A Tracking Trigger for CLAS12 Mac Mestayer What is a tracking trigger? - “level-1” type, fully pipelined How does it work? - uses FPGA logic - “nearest-neighbor” summing What’s the advantage? - increases event purity for electron scattering - increases luminosity limit for “quasi-real” electron experiments Mar. 16, 2012A Tracking Trigger for CLAS121 / 7 “It’s the luminosity, stupid !” * * {apologies to Bill Clinton}

The Challenge (and fun) of High Luminosity Problem: how do you run a large-acceptance detector at high luminosity? – ‘harden’ your wire chambers (smaller solid angle, thicker wire, faster gas) – ‘pipeline’ your data ‘flash’ ADC’s, TDC’s – add ‘tracking’ to your trigger eliminates accidental showers firing Cerenkov counters allows high-purity multi-prong triggers relieves pressure on downstream event building … all based on FPGA technology. Mar. 16, 2012A Tracking Trigger for CLAS122

What’s a tracking trigger ? based on capabilities of a new “drift chamber readout board”: amplifier, discriminator, TDC FPGA architecture allows “segment-finding” fully-pipelined readout of data and trigger logic  trigger can associate a charged track with a hit in a scintillator-based detector Mar. 16, 2012A Tracking Trigger for CLAS123

How does it work? Mar. 16, 2012A Tracking Trigger for CLAS124

Mar. 16, 2012A Tracking Trigger for CLAS125 Move triangular template across superlayer; occupancy of 2 or greater is a ‘half-cluster’, aligned ‘half-clusters’  ‘cluster’ Underlying logic?

What are the advantages? Mar. 16, 2012A Tracking Trigger for CLAS126 Experiment typeAdvantages Electron detected in CLAS (“standard”) higher event purity reduced tape costs fewer ‘offline’ events “Quasi-real” scattering, low-angle electron multi-hadron trigger reduced trigger rate higher beam luminosity shorter run periods

Summary FPGA technology enables flexible triggering schemes for charged tracks Higher-purity trigger saves tape costs, New technology reduces maintenance and power costs Addition of tracking to triggering reduces the load on the downstream DAQ  higher luminosity; shorter data-taking times lower costs, higher statistics, more physics Mar. 16, 2012A Tracking Trigger for CLAS127

Project Cost Mar. 16, 2012A Tracking Trigger for CLAS128 DescriptionQuantityPriceLaborNotesExt Price Turnkey Production252$16002 weeksProcurement$405K Delivery ARO8 wks. delivery Acceptance Testing2523 weeks Specify/Purchase 9U x 160mm VXS crate 18$10K1 weeksProcurement$180K Crate acceptance182 weeksPower test Full crate DCB test verification 183 weeksFull function test Installation & commissioning 184 weeksHall installation/test Totals 15 weeks $585K DCRB Cost and Schedule Table 1

Operating Cost Savings Mar. 16, 2012A Tracking Trigger for CLAS129 Units Saved / Year Cost / UnitYearly Savings Data Storage Tapes3000 Tbytes *.75 35$ / Tbyte80 k$ Maintenance Manpower 100 FTE days45$/day4 k$ Power Savings60,000 kW-hrs0.10$/kW-hr6 k$ Offline cpu Cycles10^8 cpu-secs?? Total Cost Savings~ 100 k$