Speaker
Description
The CTBTO’s International Data Centre (IDC) collects, processes and analyses data originating from the facilities of the CTBTO’s International Monitoring System (IMS), which uses four complementary verification methods (including radionuclide) to detect nuclear explosions. Radionuclide technique is the last step to validate whether a nuclear explosion has been carried out. Data from the 73 currently operational radionuclide particulate IMS stations consist of a daily gamma ray spectrum from each station. They are sent to the IDC, where they undergo an automated analysis process. After this, the IDC radionuclide analysts refine the results during an interactive review process resulting in Reviewed Radionuclide Reports (RRRs). Several natural radionuclides, such as Pb-212 and progeny, Bi-214, Ac-228 and Pa-234m, and those induced by neutron interactions with components of the detector shielding and the detector itself, may interfere with the detection, peak identification and quantification of CTBT relevant radionuclides such as Zn-65, Zr-95/Nb-95, Tc-99m, I-131, Cs-134, Ba-140/La-140 (among other CTBT-relevant radionuclides). This work looks at the peak identification issues and explains what methods the IDC radionuclide analysts are applying to address these issues. It also includes lessons learned from the re-measurements of a selection of collected samples at the CTBTO radionuclide laboratories and follow-up investigations.
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