Presentation on theme: "CMS - Trigger RECFA-Meeting Leopold-Franzens-Universität Innsbruck, 26 March 2004 Presented by Claudia-Elisabeth Wulz Institute for High Energy Physics,"— Presentation transcript:
CMS - Trigger RECFA-Meeting Leopold-Franzens-Universität Innsbruck, 26 March 2004 Presented by Claudia-Elisabeth Wulz Institute for High Energy Physics, Vienna
RECFA, March 2004 C. - E. Wulz2 CMS Detector at the CERN Large Hadron Collider
RECFA, March 2004 C. - E. Wulz3 Cross sections for different processes vary by many orders of magnitude inelastic: 10 9 Hz W : 100 Hz tt: 10 Hz Higgs (100 GeV): 0.1 Hz Higgs (600 GeV): 0.01 Hz Required selectivity 1 : Trigger - Cross Sections and Rates
RECFA, March 2004 C. - E. Wulz4 Only calorimeters and muon system involved Reason: no complex pattern recognition as in tracker required (appr tracks at cm -2 s -1 luminosity), lower data volume Trigger is based on: Cluster search in the calorimeters Track search in muon system CMS Level-1 Trigger
RECFA, March 2004 C. - E. Wulz5 Level-1 Trigger and Institute Responsibility 40 MHz pipeline, latency < 3.2 s HFHCALECAL RPCCSCDT Pattern Comparator Trigger Regional Calorimeter Trigger 4 4+4 4 (with MIP/ISO bits) MIP+ ISO bits e, J, E T, H T, E T miss Calorimeter Trigger Muon Trigger Responsibility of Vienna Institute max. 100 kHz L1 Accept Global Trigger Global Muon Trigger Global Calorimeter Trigger Local DT Trigger Local CSC Trigger DT Track Finder CSC Track Finder
RECFA, March 2004 C. - E. Wulz6 System Overview Global Trigger + Global Muon Trigger: 1 Rack Drift Tube Track Finder: 3 Racks
RECFA, March 2004 C. - E. Wulz7 Muon Trigger Detectors Drift Tube Chambers and Cathode Strip Chambers are used for precision measurements and for triggering. Resistive Plate Chambers (RPC’s) are dedicated trigger chambers.
RECFA, March 2004 C. - E. Wulz8 Barrel Muon Chambers Mounting of a Drift Tube Chamber into the iron yoke
RECFA, March 2004 C. - E. Wulz9 Endcap Muon Chambers Cathode Strip Chambers on endcap iron yoke
RECFA, March 2004 C. - E. Wulz10 Transport of the First Magnet Coil Module A good muon trigger needs a high magnetic field!
RECFA, March 2004 C. - E. Wulz11 Regional Muon Trigger Track Finder Processor Pipeline logic running at 40MHz (LHC bunch crossing frequency) Implemented in programmable logic devices Based on extrapolation and pattern matching methods Drift Tubes (CSC’s similar)
RECFA, March 2004 C. - E. Wulz12 Drift Tube Trigger Track Finder The trigger is based on correlating compatible track segments pointing to the vertex. At most four detector planes are used in (transverse to the magnetic field direction) and three in (along the beam axis). If possible, track candidates found in both projections are then matched. The trigger is based on correlating compatible track segments pointing to the vertex. At most four detector planes are used in azimuth (transverse to the magnetic field direction) and three in pseudorapidity (along the beam axis). If possible, track candidates found in both projections are then matched. Eta Track Finder Track segment (with direction of extrapolation) Phi Track Finder (Sector Processor)
RECFA, March 2004 C. - E. Wulz13 Muon Trigger Prototypes Sector Processor Timing Module Eta Track Finder Wedge Sorter (Bologna) Trigger Crate
RECFA, March 2004 C. - E. Wulz14 Global Muon Trigger Output: 8 bit , 6 bit , 5 bit p T, 2 bits charge/synch, 3 bit quality, MIP bit, Isolation bit Inputs: 8 bit , 6 bit , 5 bit p T, 2 bits charge, 3 bit quality, 1 bit halo/eta fine-coarse Best 4 4 RPC barrel 4 DT 4 CSC 4 RPC forw. 252 MIP bits 252 Quiet bits DR/CSC/RPC: combined in Global Muon Trigger, isolation and MIP information added
