Radioxenon net count calculations revisited

Abstract

Since 1998, there have been improvements in the capability to detect atmospheric radioxenon in the International Monitoring System operated by the Preparatory Commission of the Comprehensive Nuclear-Test-Ban Treaty Organization. The upgrades have resulted in next-generation versions of the radioxenon systems. This paper explores radioxenon data analysis improvements beyond the original radioxenon beta-gamma analysis equations that were formulated in 2000. Additionally, it provides recommendations to further improve analysis and refine the equations. The areas of improvement are described in terms of equations, physical detectors, and field-testing. These recommendations are provided with the intention of improving accuracy and precision of radioxenon measurements.

Method for calculating radon activity and radon rejection using a beta-gamma detector

“…where σ 0 is the uncertainty of the measurement from the sample, gas, and detector measurements, λ is the decay constant per isotope, V Air is the volume of air, and T is the time for collection (C), processing (P), and acquisition (A) [6]. The uncertainty equation used for this MDC calculation is…”

“…The longer-lived radon isotope, 222 Rn, will remain in the collected sample until rejected through the gas processing. The rejection of radon of the systems is generally greater than 10 5 [6]. The amount of any isotope of radon can vary drastically by location due to emanation factors from the soil type, climate, and containment in man-made structures [5,[7][8][9].…”

“…The prevailing nuclear measurement technique for radioxenon uses a coincidence measurement of the beta-gamma signature from the isotopic decay to identify the isotope and activity. The concentration and activity are calculated using the net-count method [6,10,11]. The primary sources of interfering backgrounds in the measurement are the radon daughters 214 Pb and 214 Bi, which decay via β − decay.…”