Keywords

SEM, fluoride, radiation damage, FUV mirrors

Abstract

LiF is an essential mirror coating for the upcoming LUVOIR space telescope. In order to improve the technology readiness level of this material a study was to be conducted, observing the surface changes of LiF thin films as exposed to humidity for extended periods of time. However, initial attempts to characterize the film with SEM showed that LiF is unstable under all electron beam parameters experimented with. This creates the concern that LiF is also sensitive to other forms of radiation damage. Further investigation may suggest the need to transition to another mirror coating that is more resilient to radiation damage. Our goal is to investigate other similar fluoride compounds to see if they exhibit the same instability when exposed to the electron beam or at least more resilient. The materials that we were able to study were cryolite (Na3AlF6 ), XeF2 passivated Al with LiF coating (AlF3+LiF), and AlF3 on its own