A Precision Study of the Molybdenum and Tungsten Kα₁ X-Ray Lines, and a Measurement of the Reflecting Properties of the (310) Planes of Quartz, by the Method of the Two Crystal X-Ray Spectrometer

Citation

West, William Junius (1949) A Precision Study of the Molybdenum and Tungsten Kα₁ X-Ray Lines, and a Measurement of the Reflecting Properties of the (310) Planes of Quartz, by the Method of the Two Crystal X-Ray Spectrometer. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/p5v7-wn41. https://resolver.caltech.edu/CaltechTHESIS:07302025-174745486

Abstract

Using a precision two crystal x-ray spectrometer, the K_α1 lines of molybdenum and tungsten and the (310) planes of quartz were studied primarily for the purpose of calibrating the curved crystal gamma ray spectrometer, designed and built by J. W. M. DuMond, so as to help provide a precision linkage between the gamma and x-ray regions. Absolute determinations of the Bragg angles for _α1 and WK_α1 reflected from the (310) planes of quartz are described. These were undertaken (1) to standardize the tungsten K spectrum with higher accuracy in terms of the Siegbahn x-ray scale of wavelengths, and (2) to yield on this scale a precision determination of the grating constant of the quartz (310) planes. The wavelength for the WK_α1 line was found to be

^λK_α1 = 208.575 ± 0.008 x.u. (Siegbahn scale)

The grating constant of the quartz (310) planes was determined as

d_18° = 1177.637 ± 0.020 x.u. (Siegbahn scale)

The reflecting properties of the (310) planes of quartz in the unstressed condition were measured experimentally in the wavelength range 0.123Å ≤ λ ≤ 0.710Å and a comparison made to the results calculated from the theoretical diffraction patterns for the particular quartz crystals used. It was found that the integrated reflecting power did not decrease with the first power of the wavelength (as predicted by theory), but to a power slightly less than unity. This result differs from the work of David A. Lind who found that the integrated reflecting power decreased as λ² for an identical quartz plate to the ones used here, but in the stressed condition as found in the curved crystal spectrometer

The development of a xenon filled Geiger counter is presented. This counter was used as a highly efficient detector of the x-rays.

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