Proposal by the Numbers

1. Proposal by the Numbers • 3 Trigger layers (plus 2 “short” layers) provide full coverage to eta=??? in 15 degree sectors • Hits collected in real time, sent off-detector on 5k-10k optical fibers at ~ 6 Gbit/sec • All possible track equations for each sector evaluated in parallel using FPGAs in USC to produce ROI inputs for L1 • Total of ~ 1000-2000 Virtex-6 class FPGAs could be used to build this using current technology

2. Some detector details R-phi view of rod structure Z pixel resolution Z = 5 mm Plane 2 Stack 2 Plane 1 Z = 1-2 mm Carbon fiber Rod support 40 mm ASIC Kapton Cables +R +R Plane 2  Z Stack 1 Plane 1 Readout chips  = 100 80mm inner station 70mm mid/outer stations …50... :  800 : Z 100 mm Kapton Readout Cables ASIC ASIC One Z-segment Fiber Tx

3. One 15 degree sector showing layout of “rods” (full-length layers) Doublet data rate estimate: 8x10 cm = 80 cm2 2 particles / cm2 from Monte Carlo estimate Thus 160 particles/BX 10x reduction due to 2-layer coincidences Thus 16 particles/BX per Z-segment of a rod 20 bits/hit 10 bits  6 bits Z 2 bits curvature (+/0/-) 2 spare bits 16 hits * 20 bits * 40MHz = 12.8 Gb/sec (2 fibers for inner station) 4 rods / 15o sector Outer station r=1100 2 rods Middle station r=550 1 rod Inner station r=350

4. R-Z view of 1/4 of barrel showing Z segmentation Layer 4 Projection Layer 3 Projection 28 Z segments Layer 5 Layers 3, 4, 5 Outer Station 10 Z segments Layer 4 Layer 3 28 Z segments Layer 2 -- Middle station Layer 1 -- Inner station 21 Z segments R IP Z Z-segments processed in groups of 7 One “Z-group” = 700 mm of rod Outer station - 7 Z-groups Short layers 3,4 extend eta reach Middle station - 4 Z-groups Inner station - 3 Z-groups

5. Processing for each Z-Segment of a Rod Doublets formed by readout chips Tracklets may be formed either on-detector by ASIC, or in USC by the trigger processor. x x x x x x x x ASIC Doublet (2-layer coincidence) Tracklet (4-layer coincidence with PT validation) Tracklet (4-layer coincidence with PT validation) x x x x x x x x x x x x If ASIC sends doublets off-detector, then each station requires two optical fibers per Z-segment per sector to handle the data volume If ASIC forms tracklets, this volume is reduced by about 2X

6. Outer layer divided into 12 sub-segments “home” sector sector n-1 sector n+1 Outer station divided into 12 sub-segments Routing logic sorts outputs from inner, middle layer rods to target output layer sub-segments using IP point and pT Tracks of > 2.4 GeV pT can traverse at most (2) 15o sectors. Trigger logic must handle inputs from “home” sector plus n-1 and n+1

7. Trigger Processor for one sector in USC Inputs from sector n+1 12 subsector processors Inner Station Logic processes 3 Z-groups of 7 Z-segments each 12 outputs To sector n+1 7 * 12 14 12 12 outputs to sector n-1 7 groups of 12 links from 7 Z-groups to 12 subsector processors Middle Station Logic Processes 4 Z-groups of 7 Z-segments each Input: Doublets or Tracklets from detector Output: Track candidate found 12 14 12 Outer Station Logic Processes 7 Z-groups Of 7 Z-segments each 12 14 14 Inputs from sector n-1

8. Inner/Middle Station Logic Details 2 optical fibers From each Z-segment Total of 7 Z-segments 2 Sorter block sorts tracklets using IP, pT into sub-sector of outer station 12 12 Tracklet data sent to home sector, plus 2 neighbors 12 Tracklet block converts doublets Into tracklets Outer Station Logic Details 2 Tracklet data sent to home sector only 12