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Nondestructive measurement of density and effective atomic number by photon scattering
N DT Abstracts Speller, R.D.; Koligliatis, T.; Horrocks, J.A. Compton scatter densitometry: the problem of multiple s c a t t e r i n g effects
41451
Proceedings of a one-day Meeting of the Materials and Testing Group of the Institute of Physics, 13 December 1988, London. Eds. N. MacCuaig and R. Holt. pp. 53-59 (1989) The application of x-ray sources for densitometry using Compton Scatter events makes the procedure a very attractive proposition for a clinical system. However, the detection of multiple scattering events is a problem and a Monte Carlo study is presented in order to find optimum scattering angles and correction factors so that the effects of multiple scatter are minimized. For the geometry studied it is found that a scattering angle of about 40-50 is optimum, with correction factors in the range of 0.48 - 0.53 for an examination of the lower forearm.
Lopes. R.T.: Anjos, M.J. Determination of surface defects using Compton scattering of gamma-ray of 662 KeV
41070
Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1276-1278. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. This system for the determination of surface defects consists of a collimated Caesium 137 source and a Nal(TI) detector. The scattering angle chosen was 90 deg. A set of aluminium blocks with different surface conditions has been tested, and imperfections up to 1.6 mm were detected. 41068 Omotosho, 0.I.; Plaskowski, A.; Frith, B.; Beck, M.S. A ' n o n - m o v i n g p a r t ' gamma sensor for non-destructive testing Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1087-1092. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. This paper presents the design of a computerized tomographic system capable of mapping defective spots on objects without cutting and/or rotating them. It is based on the principle of Compton-scattered gammaphotons using an external scatterer. In particular, the choice of materials that can be used as an external scatterer; criteria of such a choice are presented. Also, the potential advantages and the limitations of the system are discussed.
Bridge, B.; Harirchian, F.; lmrie, D.C.; Mehrabi, Y.; Meragi, A.R. Preliminary experiments with an automated three-dimensional Compton imaging system using a weak Barium-133 source
40865
British Journal of Non-Destructive Testing, Vol. 3 !, No. 3, pp. 134139 (Mar. 1989) A fully-automated low strength Compton forward-scatter imaging device employing a 1.4 mCi Ba gamma-ray source is described. Typical images obtained with this device are presented and discussed, in order to identify desirable improvements of the system. The Iongterm aim is to enable distributions of I mm diameter voids in novel ceramic materials to be rapidly detected. 40839 Roye, W. The C o m p t o n b a c k s c a t t e r t e c h n i q u e - a new method of x-ray
inspection
the intensity of gamma radiation scattered back from the concrete. Collimation andenergydiscrimination are used to detect gamma rays from a Co-60 source which have undergone a single Compton scatter through a prescribed angle. The system can readily locate and discriminate between voids, cracks, and high density inclusions. The data is printed in a normalized format which shows the relative density at each area in the plane. The system also demonstrated the adaptability of this technique to other matrices by locating holes in a steel block. Other possible uses include locating voids and cracks in a variety of ceramic materials and in structures containing layers of different materials. 39627 Kosanetzky, J.; Harding, G.; Fischer, K.H.; Meyer, A. Compton back-scatter tomography of low atomic number materials with the surpass system Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 2118-2132. Pergamon Press, 3173 pp. (1988) A new and simple back-scatter imaging system, based on the detection Compton scattered radiation is presented. It provides some interesting advantages over conventional transmission systems: real 3D-imaging capability, high contrast even for low atomic materials and back- scatter imaging geometry. Results will be presented demonstrating possible application areas with light metal alloys, laminates and plastics, which are of increasing importance in modem products.
Roye, W. X-ray testing of thermoplastic welding joints 39618
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 2051-2059. Pergamon Press, 3173 pp. (1988) It is well known that X-ray testing of plastics and their welds is problematic. The difficulties are discussed briefly and two ways which lead to improvements are demonstrated: the high current constant potential X-ray system and the newly developed Compton-backscatter technique. 39606 Fletcher, S. Compton/fluorescence tomography Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1529-1535. Pergamon Press, 3173 pp. 0 9 8 8 ) A Compton/Fluorescence (C/F) tomography system has been developed as an inspection tool which can yield electron density distributions and distributions of specific elements within a specimen. The system uses a High-Purity Germanium detector, acquiring scattered-photon energy spectra and transmission spectra. Low energy radioisotopes (<200 KeV) are used as sources. Compton-scatter peak intensities and K or L fluorescence peak intensities for elements of interest were extracted from the scattered spectra to obtain separate Compton and Fluorescence data matrices. These matrices were corrected for depth in the specimen using a transmission matrix obtained via transmission gauging. A reconstruction code generated distribution maps of the total electron density and individual element densities from the corrected Compton and Fluorescence data matrices. Spatial resolutions were in the 2-5 mm range.
