JOURNAL PAPER

Neutron and X-ray tomography at Necsa

F.C. de Beer

Necsa (South African Nuclear Energy Corporation Ltd)

SYNOPSIS

The utilization of computer assisted tomography (CT or CAT-scan) as general non-destructive examination (NDE) technique and as research tool for scientists in South Africa, is limited due to the relative unavailability or nonexistence of such specialized analytical equipment. Many medical hospitals are equipped with X-ray CT scanners for the diagnostic examination of patients but do not easily allow paleontologist or other scientist to utilize their very expensive equipment.
As from 2003, Necsa hosts the South African Neutron Radiography (SANRAD) and tomography facility where neutrons from the SAFARI-1 nuclear research reactor and their penetrating power as well as X-rays as a complementing tool, are utilized in many R&D applications. This facility is being made available to HEI and specifically utilized by postgraduate students as part of their studies and/or by industry on an ad hoc commercial basis.
The capability of these radiation imaging facilities at Necsa will be demonstrated in areas such as paleontology, geosciences and specifically the physical properties of rock and the distribution of minerals in borehole cores, petrophysics to predict the percentage tar/oil/water content within sandstone samples and others.
The penetration capability of neutrons through specimens with a matrix of high atomic number (dense materials) and their ability to be attenuated by low atomic number material (light density) makes neutron imaging complementary to X-ray imaging. The capability of X-ray and gamma radiation for relatively easy penetration through specimens of low atomic number allows for viewing of imbedded high atomic number materials and density variation. X-ray micro focus radiography is capable of resolving objects of micro scale size that are micro distances apart whereas Xray phase contrast radiography utilizes the wave properties of the electromagnetic spectrum of X-rays to clearly define edges of the specimen under investigation.
Many applications with neutrons as imaging probe are successfully applied at several facilities across the globe such as at NIST in USA, Neutra at PSI in Switzerland, and ANTARES at FRM2 in Germany, etc, are documented4-9, through world conferences on neutron radiography, for example. This is achieved through very well thought through and implemented instrumentation from the production of neutrons to their detection and interpretation of the images. The need arose at Necsa to upgrade the current facility from 42-year-old technology, which was successfully applied in neutron imaging over the past 10 years, to state-of-the-art technology found at European facilities. This initiative started under the auspices of an IAEA-TC programme for the period 2007-2010.

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References

1. BAYON, G., DOMANUS, J. C., GREIM, L., HARMS, A.A., LEEFLANG, H.P., MARKGRAF, J.F.W., MATFIELD, R. and TAYLOR, D.J. Practical Neutron Radiography. Domanus, J. C. (ed.). Kluwer Academic Publishers, Dordrecht/Boston/London, 1992. p. 1-6.         [ Links ]

2. VLASSENBROECK, J., DIERICK, M., MASSCHAELE, B., CNUDDE, V., VAN HOOREBEKE, L. and JACOBS, P. Software tools for quantification of X-ray microtomography. Nucl. Instr. Meth. Phys. Res, Accelerators Spectrometers Detectors and Associated Equipment. A580, 2007, pp. 442-445. DOI: 10.1016/j.nima.2007.05.073        [ Links ]

3. 3D volume rendering software VGStudio by Volume Graphics, Heidelberg, Germany. (http://www.volumegraphics.com).         [ Links ]

4. BARTON, J.P. and VON DER HARDT, P. Neutron Radiography, (Proceedings of the First World Conference, San Diego, Califonia, U.S.A. Barton, D. Reidel Publishing Company, Dordrecht/Boston/ London. 1983.         [ Links ]

5. BARTON, J.P., FARNY, G., PERSON, J. and ROTTGER, H. Neutron Radiography, (Proceedings of the Second World Conference, Paris, France. D. Reidel Publishing Company, Dordrecht/Boston/Lancaster/Tokyo. 1987.         [ Links ]

6. FUJINE, S., KANDA, K., MATSUMOTO, G. and BARTON, J.P. Neutron Radiography, (Proceedings of the Third World Conference, Osaka, Japan. Kluwer Academic Publishers, Dordrecht/Boston/London. 1990.         [ Links ]

7. BARTON, J.P. Neutron Radiography, (Proceedings of the Fourth World Conference, San Francisco, California, USA. Barton. Gordon and Breach Science Publishers, USA/Switzerland/Australia/Belgium/France/Germany/Great Britain/India/Japan/Malaysia/Netherlands/Russia/Singapore.         [ Links ]

8. FUJINE, S., KOBAYASHI, H. and KANDA, K. Neutron Radiography, Proceedings of the Sixth World Conference, Osaka, Japan. Gordon and Breach Science Publishers, Luxemburg/Switzerland/Australia Canada/France/Germany/India/Japan/Malaysia/Netherlands/Russia/Singapore. 2001.         [ Links ]

9. CHIRCO, P. and ROSA, R. Neutron Radiography, (Proceedings of the Seventh World Conference, Rome, Italy. ENEA, Italian National Agency for New Technologies, Energy and the Environment. 2005.         [ Links ]

10. DE BEER, F. C. Characteristics of the neutron /X-ray tomography system at the SANRAD facility in South Africa. Nucl. Instr. Meth. Phys. Res. A 542 2005, pp. 1-8.         [ Links ]

11. http://www.andortech.com/.         [ Links ]

12. RIVERS, M. An IDL based tomography reconstruction package. (http://cars9.uchicago.edu/software/tomography.html).         [ Links ]

13. Media Cybernetics, Image-Pro Plus. (http://www.mediacy.com).         [ Links ]

14. http://www.appscintech.com/.         [ Links ]