Nuclear activation analysis method is used in determining element concentration in the wide range of materials. The method relies mainly on neutron excitation because the sample treated produces gamma rays and thus allowing the precise quantification and identification of the trace elements and any other elements contained in the sample (Parry, 2003).
(NAA) has significant chemistry applications in addition to other fields of research such as archeology, medicine, geology, forensic science and environmental monitoring. (NAA) The method mainly relies on activating neutrons and. Therefore, a neutrons source is required for the bombardment of the sample with neutrons leads to the formation of radioactive isotopes (Smodiš, 2015). The radioactive plus radioactive decay emissions for every element are widely known. The availability of this information makes it possible to the study the spectra emitted by the sample and determination of elements concentration within it. The technique has the advantage of not destroying the samples and therefore, it is used in analysis of historical artifacts and work of arts
Neutron activation analysis has advantages and disadvantages. Using it, one can analyze a large number of elements simultaneously, only a small sample size is required to do the analysis (1-200mg), the method has a very low limit for detecting many elements and finally, this is a non-destructive method, and therefore, the samples can be analyzed for other properties. On the other hand, a nuclear reactor is needed to perform the analysis making the method expensive. The method requires working with hazardous radioactive materials and hence the need for disposal of the radioactive waste, personnel dose regulation and radioactive protection. There is Limited feasibility for determination of some trace toxicological elements like lead since they don’t result in the formation of radionuclides having suitable properties, and finally, the Analysis time might be long enough for elements that produce radionuclides that live longer.
INAA method application in agriculture involves tracking pesticides and fertilizer distribution inside the soil samples. This distribution is determined by the surface and subsurface movement as it infiltrates the water supplies. In tracking pesticides and fertilizer distribution, bromide ions are used as tracers they freely move with the water flow with minimal interaction to the soil. In geology soils, samples may be analyzed using this method to help in tracking certain elements and locating ore deposits (Sparks, 1996).
In this experiment, a soil sample will be subjected to neutron flux leading to the production of radioactive nuclides. The radioactive nuclides will decay leading to the emission of gamma rays with energy characteristics of each nuclide. The gamma rays intensity will be compared to those emitted by standard elements allowing measurement of various nuclides concentration.
References
Database of prompt gamma rays from slow neutron capture for elemental analysis. (2007). Vienna: International Atomic Energy Agency.
Parry, S. J. (2003). Handbook of neutron activation analysis. Woking: Viridian Publishing.
Smodiš, B. (2015). Radiochemistry for neutron activation analysis: Joint ICTP - IAEA Workshop on nuclear data for neutron dosimetry and analytical methods by applying research reactors, 20 - 24 April 2015, ICTP - Miramare, Trieste. Trieste: IAEA.
Sparks, D. L. (1996). Methods of soil analysis. Madison, WI: Soil Science Society of America.
