CONCENTRATIONS OF AU ATOMS IN HOLLOW-CATHODE DISCHARGE BY RESONANCE-LINE ABSORPTION.
Abstract
The determination of the concentration of sputtered gold atoms in a hollow-cathode discharge at approximately 450 mtorr of argon was made by measuring the absorption of the two resonance lines, 2428 and 2676A, of a gold hollow-cathode source. The following points are considered: effect of fluctuation in source discharge is minimized by employing double-beam reflective optics, and the continuum is accounted for by measuring separately its intensity at a monochromator setting about 4A from the position where absorption is at a maximum. Self-absorption is minimized by extrapolating the absorption-vs-source current curves; the radiation from the DC absorber discharge is eliminated by chopping the source and using a phase-sensitive detector. Taking into account the variation of the absorption coefficient with wavelength, derived relations between measured absorption and the peak absorption coefficient, ko, are employed to calculate ko for different absorber discharge currents. The average of the ratio of ko at 2428A to ko at 2676A is calculated to be 2 plus or minus 0.2, agreeing well with the literature value of 2.1 for the ratio of oscillator strengths. If the widths of the emission line and the absorption coefficient are assumed to be purely Doppler corresponding to a measured discharge temperature of 355K, the concentration of gold atoms can be calculated and is presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1968
- Accession Number
- AD0670596
Entities
People
- W. C. Kreye
Organizations
- Air Force Research Laboratory