PERFORMANCE OF THE PHENIX EM CALORIMETER

The PHENIX Electromagnetic Calorimeter is a large 15,552 channel lead/ scintillator sampling calorimeter based on the shish-kebab optical rea dout technique[1]. In this report we summarise studies leading to an o ptimal design for measurement of photons and electrons in the 1 GeV mo mentum range within the high multiplicity environment expected for eve nts at RHIC. Timing resolutions of similar to 100 ps and a sampling do minated energy resolution of 8% at 1 GeV are featured. We also present a novel scheme for monitoring gain and timing of our entire system. T est results with a 144 channel preproduction ''super-module'' exposed to electron and hadron beams at the AGS are described. The calorimeter is currently under construction in Russia and the US and will be full y installed at RHIC during 1998.