![]() ![]() “When light hits the zest, it bends a little. X-ray phase contrast imaging clearly shows the differences between the thin layers of zest and pith and how those layers look compared to the thick pulp. Amber had one in her office and, recognizing it’s really just low-density materials, she and her colleagues imaged it to demonstrate their system.Ī conventional X-ray picture of an orange is fuzzy, without detail. The phase contrast image, right, sensitive to the different materials within a sample, shows the changes from one material to another. A dark field image, center, is sensitive to a sample’s microstructure, scattering the X-ray. The absorption image, left, the same as a conventional X-ray image, shows how dense a sample is. “So they don’t know if the gaps are filled with the low-density materials or if that’s air.”ĪN ORANGE illustrates three different images from an X-ray phase contrast imaging system. “You have a dense material mixed in with a low-density material, and traditional X-rays can’t see that low-density material,” Amber says. Other current techniques aren’t sensitive enough to distinguish between materials. Sandia’s technique achieved X-ray phase contrast imaging in a lab without a synchrotron, an expensive piece of equipment the size of a football field. X-ray phase contrast imaging could be used to inspect microfabrication packaging, integrated circuits, or micro-electro-mechanical components and could be used to study ceramics, polymers, chemicals, or explosives. “For low-density materials like plastics, polymers, foams, and other encapsulants, this phase signal can be a thousand times bigger than the absorption signal of conventional X-ray,” says principal investigator Amber Dagel (5228). X-ray phase contrast imaging measures not just the number of X-ray photons that get through the sample, as in conventional X-ray imaging, but also the phase of the X-rays after they pass through, offering a complete look at interfaces inside a structure. And they can’t see the critically important foams and other materials that guard against shock, high voltage breakdown, and thermal stresses in nuclear weapon components. For example, conventional X-rays can’t see a defect called a grafoil in the laminate layers of an airplane wing without removing the protective copper mesh that diffuses energy if lightning hits. The Labs has to be able to spot defects before they might cause a high-consequence failure, because materials don’t perform well with voids or cracks or if they’re separating from adjacent surfaces. Amber is principal investigator for the Labs’ work into using the technique to study low-density materials. RESEARCHER AMBER DAGEL holds a calibration sample to be loaded into Sandia’s X-ray phase contrast imaging machine. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |