P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 1 New CMS Level-1 Trigger Design for the Upcoming Data Taking Pamela Klabbers

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


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


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


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


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


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


Muon GeometryMuon GeometryMuon GeometryMuon Geometry

2015


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.


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


CMS Calorimeter GeometryCMS Calorimeter GeometryCMS Calorimeter GeometryCMS Calorimeter Geometry

EB, EE, HB, HE map to 18 RCT crates

Provide e/ and jet, ET triggers


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


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


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


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


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.


Expected Performance: e/Expected Performance: e/Expected Performance: e/Expected Performance: e/

5x Rate reduction, similar efficiency


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


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


Higgs and SUSY PerformanceHiggs and SUSY PerformanceHiggs and SUSY PerformanceHiggs and SUSY Performance

Multijet

Single e/

& single e/

Higgs

SUSY


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


BackupBackupBackupBackup

Reference:• L1 Trigger Upgrade TDR:

• https://cds.cern.ch/record/1556311/files/CMS-TDR-012.pdf


The Large Hadron ColliderThe Large Hadron ColliderThe Large Hadron ColliderThe Large Hadron Collider


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


CMS DetectorCMS DetectorCMS DetectorCMS Detector

*

*Actually 3.8 T


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


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.


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


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)


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

Documents

P. Klabbers, U. Wisconsin, IRPD13, October 2013 New CMS Level-1 Trigger - 1 New CMS Level-1 Trigger Design for the Upcoming Data Taking Pamela Klabbers