Application of Tomography to the Nuclear Industry

While tomographic methods of reconstructing three~dimensional x-ray images are becoming more common in the medical field, their application to industrial problems has only started. Some of the features that differentiate industrial tomography from medical tomography are x-ray energies may vary from\u3c 10 keV to\u3e 22 MeV radiation dose to the object is not a constraint inspection times (within economic constraints) are not as important the anomalies to be detected offer sharp, high contrast boundaries to the inspection system high spatial resolution rather than high contrast sensitivity is the primary design goal, and the number of views may be limited by other (mechanical) constraints. This paper will describe the effort the Los Alamos Scientific Laboratory (LASL) is making to define the design parameters that affect the constraints listed above. A tomographic test bed in which various design features may be evaluated will be described. The computational facilities at LASL, which include a versatile modeling code that can simulate tomographic systems with various types of radiation, geometries, and detector types, will also be discussed

Geostatistics project of the National Uranium Resource Evaluation program

Additional work has been done to display radiometric data from the Lubbock quadrangle in pseudocolor maps. A digitized topographic map of the quadrangle was obtained from the U.S. Geological Survey and this is being incorporated into the study of the radiometric data. Single-record data from the Lake Mead calibration range and from the Slayton test line have been obtained from GeoMETRICS: Inc. and analysis of this data has begun. Principal component analyses have been used to investigate the relationship of geological formation to the location of points in a (Tl, Bi, K) coordinate system. LASL personnel attended a workshop in Grand Junction, Colorado, where some of the problems of calibrating aerial gamma-ray spectrometers were addressed

National impacts on visual air quality from a future energy scenario

A methodology was developed to evaluate impacts on atmospheric visual air quality for nonurban areas caused by regional haze. Estimated values of median visual range for 39 nonurban ambient air quality monitoring sites were shown to have a high correlation with observed values. A decline in median visual range is projected in regions of the west and the Gulf Coast where there is a substantial growth in the combustion of sulfur containing fossil fuels - coal in particular. The projected decline in median visual range in mandatory Class I Federal areas, particularly in the Western US may conflict with Congress's goal of protecting these areas against visibility impairment. Regulations for defining visibility impairment remain to be defined. The meeting of the emission limitations of the state implementation plans is projected to significantly improve the low visibilities experienced in the Eastern US, particularly in the Ohio Valley and the surrounding region

Fan to parallel beam conversion in CAT by rubber sheet transformation

A technique for converting fan-beam projections to parallel-beam projections for use in computed tomography is presented. The problem is approached by use of a rubber sheet transformation. Since the data is discretized, an interpolation step is necessary. For densely sampled data this approach appears satisfactory and a significant reduction in photon noise is observable in computer simulations

Technique for dynamic range reduction for Landsat ratio images

The LANDSAT ratio image, obtained by dividing one MSS band by another on a point-by-point basis, has become an established tool for geological applications over the past several years. Display of such images can be difficult since the dynamic range can extend from zero to infinity. A scheme for dynamic range reduction, based on a mathematical model of the multispectral image, is presented. It can be implemented on stand-alone digital image processing systems as well as general purpose computers. This technique also has potential application in machine classification of geological data. Digital image processing examples are presented in which this new scheme is compared with other commonly used techniques for dynamic range reduction

Tomographic visualization of stress corrosion cracks in tubing

A feasibility study was conducted to determine the possibility of detecting and sizing cracks in reactor cooling water tubes using tomographic techniques. Due to time and financial constraints, only one tomographic reconstruction using the best technique available was made. The results indicate that tomographic reconstructions can, in fact, detect cracks in the tubing and might possibly be capable of measuring the depth of the cracks. Limits of detectability and sensitivity have not been determined but should be investigated in any future work

Application of Tomography to the Nuclear Industry

While tomographic methods of reconstructing three~dimensional x-ray images are becoming more common in the medical field, their application to industrial problems has only started. Some of the features that differentiate industrial tomography from medical tomography are x-ray energies may vary from 22 MeV radiation dose to the object is not a constraint inspection times (within economic constraints) are not as important the anomalies to be detected offer sharp, high contrast boundaries to the inspection system high spatial resolution rather than high contrast sensitivity is the primary design goal, and the number of views may be limited by other (mechanical) constraints. This paper will describe the effort the Los Alamos Scientific Laboratory (LASL) is making to define the design parameters that affect the constraints listed above. A tomographic test bed in which various design features may be evaluated will be described. The computational facilities at LASL, which include a versatile modeling code that can simulate tomographic systems with various types of radiation, geometries, and detector types, will also be discussed.</p

Rationale of the ratio image in multispectral remote sensing

A simple mathematical interpretation of the properties of ratio images derived from LANDSAT and other sources of multispectral imagery is presented. A spectral signature is defined which is well represented by ratios of pairs of spectral bands and can be related to the problem of clustering and unsupervised learning. Some practical problems arising in the generation of LANDSAT ratio images are considered, and an effective, simple method for reduction of the dynamic range of such images is presented along with digital image processing examples. 6 figures

Application of Tomography to the Nuclear Industry

While tomographic methods of reconstructing three~dimensional x-ray images are becoming more common in the medical field, their application to industrial problems has only started. Some of the features that differentiate industrial tomography from medical tomography are x-ray energies may vary from 22 MeV radiation dose to the object is not a constraint inspection times (within economic constraints) are not as important the anomalies to be detected offer sharp, high contrast boundaries to the inspection system high spatial resolution rather than high contrast sensitivity is the primary design goal, and the number of views may be limited by other (mechanical) constraints. This paper will describe the effort the Los Alamos Scientific Laboratory (LASL) is making to define the design parameters that affect the constraints listed above. A tomographic test bed in which various design features may be evaluated will be described. The computational facilities at LASL, which include a versatile modeling code that can simulate tomographic systems with various types of radiation, geometries, and detector types, will also be discussed.</p