Speaker
Description
Dual-phase (gas-liquid) argon (Ar) and xenon (Xe) time projection chambers (TPC) are promising dark-matter (DM) detectors; hence various international collaborations plan to construct big TPCs based on them. Interactions in these detectors induce scintillation in the far ultraviolet (FUV) at ~128 mn (Ar) or ~172 nm (Xe).
Unfortunately, coatings for the FUV present an intrinsic challenge compared to other ranges like the visible due to the strong absorption of materials and the limited knowledge of optical constants in this range. Thus, TPC experiments would significantly improve from the development of high-performance FUV coatings to properly handle this radiation.
In this context, Grupo de Óptica de Láminas Delgadas (GOLD) is an expert in the development of FUV coatings. Such coatings are designed as a multilayer that alternates layers of (at least) two materials, with refractive indices and thicknesses optimized for a specific goal, such as high-reflectance narrow- or broad-band mirrors and anti-reflection coatings. FUV coatings for liquefied noble elements present an additional challenge in that they need to operate at cryogenic temperatures.
Our communication will display the main FUV coatings that are available and other coatings that could be produced with applications for rare event searches.
