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A Compton scattering method for inspecting concrete structures
N DT Abstracts a mould with tungsten powder and impregnating it with a fluid epoxy resin, by pumping through the powder. The fine strips, used as cores for the channels, are then pulled out. The collimator that was built had 49 fine slots, all converging in one little bar-shaped volume, to convey x-ray photons from this volume to the entrance window of a large scintillation crystal detector. The collimator exhibit:; a very good precision of the relative positions of slots, allowing the volume V to be very sharply shaped. Use of this collimator for nondestructive testing by the Compton scattering tomography (CST) technique allowed us to detect plane defects down to 0.1 ram, inside composite plates. 42680 Hussein, M.A.; Whynot, T.M. A C o m p t o n s c a t t e r i n g method for
inspecting concrete
structures Nuclear Instruments and Meti'lods in Physics Research, Vol. A283, No. 1, pp. 100-106 (1989) The feasibility of a Compton scattering technique for the inspection of extended concrete s:ructures fog the presence of steel robar and void enclosures is demonstrated experimentally and by Monte Carlo simulations. A parametric study is performed which identifies the source energy and Compton scattering angle as the most dominant variables affecting the technique. A simple optimization method is, subsequently, developed to aid in the determination of the most appropriate source-detector arrangement for a given depth of concrete. 42466 Pujol, P.; Loopuyt, G, T h e o r e t i c a l s t u d y of the possibilities for increasing detection
capabilities (In French: English Abstract) Etablissement Technique Central de I'Armement, Arcueil (France), PB89- 161038, ETCA-88-R-044, 71 pp. (19 Apr. 1988) The report consists of a theoretical study on the possibilities for increasing the detection capabilities of tomography. After reviewing the theoretical principles of transverse axial tomography, the problems of energy optimization and Compton diffusion, inherent in nondestructive testing, are analyzed. The study's repercussions on the equipment in place at the Central Weapons Technical Establishment am detailed. The report concludes by sketching the lines along which the system is likely to develop in the future.
Omotosho, 0.I.; Frith, B.; Plaskowski, A,; Beck, M.S. A sensing system for non-de;tructive imaging using externally Compton- scattered gamma photons
42065
Sensors and Actuators, Vol. 18, No. 1, pp. 1-15 (1989) An aluminium rod, has been used as an external scatterer suspended between two identical caesium-13"l gamma radiation sources, to produce a pencil beam of diameter 1.2 cm. Two detectors are positioned and collimated to receive singly-Compton-scattered photons from selected portions of the scatterer. An object is placed vertically between the planes of the scatterer and the detectors. The singly-Compton- scattered photons from the scatterer encompass the cross-:;ection of the object before reaching the detectors. The minimum and maximum selected angles of scatter are 36 and 54 respectively. However, a speciaJl material as a scatterer and directionallysensitive high energy resolution detectors with high count rates are required to realize fully the potential advantages of the system. The figure of merit (confidence level), suggests that, with an adequate scatterer, the data from this geometry are highly likely to be superior to those from other currently available methods.
Najos, M.J.; Lopes, R.T.; Borges, J.C. Compton scattering of gamma-rays as surface inspection technique
42061
Nuclear Instruments & Methods in Physics Research, Vol. A280, Nos. 2-3, pp. 535-538 (10 Aug. 1989) A system for surface inspection based on the physical principle of Compton scattering of gamma-rays is presented here. Our system consists of a collimated Cs source and a NaI(TI) detector. An experimental search was carried out to determine the best layout of the array. A set of aluminium blocks with different surface conditions has been tested, and imperfections up to 1.6 mm were detected.
Harding, G.; Kosanetzky, J. Scattered x-ray beam nondestructive testing 42060
Nuclear Instruments & Methods in Physics Research, Vol. A280, Nos. 2-3, pp. 517-528 (10 Aug. 1989) X-rays scatter interactions generally dominate the linear attenuation coefficient at the photon energies typical of medical and industrial radiography. Specific advantages of X-ray scatter imaging, including a
193
flexible choice of measurement geometry, direct 3D-imaging capability (tomography) and improved information for material characterization, are illustrated with results from Compton and coherent scatter devices. Applications of a Compton backscatter scanner (ComScan) in the aerospace industry and coherent scatter imaging in security screening are briefly considered.
Jackson, D.F. Non destructive physical investigation of the chemical environment 41753
International Advances in Nondestructive Testing. Edited by Warren J. McGonnagle. Vol. 14, pp. 259-283, Gordon and Breach Science Publishers (1989) Some physical methods of non destructive examination are sensitive to the chemical environment and can therefore be used to probe molecular and chemical properties of materials. The examples given include Nuclear Magnetic Resonance (NMR) imaging and spectroscopy, (ESR) imaging, Compton scattering, and materials analysis using muonic and pionic X-rays.
