F6. Calibration Sphere used to set instruments that check the manufacturing specifications for nuclear weapons parts. Crucial components of nuclear warheads must be accurately shaped to within a few millionths of an inch. Y-12 Metrology Laboratory, User Facility Skills Demonstration Center, Y-12 Plant, Oak Ridge, Tennessee. 12 January 1994.
These photographs by Robert Del Tredici are protected by copyright and are available for purchase as high-quality digital prints on archival paper or as silver gelatin prints from bdeltredici@hotmail.com.