Pixel 2002 - Carmel
The ATLAS Pixel Detector
Pixel 2002 Workshop
M. Garcia-Sciveres
Lawrence Berkeley National Lab
Sept. 9, 2002
M. Garcia-Sciveres - The ATLAS Pixel Detector
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Pixel 2002 - Carmel
Aerial View of the LHC Site
Circumference of 27 km
Main CERN Site
Sept. 9, 2002
M. Garcia-Sciveres - The ATLAS Pixel Detector
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Pixel 2002 - Carmel
A Toroidal LHC ApparatuS
Muon Detectors
Superconducting
Toroids
Inner Tracking
LHC beam
pipe
Calorimeters
Sept. 9, 2002
Tall person
Superconducting
Solenoid
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Pixel 2002 - Carmel
ATLAS Inner Detector
Sept. 9, 2002
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Pixel 2002 - Carmel
Pixel Detector
3 hit design
1.3m
Sept. 9, 2002
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Pixel 2002 - Carmel
ATLAS Pixel Collaboration
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University of Toronto, Canada
Academy of Sciences of the Czech Republic
Czech Technical University
Charles University, Czech Republic
CPPM, France
U. of Bonn, Germany
U. of Dortmund, Germany
MPI, Germany
U. of Siegen, Germany
U. of Wuppertal, Germany
INFN Genova, Italy
Sept. 9, 2002
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INFN Milano, Italy
INFN Udine, Italy
Academia Sinica, Taiwan
SUNY Albany, USA
LBNL, USA
Iowa State U., USA
U. of New Mexico, USA
Ohio State U., USA
U. of Oklahoma, USA
UC Santa Cruz, USA
U. of Wisconsin Madison. USA
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Pixel 2002 - Carmel
Detector Parameters
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3 Barrel layers, 3+3 Disks covering |h|<2.5
Inner radius: ~5cm Outer radius: ~12cm
n+ on n oxygenated sensors, 400mm (z,R) x 50mm (phi) pixels.
Number of channels 67M (barrel) + 13M (disks).
Readout type: zero-suppressed time over threshold.
Lifetime Dose, 1015 neq/cm2, 50MRad.
LHC Interaction rate: 40MHz.
Max readout rate: 160Gb/sec => 7KHz trigger at 1% occupancy.
ASICs: 0.25mm CMOS with rad. Tolerant layout .
AC signal protocol: LVDS in active volume, optical outside.
Active volume operating power: 6.5kW at 2V
Silicon operating temperature: <0oC
Cooling system: evaporative C3F8.
Radiation length at normal incidence: ~10% R.L.
Sept. 9, 2002
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Pixel 2002 - Carmel
Performance
s=9mm
s=13mm
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Test beam measurement of
single Front End chip bump
bonded assembly. For single
hits expect s=sqrt(12) x
pitch ~ 14mm.
Efficiency
Test beam measurement of
hit efficiency unirradiated
and fully irradiated
assemblies.
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Time (10ns/div.)
Sept. 9, 2002
Time (10ns/div.)
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Pixel 2002 - Carmel
Sensors
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2 Manufacturers: CIS and Tesla
Basic Requirements:
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Leakage current after 1015 neq/cm2: <50nA / pixel
Total input capacitance: <400fF
Inter-pixel capacitance: small
Signal after irradiation: >10Ke-
Simulation of 70%
depletion voltage at
innermost layer.
150% LHC nominal
fluence.
Sept. 9, 2002
M. Garcia-Sciveres - The ATLAS Pixel Detector
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Pixel 2002 - Carmel
Sensors (cont.)
Detail of p-side multi guard ring
structure
Charge collection efficiency (meas)
Sept. 9, 2002
100mm wafer with 3 “tiles”, n side
n+ implants and bias grid
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Pixel 2002 - Carmel
Custom ASIC Electronics
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Suite of chips all fabricated in 0.25mm commercial bulk CMOS.
