An efficient method for purifying noble gases using high frequency electric field discharges

Raw krypton and xenon gases obtained from the distillation of air contain impurities such as CF4 and CH4 which preclude their use in many applications. These impurities can be abated by having the gas circulating through a microwave-sustained electric discharge. The use of this technique for production proves to be beneficial in terms of energy consumption, reduction of gas losses, easiness and safety of operation. Plasma purification is therefore an useful extension of the range of available technologies for the design of high performance pure krypton/xenon production plants. It further demonstrates the feasibility and interest of achieving selective chemistry in a plasma that is nor in thermodynamic equilibrium. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.