Innovative proposal for N2 capturing in Liquid Argon using the Li-FAU molecular Sieve

Abstract In this work, we unveil the potential of nitrogen (N 2 ) adsorption from Liquid Argon (LAr) through the molecular sieves (zeolites) Li-FAU Adsorbents. We report detailed studies about N 2 gas adsorption at T = 89 K using a commercial Micromeritics ASAP-2420 equipment and N 2 purification from LAr using the Purification Cryostat (PuLArC) at IFGW/Unicamp. We argue that the N 2 adsorption by the Li-FAU is possible thanks to the stronger interaction of N 2 with the lithium cations present in zeolite Li-FAU. In fact, the experiments performed in PuLArC have unequivocally shown that the Li-FAU adsorbent was capable of capturing N 2 , reducing a N 2 contamination of 20–50 ppm to 0.1–1.0 ppm in 1–2 hours of circulation time in LAr for several runs. This result demonstrated the great potential of the Li-FAU adsorbent for N 2 capturing in LAr and invoke further tests of this material in larger scale LAr cryostats in order to confirm the innovative proposal of using the Li-FAU molecular sieve in replacement of Molecular Sieve 4A, currently used in LAr cryostats for neutrino experiments.