Accession Number : ADD095256

Title :   X-Ray Wavelengths and X-Ray Atomic Energy Levels,

Corporate Author : NATIONAL STANDARD REFERENCE DATA SYSTEM

Personal Author(s) : Bearden, J A

Report Date : 25 Sep 1977

Pagination or Media Count : 72

Abstract : Inconsistencies in accepted values (in x units) of x-ray reference lines have recently been demonstrated, although all are supposedly based on 'good' calcite crystals. Factors supporting the selection of the W K alpha(1) line as the X-Ray Wave-length Standard are critically discussed. A review is given of the experimental measurements which are used to establish the wavelength of this line on an absolute angstrom basis. Its value is lambda W K alpha(1) = 0.2090100 + or - 5 ppm) A. This may be used to define a new unit, denoted by A, such that the W K alpha(1) wavelength is exactly 0.2090100A; hence 1 A = 1 A + or - 5 ppm. The wavelengths of the Ag K alpha(1), Mo K alpha(1), Cu K alpha, and the Cr K alpha(1), have been established as secondary standards with probable error of approximately one part per million. Sixty-one additional x-ray lines have been used as reference values in a comprehensive review and reevaluation of more than 2700 emission and absorption wavelengths. The recommended wavelength values are listed in A units together with probable errors, corresponding energies are given in keV. A second table lists the wavelengths in numerical order, and likewise includes their energies in keV.

Descriptors :   *X RAY SPECTRA, *EMISSION SPECTRA, *ABSORPTION SPECTRA, *ATOMIC ENERGY LEVELS, FREQUENCY, SPECTRAL LINES, STANDARDS, CALCITE, CRYSTALS, MEASUREMENT, ELECTRON ENERGY, PHOTOIONIZATION, SILVER, COPPER, MOLYBDENUM, BETA RAY SPECTROSCOPY, GAMMA RAY SPECTROSCOPY, X RAY PHOTOELECTRON SPECTROSCOPY, CHEMICALS, TABLES(DATA)

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE