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P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 1
New CMS Level-1 Trigger Design for the New CMS Level-1 Trigger Design for the Upcoming Data TakingUpcoming Data Taking
New CMS Level-1 Trigger Design for the New CMS Level-1 Trigger Design for the Upcoming Data TakingUpcoming Data Taking
Pamela Klabbers for the CMS CollaborationPhysics Department, University of Wisconsin,
Madison, WI, USA
IRPD13
Wednesday, 9 October 2013
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 2
Large Hadron Collider (LHC) Run 2Large Hadron Collider (LHC) Run 2Large Hadron Collider (LHC) Run 2Large Hadron Collider (LHC) Run 2
LHC is currently improving the magnet interconnections so that we may safely go to proton energies of 6.5 TeV• Minimum 13 TeV p-p center of mass energies
• Second LHC run possibly another discovery run
• Additional increase in luminosity 4-8 times previous run
• 25* or 50 ns bunch spacing
• LHC will exceed the original design luminosity (~20 ev/crossing)
• A challenge to separate the interesting event from low-energy background (Pile-Up)
~ original design luminosity
Heavy Ions expect lumi increase of 4-8 times previous
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 3
CMS Triggering ChallengesCMS Triggering ChallengesCMS Triggering ChallengesCMS Triggering ChallengesOriginal specification for CMS detector electronics was to
operate at a trigger rate of up to 100 kHz• Some CMS detector systems would need replacement or major
upgrades to exceed this rate (e.g. tracker replacement)
• Increases in energy, luminosity, and pile-up require significantly higher thresholds to operate with the current L1 trigger
• Need to maintain our sensitivity for electroweak physics and TeV scale searches
• Maintain same acceptances as 2012-2013 running
• Solution is to upgrade the trigger to
• Improve resolution
• Improve efficiency
• Reduce trigger rates
• Commission in parallel to existing trigger
• Reduce the risks associated with commissioning a new system
• Validate performance, seamless switch-over when ready
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 4
L1 Trigger Upgrade GoalsL1 Trigger Upgrade GoalsL1 Trigger Upgrade GoalsL1 Trigger Upgrade Goals
• Improve e/ object isolation using calorimeter energy distributions with Pile-Up (PU) subtraction
• Improve jet finding with PU subtraction
• Improve hadronic ID with a smaller fiducial area
• Improve muon pT resolution
• Isolate muonsusing calorimeter energy distributions with PU subtraction
• Improve global Level-1 trigger menu
• Allow greater number of triggers
• Allow more sophisticated algorithms
• Simplify the hardware to reduce costs and maintenance requirements
• Use similar electronics as in other CMS upgrades
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 5
Hardware UpgradesHardware UpgradesHardware UpgradesHardware UpgradesUse Modern High-Capacity FPGAs with high speed links
• 10x increase in comparison to those currently operating in CMS
Take advantage of modern TCA technology• Standardized hardware platform (specs at: http://www.picmg.org)
• Hot swappable, inexpensive modules, very configurable
• Point to point high-speed-serial instead of parallel VME
• Significantly more backplane bandwidth
• Not including spare I/O
• Native support for several protocols
• GbE, Serial ATA, Serial Attached SCSI, PCIe, and Serial Rapid IO
• Redundant Power Supplies, TCA Carrier Hubs (MCHs), and cooling units
• CMS will use the 2nd MCH slot for DAQ and timing and trigger signal distribution (custom AMC13*)
• Smaller form factor cards
New Custom Interface to Data Acquisition (DAQ) and Trigger Timing and Control (TTC) system• AMC13* (Advanced Mezzanine Card)
*For more details go to http://amc13.info
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 6
Original CMS Level-1 Trigger Original CMS Level-1 Trigger Original CMS Level-1 Trigger Original CMS Level-1 Trigger Calorimeter, muon, and beam monitoring (not shown) systems participate in CMS L1
0.9<||<2.4
4 4 4 4 4+4 4+4
4 4 e, J, ET, HT, ETmisse, J, ET, HT, ET
miss
L1A L1A
40 M
Hz
pip
elin
e40
MH
z p
ipel
ine
Calorimeter TriggerCalorimeter Trigger
ECALTrigger
Primitives
ECALTrigger
Primitives
HCAL/HFTrigger
Primitives
HCAL/HFTrigger
Primitives
RegionalCalorimeter
Trigger
RegionalCalorimeter
Trigger
GlobalCalorimeter
Trigger
GlobalCalorimeter
Trigger
Muon TriggerMuon Trigger
RPC hitsRPC hits CSC hitsCSC hits DT hitsDT hits
Segment finder
Segment finder
Track finderTrack finder
Pattern Comparator
Pattern Comparator
Segment finder
Segment finder
Track finderTrack finder
Global Muon TriggerGlobal Muon Trigger
Global TriggerGlobal Trigger
TTC systemTTC system TTS systemTTS system
Detector FrontendDetector Frontend
StatusStatus
Link systemLink
system
32 partitions32 partitions
CMS experiment
0<||<5||<3 ||<1.2||<1.6
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 7
Muon GeometryMuon GeometryMuon GeometryMuon Geometry
2015
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 8
Muon Trigger UpgradeMuon Trigger UpgradeMuon Trigger UpgradeMuon Trigger UpgradeCurrently 3 different track finders (DT, RPC, CSC)
• Send 16 muon candidates to Global Muon Trigger
• Lateral exchange of information
• CSC Muon Port Card (MPC) has a bottleneck - max 3 track seg. to track finder
Upgrade• New CSC MPC FPGA (on mezz) – send all 18 possible track segments
• More CSCs and RPCs on Endcap (1.25 < || < 1.8)
• Upgrade to ||>2.1 CSC electronics
• Split chamber hits before track finders
• Combine in one track finder, TF
• Better overlap, moretolerant of dead channels
• Fewer fake muons
• No lateral exchangeof information
• Include calo triggerinfo for -isolation
• More, higher-resolutionmuons at Global Triggerfor improved isolation, invariant mass, etc.
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 9
Muon HardwareMuon HardwareMuon HardwareMuon HardwareLarge modular LUT processor MTF7
• Being built for Muon Endcap upgrade but designed to be compatible with other muon TFs
• To be used in overlap region
• Maximizes input from muon detectors
• Large capacity for RAM (~1GB) for track-finding
• Prototype with Virtex 6
• Virtex 7 design in progress
Optical Module
Core Module
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 10
CMS Calorimeter GeometryCMS Calorimeter GeometryCMS Calorimeter GeometryCMS Calorimeter Geometry
EB, EE, HB, HE map to 18 RCT crates
Provide e/ and jet, ET triggers
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 11
Calorimeter TriggerCalorimeter TriggerCalorimeter TriggerCalorimeter TriggerCommissioning in Parallel
• ECAL – Upgrade link mezzanine from Cu to Optical (oSLB)
• HCAL – Passively split Front-End input to Back-End (BE), keep existing BE and upgrade to new optical BE in parallel
• HF – Upgrade all BE electronics for 2015will have higher granularity for trigger
• RCT – Upgrade half of Recv. Mezz. to optical (oRM) for ECAL and HF
Architecture choice – Time multiplexed or conventional pipelined
• Time multiplexed chosen
• All calorimeter data flows through one FPGA at full granularity
• Potentially more flexible
• Demonstrated with prototype cards
• Hardware can implement either trigger architecture choice
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 12
Calorimeter HardwareCalorimeter HardwareCalorimeter HardwareCalorimeter Hardware
Layer-1 CTP6 (left), oSLB & oRM (center), and Layer-2 MP7 (right)• CTP6 – Dual Virtex 6 (XC6VHX250T) FPGAs, 48 optical inputs, 12 outputs
• Virtex 6 limits link speed to 6.4 Gb/s (validated), new CTP7 with Virtex 7 allows 10 Gb/s
• For CTP7: Zynq processor running Xilinx PetaLinux for service tasks
• oSLB and oRM Mezzanine work on existing hardware – Kintex 7 FPGA
• Links validated to 4.8 Gb/s
