Measurement and optimization of the lattice functions in the debuncher ring at Fermilab

A goal of the Tevatron Run-II upgrade requires substantial increase of antiproton production. The central step towards this goal is increasing the Debuncher ring admittance. Detailed understanding of the Debuncher's optics, aperture limitations and lattice functions is necessary. The method of the response matrix optimization has been used to determine quadrupole errors and corrections to the design functions. The measurement accuracy is about 5% due to the Beam Position Monitor system resolution and the small number of steering elements in the machine. We have used these accurate measurements to redesign the machine optics to maximize the acceptance of the Debuncher where the main limiting apertures are the stochastic cooling pickups and kickers. Accuracy of the measurements and the limitations are discussed as well as details of the optics modification.