Bridge, B.; Harirchian, F.; Imrie, D.C.; Mehrabi, Y.; Meragi, A.R. Isometric representation of data obtained using a Compton gamma-ray scanner 39485
Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 31-36. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989 This paper outlines the purpose of the Compton backscatter technique and some of its applications. Although the idea of using the Compton effect for imaging, employed in non-destructive testing of materials is relatively old, it is only recently that a method which allows cost- effective inspection, has been developed.
Nondestructive Testing Communications, Vol. 4, No. 1, pp. 1-10 (1988) An isometric graphics representation has been used to analyse the data obtained from a prototype gamma-ray Compton scanner used for the detection of mm voids in steel and other materials. The data is compared with those from contour and histogram methods of image presentation previously described.
Hill, D.W.; Peak, J.C. Development of a one-sided gamma ray tomography system
39114 Berodias, M.G.; Peix, M.G. Nondestructive measurement of density and effective atomic number by photon scattering
40136
Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7A, pp. 415-424. Edited by D.D.Thompson and D.E.Chimenti, Plenum Press, 1988. An experimental device has been constructed which has successfully determined the location and size of macroscopic features such as voids and steel bars in concrete structures. The technique measures relative density variations along a plane perpendicular to the surface of the structure using
194
Materials Evaluation, Vol. 46, No. 9, pp. 1209-1213 (Aug. 1988) A system for measurement of the density and effective atomic number of solid, a liquid, or a gas is described. An industrial x-ray tube delivers a high-photon flux with very good stability. The photons, scattered by the investigated material, are detected by a scintillating crystal. The use of a high Compton angle permits setting the detector just beside the tube, allowing measurements from a single side of the controlled part. Very large or thick objects are thus easily investigated.
41451
Proceedings of a one-day Meeting of the Materials and Testing Group of the Institute of Physics, 13 December 1988, London. Eds. N. MacCuaig and R. Holt. pp. 53-59 (1989) The application of x-ray sources for densitometry using Compton Scatter events makes the procedure a very attractive proposition for a clinical system. However, the detection of multiple scattering events is a problem and a Monte Carlo study is presented in order to find optimum scattering angles and correction factors so that the effects of multiple scatter are minimized. For the geometry studied it is found that a scattering angle of about 40-50 is optimum, with correction factors in the range of 0.48 - 0.53 for an examination of the lower forearm.
Lopes. R.T.: Anjos, M.J. Determination of surface defects using Compton scattering of gamma-ray of 662 KeV
41070
Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1276-1278. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. This system for the determination of surface defects consists of a collimated Caesium 137 source and a Nal(TI) detector. The scattering angle chosen was 90 deg. A set of aluminium blocks with different surface conditions has been tested, and imperfections up to 1.6 mm were detected. 41068 Omotosho, 0.I.; Plaskowski, A.; Frith, B.; Beck, M.S. A ' n o n - m o v i n g p a r t ' gamma sensor for non-destructive testing Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1087-1092. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. This paper presents the design of a computerized tomographic system capable of mapping defective spots on objects without cutting and/or rotating them. It is based on the principle of Compton-scattered gammaphotons using an external scatterer. In particular, the choice of materials that can be used as an external scatterer; criteria of such a choice are presented. Also, the potential advantages and the limitations of the system are discussed.
