October 20 th, 2000Lyon - DAQ2000HP Beck ATLAS Trigger & Data Acquisition Requirements and Concepts Hanspeter Beck LHEP - Bern for the ATLAS T/DAQ Group DAQ 2000 Workshop on Network-Based Data Acquisition and Event-Building at the Nuclear Science Symposium and Medical Imaging Conference

October 20 th, 2000Lyon - DAQ2000HP Beck 2 OverviewOverview LHC characteristicsLHC characteristics The ATLAS experimentThe ATLAS experiment Requirements for Trigger DAQRequirements for Trigger DAQ T/DAQ architectureT/DAQ architecture Networking for DAQ tasksNetworking for DAQ tasks Project StatusProject Status LHC characteristicsLHC characteristics The ATLAS experimentThe ATLAS experiment Requirements for Trigger DAQRequirements for Trigger DAQ T/DAQ architectureT/DAQ architecture Networking for DAQ tasksNetworking for DAQ tasks Project StatusProject Status

October 20 th, 2000Lyon - DAQ2000HP Beck 3 The Large Hadron Collider at CERN Startup of LHC: 2005

October 20 th, 2000Lyon - DAQ2000HP Beck 4 LHCCharacteristics LHC Characteristics Interaction rate (ATLAS, CMS)  10 9 Hz LHC circumference26.7 km ~100 m underground Center of mass energy14 TeV (i.e. 7 TeV per beam) Protons per bunch0.17 ·10 11 (1.67 ·10 11 for high Luminosity) Number of bunches3564(of which 2835 are filled) Size of a bunchradius σ x = σ y = 16  m length = 56 mm Spacing between bunches7.48 m  ns  40 MHz Interactions per bunch23 minimum-bias events (high Luminosity) ExperimentsALICE, ATLAS, CMS, LHCb

October 20 th, 2000Lyon - DAQ2000HP Beck 5 ATLAS Luminosity  Peak  cm -2 s  (“low luminosity”)  Peak  cm -2 s  (“high luminosity”)    dt  10 fb -1 per year at low luminosity    dt  100 fb -1 per year at high luminosity 3Bunch crossing: 25 ns 3~ 23 minimum-bias /crossing at high luminosity (pile-up) 3Detector speed 3Radiation hardness 3Trigger selection and data acquisition

October 20 th, 2000Lyon - DAQ2000HP Beck 6 The ATLAS Experiment

October 20 th, 2000Lyon - DAQ2000HP Beck 7 ATLAS Main Components 1600 ReadOut Links2.2 Mbyte Event Size

October 20 th, 2000Lyon - DAQ2000HP Beck 8 Physics Motivations Origin of masses and EW symmetry breaking –Look for a Standard Model Higgs –Final word about SM Higgs mechanism Physics beyond the Standard Model –SUSY : explore up to masses of ~ 3 TeV –Final word about low-energy SUSY –Other scenarios: leptoquarks, technicolor,... –Additional /q/w/z, etc. Up to m ~ 5 TeV Precision measurements –W, TGC, top –QCD –B-physics and CP violation

October 20 th, 2000Lyon - DAQ2000HP Beck 9 ATLAS Three Trigger Levels Calorimeter + Muon coarse trigger data Region of Interest full granularity Full event reconstruction access to latest calibration and alignment tables Rate [Hz] 25 ns ss mssec LVL140 MHz LVL275 kHz (100 kHz) Event Filter O(1) kHz Storage O(100) Hz Jets b    /K   W, Z t H   < 2.5  s ms seconds Processing Time [s]

October 20 th, 2000Lyon - DAQ2000HP Beck 10 FE channels ReadOut Buffers FE Links ReadOut Links O(1) GB/s 40 MHz 1 GHz O(1) kHz 75 kHz (100 kHz) EF Farm Event Building SF I O(100) Hz Level-2 Trigger System Full Event Building ROD <2.5  s RoI pointers RoI Data L2 Acc/Rej ~10 ms Event Filter Farm ~sec O(100) GB/s ATLAS DAQ and Trigger SFO O(100) MB/s ReadOut Drivers O(100) GB/s Request/Receive Mass Storage ROS ROB ReadOut System

October 20 th, 2000Lyon - DAQ2000HP Beck 11 Read Out Buffers TRGEBIF Local Controller LVL2 Read Out Buffers TRGEBIF ROI builder EVENT BUILDER Event Filter Mass Storage.. SFISFO... SFISFO Online s/w RunControl Configure Monitoring LVL1 Detector 1Detector 2Detector n Local Controller LVL2 ROI builder TRG.. LVL2 ROI builder.. Detector 1Detector 2Detector n Read Out Buffers Read Out Buffers LVL1 RoI LVL2.. EBIF EVENT BUILDER TRG Read Out Buffers TRG Read Out Buffers EVENT BUILDER SFI Event Filter SFI SFO Event Filter Mass Storage SFO

October 20 th, 2000Lyon - DAQ2000HP Beck 12 LVL2 DataFlow Worst case assumption according B-Physics selection at LVL2; intended for low Luminosity only.

