The vertical alignment of the DO overpass in the Fermilab Main Ring

In order to accommodate large detectors for pbar p physics at the Tevatron, the Main Ring has been modified to be non-planer in the sense of installing overpasses which create large vertical displacements of the beam orbit. The detailed placement of magnetic elements follows the screw geometry proposed by Tom Collins and implemented in a Fortran coded program, DSCREWF, by Sho Ohnuma. This program calculated the deviation of the new overpass from an assumed flat, perfectly aligned Main Ring. This paper describes the reality of working with the Main Ring as it was and fitting the new overpass into the overall pattern of the Main Ring. 4 refs., 6 figs., 1 tab