Probable X-Ray Mass Absorption Coefficients for Wave-Lengths Shorter Than the <i>K</i> Critical Absorption Wave-Length

Abstract

Absorption coefficients of all elements may be calculated, from short wave-lengths up to the K critical absorption wave-length by the expression: μ/ρ=αλ3Z2(2Z/A)−βλ4Z5(2Z/A)+σeN0(Z/A). 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.