Speaker
Description
Liquid Argon Time Projection Chambers (LArTPCs), such as those for the DUNE experiment, require oxygen contamination levels below 100 ppt to ensure long electron lifetimes and maximize physics reach. While commercial copper-based adsorbents (e.g., BASF Cu-0226 S) are the current standard, there is a continuous search for media with higher capture capacity and better cost-effectiveness.
Addionaly capturing of N$_2$ contaminants has been also a desirable feature to improve the efficiency of LAr scintilation light detection.
In this work, we present a comparative performance analysis of innovative copper oxide dispersive media based on Layered Double Hydroxides (LDH), specifically focusing on the impact of Cerium doping (Ce-doped LDH) versus pure CuMgAl-LDH (R-LDH) and describe the new recently achieved capacity of N$_2$ purification using Li-FAU Molecular Sieves.
The materials were tested at the PuLArC (Purification of Liquid Argon at Campinas, Brazil) facility, which allows for the circulation of LAr through dedicated filters under realistic experimental conditions. In a series of controlled experiments.
LAr in PuLArc was contaminated with approximately 20 ppm of contaminat (O$_2$ and N$_2$) and circulated through filters containing the innovative media and the prurification process was monitored as a function of time.
Results confirm that the LDH-based structures significantly outperform the commercial BASF counterpart in O$_2$ capture capacity. However, a detailed analysis of the Ce-doped LDH performance revealed that, while efficient, the addition of Cerium does not provide a clear advantage over the pure CuMgAl-LDH media in circulating LAr. Regarding the N$_2$ capturing the Li-FAU molecular sieve method was proved to be efficent in PuLArC and later on in related experiments in the Icerberg Cryostat at Fermilab. This dual-approach study—combining high-efficiency R-LDH for O$_2$ and Li-FAU for N$_2$—provides a potential roadmap for the next generation of cryogenic purification systems, possibly offering a superior and more economical solution for achieving the extreme purity levels required for large-scale neutrino experiments.
FAPESP Project # 2024/07128-7 and FINEP Project 01.24.0511.00 (Ref. 2345/24).