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Dimensional Measurements of Three Tubes by Computed Tomography.

DE200515014597

Publication Date	2004
Personal Author	Schneberk, D. J.; Martz, H. E.; Brown, W. D.
Page Count	12
Abstract	Low density polyethylene (LDPE), copper (Cu), and gold (Au) tubes were scanned on KCAT to identify and evaluate the impact of phase effects on quantitative object recovery. These tubes are phantoms for high energy density capsules. Digital radiographs for each tube are shown in Figure 1. The LDPE tube was scanned at 60 kV, while the Cu and the Au tubes were scanned at 140 kV. All tubes were scanned at a magnification of 3, with approximately 100-mm distance between the exit plane of the tube and the scintillator. Notice the prominence of the outer bright and inner dark edges for the LDPE tube DR, and their absence from the Cu and Au tube DRs. The bright and dark edges are a result of change in phase of the x-rays. The x-ray fluence is partly attenuated and partly refracted. The location near the outer edge of the tube appears to be more attenuating since those x-rays have refracted to locations just outside the tube. Alternatively, the added counts from the refraction result in intensities that are greater than the incident intensity effectively representing a negative attenuation. This results in more counts in that location than in the incident intensity image violating the positivedefinite requirement for standard CT reconstruction methodologies. One aspect of our CT processing techniques remove some of this signal on the outside of the object. The goal of this paper is to evaluate the accuracy of our dimensional measurement methods for mesoscale object inspection.
Keywords	Computer aided tomography Tomography Tubes Polyethylenes Three dimensional model
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200606

Dimensional Measurements of Three Tubes by Computed Tomography.

Dimensional Measurements of Three Tubes by Computed Tomography.
DE200515014597

Publication Date	2004
Personal Author	Schneberk, D. J.; Martz, H. E.; Brown, W. D.
Page Count	12
Abstract	Low density polyethylene (LDPE), copper (Cu), and gold (Au) tubes were scanned on KCAT to identify and evaluate the impact of phase effects on quantitative object recovery. These tubes are phantoms for high energy density capsules. Digital radiographs for each tube are shown in Figure 1. The LDPE tube was scanned at 60 kV, while the Cu and the Au tubes were scanned at 140 kV. All tubes were scanned at a magnification of 3, with approximately 100-mm distance between the exit plane of the tube and the scintillator. Notice the prominence of the outer bright and inner dark edges for the LDPE tube DR, and their absence from the Cu and Au tube DRs. The bright and dark edges are a result of change in phase of the x-rays. The x-ray fluence is partly attenuated and partly refracted. The location near the outer edge of the tube appears to be more attenuating since those x-rays have refracted to locations just outside the tube. Alternatively, the added counts from the refraction result in intensities that are greater than the incident intensity effectively representing a negative attenuation. This results in more counts in that location than in the incident intensity image violating the positivedefinite requirement for standard CT reconstruction methodologies. One aspect of our CT processing techniques remove some of this signal on the outside of the object. The goal of this paper is to evaluate the accuracy of our dimensional measurement methods for mesoscale object inspection.
Keywords	Computer aided tomography Tomography Tubes Polyethylenes Three dimensional model
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200606