Xenon volume measurement is essential for radionuclide verification. Xenon measured by thermal conductivity detector (TCD) was studied. The injection method for gas chromatography analysis was investigated in view of the specifications of the xenon archive samples from IMS stations noble gas equipments. The reference process for xenon volume analyzing and its uncertainty evaluation method were established. Xenon volume analyzed result and its uncertainty evaluation were exemplified by an international noble gas experiment (INGE) sample. The result shows that the standard relative uncertainty of the xenon volume is 1.96%.

The compton-suppression Spectrometer can suppress the Compton baseline and make weak full energy peaks prominent in low-level activity gamma spectra, so it is used to measure environmental radioactive samples. In order to quantify the activities of the radionuclides in the sample coincidence-summing corrections should be applied. In this article the expressions of coincidence-summing correction of Compton-Suppression Spectrometer were deduced and the validity of the expressions was verified.

The β-γ coincidence technique is a kind of important method to detect radioactive xenon isotopes for the Comprehensive Nuclear-Test-Ban Treaty(CTBT).The energy and resolution calibration of detectors is the first key technique.This paper describes in detail the energy and resolution calibration methods of NaI(Tl)and plastic scintillator detectors for the noble gas β-γ coincidence system SAUNAⅡ-Lab.NaI(Tl) detector’s energy and resolution for γ-ray were calibrated with γ radioactive point sources.Plastic scintillator detector’s energy and resolution for β-ray were calibrated by Compton scattering electrons of 137 Cs 661.66keV γ-ray.And the results of β-ray energy resolution calibrated by Compton scattering electrons of 137Cs were compared with the results of conversion electron of 131 Xem.In conclusion,it is an easy and feasible method of calibrating plastic scintillator detector’s energy by Compton scattering electrons of 137Cs,but detector’s resolution calibrated by Compton scattering electrons is higher than factual result.

A Compton-suppress spectrometer was introduced and its performance was tested.The measurement geometry position of Φ20mm plate source,Φ50mm and Φ70mm filter source were optimized.

The β-γ coincidence technique is a kind of the key important method to detect radioactive xenon isotopes for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). This paper describes noble gases memory effects of β-γ coincidence detector. Xenon memory effects were measured and its influence on detector’s minimum detectable activity (MDA) was evaluated. The methods of reducing xenon memory effects were studied. In conclusion, aluminium coated plastic scintillator and YAP scintillator can remarkably decrease xenon memory effects.

Monitoring radioactive Xenon concentration in air is effective way to screen nuclear event in CTBT verification regime. This article introduces the theory and process of radioactive Xenon measurement by HPGe gamma spectrometer and researches MDA trend of Xenon isotope base on background data. (authors)

In this paper,the several analysis software for gamma-ray spectra,including IDC radionuclide monitoring data processing system,Aatami software and Shaman expert system,were evaluated using the artificial spectra data of the First System-wide Performance Test(SPT1) organized by CTBTO.The results showed that Aatami software has the best capability to identify small peak in samples,and Shaman expert system has the best capability of radionuclide identification.

This paper introduces the method of dating the zero time by utilizing the activity ratio of two fission products in no-isobaric or parent-daughter fission products in isobaric. The method was applied to determine the zero time of filter sample in the CTBT radionuclide laboratories intercomparison from 2001 to 2004. The calculated results are in very good agreement with referent values in the range of uncertainty.