RECFA meeting, Bratislava, 1 October 2004L. Šándor, IEP SAS, Košice 1 Building ALICE for heavy-ion physics at LHC Ladislav Šándor Slovak Academy of Science

RECFA meeting, Bratislava, 1 October 2004 L. Šándor, IEP SAS, Košice 1

Building ALICEfor heavy-ion physics at LHC

Building ALICEfor heavy-ion physics at LHC

Ladislav ŠándorSlovak Academy of Science

Institute of Experimental PhysicsKošice

• Slovak participation in ALICE• Contribution of Košice team


Why Slovak involvement in ALICE ?

• Active work of Slovak physicists (both experimentalists and theorists) in heavy-ion physics for more then a decade

• Fruitful experience from a number of SPS experiments (NA34-Helios, WA97, NA49, NA57)

• Unique potential of ALICE – the only dedicated heavy-ion experiment at LHC – for A-A, p-A and also p-p physics attracting interest of

qualified teams from Bratislava and Košice

to continue working in heavy-ion physics


SOUTH AFRICA

UKPORTUGAL

JINR

GERMANY

SWEDEN

CZECH REP.

HUNGARYNORWAY

SLOVAKIA

POLANDNETHERLANDS

GREECEDENMARK

FINLAND

SWITZERLAND

RUSSIA CERN

FRANCE

MEXICOCROATIA

ROMANIA

CHINA

USAARMENIA

UKRAINE

INDIA

ITALY

S. KOREA

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1990 1992 1994 1996 1998 2000 2002 2004

ALICE

Collaboration statistics

LoI

MoU

TP

TDR

937 members (63% from CERN MS)

77 institutions 29 countries

~ 25 Slovak physicists and engineers

ALICE collaboration


ALICE physics goals

• Deconfinement: charmonium and bottonium spectroscopy•Chiral symmetry restoration: neutral to charged ratios, res. decays •Fluctuation phenomena - critical behavior: event-by-event particle comp. and spectra• Geometry of the emitting source: HBT, impact parameter via zero-degree energy flow• pp collisions in a new energy domain

Selective triggering Excellent granularity Large acceptance Good tracking capabilities

Wide momentum coverage PID of hadrons and leptons Good secondary vertex reconstruction Photon detection

Use a variety of experimental techniques !

Global observables: Multiplicities, distributions

Degrees of freedom as a function of T: hadron ratios and spectra, dilepton continuum, direct photons

Early state manifestation of collective effects: elliptic flow

Energy loss of partons in quark gluon plasma: jet quenching, high pt spectra, open charm and open beauty


The ALICE experiment

ITSLow pt trackingVertexing

ITSLow pt trackingVertexing

TPCTracking, dEdxTPCTracking, dEdx


Slovak contribution to ALICE

•Comenius University Bratislava

(see talk by B. Sitár)

read-out chambers

for the TPC detector pixel testing set-up, SPD on-line software

• IEP SAS and Šafárik University Košice electronics for silicon pixel detector electronics for central trigger unit physics simulations

Total CORE commitment: 700 kCHF


Košice ALICE team activities• Contribution to the Silicon Pixel Detector

(SPD) electronics• Contribution to the central trigger

electronics and software• Simulations of the radiation situation

in ALICE environment• Physics simulations, analysis tools

development (new, just starting activity)

Košice team: 12 physicists and engineersfrom Institute of Experimental Physics, SAS and Physics Institute of P.J. Šafárik University

Laboratory for design and development of electronics built at the IEP SAS (Quartus & PADS software, 6U/9U VME crate, …)


Rout=43.6 cm

2 strips

2 drifts

2 pixels

The Inner Tracking System (ITS)Silicon Pixel Detector

The ALICE SPDALICE

• Magnetic field < 0.5 T• Charged particle multiplicity up to 8000 per rapidity unit in central Pb-Pb collisions

• Two SPD layers at r = 3.9 & 7.6 cm• Structured to 60 staves containing 9.8 M active pixel channels


SPD readout architectureDCS

Trig

DAQ

JTAG, CLK, Detector Data

~100m

PCI-MXI-II-VME

VME Router Card

1 router services 6 halfstavesSPD contains 20 router boards

Košice commitment(J. Bán, M. Krivda)


Main tasks of SPD Router

• Receive trigger signals from the Local Trigger Unit (L0 - only for synchronization, L1, L2Y, L2N) and send them to detector

• Send busy signal to ALICE trigger and DAQ• Read-out data from 6 half staves ( after receiving L2Y )• Assert the flag “flush event” (no read-out) after receiving L2N• Check errors and store them in status register accessible from

VME (DCS)• Merge data to one block with a defined ALICE data header • Send data to DAQ• Extract data flowing to DAQ and store them to SPY memory

available for analysis via VME (for debugging purposes) • Automatic configuration of SPD after power up• Autocalibration of SPD• Processing power available to run complex algorithm (future)


