Measurement of mass attenuation coefficients of moderate-to-high atomic-number elements at low photon energies

Mass attenuation coefficients for 12 selected moderate-to-high atomic-number elements have been obtained from good-geometry measurements made at five 241Am photon energies of significant emission intensity. Particular interest focuses on measured values for photon energies close to absorption edges. Comparisons with renormalized cross-section predictions indicate agreement to within stated error limits for the majority of cases. Significant discrepancies (>10%) are noted for Ta at 17.8 and 26.3 keV and W at 59.5 keV. Some support for a discrepancy between measurement and theory for W in the region of 60 keV is found in the reported measurements of others.