  The CDF Central Preshower and Crack Detector Upgrade consist of scintillator
tiles with embedded wavelength-shifting fibers, clear-fiber optical cables, and
multi-anode photomultiplier readout. A description of the detector design, test
results from R&D studies, and construction phase are reported. The upgrade was
installed late in 2004, and a large amount of proton-antiproton collider data
has been collected since then. Detector studies using those data are also
discussed.
