With the document in position, the cover glass was placed over it to keep it from wrinkling. Before placing the bronze bracket, two leak detector cells were sealed in slots cut in the bracket. These cells detected any change in the composition of the gas within the enclosure. Wires leading to the cells passed through a Kovar tube in which they were fixed by a glass bead. Louis Gilles of the Libbey-Owens-Ford Glass Company seals the Kovar tube in a hole in the lead strip which is attached to the glass panels of the enclosure.
National Institute of Standards and Technology
National Institute of Standards and Technology