Initial Results of Argon Purification in the Liquid State

Argon, deliberately contaminated with air, has been purified in the liquid state by the use of molecular sieves to a level better than one part per billion (02 equivalent). This argon was maintained for a period exceeding 10 days with no detectable increase in impurity concentration. Twelve hours after transfer to a test detector, an attenuation length of 170 cm in a drift field of 1 kV/cm was measured for ionization electrons. These results are essential steps toward the realization of large liquid argon time projection chambers.