The elemental analysis of biological and environmental materials using a 2MeV proton beam.

A summary of the fundamental principles which form the basis of proton induced X-ray emission (PIXE) analysis, proton induced gamma-ray emission (PIGE) analysis, Rutherford backscattering spectrometry (RBS) and instrumental neutron activation analysis (INAA) has been given which is followed by a brief description of the experimental facilities used in this work and their characterization. Knowledge of optimum experimental conditions is always helpful, therefore a programme has been developed to simulate the PIXE spectra and its uses have been described. Reference materials with certified elemental concentrations play an important role in ensuring the accuracy of the elemental analysis work. The FIXE technique has been applied to the analysis of new biological reference materials which consist of IAEA human diet samples and NIST leaf samples, to be introduced in the future. Homogeneity of these and two existing reference materials that is, IAEA soil-7 and Bowen's kale has also been determined at the mug scale. A subsample representative of a material is ascertained by determination of sampling factors for the elements detected in the material. Use of PIXE has been established in experimentally obtaining sampling factors for the above mentioned materials. PIGE analysis in conjunction with PIXE has been employed to investigate F and other elemental concentrations found in human teeth samples. The mean F concentration in enamel and dentine parts of teeth followed an age dependent model. The lowest F concentrations were observed in two out of three careous teeth. Concentrations of Ca and P were found to be higher in the enamel than in the dentine in all the teeth analyzed. Analysis of blood and its components in the study of elemental models in sickle cell disease in Nigerians has been carried out. A total of eight elements were detected. Comparision was made between controls and diseased groups which revealed that Cl, Ca and Cu were at significantly higher levels whereas K, Fe, Zn and Rb were at significantly lower levels in the whole blood of the sicklers as compared to the controls. Similar results were obtained for the erythrocytes except that Br was also found at significantly higher concentration in erythrocytes of the sicklers. Significantly higher concentrations of Cl, K, Fe and Cu were also observed in plasma of the sicklers as compared to that of the controls. Elemental status of the normal controls was found to be comparable to that of the Uzbekistanians (USSR) and North Americans but was better than that of the Bangladeshi population. PIXE and scanning electron microscopy (SEM) was used in the characterization of the Harmattan dust particulates collected at Kano and Ife, two cities of Nigeria. Most of the elements were found to be at higher concentrations as compared to those found in Recife (Brazil) and Toronto (Canada). The value of total suspended particulate matter (TSPM) at both collection sites was also above the relevant national (USA) air quality standards. FIXE in conjunction with RBS and INAA was employed in the analysis of soil samples taken at various depths from within and around two cement factories in Nigeria thereby detecting 31 elements. The results have been discussed with reference to elemental concentrations and Ca/Si ratio. The latter was found to offer a valid indicator of soil pollution by the cement dust