• MP7 – Single Virtex 7 FPGA, up to 72 input & output links dep. on Virtex 7 part
• Links validated at 10 Gb/s
• Extensive Firmware and Software development
• Latest version of MP7 with XC7VX690T uses all 72 input and output links
MMC Power Supplies
BEFPGA
FEFPGA
AvagoRx
Avago Tx
Dual SDRAMFor DAQ & TCP/IP
JTAGUSBInterface
Rx
Tx
Rx
Tx
FPGA
1V0
2xQDR(Bottom)
2V53V3
1V51V8
SD
USB
C(Bottom)oRM
oSLB
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 13
Global TriggerGlobal TriggerGlobal TriggerGlobal Trigger
Remove current 128 algorithm limit
• Most of the 128 algos were used in 2012
Receive more objects
• Increase over current 12 jets, 8 electrons, 8 muons, and global quantities
Higher resolution with increased logic
• More sophisticated correlations, e.g. invariant mass calculations
Trigger Control System merges with Trigger Timing and Control System
Utilize MP7 calorimeter processor card
• FW and SW development already under way with Virtex 6 based card
L1 Calorimeter Trigger
L1 Muon Trigger
TechnicalTriggers
GLOBALTRIGGER
PROCESSOR
TriggerControlSystem
TTCSystem
DetectorFront-Ends
Present Global Trigger
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 14
Trigger Control and Distribution Trigger Control and Distribution SystemSystem
Trigger Control and Distribution Trigger Control and Distribution SystemSystem
TCDS provides clock and triggers to CMS detectors and sends and receives control signals
Slows or stops triggers if detector buffers are full or there are errors
New system allows for more slices of detector to run in parallel, helping the (re)commissioning of CMS
Installation during mid 2014 as part of the DAQ upgrade
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 15
Expected Performance: MuonsExpected Performance: MuonsExpected Performance: MuonsExpected Performance: Muons
Barrel
Endcap
2012 High Pileup Data (~66 ev/crossing)
Tail clip: after pT lookup, candidates sent back to FPGA and muons in 5, 10, or 15% tails of distributions demoted to lower pT.
Result: Much lower rate for a slight efficiency loss.
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 16
Expected Performance: e/Expected Performance: e/Expected Performance: e/Expected Performance: e/
5x Rate reduction, similar efficiency
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 17
Expected Performance: Taus Expected Performance: Taus and Jetsand Jets
Expected Performance: Taus Expected Performance: Taus and Jetsand Jets
Current algo based on jet trigger with large fiducial area, is useless with high PU
Upgrade based on e/ algo with a significantly smaller fiducial area.
Jet goes from 12x12 towers square to 8x8 circular and now includes PU subtraction, resulting significant rate reduction for multi-jet triggers
Single Tau Quad Jet
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 18
Trigger MenuTrigger MenuTrigger MenuTrigger Menu
Sample Menu for Lumi =1.1e34• Significantly
reduced lepton thresholds
• Improved efficiency with slightly shallower turn-on
• Improved multi-jet triggers
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 19
Higgs and SUSY PerformanceHiggs and SUSY PerformanceHiggs and SUSY PerformanceHiggs and SUSY Performance
Multijet
Single e/
& single e/
Higgs
SUSY
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 20
SummarySummarySummarySummary
This upgrade is currently under way• With our new hardware CMS will be able to keep our thresholds
and rates low without sacrificing physics!
How will this proceed?• Until end of 2014* - cards and splitting
• New Back End for HF
• Mezzanine cards for ECAL Back-End and Splitting for HCAL
• Mezzanine cards on existing RCT for HF and ECAL Back-End
• Mezzanine cards for Endcap Muon Track Finder
• 2015 – Commissioning in parallel
• New calorimeter trigger
• New muon trigger, using slice of DT and full CSC and RPC data
• 2016
• New Trigger ready for 2016 LHC physics run!
