Status of the Level 0 Trigger Processor of the NA62 Liquid Krypton Electromagnetic Calorimeter

The NA62 experiment at the CERN SPS aims to measure the Branching Ratio of the ultra-rare decay , collecting about 100 events in two years of data taking with a signal to background ratio of 10:1. A hermetic photon veto system has been designed to efficiently reject the π0 background, one of the main background sources, and the 20-ton liquid krypton calorimeter is a fundamental component of such system in the angular acceptance region 1-10 mrad. In this paper, we present the design of the Level 0 trigger processor that is able to identify electromagnetic clusters in the calorimeter providing information on time, position and energy reconstruction for each cluster. In particular, it is composed of 36 readout boards (TEL62), organized in a three layer parallel system, 108 mezzanines and 215 high-performance FPGAs. The system has been designed to sustain an instantaneous hit rate of 40 MHz, to process data with a latency of about 100 µs, and to achieve a time resolution of 1.5 ns on the single cluster. Performance and functionality test results of a trigger slice, together with an updated status report of the whole level 0 trigger project, will be presented.