The total attenuation cross-sections in elements 6⩽Z⩽82 forK_α andK_β groups of lines of elements Zr, Sn and Ba andL_l,L_α,L_β andL_γ groups of lines of the elements Au, Pb, Th and U have been measured. The experimentally measured attenuation cross-sections have been found in good agreement with the theoretical estimates.

In an effort to resolve the existing discrepancy between experiment and theory, the cross-sections for the production ofL_l,L_α,L_β andL_γ groups ofL-shell X-rays of Ho by photons of nine energies in the range 10–40 keV have been measured using an improved version of annular source double reflection geometrical set-up. Contrary to the earlier findings of Garget al that the measured values of the cross-sections are consistently higher than those calculated theoretically, the present results do not confirm this. The plausible deficiencies in the experiments of Garget al are pointed out and possible remedies to overcome them are suggested. It is concluded that the higher values obtained by Garget al are probably due to systematic errors in their method of measurement.