Experimental High Energy Nuclear Physics in Norway

download Experimental  High Energy Nuclear Physics  in Norway

of 38

  • date post

  • Category


  • view

  • download


Embed Size (px)


Experimental High Energy Nuclear Physics in Norway. Kalliopi Kanaki University of Bergen. Norwegian activities in…. ALICE@CERN hardware/software contribution physics analysis ALICE upgrades Side activities CBM@FAIR Medical physics. Physics goals of ALICE. - PowerPoint PPT Presentation

Transcript of Experimental High Energy Nuclear Physics in Norway

  • *Experimental High Energy Nuclear Physics in Norway Kalliopi KanakiUniversity of Bergen

  • *Norwegian activities inALICE@CERNhardware/software contributionphysics analysisALICE upgradesSide activitiesCBM@FAIRMedical physics

  • *Physics goals of ALICE LHC accesses the QCD phase diagram at low B, high T What can we learn about the system produced in the collisions? Does it have the same properties as the state produced at RHIC? Is the QGP weakly or strongly (fluid) coupled? Is there a sharp phase transition? How do partons interact with the medium?

  • *Di-hadron correlations & jet quenching Hard parton scattering observed via leading (high momentum) particles Strong azimuthal correlations at = expected Result: complete absence of away-side jet away-side partons are absorbed in the medium strong energy loss medium is opaque to fast partons

  • *-hadron correlationsThe point-like photon remains unmodified by the medium and provides the reference for the hard processThe prompt photon provides a measurement of the medium modification on the jet because they are balanced

  • *Direct photonsSources of direct pQCD (prompt) photonsComptonAnnihilationBremsstrahlungThermal photons sensitive to initial temperatureChallenging to obtain, necessary for -jet studiesmeasure inclusive spectrumsubtract background from hadronic decays

  • *Nuclear modification factor RAA At RHIC the matter produced is opaque High pT particles are suppressed The medium is transparent to photons

  • *Collective flow Initial state spatial anisotropy of reaction zone causes final state momentum anisotropy asymmetric particle emission Higher initial density results in larger pressure gradient The system has very low viscosity/ideal hydrodynamical fluid Flow is formed at the partonic level

  • *ALICE setupHMPIDMuon ArmTRDPHOSPMDITSTOFTPCSize: 16 x 26 metersWeight: 10,000 tonsAdded since 1997:V0/T0/ACORDE TRD(99) EMCAL (06)

  • *Technical contribution to ALICETime Projection Chamber (TPC)radiation tolerant readout electronicscalibration and online processingPHOton Spectrometer (PHOS)readout electronics and trigger (L0 and L1)calibration and online processingHigh Level Trigger (HLT)calibration framework interfaces to other systems (ECS, DCS, DAQ, CTP)online event reconstruction/display and analysis softwareCommissioning of all the aboveGRID computing part of Nordic distributed Tier1 center

  • *The ALICE TPCmain tracking device for momentum reconstruction || 1 kHz for pp

  • *

  • *Readout Control Unit (RCU)

  • *TPC calibrationgainreconstructionalignmentt0, drift velocityelectrostatic distortionsE x B effectselectron attachment

    raw data

    calibrated data

    reconstructed tracksmomentum and dE/dx

  • *Drift velocity calibration (I)Drift velocity = f(E-field, gas density (T, p), ...)Monitoring tools:Laser tracksElectrons from the central electrodeTracks from collisionsTraversing central electrodeMatching with ITSCosmicsExternal drift velocity monitor

  • *Drift velocity calibration (II)

  • *PbO4W crystal calorimeter for photons, neutral mesons (1 - 100GeV/c)Crystal size 2.2 2.2 cm2, 20 X0, APD readout, operated at 25 C(E)/E 3%, (x,y) 4 mm, (t) 1 ns at 1 GeV|| < 0.12, = 100 at R = 460 cmL0 trigger available at < 900 ns

    The ALICE PHOS spectrometer

  • *Trigger hierarchy01.26.588t [sec]CollisionL0: Trigger detectors detect collision(V0/T0, PHOS, SPD, TOF, dimuon trigger chambers)L1: select events according to centrality (ZDC, ...) high-pt di-muons high-pt di-electrons (TRD) high-pt photons/0 (PHOS) jets (EMCAL, TRD)L2: reject events due to past/future protectionHLT rejects events containing no J/psi, Y no D0 no high-pt photon no high-pt pi0 no jet, di-jet, -jet

  • *The PHOS L0 and L1 triggersArray of crystals + APD + preamp + trigger logic + readout DAQL0 trigger tasks shower finder energy sum implementation FPGA VHDL firmwareL0/L1 trigger

