I-129 level in seawater near a nuclear power plant determined by accelerator mass spectrometer

(129)I concentration in the seawater samples near a nuclear power plant was determined in the Xi&#39;an Accelerator Mass Spectrometer (AMS) Center. Isotope dilution method was used via addition of excessive amount of stable iodine ((127)I) in the sample before separation, and iodine in the seawater was separated by solvent extraction, and the back extracted iodine in iodide form was precipitated as Agl, which was used as AMS target for (129)I measurement. (125)I tracer was added to monitor the recovery of iodine in the whole separation process. (129)I/(127)I ratios in the prepared target were determined by AMS. The concentration of (127)I in seawater samples was determined by inductively coupled plasma mass spectrometry. The results show that the (129)I/(127)I atomic ratios in the seawater range from 8.29 x 10(-11) to 9.45 x 10(-10), approximately one order of magnitude higher than that in seaweed collected in the pre-nuclear era, but fall in the environmental level of global fallout.</p

A preliminary study of small-mass radiocarbon samplemeasurement at Xi’an-AMS

To meet the measurement demands on small-mass radiocarbon (carbon content at 10&minus;6 g level) which are becoming increasingly significant, Xi&rsquo;an-AMS has made improvements to the existing method of sample loading and has upgraded the Cs sputter ion source from the original SO-110 model. In order to study the feasibility of small-mass samples in Xi&rsquo;an-AMS and evaluate the radiocarbon sample preparation ability using existing routine systems of H2/Fe and Zn/Fe, the small-mass samples prepared by four different methods are tested. They are the mass division method, mass dilution method, H2/Fe reduction method and Zn/Fe reduction method. The results show that carbon mass above 25 &micro;g can be prepared using the existing Zn/Fe system, but no less than 100 &micro;g is required using the existing H2/Fe system, which can be improved. This indicates Xi&rsquo;an-AMS are now able to analyze small-mass radiocarbon samples.</p