October 20 th, 2000Lyon - DAQ2000HP Beck 13 LVL2 DataFlow LVL1 TriggerReadOut System EventBuilding Online SoftwareLVL2 Selection RoI & LVL1 data Event data Event data request LVL2 decisions RunControl configure monitoring Event data requests LVL2 decisions RoI & LVL1 data Requested event data LVL2 accept LVL2 DataFlow Context Diagram

October 20 th, 2000Lyon - DAQ2000HP Beck 14 LVL2 DataFlow For prototype implementations testbed measurements and modeling activities for the LVL2 dataflow: See the talks of Denis Calvet and Micheal Le Vine later this afternoon.

October 20 th, 2000Lyon - DAQ2000HP Beck 15 EventBuilding DataFlow

October 20 th, 2000Lyon - DAQ2000HP Beck 16 EventBuilding DataFlow Event Building TriggerROS Online SoftwareSFI Accept Event Control Event fragments RunControl configure monitoring EventBuilding Context diagram Event fragments Control

October 20 th, 2000Lyon - DAQ2000HP Beck 17 Event Builder Model DFM ROS SFI Local Controller Trigger Data transfer End of Event, Busy/NonBusy Destination assignment Run control DFM DataFlow Manager EoE, B/B

October 20 th, 2000Lyon - DAQ2000HP Beck 18 DataFlow - Two-layer Approach DataFlow - Two-layer Approach Split Functionality and Technology Upper layer: OS and technology independence functionality:LVL2 DataFlow + Event Building data + control messages Lower layer: technology dependent functionality:data transfer Decoupling of upper and lower layer: with technology independent API and different technology implementations ATM / AAL5 TCP / IP... Message Passing Appl Baseline candidate technology is Fast+Gigabit Ethernet using various protocols on it, from raw frames (MESH) up to TCP/IP. (Other technologies have been studied and could still be resurrected, e.g. ATM, FC)

October 20 th, 2000Lyon - DAQ2000HP Beck 19 EventBuilder Testbeds Fast Ethernet & ATM Gigabit Ethernet

October 20 th, 2000Lyon - DAQ2000HP Beck 20 EventBuilder Event Rates Simulation (Ptolemy model) Measured Performance (Gigabit Ethernet TCP/IP)

October 20 th, 2000Lyon - DAQ2000HP Beck 21 Status of the Project DAQ/EF -1 ( ) Prototype implementing a full slice of DAQ system (excluding LVL2 trigger). Emphasis on system aspects, i.e. full functionality incl. configuration and monitoring from ROB, EB, SFI, EF to SFO and storage. Was successfully used for ATLAS testbeam this year. Pilot Project ( ) Based on previous demonstrator programs, it aimed on proving the principle of function of LVL2. Emphasis on trigger aspects i.e. implications of RoI concept and exploiting the full performance potential of networks i.e. usage of raw frames, drivers... In the past few years DAQ aspects have been studied separately from LVL2 (trigger and dataflow). Two groups were since working in parallel, exploiting feasibility of their respective system aspects:

October 20 th, 2000Lyon - DAQ2000HP Beck 22 Status of the Project The outcome of both projects enabled us to define the architecture of the final TDAQ system (March 2000). HLT, DAQ and DCS Technical Proposal (LHCC/ ) Currently, the fusion of the DAQ/EF -1 prototype and the Pilot project into an integrated prototype is in planning. A testbed running the full TDAQ architecture is expected to be exploited by summer next year. The Technical Design Report (TDR) will be based on the assessments of this integrated prototype. Only then, the final TDAQ system will be built according to the needs of the assembly of the ATLAS detector.

October 20 th, 2000Lyon - DAQ2000HP Beck 23 SummarySummary The experiments at LHC will allow us to shed light on the particle mass generation mechanism; to do precision measurements on many parameters of the Standard Model; and to peek into new physics domains beyond the current Standard Model of particle physics. The high luminosity at LHC and the size of the ATLAS detector require the development of a sophisticated data acquisition system, with online event selection. The efficient use of high performance (low latency, high throughput) networks will play a key role in the success of LHC.