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Use circuit library with special layout rules for radiation tolerance
(based on RD49 library)
Front End Chip
2880 channels
Module Control Chip
Manages data & control
between module’s 16 chips
Optical interface
chips
Doric
(from PIN diode to
decoded LVDS)
VDC array
(from LVDS to
laser diodes)
Sept. 9, 2002
M. Garcia-Sciveres - The ATLAS Pixel Detector
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Pixel 2002 - Carmel
Readout architecture
sensor
FE chip
Module
Control
Chip
FE chip
FE chip
Optical
driver
1m
100m
Optical
receiver
power
HV bias
bump bonds
LVDS control
optical
LVDS data out
Sept. 9, 2002
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Pixel 2002 - Carmel
The “Bare” Module
Indium Bumps
Solder Bumps
OR
2cm
50mm
16 chips. 46,080 bump bonds
Sensor
Xray of bumps
ICs
6.3cm
Sept. 9, 2002
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Pixel 2002 - Carmel
Pixel Module
Pigtail (beyond)
Sensor
ASICs
Flex Hybrid (green)
Bumps
Wirebonds
Schematic Cross Section
(through here)
Sept. 9, 2002
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Pixel 2002 - Carmel
Interconnection
Flex hybrid. Interconnects 16 Front End
chips to 1 Module Control. Distributes
power to all chips and bias to sensor.
All connections wirebonded.
Flex pigtail + Al/Cu wire
bundle connect flex hybrid to
patch panels at either end of
pixel detector.
Transition to optical at ends of
pixel detector. Power
continues on Al/Cu wires to
end or inner detector.
Sept. 9, 2002
M. Garcia-Sciveres - The ATLAS Pixel Detector
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Pixel 2002 - Carmel
Production line oriented design
Bar code
Fully
assembled
module on
frame
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Flex hybrids mounted on frames immediately after fabrication.
All module assembly proceeds on frame.
Allows safe shipping & handling, testing, bar-code tracking, storage.
Modules are removed from frame (by cutting sacrificial ends of flex)
only at the time of attaching to a local support.
Sept. 9, 2002
M. Garcia-Sciveres - The ATLAS Pixel Detector
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Pixel 2002 - Carmel
Detector building blocks
Sector is replicated to
form disks. 3+3 modules
(back side looks the same)
Bi-stave assembly
Is replicated to form
Barrel layers. 2x13 modules
Same unit repeated many times for production line
assembly, uniformity of work at different sites
Sept. 9, 2002
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Pixel 2002 - Carmel
Mechanics and services
• In the detector volume:
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high power density
minimum material (=> no thermal mass)
cold operation
<10mm alignment maintained between room and operating
temperatures
– Remain cold & dry even during down times
• Outside detector volume:
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Supply 2V power from 100m away with acceptable voltage drop
Supply adequate cooling with minimal plumbing
Meet overall detector geometry and installation constraints
Minimize material in front of calorimeters at low angles
Sept. 9, 2002
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Pixel 2002 - Carmel
Module support
Stave
Disk Sector Concept
PEEK buttons
Carbon-carbon
faceplate 0.43 mm
Aluminum tube
Carbon foam
CGL-7018
Exploded view
of sector
Carbon-carbon
hard points
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Sept. 9, 2002
Cyanate-ester
film adhesive
M. Garcia-Sciveres - The ATLAS Pixel Detector
Carbon-carbon
faceplate 0.43 mm
M. Gilchriese
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Pixel 2002 - Carmel
Global Support
Solid computer model of
frame (cutaway view)
disks
Need very stiff low mass
structures with near zero CTE
(build at room temperatureoperate down to –25C). Use
carbon composites, intense
computer modeling & simulation
Real life prototype
Disk section of frame
TV Holograph image
disks
barrel
F.E.A.
1st mode546 Hz
Sept. 9, 2002
M. Garcia-Sciveres - The ATLAS Pixel Detector
1st mode
515.6 Hz
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Pixel 2002 - Carmel
Pixel and Beam Pipe Assembly
A “package” that can be inserted in
place into the inner detector
(and removed
also)
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Pixel Detector
Fits into a support tube
that provides mechanical support,
but also electrical and environmental isolation
from the outside. Cold inside & dry inside & out no
matter outside conditions
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Pixel 2002 - Carmel
Construction Timeline
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Sensor production: started
Pre-production chip submission: Dec. 2002
Production chip submission: Summer 2003
End Production Module assembly: Dec. 2004
Start integration at CERN: Jan. 2005
Start lowering detector into cavern: Fall 2005
Begin commissioning: Spring 2006
First collisions: 2007
Sept. 9, 2002
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