Purification System for Large Quantities of Noble Gas

75526-Large quantities of highly purified liquid noble gases (noble liquids) will be required in several upcoming non-accelerator, Nuclear Physics experiments aimed at rare particle searches and studies of rare interactions. These studies include: XENON, a search for cold dark matter using up to 1 ton of xenon; EXO, a search for neutrinoless double beta-decay, using up to 10 tons of xenon; CLEAN, a solar or supernova neutrino detector, based on a 6-in diameter, liquid neon scintillator; and an investigation at the Lawrence Livermore Laboratory to study antineutrino coherent scattering, which will employ 10 kg of argon as the active medium. Detectors intended for the study of these rare phenomena require ionization electrons to drift meter-long distances through the noble liquids. This project will develop a highly efficient, noble liquid purification device, which will employ a spark discharge purifier combined with a purity control monitor, and which will not contaminate nor activate the working medium. The purification device must be able to operate within the cryostats or high-pressure cylinders used to store the noble fluids, or directly inside the active volume of the detector. Phase I will evaluate the feasibility of a spark discharge purification and purity monitoring system operating in liquid xenon. The purified xenon will be used in a high-pressure xenon gamma ray spectrometer, and its performance will be compared to a Constellation spark purifier working with gaseous xenon. Commercial Applications and Other Benefits as described by the awardee: The spark discharge device should find use in the purification of large amounts of noble gases for large nuclear detectors used to monitor nuclear materials. Another application for pure noble gases would be in the production of pure metals, silicon, and other semiconductor materials.