Non-destructive Nuclear Method Research Articles

Multipurpose ion beam analysis chamber for fusion material science applications

In the fusion industry, there is a need for the development of new steel alloys, which could fulfil the requirements that are, in some cases, very much different from those of other fields of industry. High temperature and radiation levels alone are reasons why the currently available alloys could hardly be used in certain areas of a (e.g.) tokamak. In future fusion devices the utilization of novel steel compounds, such as Oxide Dispersion-Strengthened (ODS) alloys or reduced activation steels, would have considerable advantages over conventional steels. Diffusion bonding of ODS steels is a focus-area of nowadays research. The quality of the bonds can be investigated with non-destructive nuclear methods, such as RBS, PIXE and PIGE.The Centre for Energy Research has developed an ion beam analysis chamber, which provides the possibility to perform multiple nuclear measurements simultaneously on small-sized samples.This paper outlines the design driver considerations and an overview of the design is also given.

Comparison of neutron activation analysis techniques for the determination of uranium concentrations in geological and environmental materials

We have described the determination of uranium in environmental, geological, and agricultural specimens by three different non-destructive nuclear methods. The effectiveness, as defined as the lower limits of detection in this work, of quantifying trace levels of bulk uranium in geological samples was evaluated for several common NAA techniques. These techniques include short-lived and medium-lived neutron activation analysis using thermal and epithermal neutrons; these results were compared with an assessment of Compton suppressed gamma-ray counting. A careful evaluation of three major (n,γ) reactions with chlorine, manganese and sodium that could impede determining low levels of uranium due to high Compton continuums was done. The evaluation of Compton suppressed passive gamma counting revealed that uranium concentrations below 50 mg kg−1 were not adequate to achieve good counting statistics using the 234mPa the second daughter product of 238U.

Radioactive trace measurements of some exported foods from the South of Brazil

Investigation of radioactive traces in foods produced and exported mainly in Paraná State, Brazil, was carried out by gamma-ray spectrometry, a non-destructive nuclear method. The redistribution of 40K concentration during the processing of soy ( Glycine max) primary products (745±9 Bq kg −1 for soybean, 1473±15 Bq kg −1 for soy bran, and ⩽8.8 Bq kg −1 for commercial refined soy oil) was verified. The 40K activity for all oil stages analyzed was lower than the limits of detection. Others foods such as sulfite-treated sugar, mate tea, and mint were analyzed. The activities for the natural nuclear chain ( 228Th and 226Ra) and the 137Cs (artificial radionuclide) were presented.

Non-destructive analysis of archaeological bronzes by nuclear techniques

This paper studies a method for overcoming the difficulty of corroded surfaces by means of nondestructive nuclear methods in the determination of the composition of archaeological bronzes. It consists of the combination of PIXE or XRF information with Gamma Ray Transmission (GRT) data. A wide range applicability of this combined method is established by comparison with profiles of concentrations along the bronzes' patina obtained by SEM-EDAX.

A non-destructive nuclear method for the determination of nitrogen in solids

The nitrogen concentration in diamonds and in SiC was determined by charged particle activation analysis. The activation reaction used was 14N (α, n) 17F, the decay proceeding with the following characteristics: 17 F → 17 O + β + + ν (τ 1 2 = 66 sec) . The annihilation radiation was detected. Nitrogen concentrations between ∼5 ppm and ∼2000 ppm were found in the samples.

Assessment of neutron capture γ-ray analysis

Analysis by the measurement of thermal neutron capture gamma rays is described, and the technique compared with other non-destructive nuclear methods for the elements of interest. The accuracy attainable in the analysis of practical samples has been examined and shown to be strongly dependent on the extent of matrix interferences. In favourable cases an accuracy of ±1% is attainable. The sensitivity of the technique is limited by the neutron absorption cross section of the element of interest. With the apparatus described boron and rare earths can be determined in trace quantities, whilst hydrogen can only be determined in the percentage range.