A high-resolution TDC-based board for a fully digital Trigger and Data AcQuisition system in the NA62 experiment at CERN

The NA62 experiment at CERN will test the Standard Model (SM) of Particle Physics by measuring the Branching Ratio (BR) of the ultra-rare decay of a charged Kaon into a charged pion and two neutrinos (K+→π+νν). The main goal is to collect 100 such events in two years of data-taking, using high-energy in-flight Kaon decays from a 750 MHz hadron beam produced by 400 GeV/c SPS protons impinging on a Beryllium target. Readout uniformity of sub-detectors, scalability, efficient online selection and lossless high rate readout are key issues. A Time to Digital Converter (TDC) based system, to be used for most sub-detectors in the high-flux rare-decay of the experiment, was built as part of the NA62 fully digital Trigger and Data AcQuisition system (TDAQ), in which the TDC Board (TDCB) and a general purpose carrier board (TEL62) will play a fundamental role. While TDCBs, housing four High Performance Time to Digital Converters (HPTDC), measure hit times from sub-detectors, the TEL62 board processes and stores them in a buffer, produces trigger primitives from different detectors and extracts only data related to the first trigger level decision, once this is taken on the basis of the trigger primitives themselves.