SPD Router architecture

• 9U-VME board with mezzanine boards• 3 Link receivers on mezzanine board (6 half staves)• TTC Rx chip (BGA package) soldered on board –

interface to ALICE trigger • SIU DDL module on mezzanine board – interface to ALICE DAQ• JTAG controller with 6 ports (half staves)• SPY controller and memory for sampling DAQ data• SPY memory (external big dual port RAM) for debugging purposes and calibration data• Parallel synchronous bus (32 bit data, 21 bit address, control lines)• All controllers implement I/O buffers in one FPGA


Router architecture – data flow

Routercontroller

JTAGcontroller

TTC rx DDL

Link receiver 1

Link receiver 2

Link receiver 3

Clock distribution

SPYcontroller

Data (32)

Address (21)

Op

tica

l lin

ks

of d

etec

tor

ALICE

Trigger DAQ

SPYmemory

DCS

VME bus


SPD router board prototype

First router board prototype (designed by M. Krivda in co-operation with CERN team) has been produced at CERN, now undergoing testing

Complex tests of router prototype functionality during the forthcoming SPD testbeam run (October 2004)

Production of the second prototype in Slovak industry (end 2004 / beginning 2005)


JTAG controller card• Fully functional part of the router produced as a stand-alone card for pixel testing set-ups• 6U VME board with 4 JTAG channels • control of data processing with macroinstructions• very complex design fitting specific ALICE requirements with possibility to implement new algorithms in future• 24 JTAG controllers produced in Slovak industry for usage in testing set-ups at CERN, Italian and Slovak laboratories Used in test setups of pixel chip for:• configuration and testing of pixel chip registers • control and monitoring of test setup environment


JTAG controller


VME Master

JTAG Controller

R/OController

PixelCarrier

DAQAdapter

PixelChip

Pixel test system components


ALICE trigger development• Close collaboration with the University of Birmingham• Design and prototyping the TTCit (Trigger Timing and Control interface test) board – an optional debugging and monitoring tool at the level of the subdetector TTC partition (S. Fedor)• Development of corresponding monitoring

software (I. Králik)• Design and implementation of the CTP online software (A. Jusko, now at Birmingham)• Participation in design and production of a part of the CTP hardware (future)


TTCit board• 6U-VME board• Dedicated L0 input in LVDS format• Single TTC optical channel• Reprogrammable TTCit logic via VME bus• Oscilloscope access to FPGA and TTCrx signals • Design in final stage• Review of design in October• First prototype end 2004


Radiation levels in ALICE

The ALICE design parameters together with running plans (collision systems, luminosity,running time) determine the radiation load.Order of magitude of the problem: 4 x 1015 particles produced in all planned primary collisions (6 x 1014 particles in Pb-Pb interactions) 2 x 1014 particles are produced in beam-gas collisions inside

the ALICE experimental area (IP +/- 20 m) 8 x 1014 particles enter ALICE environment as a beam-halo

Detailed knowledge of radiation level importantfor optimization of detector and electronics design


Simulations• Detailed estimate of the radiation level can

only be obtained from simulations using transport codes– Input primary particles simulated with HIJING, Pythia,

DPMJET and boundary source for beam halo– Transport code: FLUKA – Scaling of results performed for 10 years running

scenario of ALICESimulations of the radiation level in ALICE – commitment of Košice team from 1998 (principal investigator - B. Pastirčák)

Large-scale amount of simulations performed resulting in : optimisation of radiation level in the muon and trigger chambers leading to proposal of a shielding (small angle absorber) in the ALICE muon arm global calculation of radiation level in all subdetectors (including electronics racks) assuming 10 years of ALICE operation


Dosesand

neutron fluences

in mid-rapidity ALICE detectors

For more details see ALICE internal publications


Neutron fluence map

z (cm)


Dose map (Gy)

z (cm)


Charged hadrons fluence map

z (cm)


Lessons from simulations …• Primary physics collisions in the IP are the dominant

source of radiation load. However, with more pessimistic assumptions on residual gas pressure the beam-gas contribution could be of equal order of magnitude

• Highest doses (several kGy) are reached in the inner SPD layer and at the inner radii of forward detectors (FMD, V0, T0)

• Hadron fluences are up to 4 x 1012 cm-2 (SPD1)• The highest doses in the electronic racks are on the level

of 10 mGy with n-fluences up to 109 cm-2

• Radiation simulations now practically completed and the

results were utilitized at different stages of detector and

electronics design and prototyping

Documents

RECFA meeting, Bratislava, 1 October 2004L. Šándor, IEP SAS, Košice 1 Building ALICE for heavy-ion physics at LHC Ladislav Šándor Slovak Academy of Science