Absorption coefficients of all elements may be calculated, from short wave‐lengths up to the K critical absorption wave‐length by the expression: . This formula holds for all elements when suitable values for α and β are chosen. Factors α and β are related to the atomic number, Z, by the expressions α=(aZ2+bZ−c), and β=(dZ2−eZ+f). Different values of the constants a, b, c, d, e, and f are required for each side of the critical absorption wave‐lengths and for either side of Z=5, and are given for the short wave‐length side of the K critical absorption wave‐lengths. The values of αZ2(2Z/A) and βZ5(2Z/A) computed for all elements, are shown in the tables. The calculated mass absorption coefficients of a few elements are also furnished together with comparison of calculated mass absorption coefficients with published experimental data. No anomalies were found and the average agreement is of the order of 1 to 2 percent for all elements and all wave‐lengths on the short wave‐length side of the K critical absorption wave‐length. Values for the region between the K and L1 critical absorption wave‐lengths will be published later.
REFERENCES
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A. H. Compton and S. K. Allison, X‐Rays in Theory and Experiment (D. Van Nostrand Company, New York, 1935).
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Hubbard, Periodic Chart of the Atoms (W. M. Welch Manufacturing Company, Chicago, Illinois, 1935).
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E. Jönsson, Thesis, Upsala. See Compton and Allison’s, X‐Rays in Theory and Experiment (D. Van Nostrand Company, New York, 1935).
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© 1943 American Institute of Physics.
1943
American Institute of Physics
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