1 “Fast FPGA-based trigger and data acquisition system for the CERN experiment NA62: architecture and algorithms” Authors G. Collazuol(a), S. Galeotti(b), E. Imbergamo(c), G. Lamanna(d), G. Magazzù(b), M. Sozzi (d) (a) Scuola Normale Superiore and INFN section of Pisa, Italy (b) INFN section of Pisa, Pisa, Italy (c) University of Perugia and INFN section of Perugia, Italy (d) University of Pisa and INFN section of Pisa, Italy Speaker: E. Imbergamo DSD08, September , Parma, Italy

2 Application framework Elementary particle physics NA62 experiment (CERN laboratories) Status of designing/prototyping Design of the DAQ and trigger system  Input data rate Mhz  Input data bandwidth ~ 2 TB/sec  Number of input channels ~ 20K  No undetected electronics failures up to Out of the shelf electronics

3 Trigger & daq tradition / our challenge L0 & L1: very fast & fast (~0.1 & 1. µs) logic conditions in dedicated hardware  Duplicate channels // create special assemblies L2: partial reconstruction in on-line processors (~1-10ms) L3: full reconstruction in off- line pc-farm Our challenge: a common trigger & daq system

4 Hardware building blocks HPTDC chip (Time to Digital Converter, developed by CERN)  100 ps resolution/channel  32 input channels (LVDS) // daisy chain-able  Programmable via JTAG TDCB board (4xHPTDCs, Altera StratixII, QPLL, miniature connectors)  TDCs configuration // readout // emulation // data pre- processing TELL1 board (4xTDCB, 4+1xAltera Stratix, 4x96MB SDRAM, 4x GigaBitEthernet, 1xControl PC, developed by EPFL Lausanne)  Data buffering // Implement L0 trigger primitive // Interface to the software level of trigger

5 Hardware building blocks (TDCB)

6 Hardware building blocks (TELL1) GBE CCPC

7 Example of building blocks assembly 4x512 input channels (times) Input data buffered in TELL1 L0-L1 primitives evaluated in daisy chained TELL1s Make trigger decision (L0T) Send trigger decision (TTC) Transmit input data to PCs  Trigger decision evaluated on the same readout data

8 L0-L1 primitive definition (I) Tell1 Count matching times  Multiplicity threshold

9 L0-L1 primitive definition (II) Produce full list of times (no append, rather merge) Send the list to the L0T Predictable/fixed latency

10 L0-L1 primitive implementation Histogram-like algorithm Map times into time-bins of preset length For any new time increment the number of entries for the corresponding time-bin Simple VHDL description Naively: N counters and one mux Very few resources: 100 Stratix LEs Up to 260 Mhz operating rate on our -7 speed grade Scalable

11 Preliminary hardware characterization Clock stability issue (40MHz input to TDCs)  Measured ~20ps (rms) jitter Cables (signal detector inputs to TDCs)  Delicate issue (hard manufacturing) TDC resolution (pulser inputs to TDCs)  Better than 90ps (rms) resolution  Intrinsic TDC performance seems to be achieved

12 Conclusion We are developing a triggerless-like trigger and daq system for high energy physics application Key building blocks functionality looks fine Time-matching algorithms have been designed for implementation in FPGA replacing traditional electronics for “coincidences”. Hardware characterization/prototyping has started