The muon system upgrade for the CDF II experiment

During Run II, the Tevatron collider will operate with a 20-fold decrease of bunch crossing time and a similar increase of luminosity with respect to Run I: these new running conditions called for extensive improvements and extensions of the CDF muon system. The low light yield of aging scintillators has been effectively fixed by gluing light fibers to the long sides of these counters for added light output. The higher backgrounds of the Main Injector era will be suppressed by custom-shaped steel shielding structures. A new muon system has been developed to extend rapidity coverage up to |η|=1.5 with performances comparable to those of the central muon system. New front-end electronics will handle the reduced gas gain set in the central muon system. Several mechanical problems have been solved to allow the completion of azimuthal coverage.