THE KLOE ELECTROMAGNETIC CALORIMETER

A general purpose detector, KLOE, is under construction for operations at the Frascati phi factory, DA Phi NE. Its central mission is the study of direct CP violation in K-0 decays, which places very stringent requirements on electromagnetic shower measurements in the 20-280 MeV/c region. We have chosen to use a lead-scintillator sampling calorimeter, EmC, consisting of very thin (0.5 mm) lead layers in which are embedded 1 mm diameter scintillating fibers. Much prototyping and testing has been done during its design, yielding, for the final EmC, an expected energy resolution of sigma(E)/E similar to 4.4%/root E(GeV) and a time resolution of similar to 46 ps/root E(GeV), with excellent linearity in the region of interest and with little dependence on incidence angle and entry position.