Henry J. Kostkowski

Slit Function Effects in the Direct Measurement of Absorption Line Half-Widths and Intensities*†

The distortion of spectral lines by the finite band pass of spectrometers is an effect which must be considered in measuring line shape parameters. The differences between actual line half-widths and line intensities and those which would be obtained directly from measurements by spectrometers with Gauss and Cauchy shaped slit functions have been calculated for Lorentz and Doppler lines of varying widths and intensities. A method of utilizing these results to correct actual measurements is developed.

Spectral Absorption Method for Determining Population “Temperatures” in Hot Gases*†

A spectroscopic method, useful for strongly absorbed lines, has been investigated for measuring temperatures of hot gases. The minimum transmission of discrete spectral lines in gases at equilibrium has a simple dependence upon the absolute temperature and this relation is used to measure temperature from a straight line plot. An experimental study has been made of the absorption due to the rotational lines of OH (2∑←2Π) between 3067 and 3090 A in an oxygen-acetylene flame. It is shown that temperatures measured by this method are less affected than the conventional one by lack of sufficient resolving power, flame thickness, and various light sources (either continuous or line).

Comparison of the NBS SURF and tungsten ultraviolet irradiance standards

Detailed comparisons of the spectral irradiance of the NBS Synchrotron Ultraviolet Radiation Facility II and tungsten FEL Scale of Spectral Irradiance at 297 and 254 nm with an uncertainty of ~1% show that these irradiance standards are consistent at both wavelengths to within the uncertainties assigned to them by NBS.

Absolute Intensities of the 721 and 742 cm—1 Bands of CO2

The absolute intensities of the 0110→1000 and 0220→1110 bands of CO2 at 721 and 742 cm—1, respectively, have been determined with a curve‐of‐growth method utilizing the Elsasser periodic line pattern and a slit function calculation. The resulting intensities were S0110→1000329 °K=7.5 cm−2 atmos—1 and S0220→1110329 °K=0.22 cm−2 atmos—1. In addition the intensity of the 0310→1200 band at 740 cm—1 was estimated to be S0310→1200329 °K=0.032 cm−2 atmos—1.

Roughened quartz surfaces and Teflon as small angle diffusers and depolarizers between 200 and 400 nm

Laboratory tests of transmission diffusers are reported for quartz and Teflon. These tests were conducted to select transmission diffusers for the NOAA rocket flight UV spectroradiometers.

Comparison of the NIST SURF and argon miniarc irradiance standards at 214 nm.

Comparison of NISTs SURF-II primary irradiance standard and argon miniarc irradiance standard at 214 nm with an uncertainty of ~3% shows that at this wavelength these irradiance standards agree to within the uncertainties of 1.3 and 7%, respectively, assigned to them by NIST.

Appraisal of Interpolation Instruments for the International Practical Temperature Scale from 630.74 to 1064.43°C

A better interpolating instrument has long been needed to replace the standard platinum-10% rhodium/platinum thermocouple for the International Practical Temperature Scale. In this paper we compare the characteristics of the high temperature platinum resistance thermometer and the photoelectric spectral pyrometer with those of the standard thermocouple and conclude that the resistance thermometer is the better replacement, in terms of both accuracy and convenience.