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In Cambodia, artisanal mining has recently come to a social concern because of the possibility to cause environmental degradation and human health problems. The General Department of Mineral Resources of Cambodia is collecting environmental specimens in mining sites to watch the situation. This time, four water samples from Sampov Loon and one from Memong mining site were sent from the Department to Hiroshima University, Japan, and the samples were analyzed by means of PIXE at the University. A volume of 10 μl from each sample was separated and dropped onto 4 μm polypropylene backing foil. The measurement was carried out by using 2.5 MV single-ended Van de Graaff accelerator. A Si(Li) detector (active area, 80mm²; sensitive depth, 5mm; Be-window's thickness, 25 μm; resolution, 167 eV fwhm at 5.9 keV) was used for both of in vacuo PIXE and non-vacuum external beam PIXE measurement. A computer code PIXS was used for the quantification. The result indicates that there are at least two kinds of water in Sampov Loon and one of them possibly represents polluted condition.

About 40 subjects of PIXE have been studied in various research fields at Nishina Memorial Cyclotron Center (NMCC), and many satisfactory results have been obtained and reported. As the results, samples to be analyzed are highly diversified both in form and in elemental composition. Among them, samples most hard to be dealt with by PIXE are ones which contain a great quantity of specific elements. In order to solve this problem, we have developed and tried various absorbers which are specially designed for each kind of sample and are capable of decreasing some distinguished x-ray peak and making x-ray spectra gentle-sloping. It is found that not only the measuring time is fairly shortened but also highly sensitive and highly accurate analysis can be performed for each sample only by selecting absorbers.