The ALICE Transition Radiation Detector
(TRD) Read-Out Electronics
J. Mercado
Physikalisches Institut
Universität 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 -
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 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 -
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 -
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 -
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
B. Windelband, Uni-HD procedure in Heidelberg.
31.08.2004 Jorge Mercado - I3HP Topical Workshop -
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 -
The TRD Front-End
Electronics
31.08.2004 Jorge Mercado - I3HP Topical Workshop -
The TRD electronics chain
• 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.
L1 trigger
Multi-Chip Module (MCM) to CTP
Tracklet Tracklet Tracklet
To HLT
TRD PASA ADC Preprocessor Processor Merger GTU
TPP & DAQ
TP TM
event buffer
Store RAW data until L1A
detector charge ADC dig . filter fit tracklets Readout Merge tracklets
6 layers sensitive 10 Bits (pedestal, @L1A tree into tracks
1200000 preamplifier 10 MHz tail corr) compress & 270 GB/sec Compute RoI
Channels Shaper 18 + 3 preprocess ship RAW Ship RAW data
Channels data data @L2A
31.08.2004 Jorge Mercado - I3HP Topical Workshop -
Multi-Chip Module (MCM)
4 cm
31.08.2004 Jorge Mercado - I3HP Topical Workshop -
Time budget
31.08.2004 Jorge Mercado - I3HP Topical Workshop -
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 -
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 -
TRD electronics integration
setup
MCMs
Readout Board
Readout Chamber
31.08.2004 Jorge Mercado - I3HP Topical Workshop -
Pedestal and noise
measurements
31.08.2004 Jorge Mercado - I3HP Topical Workshop -
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 -
Thank You
31.08.2004 Jorge Mercado - I3HP Topical Workshop -