X-Ray Absorption Coefficients in the Range 0 $ \cdot $ 3 to 2 $ \cdot $ 0 angstrom

An account is given of two methods which have been devised in an attempt to eliminate some of the experimental difficulties associated with the measurement of X-ray absorption coefficients. Although the accuracy claimed for these measurements does not represent an improvement on that claimed by previous workers, it is hoped that the methods possess some features of interest, and it is believed that the data obtained, even where they refer to materials previously investigated, are of value in a field of measurement remarkable for the lack of agreement between different workers. In the first method ionisation chambers are used for the measurement of intensity, the wave-lengths investigated lying within the range 0•3 A. to 0•6 A. In the second method the photographic effect is used for the comparison of X-ray intensities, and the wave-length range is extended to 2•0 A.