Quantitative Mass Density Image Reconstructed from the Complex X-Ray Refractive Index.
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The mass density was obtained from the experimentally observed ratio of the imaginary and real parts of the complex X-ray refractive index.An empirical linear relationship between the X-ray mass attenuation coefficient of the materials and X-ray energy was found for X-ray energies between 8 keV and 30 keV.The reconstructed mass density agrees well with the calculated one.
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Affiliation: Nanomaterials R&D Center, Canon Inc., Ohta-ku, Tokyo, Japan.
ABSTRACT
We demonstrate a new analytical X-ray computed tomography technique for visualizing and quantifying the mass density of materials comprised of low atomic number elements with unknown atomic ratios. The mass density was obtained from the experimentally observed ratio of the imaginary and real parts of the complex X-ray refractive index. An empirical linear relationship between the X-ray mass attenuation coefficient of the materials and X-ray energy was found for X-ray energies between 8 keV and 30 keV. The mass density image of two polymer fibers was quantified using the proposed technique using a scanning-type X-ray microbeam computed tomography system equipped with a wedge absorber. The reconstructed mass density agrees well with the calculated one. No MeSH data available. Related in: MedlinePlus |
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Mentions: Fig 2 shows X-ray energy dependence of the A and B between 8 keV and 30 keV. The values of A and B at each X-ray energy were obtained by weighted least-squares regression of μ/ρ as a function of β/δ. Because the values of B were much smaller than μ/ρ at 10 keV for the materials analyzed, as shown in Figs 1 and 2(b), A was assumed to be inversely proportional to E from Eqs (2) and (4), and the best fit curve was obtained using least-squares regression asA=2.151×104E-1-19.27.(6)We assumed that the X-ray energy dependence of B correlated strongly with the X-ray energy dependence of the σa from Eqs (2), (4) and (5). Therefore, we assumed a calibration function for B asB=mE-n+lσKN,(7)where m, n, and l are fitting parameters and σKN is the Klein-Nishina cross section [16]. The first term in Eq (7) corresponds to the X-ray energy dependence of the photoelectric cross section (n ≈ 3.1) [17]. The second term in Eq (7) is the incoherent scattering cross section. In Eq (7), X-ray energy dependence of the coherent scattering cross section is neglected because its contribution to the σa is small in the X-ray energy region investigated here (8–30 keV). The values of m, n, and l obtained using least-squares regression are 194.6, 3.116, and 6.534 × 10−3, respectively. |
View Article: PubMed Central - PubMed
Affiliation: Nanomaterials R&D Center, Canon Inc., Ohta-ku, Tokyo, Japan.
No MeSH data available.