Design Challenges for a Future Liquid Xenon Observatory

Abstract

An ultimate liquid xenon experiment would be limited in its dark matter science reach by irreducible neu-
trino backgrounds, which are an exciting signal in their own right. To achieve such sensitivity, other back-
grounds that currently plague these detectors must be better mitigated, and extreme care must be taken in
the design and construction phases. A 100-tonne xenon target is compelling to search for weakly interact-
ing massive particle dark matter and has capabilities to study coherent elastic neutrino-nucleus scattering
and search for neutrinoless double-beta decay signatures. Historically, liquid xenon time projection cham-
bers have scaled to larger target masses with great success. This paper gives an overview of challenges
that need to be met for the next generation of detectors to obtain a kilotonne×year exposure. Such tasks
include the procurement and purification of xenon, radiopure, and reliable detector components, sensitive
outer detector vetoes, powerful data handling and analyses, and an ability to operate stably for timescales
of over a decade.