Method of operation of the MRL interferometric manometer

Instructions are given for the mechanical and electrical operation of a U-tube manometer in which the mercury surfaces are the reflectors of a Michelson interferometer and the heights of the mercury surfaces are detected and measured by laser interferometry techniques using a helium-neon laser. Special floats made from stainless steel and tungsten, and incorporating a cat's eye, are used in each tube to reduce the effects of vibration. The U-tube and the laser interferometer are mounted on a cast-iron surface plate which in turn is borne by a 5 tone concrete block supported by air-operated antivibration mountings. Vacuum pumps and associated plumbing are also mounted on the surface plate. Procedures for installing the floats and for adjusting and aligning the optical system are included.