Xe quantification method development and intercomparison exercise.

Monitoring of the atmosphere for fission products (Xe, Xe, Xe, and Xe) is performed by various laboratories to detect nuclear explosions. Quantification of Xe is not routinely performed by laboratories measuring atmospheric radioxenon because it is not a fission product. Xe was recently detected by a ground-based beta-gamma air monitoring system.

Deployment of portable, modular gas samplers as part of an atmospheric tracer experiment.

Underground nuclear explosions release noble gases into the atmosphere that can be detected to support international monitoring efforts. Atmospheric transport models help predict the movement of these gases over long distances, but struggle to predict the movement in the atmosphere local to the release. A field experiment was designed to monitor the movement of Xe within a 5-km radius.

Detecting Xe in an atmospheric tracer experiment.

The Xcounts algorithm for calculating air concentrations of radioactive xenon isotopes (Eslinger et al., 2023) has been extended to estimate Xe in addition to Xe, Xe, Xe, and Xe. The algorithm was applied to 119 samples collected with a SAUNA Q system (Ringbom et al.

Determining the source of unusual xenon isotopes in samples.

Three unusual radioactive isotopes of xenon-Xe, Xe, and Xe-have been observed during testing of a new generation radioxenon measurement system at the manufacturing facility in Knoxville, Tennessee. These are possibly the first detections of these isotopes in environmental samples collected by automated radioxenon systems. Unfortunately, the new isotopes detected by the Xenon International sampler can interfere with quantification of the radioactive xenon isotopes used to monitor for nuclear explosions.

Trace explosive residue detection of HMX and RDX in post-detonation dust from an open-air environment.

Explosives are often used in industry, geology, mining, and other applications, but it is not always clear what remains after a detonation or the fate and transport of any residual material. The goal of this study was to determine to what extent intact molecules of high explosive (HE) compounds are detectable and quantifiable from post-detonation dust and particulates in a field experiment with varied topography. We focused on HMX (1,3,5,7-Tetranitro-1,3,5,7-tetrazocane), which is less studied in field detonation literature, as the primary explosive material and RDX (1,3,5-Trinitroperhydro-1,3,5-triazine) as the secondary material.

Shape changes of Pt nanoparticles induced by deposition on mesoporous silica.

Polyvinylpyrollidone (PVP)-capped platinum nanoparticles (NPs) are found to change shape from spherical to flat when deposited on mesoporous silica substrates (SBA-15). Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and extended X-ray absorption fine structure (EXAFS) analyses are used in these studies. The SAXS results indicate that, after deposition, the 2 nm NPs have an average gyration radius 22% larger than in solution, while the EXAFS measurements indicate a decrease in first neighbor co-ordination number from 9.