Measurements of 79Se with AMS based on extracting molecular negative ions
- Received Date: 2008-07-17
- Accepted Date: 1900-01-01
- Available Online: 2008-01-03
Abstract: A new method for measuring selenium-79 with AMS, which is based on extracting molecular negative ions, is described in this paper. According to the experimental results, the extraction ion form SeO2－ could depress the interference of Bromine-79 as much as 5 order levels, that is to say, the background of 79Br can be deducted to 79Br/Se≈10－10. By the way, the chemical form of sample and preparation flow was also developed. Finally, three 79Se AMS calibration standard samples with theoretical 79Se/Se ratios of 5.06×10－7, 6.87×10－8, 5.40×10－10 were obtained and the method of 79Se measurement was set up, which actualized transmission and detection of 79Se. By using our Bragg curve detector, the two isobars 79Br and 79Se could be partly identified to a certain extent and 79Se can be identified from 79Br about 1 order level. AMS measurements of the three calibration standard samples above were performed and good linearity was obtained. The sensitivity of the measurement is (5.16±1.80)×10－11.