NIST DEVELOPS NEW FORM OF NEUTRON RADIOGRAPHY PROVIDING FINE INTERNAL DETAILS.
The experiments were performed at the NIST Center for Neutron Research, using a position-sensitive two-dimensional Charged Coupled Device neutron detector with nominal resolution of about 50 [micro]m. A lead bullet and a common wasp were chosen as specimens because these are representative of difficult cases for radiography by traditional methods with either x rays or neutrons.
One of the most important aspects of these experiments is that the researchers were able to extract the quantitative phase values, as well as the phase-contrast images. These phase values are critical to the interpretation of the images obtained. This phase extraction is possible by the application of the so-called paraxial "Transport of Intensity Equation" (TIE) to the image intensity profiles, which allowed the researchers to employ a simple, robust experimental setup without the need for stringent environmental control required in a typical interferometry experiment.
These experiments open the exciting possibility of investigating very fine structural details such as fractures and strain in commonly used industrial components, magnetic domains, and thin film-substrate interface boundaries. Further experiments are planned in the near future using polarized neutrons and magnetic samples.
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|Publication:||Journal of Research of the National Institute of Standards and Technology|
|Article Type:||Brief Article|
|Date:||Mar 1, 2001|
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