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

Absorption coefficients of all elements may be calculated, from short wave‐lengths up to the K critical absorption wave‐length by the expression: $${\mathrm{\mu /\rho =\alpha \lambda }}^3{Z}^2{\text{(2Z/A)−βλ}}^4{Z}^5{\text{(2Z/A)+σ}}_e{N}_0\mathrm{(Z/A)}$$ . 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.