[en] A new approach for the detection of flaws in materials is proposed, making use of backscattered gamma radiation from a ¹⁹²Ir source. The technique permits the detection of flaws by approaching the material only from the same side as that of the incident radiation

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No abstract available

No abstract available

No abstract available

[en] The thermal-neutron flux produced by a ²⁵²Cf spontaneous fission neutron source was computed for various spherical assemblies with moderators of iron, aluminum, carbon, D₂O, beryllium, and H₂O and reflectors of H₂O and carbon. Consideration of spherical assemblies with a ²⁵²Cf source located at the center and at various distances from the center lead to a configuration, adaptable to neutron radiography, that has a small thermalization factor and a flat thermal-neutron flux

[en] Recently obtained experimental results with small pipe samples have indicated the usefulness of Computed Tomography (CT) as a diagnostic tool to detect and quantify the presence and extent of Intergranular Stress Corrosion Cracking (IGSCC). These results show potential in augmenting current Ultrasonic Techniques (UT) by providing a reliable measure of crack depth. The detailed quantification of crack geometry is particularly difficult using UT both because of the granular nature of the steels commonly used, as well as the multi-branched and dendritic nature of the IGSCC patterns. Computed Tomography with its reproducibly high sensitivity to small density changes within the sample volume can be an effective tool if the change in density due to the volume of the crack is greater than the resolution of the system. Destructive metallurgical analysis has been performed at locations where the CT indicated extensive cracking. Agreement between the CT measurement and direct observation is excellent. CT studies were also performed on two samples of 12-inch pipe using a Co-60 source. While not as dramatic as that of the smaller pipes, there are indications of cracking starting near e inner weld root and cupping outward and away from the root. Data was taken at axial-slice widths of approximately 2mm. Because of the lower sensitivity and statistical accuracy available from the Co-60 source, this data requires some spatial filtering in order to sense these trends. Additional data taken with longer counting periods should reduce the statistical spread and improve the measured sensitivity to small changes in average, effective density caused by the cracks

[en] The possible application of the γ-ray backscattering method for in situ measurement of the density profile in aqueous solutions was studied experimentally, following Monte Carlo calculations. (orig.)