This survey monument, located at Fermilab’s Buffalo Farm, and several similar monuments on site form a GPS surface geodetic control network established to determine the accurate position of each monument. These coordinates are then used to establish a control network for aligning dipoles, quadrupoles and other components in the laboratory’s tunnels.

What is it? It’s the precision measuring head of a Zeiss coordinate measuring machine in Lab A. Coordinate measuring machines use probes, such as the one pictured above, to measure objects’ geometries. For example, you can place the probe inside a cylinder to measure its diameter and out-of-roundness.