Patent ID: 7434580
Filing Date: 2008-10-14
Classification: G01N

Abstract:
1. A method of monitoring concentration of xenon in a medical gas mixture recirculating through a medical device in which carbon dioxide is introduced into the mixture resulting in a carbon dioxide-contaminated gas mixture, said medical gas having xenon as an active component and being selected from oxygen-containing mixtures consisting of oxygen and xenon and mixtures of xenon with a composition consisting of oxygen and nitrogen and/or helium in known proportions, said method comprising removing carbon dioxide from said carbon dioxide-contaminated gas mixture downstream of the medical device to provide a carbon dioxide-free gas mixture and subsequently upstream of the medical device the concentration of xenon is measured by measuring a time delay between transmission of an ultrahigh ultrasonic pulse of at least 100 kHz axially through the carbon dioxide-free gas mixture in an internally reflective cylindrical sample chamber from a location at one end thereof and reflection of said pulse axially from the other end of the chamber back to said location.