A method to concentrate heavy noble gases from the atmosphere using certain organic fluids is being developed. To use this technique in a system to monitor the atmosphere for important noble gas fission products (Xe-131, Xe-l3lm, Xe-133, Xe-l33m, and Xe-135) generated by nuclear testing, the radionuclides captured in the fluid must either be detected in the fluid or degassed. This study presents experimental results for a number of possible degassing methods, including heating bubbling with a purge gas, ultrasonic agitation, vacuum, and combinations thereof. Methods were evaluated for energy and time requirements and dilution of the degas product. Initial experiments indicate that in addition to overcoming the standard desorption process dictated by partial pressures per Henry's Law, a capture mechanism must also be overcome to degas. Some type of agitation, thermal or mechanical, can be used to release weakly trapped gas atoms from the fluid, while diffusional mass transfer can be enhanced through entrainment with a purge gas or use of a vacuum. Ultrasonic agitation of a thin film in a strong vacuum has been shown to be the most effective method of those tested. Implementation of an efficient degas system, along with an absorption system and radioxenon detector could result in an ultrasensitive fluidbased radioxenon measurement system that is more portable, less expensive, and simpler than charcoal-based systems which use cryogenic techniques.Keywords: xenon, noble gas, radioxenon, radionuclide
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OBJECTIVE
IWhen nuclear weapons are tested underground, radioxenon is one of a few fission products released into the atmosphere that can be detected outside the immediate vicinity of the test. The detection and measurement of elevated levels of ambient radioxenon in the atmosphere can provide corroborative evidence to positively confirm a nuclear detonation or even detect an explosion when other methods are inconclusive. However, the radiation signature of ambient radioxenon cannot typically be dis...
