Investigation by neutron diffraction utilizing white neutron radiation
"The most probable reactor core neutron velocity was determined by analysis of data obtained from single crystals of copper and lithium fluoride. Derivation of the relationship between the maximum in experimental count rate and the most probable velocity, an error analysis of the method, and the computer routine are given for the method used to obtain the most probable velocity. The most probable velocity was used to index the maxwellian distributions from polycrystalline materials. Investigations were done with white neutron radiation of various silicon steel samples of different preferred orientation. A method is described by which the preferred orientation of samples may be easily determined. This method involves analysis of maxwellian distributions and rocking crystal curves for various important sample directions, e.g., rolling direction, rolling direction + 45⁰, and cross rolling direction. A computer program is given which will determine the full width at half maximum for a rocking crystal curve and a method to relate this to the grain distribution about a mean orientation. If sufficient data points are taken, pole figures can easily be constructed for orientations of any type. The amount of data necessary is inversely proportional to the degree of preferred orientation of the sample, that is, a fairly random will require more data to specify its orientation than a highly oriented sample. The effects of the stacking of sheets of samples was investigated. It was found that it is feasible to determine the average orientation of large numbers of thin sheets of silicon steel by investigation of the samples as a stack. The method used has several advantages over x-ray methods. Some of these are: samples of greater thicknesses can be investigated, a larger portion of the sample can be examined without oscillating the sample, and groups of samples can be investigated at the same time for a uniform preferred orientation"--Abstract, page ii-iii.
Missouri University of Science and Technology
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