Automated separation and measurement of radioxenon for the Comprehensive Test Ban Treaty

Abstract

A fully automatic radioxenon sampler/analyzer (ARSA) has been developed and demonstrated for the collection and quantitative measurement of the four xenon radionuclides, 13hnXe(11.9 d), 133mXe(2.2 d), 133Xe(5.2 d), and 135Xe(9.1 hr), in the atmosphere. These radionuclides are important signatures in monitoring for compliance to a Comprehensive Test Ban Treaty (CTBT). Activity ratios of these radionuclides permit source attribution. Xenon, continuously and automatically separated from the atmosphere, is automatically analyzed by electron-photon coincidence spectrometry providing a lower limit of detection of about 100 ~tBq/m 3. The demonstrated detection limit is about 100 times better than achievable with reported laboratory-based procedures for the short-time collection intervals of interest.

Machine learning for radioxenon event classification for the Comprehensive Nuclear-Test-Ban Treaty

“…Namely, the bottom left rectangular area has been classified as background by the decision tree, whereas the rest of the graph has been classified as background plus explosion. With this method there are 7 data points which the decision tree has misclassified as B þ E. The dashed line shows the results of a simple ratio of 135 Xe/ 133 Xe of 0.4 (Bowyer et al, 1998), where everything greater than 0.4 would be classified as B þ E and everything less than 0.4 is B. Clearly there are many B þ E data points on both sides of the line and this single ratio classifier fails.…”

Methodology for using prompt gamma activation analysis to measure the binary diffusion coefficient of a gas in a porous medium

“…The ratios of noble gas isotopes are commonly used to screen for underground nuclear tests and the subsurface movement of these anthropogenic radionuclides is important for the detection of belowground nuclear tests [3][4][5][6][7][8]. The detection of anthropogenic noble gas isotopes at ground surface can also be used as an indicator of contamination from buried radioactive materials [9].…”

The АРИКС-01 Automatic Facility for Measuring Concentrations of Radioactive Xenon Isotopes in the Atmosphere

“…The monitoring facilities are now being prepared by Russian, French, Swedish, and American experts [9][10][11]. Four versions of a system for automatically measuring concentrations of Xe isotopes in the air have been produced through their efforts.…”