A high strength window for a radiation detection system includes a plurality of intersecting ribs defining a grid having openings therein with tops of the ribs terminate substantially in a common plane. The intersecting ribs are oriented non-perpendicularly with respect to each other and define non-rectangular openings. The window also includes a support frame around a perimeter of the plurality of intersecting ribs, and a film disposed over and spanning the plurality of intersecting ribs and openings. The film is configured to pass radiation therethrough. An associated radiation detection system includes a sensor disposed behind the window. The sensor is configured to detect radiation passing through the high strength window.