International Journal of PIXE

Thick targets consisting in Al/Si alloys were bombarded with 1.0 to 5.0 MeV Ar ions. The K X-ray production cross sections were deduced from the measured yields by using the Merzbacher-Lewis formula extended to heavy ion bombardment. The density dependence on the K X-ray production cross sections of Al and Si was observed. This phenomena can be interpreted within the molecular orbital double-scattering mechanism.

The study of single raindrops is expected to give new and great information such as drop formation processes and pollutant scavenging mechanisms. To investigate the characteristics of individual raindrops, PIXE method was applied to elemental analysis. Size-segregated individual raindrops were collected at Kyoto University during rain event in October 2001. Detection limit of each element for polycarbonate filter used as the substrate of raindrops was calculated. The significant peaks of several elements in single raindrop corresponding to the channel number of PIXE could be resolved. Chlorine, potassium, and sulphur were found as major elements in each size raindrop. Strong raindrop size-dependence of every elemental concentration was shown. Chlorine, chromium, potassium, and calcium show the distinctively high scavenging rate at the beginning rainfall. They show 98 %, 97 %, 96 %, and 84 % scavenging rate, respectively and followed by iron and sulphur.

The groundwater pollution by arsenic in Bangladesh causes a serious problem for millions of people who are exposed to poisoning by this toxic element. In an attempt to evaluate the extent of arsenic poisoning, hair samples of people living in Pabna district were collected. The hair samples were analyzed using Proton Induced X-ray Emission (PIXE) through exciting the atoms of a specimen so that their intensities can be converted into elemental concentrations in the specimen. The elements present in the specimen are identified by the corresponding X-ray energies and their concentrations are deduced from the X-ray intensities. The results from hair samples indicate substantially higher level of arsenic than those demarcated as toxic levels, in people from member families both affected and non-affected by poisoning. We correlate it with exceedingly high arsenic concentration in drinking water far above the permissible limit. The analytical results are compared with the results of arsenic and other elemental analysis of 160 Bangladeshi hair samples with that of 250 Japanese samples. The results show markedly higher levels of arsenic, manganese, iron and lead where the latter three elements show a positive relation with arsenic in the case of Bangladeshi as compared to the samples from Japan. On the other hand, selenium concentrations show very low level in the Bangladeshi samples compared to Japanese, displaying an inverse relationship with arsenic. The mechanism of arsenic in relation to other elements in the human body needs further investigation. The preliminary results call for detailed experimental and epidemiological studies to further characterize these aspects.

We studied the effects of aluminum on macro- and microelement concentrations in white roots of Chamaecyparis obtuse and Quercus serrata Thunb. through analysis by Particle Induced X-ray Emission (PIXE). One-year-old seedlings were exposed to various concentrations of Al for nine weeks. In both species, the Al and P concentrations increased as the Al concentration in the nutrient solution increased, but the concentrations of the divalent cations Mg, Zn, and Mn decreased in both species.

Fluctuations of the concentration levels of trace elements play an egregious role in enhancing carcinogenic effect in healthy persons and in the pathogenesis of oral malignancies. Epidemiological studies regarding the role of external carcinogenic agents in oral cancer have documented the involvement of certain trace elements either directly or indirectly. An analysis of trace elements like K, Ca, Fe, Cu, Zn, Se And Pb was done in seventeen oral cancer patients having tobacco habits by drawing their whole blood and determining their concentrations using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopic technique at Institute of Physics. Bhubaneswar, India which is rapid, efficient, multi-elemental and non-destructive in nature and in principle sensitive to all elements from Na to U. Fifteen healthy non-cancerous persons with tobacco habits were also taken as control. The results of the study group when compared with the control group illustrated that K, Cu and Se concentrations were significantly higher in the oral cancer patients as an effect of deleterious tobacco upon their blood whereas the rest of the elements like Ca, Zn, Fe and Pb did not reveal significant changes.

Elements like potassium, calcium, iron, zinc, copper, selenium and lead were analyzed in human blood samples collected from different cancer patients as well as some healthy persons applying Particle Induced X-ray Emission (PIXE) technique at the Institute of Physics, Bhubaneswar. The results obtained were compared and discussed with the reported literature values. Some blood elements were found varying significantly in cancer patients compared to those of their healthy counterparts, which could suggest that fluctuations in trace element profiles in whole blood possibly can be used as a diagnostic tool as well as a prognostic index in cancer.

A PIXE analysis was performed at Nishina Memorial Cyclotron Center (NMCC) for some leaf and ash samples from bottom of a waste pond at the Fankou Pb-Zn mine, Guangdong, China. The ash is the product after burning "Luzhu" that is planted by the mine for the environmental cleaning purpose in the waste pond. The PIXE detected high level of zinc and lead for both of the samples. As Fankou is one of the largest Pb-Zn producer in Asia, careful and urgent treatment is necessary for the deposited ash in the pond. This analysis was performed due to a request of analysis of the Fankou mine to promote environmental protection of the area.

Tailings from an indigenous mining community were analyzed by PIXE to study the residual amount of gold and to check the relative increase in mercury content after the mineral dressing. The result showed that gold is sometimes left in the tailings at ore-grade concentration up to 30 ppm, and that relative mercury content is not increasing drastically. Since the tailings are trade target in the local community, it would be necessary for stakeholders to have a common and fair facility where they can assay gold content of the tailing at regular interval.