K + → p + nn The NA62 liquid krypton electromagnetic calorimeter Level 0 trigger V. Bonaiuto (a), A. Fucci (b), G. Paoluzzi (b), A. Salamon (b), G. Salina (b), E. Santovetti (a), F. Sargeni (a) (a) Universita’ degli Studi di Roma Tor Vergata (b) INFN Sezione di Roma Tor Vergata ABSTRACT –The NA62 experiment at the CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K + →  + collecting ~100 events with a 10% background in two years of data taking. An efficient photon veto system is needed to reject the K + →  + p 0 background. The NA48 liquid krypton electromagnetic calorimeter will be used in the 1-10 mrad angular region. The design, current status and test results of the liquid krypton electromagnetic calorimeter level 0 trigger is presented Nuclear Science Symposium October 30, 2010 – November 6, 2010 – Knoxville, Tennessee K + →  + (and K L →  0 ) are exceptionally clean modes dominated by short distance dinamics Inst p rate / eff s: 1.1 x Momentum: 75 GeV/c Duty cycle: 0.3 K + Decays / year: 4.5 x10 12 SM events / year: : technical run data taking Precise measurement of BR(K + →  + ) offers: an independent measurement of the unitary triangle a precise test of the SM and New Physics search opportunity LKr read-out Boards (CREAM) 13k analog channels trigger sums LKr calorimeter DAQ 864 super- cells sums L0 LKr trigger read-out after L1 L0TP read-out after L analog channels digitized by the readout modules; Trigger tiles (864) from the readout module to the L0 trigger processor (1 trigger tile = 2x8 or 4x4 calorimeter cells) Trigger primitives (clusters in a given time slice) to the L0 trigger supervisor Low granularity (not zero-suppressed) readout independent from the full granularity readout and suitable for the L1/L2 software triggers Concentrator board: merging, sorting 8 Front-End boards Front-end board: pulse reconstruction (time, position and energy) 32 trigger tiles 1 trigger tile = 2x8 Lkr cells 4 x gbit ethernet input mezz. credit card PC TTC 1 D + 1 D pixel based algorithm Calorimeter divided in slices parallel to the x axis Front-End boards (28): peaks in space and time independently searched in each slice; digital constant fraction discriminator + linear interpolator for fine timing Concentrator boards (7+1): peaks close in space and time merged and assigned to the same electromagnetic cluster 864 input channels (tiles); MHz per tile 1 trigger output channels (Gbit Ethernet) 28 raw data + 7 reconstructed clusters readout channels 36 TEL62 electronic modules dedicated mezzanines Less than 100 us output latency 80 MHz sampling: 50 ps/bin full scale pulse -> 100 ps rms 40 MHz sampling: 100 ps/bin 1/40 full scale pulse + noise and jitter -> 700 ps rms VHDL simulation 1 The NA62 experiment at CERN SPS The TDAQ system 12 sub-detectors, ~ 80 ' 000 channels, 25 GB/s raw data Three-level trigger system L0 hardware trigger based on few sub-detectors; after L0 data readout from the front-end electronics to dedicated PCs (for most sub-detectors); max output rate 1 MHz, max total latency 1 ms L1 software trigger executed independently by each sub-detector using data stored on dedicated PCs; max output rate 100 kHz, max total latency 1s; L2 software trigger based on assembled and partially reconstructed events; max output rate O(15 kHz), max total latency spill period TEL62 board, based on the LHCb TELL1 board, being designed at INFN Pisa 9U, 2-4 input mezzanine cards, 4+1 large FPGAs, credit card PC, 4 Gbit ethernet output The liquid krypton calorimeter L0 trigger Architecture & implementation Trigger algorithm Simulations and tests input mezz. L0TP TEL62 28 x Front-End LKr RX 1-3 m copper 32 ch Trigger & RO TX TEL62 7 x Concentrator LKr RX 1-3 m copper 8 ch Trigger & RO TX GbE 32 trigger tiles DAQ LKr RX 8 ch Quad GbE GbE GbE reconstr clust GbE raw data BR SM =(8.5 ± 0.7)× Lkr RX board mounted on the TELL1 and tested Lkr trigger & RO TX being designed TEL62 VHDL simulations with simple test functions to check the peak time reconstruction algorithm 1 x Concentrator not to scale In flight kaon decay technique K tagging Cherenkov (CEDAR) Kinematical rejection: K + momentum: beam tracker (gigatracker) p + momentum: magnetic spectrometer (straw chambers) Particle ID and veto g veto: liquid krypton calorimeter (LKr), large angle vetoes (LAV), small angle calorimeter (SAC), IRC p / m separation: muon detector, RICH Multi-track events veto: straw tracker