Bridge, B.; Harirchian, F.; lmrie, D.C.; Mehrabi, Y.; Meragi, A.R. Preliminary experiments with an automated three-dimensional Compton imaging system using a weak Barium-133 source
40865
British Journal of Non-Destructive Testing, Vol. 3 !, No. 3, pp. 134139 (Mar. 1989) A fully-automated low strength Compton forward-scatter imaging device employing a 1.4 mCi Ba gamma-ray source is described. Typical images obtained with this device are presented and discussed, in order to identify desirable improvements of the system. The Iongterm aim is to enable distributions of I mm diameter voids in novel ceramic materials to be rapidly detected. 40839 Roye, W. The C o m p t o n b a c k s c a t t e r t e c h n i q u e - a new method of x-ray
inspection
the intensity of gamma radiation scattered back from the concrete. Collimation andenergydiscrimination are used to detect gamma rays from a Co-60 source which have undergone a single Compton scatter through a prescribed angle. The system can readily locate and discriminate between voids, cracks, and high density inclusions. The data is printed in a normalized format which shows the relative density at each area in the plane. The system also demonstrated the adaptability of this technique to other matrices by locating holes in a steel block. Other possible uses include locating voids and cracks in a variety of ceramic materials and in structures containing layers of different materials. 39627 Kosanetzky, J.; Harding, G.; Fischer, K.H.; Meyer, A. Compton back-scatter tomography of low atomic number materials with the surpass system Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 2118-2132. Pergamon Press, 3173 pp. (1988) A new and simple back-scatter imaging system, based on the detection Compton scattered radiation is presented. It provides some interesting advantages over conventional transmission systems: real 3D-imaging capability, high contrast even for low atomic materials and back- scatter imaging geometry. Results will be presented demonstrating possible application areas with light metal alloys, laminates and plastics, which are of increasing importance in modem products.
Roye, W. X-ray testing of thermoplastic welding joints 39618
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 2051-2059. Pergamon Press, 3173 pp. (1988) It is well known that X-ray testing of plastics and their welds is problematic. The difficulties are discussed briefly and two ways which lead to improvements are demonstrated: the high current constant potential X-ray system and the newly developed Compton-backscatter technique. 39606 Fletcher, S. Compton/fluorescence tomography Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1529-1535. Pergamon Press, 3173 pp. 0 9 8 8 ) A Compton/Fluorescence (C/F) tomography system has been developed as an inspection tool which can yield electron density distributions and distributions of specific elements within a specimen. The system uses a High-Purity Germanium detector, acquiring scattered-photon energy spectra and transmission spectra. Low energy radioisotopes (<200 KeV) are used as sources. Compton-scatter peak intensities and K or L fluorescence peak intensities for elements of interest were extracted from the scattered spectra to obtain separate Compton and Fluorescence data matrices. These matrices were corrected for depth in the specimen using a transmission matrix obtained via transmission gauging. A reconstruction code generated distribution maps of the total electron density and individual element densities from the corrected Compton and Fluorescence data matrices. Spatial resolutions were in the 2-5 mm range.
Bridge, B.; Harirchian, F.; Imrie, D.C.; Mehrabi, Y.; Meragi, A.R. Isometric representation of data obtained using a Compton gamma-ray scanner 39485
Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 31-36. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989 This paper outlines the purpose of the Compton backscatter technique and some of its applications. Although the idea of using the Compton effect for imaging, employed in non-destructive testing of materials is relatively old, it is only recently that a method which allows cost- effective inspection, has been developed.
Nondestructive Testing Communications, Vol. 4, No. 1, pp. 1-10 (1988) An isometric graphics representation has been used to analyse the data obtained from a prototype gamma-ray Compton scanner used for the detection of mm voids in steel and other materials. The data is compared with those from contour and histogram methods of image presentation previously described.
Hill, D.W.; Peak, J.C. Development of a one-sided gamma ray tomography system
39114 Berodias, M.G.; Peix, M.G. Nondestructive measurement of density and effective atomic number by photon scattering
40136
Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7A, pp. 415-424. Edited by D.D.Thompson and D.E.Chimenti, Plenum Press, 1988. An experimental device has been constructed which has successfully determined the location and size of macroscopic features such as voids and steel bars in concrete structures. The technique measures relative density variations along a plane perpendicular to the surface of the structure using
194
Materials Evaluation, Vol. 46, No. 9, pp. 1209-1213 (Aug. 1988) A system for measurement of the density and effective atomic number of solid, a liquid, or a gas is described. An industrial x-ray tube delivers a high-photon flux with very good stability. The photons, scattered by the investigated material, are detected by a scintillating crystal. The use of a high Compton angle permits setting the detector just beside the tube, allowing measurements from a single side of the controlled part. Very large or thick objects are thus easily investigated.