Albugues, F. Nondestructive tests structures
41585
and
high
performance
composite
Societe Nationale Industrielle Aerospatiale, Saint-Medard-en-Jalles (France), N88-28969/9/GAR, 17pp (1988) The most efficient nondestructive test methods applicable to high performance carbon or kevlar reinforced plastics are reviewed including the hard X or gamma radiation methods such as X-ray tomography, neutron photography and Compton scattered diffusion, holographic methods, acoustic emission methods, and microwaves. The examples show that each method has a definite area of application.
Lillicrap,S.C. Coherent/Compton scattering for in-vivo tissue measurement
41480
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. 61-65 (1989) The measured ratio of coherent scattering to Compton scattering depends on the elemental composition of the scatterer for a given incident photon energy and angle of scatter, Measurements have been made on a range of tissues and tissue substitutes to determine the sensitivity of the technique in differentiating between tissues. Clear differences are predicted between fat, muscle, trabecular bone and cortical bone, although the measured amounts are somewhat less.
Harding, G.; Kosanetzky, J. X-ray scatter imaging in non.destructive testing
41454
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. 1-15 (1989) X-ray scatter radiation may conveniently be used for imaging purposes in non-destructive testing (NDT). The feasibility of both Compton and Rayleigh scatter imaging has been successfully demonstrated: the former i n the aerospace industry for back-scatter analysis of near-surface defects, the latter for investigating the diffraction properties of arbitrary volume elements (voxels) of medical and industrial objects. Compton and Rayleigh scatter imaging devices are described, and representative scatter images drawn from various fields of NDT are presented.
Bridge,B.; Harirchian, F.; Imrie, D.C.; Mehrabi, Y.; Meragi, A.R. Compton scatter imaging: corrosion, thickness monitoring and void detection
41452
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. 17-39 (1989) An overview is presented of the research programme on Compton scatter imaging at Brunel University carried out with the use of 1.5 mCi Ba-133 and 10 Ci Co-60 gamma sources. Effective methods of radiological imaging were established for the underwater non-destructive inspection of thick structural sections, of offshore oil production platforms. The problems associated with the design of imaging systems sufficiently mobile and robust for subsea usage are discussed. Typical results for the detection of inner wall corrosion pits and wall thickness measurements are given. The performance of the technique in detecting voids is insensitive to material density. Thus the measurement time required to achieve a specified detection probability for a given void size, is almost the same in polyethylene, as in steel.
inspecting concrete
structures Nuclear Instruments and Meti'lods in Physics Research, Vol. A283, No. 1, pp. 100-106 (1989) The feasibility of a Compton scattering technique for the inspection of extended concrete s:ructures fog the presence of steel robar and void enclosures is demonstrated experimentally and by Monte Carlo simulations. A parametric study is performed which identifies the source energy and Compton scattering angle as the most dominant variables affecting the technique. A simple optimization method is, subsequently, developed to aid in the determination of the most appropriate source-detector arrangement for a given depth of concrete. 42466 Pujol, P.; Loopuyt, G, T h e o r e t i c a l s t u d y of the possibilities for increasing detection
capabilities (In French: English Abstract) Etablissement Technique Central de I'Armement, Arcueil (France), PB89- 161038, ETCA-88-R-044, 71 pp. (19 Apr. 1988) The report consists of a theoretical study on the possibilities for increasing the detection capabilities of tomography. After reviewing the theoretical principles of transverse axial tomography, the problems of energy optimization and Compton diffusion, inherent in nondestructive testing, are analyzed. The study's repercussions on the equipment in place at the Central Weapons Technical Establishment am detailed. The report concludes by sketching the lines along which the system is likely to develop in the future.
Omotosho, 0.I.; Frith, B.; Plaskowski, A,; Beck, M.S. A sensing system for non-de;tructive imaging using externally Compton- scattered gamma photons
42065
Sensors and Actuators, Vol. 18, No. 1, pp. 1-15 (1989) An aluminium rod, has been used as an external scatterer suspended between two identical caesium-13"l gamma radiation sources, to produce a pencil beam of diameter 1.2 cm. Two detectors are positioned and collimated to receive singly-Compton-scattered photons from selected portions of the scatterer. An object is placed vertically between the planes of the scatterer and the detectors. The singly-Compton- scattered photons from the scatterer encompass the cross-:;ection of the object before reaching the detectors. The minimum and maximum selected angles of scatter are 36 and 54 respectively. However, a speciaJl material as a scatterer and directionallysensitive high energy resolution detectors with high count rates are required to realize fully the potential advantages of the system. The figure of merit (confidence level), suggests that, with an adequate scatterer, the data from this geometry are highly likely to be superior to those from other currently available methods.
