Abstract
The mass absorption coefficients for X-ray of λ=31.5 Å (NKα) and λ=67.6 Å (BKα) have been determined by the use of EPMA and a special composite target.
The composite target was prepared by means of the evaporation of Al, Ca, Cr, Cu, Se, Zr, Ag, Sb, La, Gd, Au or Bi on BN base in vacuum (∼10−5 mmHg).
The mass absorption coefficients of these metals for the NKα line and the BKα line were determined from the experimental results by using the following equation:
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oindentHere, I1 and I2 are the relative intensities of the NKα (or BKα) line measured from the composite target with Al surface film of t1 g/cm2 and another surface film of t2 g/cm2, respectively, where t1 and t2 are the “equivalent thickness” to each other and θ is a take-off angle of X-rays.
The results, in most cases (for absorbers of high atomic number), are considerably lower than the values in early work of Veigele et al. and in the tables of Dewey et al. on X-ray mass absorption coefficients, but they are somewhat higher than the new values of Veigele et al. The data of Gray et al. are lower in values than the present results at Z>40 and agree fairly well with each other at Z<40.
The accuracy of the present μ⁄ρ values is about 20% on the average, and the precision of the measurements is better than about 2% standard deviation in most cases.