RECFA, March 2004 C. - E. Wulz15 Global Muon Trigger Efficiencies Sophisticated, flexible algorithm using geometry and quality to achieve: good efficiency reasonable rates ghost suppression DT CSC RPC GMT smart GMT OR GMT AND GMT smart Muon Trigger Efficiency GMT Efficiency Optimal combination high efficiency, small rate AND SMART OR Rate kHz for 14 GeV GMT Option Rates for L=2x10 33 cm -2 s - 1
RECFA, March 2004 C. - E. Wulz16 Hadron Calorimeter The Global Muon Trigger adds information to muon candidates by correlating them with calorimeter regions. It confirms muon candidates with MIP information and determines their isolation. Barrel Hadron Calorimeter Forward Hadron Calorimeter
RECFA, March 2004 C. - E. Wulz17 Global Trigger trigger decision The trigger decision may be based on simple or more complex criteria, similar to data analysis: Logic combinations of trigger objects sent by the Global Calorimeter Trigger and the Global Muon Trigger Best 4 isolated electrons/photonsE T, , Best 4 non-isolated electrons/photonsE T, , Best 4 jets in forward regionsE T, , Best 4 jets in central regionE T, , Best 4 -JetsE T, , Total E T E T Total E T of all jetsabove thresholdH T Missing E T E T missing, (E T missing ) 12 jet multiplicities N jets (different E T thresholds and -regions) Best 4 muonsp T, charge, , , quality, MIP, isolation Thresholds (p T, E T, N Jets ) Optional topological and other conditions (geometry, isolation, charge, quality)
RECFA, March 2004 C. - E. Wulz18 Global Trigger Algorithms Logical Combinations Object Conditions 128 flexible algorithms running in parallel are implemented in programmable logic devices. The trigger decision (Level-1-Accept) is a function of the 128 trigger algorithm bits (for physics). 64 more technical algorithms are possible.
RECFA, March 2004 C. - E. Wulz19 Global Trigger Boards Every 25 ns the Global Trigger takes the decision to reject an event or to make it available to the High Level Trigger for further consideration. It consists of the following electronics boards: PSB (Pipelined Synchronizing Buffer)Synchronization of inputs (7 modules) GTL (Global Trigger Logic) Logic (1-2 modules) FDL (Final Decision Logic) Trigger decision (1 module) TCS (Trigger Control System Module)Central trigger control (1 module) L1A (Level-1 Accept Module)Distribution of trigger decision (1 module) TIM (Timing Board)Timing (1 module) GTFE (Global Trigger Frontend) Readout (1 module) PSB (Pipelined Synchronizing Buffer)GTL (Global Trigger Logic)
RECFA, March 2004 C. - E. Wulz20 Trigger Control System and Timing Trigger Control System Module Timing Module The TCS Module controls the data taking based on fast status signals sent by the subsystems. The Timing Module is used for the distribution of the LHC clock.
RECFA, March 2004 C. - E. Wulz21 Physics, Software, Management – Trigger studies (Level-1, High Level Trigger) – Software for testing and operation of the trigger hardware – Coordination of the complete level-1 trigger software – Software for the reconstruction of muons – Preparations for physics analysis, especially with studies in the field of Supersymmetry – Membership in CMS Management Board – Membership in Editorial Boards for Trigger and Physics Reconstruction and Selection
RECFA, March 2004 C. - E. Wulz22 Summary The CMS-Trigger Group of the Vienna Institute for High Energy Physics is responsible for the Level-1 Drift Tube Track Finder, the Global Muon Trigger and the Global Trigger and is developing software for triggering. It is working on the reconstruction of muons and is performing studies for physics analysis, in the field of supersymmetry. The current group members are: Scientists (physics, electronics, computer science): J. Erö, M. Jeitler, A. Nentchev, N. Neumeister, P. Porth, H. Rohringer, H. Sakulin, J. Strauss, A. Taurok, C.-E. Wulz Technicians: H. Bergauer, Ch. Deldicque, K. Kastner, M. Padrta Students: M. Galánthay, S. Kostner, B. Neuherz