In the following image of Exploration Extravehicular Mobility Unit (xEMU) or Artemis Generation Space Suit, it can be seen the helmet contains double-pane of glass (inside the black rectangle)
What is in between the two glass layers - air, inert gases (Helium, Neon, Argon, Krypton, Xenon), or vacuum?
What are the advantages of having a double-pane space helmet? Some of the possible advantages that I could think are as follows:
For additional safety, to avoid accidental decompression in case of damage in the outermost glass layer.
For radiation protection (I can't think how this can happen)?
For thermal insulation (like the double-pane windows used in some houses)?
Or is that any other thing? Are the current generation space-helmets double-paned or single-paned (I can't see any difference clearly)?