The main objective of this website is to make available scientific articles written by  Eduardo J. C. Martinho, José F. Salgado and Isabel Maria F. Gonçalves, from the Instituto Tecnológico e Nuclear, Sacavém, Portugal.

The research, published between 2001 and 2004, was about a relevant phenomenon in nuclear reactors and neutron physics called neutron self-shielding, which comprises resonance neutron self-shielding (Gres) and thermal neutron self-shielding (Gth). The practical importance of our work resides in the final conclusion that the phenomenon can be quantified by a universal law of Gres and Gth for foils, wires, spheres and cylinders.

BLOG Gráfico 03 Neutron flux profile resulting from the self-shielding effect in a sample

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The innovation of our final results has been summarized by a Canadian team* as follows:

«(…) Historically, the calculation of Gth and Gep [or Gres] was extremely difficult, and it was recommen­ded to dilute the samples to avoid self-shielding. Fortunately, reactor physicists recently showed that the amount of epithermal as well as thermal self-shielding could be expressed by the same analytical function, a sigmoid, for all nuclides [2–4]**. (…)»

* C. Chilian, R. Chambon, G. Kennedy: Neutron self-shielding with k0NAA irradiations. Nuclear Instruments and Methods in Physics Research A 622 (2) (2010) 429-432].


[2] E. Martinho, I.F. Gonçalves, J. Salgado, Universal curve of epithermal neutron resonance self-shielding factors in foils, wires and spheres. Applied Radiation and Isotopes 58(3) (2003) 371-375;

[3] I.F. Gonçalves, E. Martinho, J. Salgado, Extension to cylindrical samples of the universal curve of resonance neutron self-shielding factors. Nuclear Instruments and Methods in Physics Research B 213 (2004) 186-188;

[4] E. Martinho, J. Salgado, I.F. Gonçalves, Universal curve of thermal neutron self-shielding factors in foils, wires, spheres and cylinders. Journal of Radioanalytical and Nuclear Chemistry 261 (3) (2004) 637-643.

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Scientists from several countries [Algeria, Argentina, Australia, Austria, Bangladesh, Belgium, Brazil, Bulgaria, Canada, Chile, China, Cuba, Denmark, Egypt, France, Germany, Greece, Hungary, India, Indonesia, Iran, Italy, Japan, Kazakhstan, Malaysia, Mexico, Pakistan, Peru, Portugal, Romania, Slovenia, South Korea, Switzerland, Taiwan, The Netherlands, Turkey, United Kingdom, United States of America, Uzbekistan and Vietnam] and international institutions [Joint Research Centre/EU (Geel, Petten, Ispra) and International Atomic Energy Agency (Vienna)] are using our results in works related to various­ domains, namely reactor neutron metrology, determination of nuclear parameters (thermal neutron cross-sections and resonance integrals), neutron activation analysis, production of radioisotopes for medical applications.


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CONTENTS: (in portuguese)

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