In one embodiment, the disclosed apparatus is a heat-pipe cooling system that includes a conical structure having an upper portion that is truncated. The conical structure is configured to be formed above a dielectric window with the conical structure being configured to condense vapor from a heat-transfer fluid placed or formed within a volume formed between the dielectric window and the conical structure. At least one cooling coil is formed on an exterior portion of the conical structure. Other apparatuses and systems are disclosed.