  • *The ALICE High Level TriggerdNch/d = 2000 4000 for Pb+PbAfter L0, L1 and L2 rates can still be up to 25 GB/sDAQ archiving rate: 1.25 GB/s imperative need for HLT

    Goals:Data compression Online reconstruction of all eventsHandle rates of > 1 kHz for p+p and 200 Hz for central Pb+PbPhysics triggers application for event characterization

  • *HLT Processing Data Flow

  • *HLT cluster status2010 Run Setup123 front-end nodes968 CPU cores1.935 TB RAM472 DDL53 computing nodes424 CPU cores1.152 TB RAMPb+Pb upgrade100 computing nodes2.4 TB RAMFull network infrastructureFull service infrastructureHLT decision sent to DAQ for every event

  • *HLT activities in NorwayAnalysis frameworkBoth online and offline (emulation) versionAnalysis softwareTPC cluster finder and calibrationITS reconstructionPHOS reconstruction and calibrationEMCAL and PHOS analysis integrationESD production onlineTrigger implementation and trigger menu for DAQInfrastructure maintainance and improvementReconstruction and trigger evaluationInterfaces to other online systems

  • *HLT online display

  • *Physics contribution to ALICEHigh pT 0 (calorimeters)High pT 0 from conversions (TPC)High pT charged particles and jet reconstructionTotal ET (calorimeters+TPC)High pT direct (calorimeters)-hadron and 0-hadron correlations (calorimeters+TPC)Collective flowUltra-peripheral collisionsOnline D0 reconstruction (ITS+TPC)Online 0 reconstruction (TPC)

  • *Invariant mass in PHOS in pp@7 TeV

  • *0 reconstruction from conversion -ray picture of ALICE

  • *Di-hadron correlationsDecember status for 900 GeV data

  • *D0 in ALICEImplementation of online D0 trigger in the HLT framework

  • *Ultra-peripheral collisions Photon induced interactions with photons produced by the EM field of the protons/nuclei Possible in pp and in Pb+Pb interactions Ongoing work: simulation studies+trigger conditions (software & hardware)

    p+p p+p+++- purely QED part + ++- photonuclear part +p J/+p +-+p

  • *ALICE upgrade plansTimeslots for potential upgrades2012: 1 year shutdown (minor upgrades)2018 (?): 1 year shutdown (major upgrades, e.g. beam line modifications)Ongoing projectscompletion of PHOS triggerupgrade of TPC and PHOS readoutHLT dynamic upgrade Potential new project: Forward calorimeters

  • *Forward physics at LHCMeasurements at small angle/large low-x parton distributionsMain physics topicsp(d)+Agluon saturationstudy of cold nuclear matter probing the initial conditionA+Aelliptic flowjet quenchinglong-range rapidity correlationsbaryon transfer

  • *RHIC vs. LHC

  • *Proposal for a forward spectrometerEM calorimeter for , 0, , J/ at y=5O(10) meters away from IPlarge dynamic rangehigh occupancy to cope with A+Atwo separation (0 2 kinematics)

    highly segmented (also longitudinally) tracking calorimeter

  • *Other activities (I)CBM@FAIRFixed target experiment, Ebeam = 30 AGeVProduction of super-dense baryonic matterChiral symmetry restoration/in-medium properties of hadrons

    Potential Norwegian contribution:Monolithic Active Pixel Sensor readout (3D stacking)Projectile Spectator Detector (forward calorimeter)High Level TriggerSo far no Norwegian funding for FAIR

  • *Other activities (II)Generic R&D projects with potential medical physics applicationsHighly segmented calorimetersCharacterization of pixel arrays of G-APD (Avalanche Photodiodes operated in Geiger mode)Collaboration with the microelectronics group at UiB and the PET-center of Bergen University Hospital (HUS) high resolution TOF PET-scanner

    Radiation effects in microelectronicsSEU in SRAMs: neutron dosimetryCollaboration with HUS, biophysics@GSI and CERN (EN/STI) hadron therapy purposes

  • *Other activities (III)Next generation pixel detectorsSensor: Monolithic Active Pixel Sensor 3D integrationhigh spatial resolution, lower capacitance (and hence, lower noise), and enough logic per pixel cell to implement fast, intelligent readout by thinning the wafers lower material budget is obtainedcollaboration with the microelectronics group at UiB

  • *SummaryNorway has a strong presence in:Hardware design/prototyping/constructionSoftwareCommissioning of hardware & softwareRun coordination for detectors & the whole of ALICETime to harvest the fruit of physics for the next 10-15 yearsAmbitious ALICE upgrade program

    ***RCU figure*copy previous slide here**