Yankuang ceshi (May 2013)
Joint and Rapid Determination of 210Pb-210Bi-210Po in Rock, Soil and Sediment Samples by Constant Temperature Spontaneous Deposition on Cu-foil with Gross α and Gross β Counting
Abstract
Measurement techniques of uranium series nuclides 210Pb, 210Bi and 210Po are relatively independent at present for most cases, and there are still some technical issues that need to be overcome. Joint measurement techniques of these nuclides reported in the literature require expensive testing apparatus and radioactive tracers, or the capacity of resisting disturbance of the deposition conditions is relatively weak and the test period is relatively long. The study conducted of the optimum spontaneous deposition conditions of 210Bi and 210Po on Cu simultaneously and quantitatively is reported in this paper, and the establishment of a new joint measurement technique of 210Pb, 210Bi and 210Po in rock, soil and sediment samples. It was found that 210Bi and 210Po were deposited on Cu foil simultaneously, while 210Pb was not deposited on a 3.14 cm2 Cu foil under the conditions of 0.5 mol/L HCl, 3.5 mol/L NaCl in the total 20 mL solution at 90℃, with a vibration frequency of 120 r/min and vibration amplitude of 20 mm for 70 min. Due to the presence of ascorbic acid, lots of coexisting elements have no interference with target nuclides. The precision of this testing technology was higher than 5% and total recovery rates were 99.5%-100.5%. This new measurement technique has a strong capacity to resist Bi disturbance, the recovery rate is more constant than traditional methods and the test period is short with one set of home-made testing apparatus and no radioactive tracers required. Moreover, this measurement technique is also suitable for the determination of one of these three nuclides separately.
