to 82 are measured at an angle of 90 degrees using monoenergetic unpolarised Mo K alpha radiation. The measurem ents are based on a new method developed to estimate the degree of monochro maticity, the efficiency of the detecting system solid angle correction and some considerations which are necessary in experiments using secondary tar gets as excitation sources. Unpolarised monoenergetic radiation is produced using an X-ray tube and a secondary target To reflect the data on the curr ent knowledge, the results are compared with theoretical estimates based on form factor formalisms including the anomalous scattering factors and with the recent S-matrix values. Based on the experimental evidence, the presen t results indicate the influence of solid state environmental effects, the importance of anomalous corrections near thresholds, superiority of S-matri x values over form factor values, correctness of high energy limit values o n measured elastic scattering cross sections. However, the comparison of th e experimental results with theoretical estimates indicates the importance of numerical calculations based on the multipole expansion of the S-matrix approach and high energy limit values.