Najos, M.J.; Lopes, R.T.; Borges, J.C. Compton scattering of gamma-rays as surface inspection technique
42061
Nuclear Instruments & Methods in Physics Research, Vol. A280, Nos. 2-3, pp. 535-538 (10 Aug. 1989) A system for surface inspection based on the physical principle of Compton scattering of gamma-rays is presented here. Our system consists of a collimated Cs source and a NaI(TI) detector. An experimental search was carried out to determine the best layout of the array. A set of aluminium blocks with different surface conditions has been tested, and imperfections up to 1.6 mm were detected.
Harding, G.; Kosanetzky, J. Scattered x-ray beam nondestructive testing 42060
Nuclear Instruments & Methods in Physics Research, Vol. A280, Nos. 2-3, pp. 517-528 (10 Aug. 1989) X-rays scatter interactions generally dominate the linear attenuation coefficient at the photon energies typical of medical and industrial radiography. Specific advantages of X-ray scatter imaging, including a
193
flexible choice of measurement geometry, direct 3D-imaging capability (tomography) and improved information for material characterization, are illustrated with results from Compton and coherent scatter devices. Applications of a Compton backscatter scanner (ComScan) in the aerospace industry and coherent scatter imaging in security screening are briefly considered.
Jackson, D.F. Non destructive physical investigation of the chemical environment 41753
International Advances in Nondestructive Testing. Edited by Warren J. McGonnagle. Vol. 14, pp. 259-283, Gordon and Breach Science Publishers (1989) Some physical methods of non destructive examination are sensitive to the chemical environment and can therefore be used to probe molecular and chemical properties of materials. The examples given include Nuclear Magnetic Resonance (NMR) imaging and spectroscopy, (ESR) imaging, Compton scattering, and materials analysis using muonic and pionic X-rays.
Albugues, F. Nondestructive tests structures
41585
and
high
performance
composite
Societe Nationale Industrielle Aerospatiale, Saint-Medard-en-Jalles (France), N88-28969/9/GAR, 17pp (1988) The most efficient nondestructive test methods applicable to high performance carbon or kevlar reinforced plastics are reviewed including the hard X or gamma radiation methods such as X-ray tomography, neutron photography and Compton scattered diffusion, holographic methods, acoustic emission methods, and microwaves. The examples show that each method has a definite area of application.
Lillicrap,S.C. Coherent/Compton scattering for in-vivo tissue measurement
41480
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. 61-65 (1989) The measured ratio of coherent scattering to Compton scattering depends on the elemental composition of the scatterer for a given incident photon energy and angle of scatter, Measurements have been made on a range of tissues and tissue substitutes to determine the sensitivity of the technique in differentiating between tissues. Clear differences are predicted between fat, muscle, trabecular bone and cortical bone, although the measured amounts are somewhat less.
Harding, G.; Kosanetzky, J. X-ray scatter imaging in non.destructive testing
41454
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. 1-15 (1989) X-ray scatter radiation may conveniently be used for imaging purposes in non-destructive testing (NDT). The feasibility of both Compton and Rayleigh scatter imaging has been successfully demonstrated: the former i n the aerospace industry for back-scatter analysis of near-surface defects, the latter for investigating the diffraction properties of arbitrary volume elements (voxels) of medical and industrial objects. Compton and Rayleigh scatter imaging devices are described, and representative scatter images drawn from various fields of NDT are presented.
Bridge,B.; Harirchian, F.; Imrie, D.C.; Mehrabi, Y.; Meragi, A.R. Compton scatter imaging: corrosion, thickness monitoring and void detection
41452
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. 17-39 (1989) An overview is presented of the research programme on Compton scatter imaging at Brunel University carried out with the use of 1.5 mCi Ba-133 and 10 Ci Co-60 gamma sources. Effective methods of radiological imaging were established for the underwater non-destructive inspection of thick structural sections, of offshore oil production platforms. The problems associated with the design of imaging systems sufficiently mobile and robust for subsea usage are discussed. Typical results for the detection of inner wall corrosion pits and wall thickness measurements are given. The performance of the technique in detecting voids is insensitive to material density. Thus the measurement time required to achieve a specified detection probability for a given void size, is almost the same in polyethylene, as in steel.