The ATLAS Level1 Central Trigger Processor On behalf

The ATLAS Level-1 Central Trigger Processor On behalf of P. Borrego Amaral 1), N. Ellis 1), P. Farthouat 1), P. Gallno 1), J. Haller 1), A. Krasznahorkay 1)2), T. Maeno 1), T. Pauly 1), H. Pessoa Lima Jr. 3)4), I. Resurreccion Arcas 1), G. Schuler 1), J. M. de Seixa 3), R. Spiwoks 1), R. Torga Teixeira 1), T. Wengler 1) CERN, Switzerland 2) University of Debrecen, Hungary 3) Federal University of Rio de Janeiro, Brazil 4) Brazilian Center for Physics Research, Brazil 1) Thilo Pauly, CERN-PH 1

The ATLAS Experiment • General-purpose experiment at CERN’s Large Hadron Collider. • Watches collisions of two pulsed high energy and high intensity proton beams. • Bunch-crossings every 25 ns (40 MHz). • Trigger system: Reduce the rate, but keep interesting events Thilo Pauly, CERN-PH 2

The Trigger-DAQ System Trigger custom hardware event selection in software 40 MHz H Lvl 1 acc = 75 k. Hz Ro. I requests LVL 2 ~10 ms L Readout System (ROS) Ro. I data Lvl 2 acc = ~3 k. Hz Event Building T event data Event Filter ~ sec DAQ Pipeline Memories DETECTOR READOUT ELECTRONICS <2. 5 ms Region of Interest LVL 1 This Presentation Calo Mu. Tr. Ch Other detectors D A T A F L O W Storage EFacc = ~200 Hz Thilo Pauly, CERN-PH 3

The Level-1 Trigger System Calorimeter Detectors Muon Detectors Barrel Muon Trigger Pre-processor Cluster Processor (e/γ and τ/h) Jet/Energy Processor LTP TTC Busy TTC Partition Central Trigger Processor Muon-CTP-Interface . . . LTP TTC Busy Detector Front-Ends/Read-out Thilo Pauly, CERN-PH End-cap Muon Trigger • Synchronous, pipelined processing at 40 MHz • LTP = Local Trigger Processor (Standard sub-detector interface to the CPT) • TTC = Timing, Trigger & Control • Busy = Tree of Busy Modules • ATLAS has about 40 TTC Partitions 4

Central Trigger Processor - Functionality • Trigger Inputs: – Multiplicities from Calorimeter and Muon Triggers for e/γ, τ/hadron, jets, and muons – Energy flags from Calorimeter Trigger: ∑ET, ETmiss, ∑ETjet – Calibration requests from sub-detectors – Specialized triggers: Beam pick-ups, etc. – Up to a total number of 160 trigger inputs at any one time • Internal triggers from CTP Core Module: – Random triggers – Pre-scaled clock – Bunch crossing groups Thilo Pauly, CERN-PH 5

CTP – Functionality (2) • Level-1 Accept (L 1 A): – Derived from trigger inputs according to trigger menu: • Up to 256 trigger items are made from combinations of up to 256 conditions on the trigger inputs, e. g. 1 EM 10 = “At least one e/γ with ET≥ 10 Ge. V” XE 20 = “Missing energy of at least 20 Ge. V” • Each trigger item has a mask, a priority and a pre-scale factor • Example: 2 EM 10 AND XE 20, mask=ON, priority=LOW, prescale=100 • L 1 A = OR of all trigger items Thilo Pauly, CERN-PH 6

CTP – Functionality (3) • Additional Functionality: – Trigger Type word (8 bits) accompanying every L 1 A – Dead-time in order to prevent front-end buffers from becoming full – Information for the Level-2 Trigger – Event data for the Read-out and Monitoring – Scalers for monitoring • Constraints: – Trigger latency budget: 100 ns (4 clock ticks) from trigger input to L 1 A output – Trigger menu changes with physics/beam/detector conditions. Thilo Pauly, CERN-PH 7

CTP Design VME Bus (Calibration requests) (pattern-in-time) PIT bus CAL bus CTP_IN Machine Interface BC/Orbit 4 x. SPD [30. . 0] CTP_IN 4 x. SPD [30. . 0] Input Modules: Trigger Inputs CTP_IN 4 x. SPD [30. . 0] CPT_MI Bunch-to-bunch monitoring CTP_MON CTP_CORE L 2/Read-out CTP_OUT 5 x. LTP-Link CTP_CAL Beam Pick-up/ Calibration Requests, Patch-Panel Other COM bus (common) Thilo Pauly, CERN-PH Trigger Menu and Read-out Trigger fan-out/Busy fan-in The CTP is in a single 9 U VME 64 x crate + custom backplanes. 8

