a tracking trigger for clas12 mac mestayer what is a tracking trigger? - “level-1” type, fully...
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A Tracking Trigger for CLAS12Mac 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, 2012 A Tracking Trigger for CLAS12 1 / 7
“It’s th
e luminosity, st
upid !” *
* {
apologies to Bill C
linton}
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, 2012 A Tracking Trigger for CLAS12 2
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, 2012 A Tracking Trigger for CLAS12 3
How does it work?
Mar. 16, 2012 A Tracking Trigger for CLAS12 4
Mar. 16, 2012 A Tracking Trigger for CLAS12 5
Move triangular template across superlayer; occupancy of 2 or greater is a ‘half-cluster’, aligned ‘half-clusters’ ‘cluster’
0000321000000002310000
Underlying logic?
What are the advantages?
Mar. 16, 2012 A Tracking Trigger for CLAS12 6
Experiment type Advantages
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 DAQhigher luminosity; shorter data-taking times
lower costs, higher statistics, more physics
Mar. 16, 2012 A Tracking Trigger for CLAS12 7
Project Cost
Mar. 16, 2012 A Tracking Trigger for CLAS12 8
Description Quantity Price Labor Notes Ext Price
Turnkey Production 252 $1600 2 weeks Procurement $405K
Delivery ARO 8 wks. delivery
Acceptance Testing 252 3 weeks
Specify/Purchase 9U x 160mm VXS crate
18 $10K 1 weeks Procurement $180K
Crate acceptance 18 2 weeks Power test
Full crate DCB test verification
18 3 weeks Full function test
Installation & commissioning
18 4 weeks Hall installation/test
Totals 15 weeks $585K
DCRB Cost and Schedule Table 1
Operating Cost Savings
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Units Saved / Year
Cost / Unit Yearly Savings
Data Storage Tapes 3000 Tbytes * .75
35$ / Tbyte 80 k$
Maintenance Manpower
100 FTE days 45$/day 4 k$
Power Savings 60,000 kW-hrs 0.10$/kW-hr 6 k$
Offline cpu Cycles 10^8 cpu-secs ? ?
Total Cost Savings ~ 100 k$