"Calorimeter Timing System at CDF"

In this talk we describe the design and performance of the electromagnetic calorimeter timing readout system (EMTiming) for the Collider Detector at Fermilab (CDF), including measurements of the efficiency as a function of energy deposited, the noise level, and the timing resolution. The installation and commissioning was completed in Fall 2004 as part of an upgrade to the Run~II version of the detector The system is used in searches for rare events with high energy photons to verify that the photon is in time with the event collision, to reject cosmic ray and beam halo backgrounds, and to allow direct searches for new heavy long-lived particles that decay to photons.