Speaker
R. Benton Pahlka
(The University of Texas at Austin)
Description
We are constructing a 30 ton liquid argon (LAr) vessel at Fermilab to test whether sufficient purity can be achieved from a non-evacuated environment for electron drift lifetimes of 2.5 m. There are two phases to the experiment. In the first phase, we will consider the initial purification by exchanging several vessel volumes of clean, warm argon gas to push out ambient air and to dry out the vessel surfaces. The gas will be recirculated through a filtration system to achieve less than 50 ppm oxygen contamination. When this purity is achieved, the vessel will be cooled and filled with LAr. In the second phase, candidate materials for use in time projection chambers will be placed in the vessel to determine if electron drift lifetimes can be maintained. We will will study the temperature and oxygen concentrations at various depths in the vessel over time and compare the results to models for scalability to larger volumes. We will also study the number of LAr volume exchanges and the exchange rate needed to maintain nominal purity. Our poster describes the vessel, the instrumentation and installation methods, and summarizes the current status of the experiment.
Author
Benton Pahlka
(Fermilab)
