Implementation of ALICE dHLT Monitoring Tool

Implementation of DHLT Monitoring Tool for ALICE Seforo Mohlalisi – UCT Supervisor : Z. Buthelezi (iThemba Labs)‏ Co-Supervisors : Z.Z. Vilakazi (iThemba Labs)‏ R. Fearick (UCT)‏

Outline • Introduction to ALICE • Muon Spectrometer • Dimuon High Level Trigger (dHLT)‏ • Purpose of dHLT monitoring • How to implement monitoring • Other work

Introduction to ALICE • Its assemble of detectors • Study strongly matter at extreme energy densities • Production of hadrons, electrons, muons, photons • SA works on muon arm

ALICE

Muon Spectrometer • Detects muon from decays of J/Ψ and γ • Lots data of produced and bottle neck DAQ • High Level Trigger (HLT) – high selectivity • Triggering • Select region of interest • Data Compression • HLT is made up of cluster of computers placed between FEE and DAQ • Dimuon HLT specifically for dimuon arm

HLT Architecture

DHLT • Analyses data online to select events relevant to muons • reconstructing clusters, hits, trigger records, tracks • Pub/Sub framework • Monitoring e.g. visualization and error handling

DHLT COMPONENTS Trigger Chamber Readout Detector Control System And Conditions Database HLT Control Task Manager Tracking Chamber readout Detector Calibration Data Detector Configuration data DDL stream data DDL stream data Online hit reconstruction Tracking Algorithm dHLT decision maker DDL stream data Monitoring data To DAQ To dHLT Monitoring

Monitoring • Visualization of event • Raw data, Hits, tracks, trigger records • Plots • Transverse momentum (pt) - distributions and cuts • Efficiency curves (iii) Invariant mass spectra, etc • Scalers : number of tracks found, number of events processed etc. • Status information : connection status, error messages

Objectives Improving existing framework • message queue • Data channels and channel manager • Extend ALIEVE (ALICE Event Visualization Environment) • Displaying and handling of errors

Monitoring Structure

Other work: Auxiliary Tools • Implemented dHLTdumpraw for dumping • DDL data from muon spectrometer • DHLT internal data block clusters, tracks etc • Implemented findLibDeps.py • Locates library dependencies • For standalone compilation • Testing muon raw data decoder

Other work: Analysis • CERN summer school project – Offline Based • Convert existing macro to analysis task • CheckESD.C to AliAnalysisTaskCheckESD • Calculate physics efficiency, PID, Resolution • Core components of Analysis Task: • UserCreateOutputObjects, UserExec, Terminate • All tasks inherit from AliAnalysisTaskSE

Analysis Cont... • Multiple data sources • ESD, AOD, MC Truth • Multiple platforms • Locally,Proof,Grid • Discovered several problems • Missing track in muon reconstruction • Low efficiency in PHOS detector

…..END “I do not know what I may appear to the world, but to myself I seem to have been only a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.” Isaac Newton

Implementation of ALICE dHLT Monitoring Tool