CTP – Trigger Path VME Bus (Calibration requests) CAL bus CPT_MI Trigger Inputs (pattern-in-time) PIT bus CTP_IN CTP_MON CTP_CORE CTP_OUT L 1 A CTP_OUT CTP_CAL CTP_IN modules receive, synchronize and align 1) the trigger inputs, and route them to the PIT bus CTP_CORE: receives the PIT signals, compares trigger menu and generates Level-1 Accept, and sends L 1 A to the COM bus CTP_Out: Receives the L 1 A from the COM bus and fans it out to subdetector LTPs (common solution for all sub-detectors) COM bus (common) 1) Thilo Pauly, CERN-PH See Poster #1010 presented by Ralf Spiwoks “The ATLAS Level-1 Trigger Timing Setup” 9

The CTP at the Combined Testbeam Particle Beam Combined test-beam in 2004 with periods of 25 ns structured beam in order to test prototypes and final modules of all ATLAS subdetectors with full trigger and data acquisition chain. Thilo Pauly, CERN-PH 10

The CTP at the Combined Testbeam Calorimeter Trigger Barrel Muon Trigger End-cap Muon Trigger Common Merger Modules Sector Logic Test-beam specific scintillators Muon-CTP-Interface CTP MIMC O I NO O U NR T E LTP (fan-out to sub-detectors) Thilo Pauly, CERN-PH Trigger Inputs: Calorimeter Trigger: 4 x 3 bit e/γ 4 x 3 bit jet multiplicities 1 bit total ET Muon Trigger: 6 x 3 bit muon multiplicities Scintillators: 3 x 1 bit 11

The CTP at the Combined Testbeam CTP_CORE CTP_MI CTP_OUT CTP_IN Thilo Pauly, CERN-PH CTP_MON 12

Some Results • Trigger Generation: – 46 signals from the PIT bus were used to form 18 trigger items – Prescaling and masking tested to work correctly – L 1 A used as trigger for read-out of the combined subdetectors • Latency Measurements: – Measured latency between reference scintillator and L 1 A as it arrives at the Muon Trigger read-out. Projection (cable length + time-of-flight corrections) for final ATLAS latency: 2. 13μs (budget is 2. 5μs) – CTP Latency (budget 100 ns): • 125 ns at testbeam (non-optimized timing) • 95 ns in lab after further optimisation Thilo Pauly, CERN-PH 13

Conclusions • The CTP has been successfully tested during the test-beam to generate triggers using 46 trigger inputs and 18 trigger items • The CTP latency is measured to be 95 ns • Work is continuing in the laboratory (read-out, additional firmware, software, monitoring, GPS-based time-stamp) • The CTP will be available for ATLAS commissioning in September 2005. Thilo Pauly, CERN-PH 14

Backup - Slides Thilo Pauly, CERN-PH 15

CTP – Timing & Control Signal Path VME Bus (Calibration requests) (pattern-in-time) PIT bus CAL bus CPT_MI CTP_IN CTP_MON Bunch Clock, Orbit CTP_MI module receives timing signals from LHC, generates additional timing signals and sends all to the COM bus CTP_CORE CTP_OUT CTP_CAL COM bus (common) Thilo Pauly, CERN-PH CTP_Out module receives busy signals from sub-detector LTPs Busy from and send them to the COM bus. subdetectors/ It receives clock signal from the Bunch Clock COM bus and fans it out to the to sub-detectors. All CTP modules receive timing signals from the COM bus. 16

CTP – Read-out and Monitoring VME Bus (Calibration requests) (pattern-in-time) PIT bus CAL bus CPT_MI CTP_IN CTP_MON CTP_CORE CTP_OUT Ro. I to Level-2 Event data to Read-out CTP_MON produces bunch-bybunch histograms of signals on the PIT bus CPT_CORE sends Region-of. Interest (Ro. I) information to the Level-2 Trigger and event data to the Read-out System CTP_OUT CTP_CAL COM bus (common) Thilo Pauly, CERN-PH All CTP modules provide monitoring data to the VME bus. 17

CTP – Calibration Requests VME Bus (pattern-in-time) PIT bus CPT_MI CTP_IN CTP_MON CTP_CORE (Calibration requests) CTP_OUT CAL bus CTP_CAL COM bus (common) Thilo Pauly, CERN-PH CTP_OUT receive calibration requests from sub-detector LTPs and send them to the CAL bus CTP_CAL: • Time-multiplexes calibration requests • Receives additional trigger inputs and sends them to a CTP_IN module Additional Trigger Inputs (e. g. Beam-Pick-up) 18