The%20BTeV%20Level%201%20Muon%20Trigger%20Update

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The BTeV Level 1Muon Trigger Update

• Michael J. Haney
• 27 January 2001
• www.hep.uiuc.edu/engin/btev/reports/27jan01.ppt
  (and .pdf)

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Algorithm

• compress adjacent tube hitsand AND/OR
  (selectable) RR views
• working radially inward,form valid RR2-U2
  pairs(fixed table size gt outer bias)
• look-up V2s from RRU2sform RRUV2s
• and RRV2s and UV2s, etc.as space/time
  permits...

U
2
V
2
3
3
4
4
6
8
R
10
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Algorithm (continued)

• window-search RR3sbased on RRUV2s
• look-up U3s and V3sfrom RRUV2RR3s
• look-up RR1s, U1s, V1sfrom RRUV2RRUV3s
• declare RRUV1RRUV2RRUV3s(and various lessers)
  as tracks
• calculate c2s (?)

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Algorithm Notes

• radially-inward processing
• biased in favor of higher PT
• implications on front end readout (order)
• fixed table sizes
• accommodates wall of fire near beam pipe
• octant-arm specific
• 16-fold symmetry in hardware
• no inter-octant communications

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Algorithm Notes (continued)

• combinatoric explosion - suppressed
• RRU2s require O(N2)
• look-up steps require O(M)
• window search? O(M) to O(M2)
• could be fully implemented inthe Pixel Trigger
  DSP Farm
• but compression/table-building may be donein
  (Pixel Trigger?) FPGAs

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Status

• Fortran code to analyze efficiency
• work-in-progress
• DSP code implementation
• next
• FPGA implementation (table building)
• next