proposal by the numbers 3 trigger layers (plus 2 “short” layers) provide full coverage to...
TRANSCRIPT
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
40 mm
Z = 5 mm
Z = 1-2 mmPlane 1Plane 2
Stack 2
Z
+R+R
Readout chips
80 mm inner station70mm mid/outer stations
Z
100 mm
800
…50...
:
:
ASIC ASICKaptonReadoutCables Fiber Tx
One Z-segment
KaptonCables
ASIC
Z pixel resolution
Carbon fiberRod support
Plane 1Plane 2
Stack 1
R-phi view of rod structure
Some detector details
r=350
r=550
r=1100
4 rods / 15o sector
2 rods
1 rod
One 15 degree sectorshowing layout of “rods” (full-length layers)
Doublet data rate estimate:
8x10 cm = 80 cm2
2 particles / cm2 from Monte Carlo estimateThus 160 particles/BX
10x reduction due to2-layer coincidences
Thus 16 particles/BXper Z-segment of a rod
20 bits/hit10 bits 6 bits Z2 bits curvature (+/0/-)2 spare bits
16 hits * 20 bits * 40MHz =12.8 Gb/sec(2 fibers for inner station)
Inner station
Middle station
Outerstation
IP
Layer 1 -- Inner station
Layer 2 -- Middle stationLayer 3
Layer 4
Layer 5Layer 4Projection
Layer 3Projection
21 Z segments
28 Z segments
28 Z segments
10 Z segments
Z
R
R-Z view of 1/4 of barrel showing Z segmentation
Z-segments processed in groups of 7One “Z-group” = 700 mm of rod
Inner station - 3 Z-groups
Layers 3, 4, 5Outer Station
Middle station - 4 Z-groups
Outer station - 7 Z-groups
Short layers 3,4extend eta reach
x
x
x
x
x
x
x
x
x
x
Doublet(2-layer coincidence)
Tracklet(4-layer coincidence
with PT validation)
Doublets formed by readout chips
Tracklets may be formed eitheron-detector by ASIC, or in USCby the trigger processor.
Processing for each Z-Segment of a Rod
x
x
x
x
x
x
x
x
x
x
Tracklet(4-layer coincidence
with PT validation)
ASIC
If ASIC sends doublets off-detector,then each station requires twooptical fibers per Z-segment per sectorto handle the data volume
If ASIC forms tracklets, this volumeis reduced by about 2X
Outer station dividedinto 12 sub-segments
Routing logic sorts outputsfrom inner, middle layer rodsto target output layer sub-segmentsusing IP point and p
T
Outer layer divided into 12 sub-segments
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
“home” sector
sector n-1 sector n+1
14
12 outputsTo sector n+1
12 outputsto sector n-1
14
12
12
12
14
14
12
Inner Station Logicprocesses 3 Z-groupsof 7 Z-segments each
Middle Station LogicProcesses 4 Z-groupsof 7 Z-segments each
Outer Station LogicProcesses 7 Z-groupsOf 7 Z-segments each
7 * 12
7 groups of 12 links
from 7 Z-groups to 12 subsector processors
12 subsectorprocessors
Inputs fromsector n+1
Inputs fromsector n-1
Inpu
t:
Dou
blet
s or
Tra
ckle
ts f
rom
det
ecto
r
Out
put:
Tra
ck c
andi
date
fou
nd
Trigger Processor for one sector in USC
Inner/Middle Station Logic Details
22 optical fibersFrom eachZ-segment
Total of 7 Z-segments
Tracklet block converts doublets Into tracklets
12
12
12
Sorter blocksorts trackletsusing IP, pT into sub-sectorof outer station
Tracklet datasent to homesector, plus 2neighbors
2
12 Tracklet datasent to homesector only
Outer Station Logic Details