10.
Summary The paper presents a procedure to prepare soil samples for U and Th isotope measurement by alpha-spectrometry after coprecipitation
with LaF
3. In this procedure the reduction of U(VI) to U(IV) was performed by Zn metal in 4M HCl solution. The recoveries of chemical
separation equal to
eU-chemistry = 78±4% for uranium and
eTh-chemistry = 82±4% for thorium. Canberra alpha-spectrometer was used with PIPS detectors of A-1200-37-AM Model of 1200 mm
2 active area. The counting efficiency of the measuring system equals to
ecounting = 18% and the total efficiencies were
eU =
ecounting .e
U-chemistry = 14.0±0.7% for uranium and
eTh =
ecounting .e
Th-chemistry = 14.7±0.7% for thorium. The recoveries of chemical separation were rather high (about 80%), that leads to the use of a small
weight of soil sample (about 0.5 g). The efficiencies were also stable, that allows analyzing the soil sample without using
radiotracers. They are advantages of the sample preparation procedure of this work.
相似文献