31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

The ALICE Transition Radiation Detector (TRD) Read-Out Electronics

J. Mercado

Physikalisches InstitutUniversität Heidelberg

Outline:

The ALICE experiment The ALICE Transition Radiation Detector (TRD) The TRD Front-End Electronics (FEE) Integration, tests and measurements

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

The ALICE experiment

A Large Ion Collider Experiment (ALICE) at the LHC at CERN

Chief goal:

Quark-Gluon Plasma, QGP

Large Hadron Collider:• Pb+Pb at 5.5A TeV

LHC HI physics program:• 2 - 3 years Pb+Pb

L ~ 1027 cm-2 s-1

• 1 year p+Pb ‘like’

L ~ 1029 cm-2 s-1

• 1 year light ions (Ar+Ar)

1027 < L < 1029 [cm-2 s-1]

• p+p run at 14 TeV

1029 < L < 3×1030 [cm-2 s-1]

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

The ALICE experiment

ITSLow pt trackingVertexing

ITSLow pt trackingVertexing

TPCTracking, dE/dxTPCTracking, dE/dx

TRDElectron IDTRDElectron ID

TOFPIDTOFPID

HMPIDPID (RICH) @ high pt

HMPIDPID (RICH) @ high pt

PHOS,0 PHOS,0 MUON

-pairs MUON -pairs

PMD multiplicityPMD multiplicity

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Transition Radiation Detector (TRD)

Purpose: Electron ID in the central barrel

at p > 2 GeV/c Fast (6 μs) trigger for high-pt

particles (pt > 3 GeV/c)

Parameters: 540 modules → 767 m2 area 6 layers, 5 longitudinal stacks Length: 7 m, weight: ~21 tons. 28 m3 Xe/CO2 (85:15)

1.2 million analog channels 15 TB/s on-detector bandwidth

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Working principle of the TRD

• Transition Radiation (TR) is emitted whenever a charged particle crosses an interface between two media with different dielectric functions.

• TR photons (< 30 keV for e-) are absorbed by a heavy gas mixture (Xe,CO2).

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

TRD signals: electrons, pions

Test beam response of TRD for

charged pions and electrons.

For electrons, larger dE/dx with

characteristic TR energy deposit.

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

The TRD readout chamber design

Pad plane HEXCELL/CF

Amplification region

Drift region

Radiator

• 16 different types (sizes)

• Production sites:

Bucharest, Dubna, Frank

furt, GSI, Heidelberg.

• Standardized assembly

procedure in Heidelberg. B. Windelband, Uni-HD

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

The TRD supermodule

• 30 (6 × 5) chambers are arranged in

the so-called supermodule (18 in total).

Right: setup at Heidelberg for testing de-

formations under different orientations.

• Length: 7 m, weight: 300 kg.

Left: supermodule insertion in

the ALICE space frame (lifting

device already ordered).

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

The TRD Front-End Electronics

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

The TRD electronics chain

18 + 3Channels

PASA ADCTracklet

Preprocessor

TPP

TrackletProcessor

TPTRD

TrackletMerger

TM

event buffer

GTU

L1 triggerto CTP

To HLT & DAQ

chargesensitive

preamplifierShaper

ADC10 Bits10 MHz

detector6 layers1200000Channels

dig . filter(pedestal,tail corr)

preprocessdata

fit tracklets@L1A

compress &ship RAW

data

Readouttree

270 GB/sec

Merge trackletsinto tracks

Compute RoIShip RAW data

@L2A

Store RAW data until L1A

Multi-Chip Module (MCM)

• Custom preamplifier and shaper (PASA) analog IC (CMOS 0.35 μm).

• Custom 10-Bit, 10 MSPS ADC designed in the UMC 0.18 μm process.

• Custom MIMD Tracklet Processor (TRAP) implementing 4 RISC CPUs.

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Multi-Chip Module (MCM)

4 cm

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Time budget

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Detector Control System (DCS)

DCS will control and operate

the whole experiment during

all modes of operation

DCS board overview:

• Altera FPGA (100k gates)

• Ethernet physical layer chip

• 32 MByte SDRAM

• 4 MByte flash EPROM

• TTCrx clock recovery

• 3.3 and 1.8 voltage regs.

• RS422 JTAG driver

• LVDS Clk and trigger driver

• 16 bit ADC (10 SPS)

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Detector Control System (DCS)

DCS status:

• Prototype finished (submitted)

• Extended radiation tests

• Communication via Ethernet

in B-field tested

• TRAP chips fully configured

through DCS board

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

TRD electronics integration setup

Readout Board

Readout Chamber

MCMs

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Pedestal and noise measurements

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Outlook & test beam plans

Outlook:Chamber production underway at several production sites.

Supermodule and services infrastructure well under way.

PASA: ready, TRAP3: ready, final MCM: in production.

Final Readout Boards: in production.

Test beam plans at CERN:From Oct. 11th until Nov. 5th, 2004 (e-,π up to 10 GeV/c at T9 site).

Full stack test (6 chambers): Chambers, final electronics, DCS and, possibly, DATE.

Verifying all possible detector orientations.

Calibration data set for e-,π –separation.

Further TR measurements.

31.08.2004 Jorge Mercado - I3HP Topical Workshop - St. Andrews

Thank You