*end of Long Shutdown 1, currently under way
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 21
BackupBackupBackupBackup
Reference:• L1 Trigger Upgrade TDR:
• https://cds.cern.ch/record/1556311/files/CMS-TDR-012.pdf
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 22
The Large Hadron ColliderThe Large Hadron ColliderThe Large Hadron ColliderThe Large Hadron Collider
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 23
LHC p-p CollisionsLHC p-p CollisionsOperations Operations
LHC p-p CollisionsLHC p-p CollisionsOperations Operations
2012: √s = 8 TeV • Peak Instantaneous
Luminosity:> 7.5e33?
2015: √s = 13 TeV• Predicted Peak
Instantaneous Luminosity:
3.5 TeV Beam Energy2808 Bunches/Beam (25 ns)1011 Protons/Bunch1034 cm-2 s-1 Max Inst Lumi
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 24
CMS DetectorCMS DetectorCMS DetectorCMS Detector
*
*Actually 3.8 T
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 25
CMS Trigger & DAQ SystemsCMS Trigger & DAQ SystemsCMS Trigger & DAQ SystemsCMS Trigger & DAQ Systems
Level-1 Trigger•LHC beam crossing rate is 40 MHz & at full Luminosity of 1034 cm-2s-1 yields 109 collisions/s
•Reduce to ~100 kHz output to High Level Trigger and keep high-PT physics
•Pipelined at 40 MHz for dead time free operation
•Latency of only 3.2 sec for collection, decision, propagation
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 26
e/e/and Jetand Jet Algorithms Algorithmse/e/and Jetand Jet Algorithms Algorithms
4x4 Tower sums from RCT to GCTJet or ET
• 12x12 trig. tower ET sliding in 4x4 steps w/central 4x4 ET > others
: isolated narrow energy deposits• Energy spread outside veto pattern
sets veto• Jet if all 9 4x4 region vetoes off
GCT uses tower sums for ET,MET jets for HT, MHT
Electron (Hit Tower + Max)• 2-tower ET + Hit tower H/E • Hit tower 2x5-crystal strips
>90% of ET in 5x5 (Fine Grain) Isolated Electron (3x3 Tower)
• Quiet neighbors: all towers pass Fine Grain & H/E
• One “L” of 5 EM ET < Thr.
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 27
Muon TriggerMuon TriggerMuon TriggerMuon TriggerMuon Trigger
•3 muon detectors to ||<2.4
• Drift Tubes
• Track Segment ID and Track Finder
• Cathode Strip Chambers
• Track Segment ID and Track Finder
• Resistive Plate Chambers
• Pattern Matching
•4 candidates per subsystem to Global Muon Trigger
•Global Muon Trigger sorts, removes duplicates, 4 top candidates to Global Trigger
•Track building at 40 MHz!
• In 2015: ME1/1 electronics upgradeNew CSC and RPC Chambers
2015
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 28
L1 Trigger Custom HardwareL1 Trigger Custom HardwareL1 Trigger Custom HardwareL1 Trigger Custom Hardware
• Hundreds of boards
• Thousands of:
• ASICs
• FPGAs
• Copper Cables
• Optical Fibers
• (Wo)man hours
Global Muon Trigger&
Global Trigger(Vienna)
RCT(Wisc.)
CSCTF(Florida)DTTF
(Vienna)
GCT(Imperial)
RPC PaC(Warsaw)
P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 29
Calo Trigger StagingCalo Trigger StagingCalo Trigger StagingCalo Trigger StagingTalk covers final version of calorimeter trigger, Stage 2
• CMS will have a Stage 1 intermediate solution to reduce rate and improve algorithms with higher lumi in 2015
• Install inexpensive oRSC card in RCT (18 total cards – one per crate)
• Xilinx Kintex part, multiple optical outputs for GCT and new calo trigger
• Provide readout of RCT output (VME or via optical connection to new card)
• Additional processing for current calorimeter trigger
HCAL OpticalSplitters
RegionalCalo Trigger
GlobalCalo Trigger
Layer 2Calo Trigger
Layer 1Calo Trigger
HCALEnergyHTR
ECALEnergyTCC
HFEnergyHTR
HCALEnergymHTR
CopperOptical
EMCandidates Region
EnergiesEntire Summary
oSLBoRMoRSC
CTP
MP7
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