Abstract: A fracture-safe viewport for a pressure system having a pressure port which is pumped by said pressure system to a pressure above or below atmospheric pressure, comprising a plurality of panes each capable of passing electromagnetic radiation therethrough, each pane being mounted inside a tubular structure and being hermetically sealed to the wall of the pressure chamber. Each of the panes may be a different material or any combination of materials may be used from the group comprising sapphire, glass and quartz or any other material through which a high powered laser or other electromagnetic beam may be directed without adverse consequences. Highly pure, defect-free, ultra-polished, single-crystal sapphire is preferred. Spacing between the panes is used in most embodiments to avoid shrapnel damage in case of catastrophic failure of a pane.

Abstract: A fracture-safe viewport for a pressure system having a pressure port which is pumped by said pressure system to a pressure above or below atmospheric pressure, comprising a plurality of panes each capable of passing electromagnetic radiation therethrough, each pane being mounted inside a tubular structure and being hermetically sealed to the wall of the pressure chamber. Each of the panes may be a different material or any combination of materials may be used from the group comprising sapphire, glass and quartz or any other material through which a high powered laser or other electromagnetic beam may be directed without adverse consequences. Highly pure, defect-free, ultra-polished, single-crystal sapphire is preferred. Spacing between the panes is used in most embodiments to avoid shrapnel damage in case of catastrophic failure of a pane.