Overview of the ATLAS Insertable B-Layer (IBL) Project

14th International Workshop on Radiation Imaging Detectors
1st-5th July 2012, Figueira da Foz, Portugal
Overview of the ATLAS Insertable
B-Layer (IBL) Project
F. Djama (CPPM Marseilles)
On behalf of the ATLAS Collaboration
July 4th, 2012
IBL: A Fourth Layer for the ATLAS Pixel Detector

IBL: Insertable B-Layer (Present Pixel Detector barrel layers
are called: B-Layer, Layer 1 and Layer 2).

Performance of present Pixel Detector shown by P. Morettini.

Sensors at a radius of 3.3 cm (Current B-Layer at 5.5 cm). A
new, lighter and smaller beam pipe.
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Tracking robustness:
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Better performance:
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F. Djama
Compensates for module failures.
Helps with effects of increasing luminosity: Local saturations in
the current B-Layer modules.
Provides additional redundancy against fake combinations of hits.
Small z pitch (along the beam direction).
Closer to interaction point: Better vertexing and b-tagging
capabilities.
Better Front-End (FE) chip performance.
_
Physics use case: Study of Higgs boson properties in WH → b b.
Goal: Install the IBL in the first long shutdown of the LHC (LS1, beamto-beam: December 2012-July 2014).
ATLAS IBL Overview
2
LHC Upgrades and Long Shutdowns
 LHC startup, s = 900 GeV
bunch spacing
s=7~8 TeV, L=6x1033 4x
cm-2 s-1, bunch, spacing
50 ns 50 ns
~20-25 fb-1
Go to design energy, nominal luminosity
2525
nsns
s=13~14 TeV, L~1x1034 cm-2 s-1, ,bunch
bunchspacing
spacing
~75-100 fb-1
Injector and LHC Phase-1 upgrade to full design luminosity
s=14 TeV, L~2x1034 cm-2 s-1, ,bunch
bunchspacing
spacing25
25ns
ns
~350 fb-1
HL-LHC Phase-2 upgrade, IR, crab cavities?
?, IR
s=14 TeV, L=5x1034 cm-2 s-1, luminosity levelling
3
F. Djama
ATLAS IBL Overview
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Radiation Environment

IBL will operate:
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This corresponds to an integrated luminosity of
about 550 fb-1 .
PHOJET/FLUKA simulation, including safety factors:
IBL elements in the detector volume must withstand
benchmark of:
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F. Djama
Till the long shutdown LS3, in 2022.
at a peak luminosity 2 x 1034 cm-2 s-1.
at a radius of 3.3 cm.
A NIEL of 5 x 1015 1 MeV neutrons/cm2 .
A dose of 2.5 MGy (250 Mrad).
Comparison with B-Layer: 1015 1 MeV neutrons/cm2
and 0.5 MGy.
ATLAS IBL Overview
4
Main Requirements
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IBL to be inserted in a very small space between
new beam pipe and B-Layer:
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F. Djama
No possible overlap between modules along the beam
direction (no « shingling »).
Gaps in z direction between modules: Unvoidable
inefficiencies.
Minimize inefficiencies by developping sensors with
active edge or slim edge.
Minimize the material. Target is 1.5 % of radiation
length. Consequences on sensors, front-ends,
mechanics, cooling and services.
Tight clearances: Development of complex toolings
for present beam pipe removal, IBL integration and
insertion.
ATLAS IBL Overview
5
Requirements on Sensors
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F. Djama
Inactive edge less than 450 µm for two-chip
sensors and less than 225 µm for single chip
sensors.
Thickness less than 250 µm.
Power dissipation less than 200 mW/cm2 at -1000 V
bias (planar sensors) at a temperature smaller than
-15° C.
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Leakage current less than 100 nA/pixel.
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Hit efficiency greater than 97 % after irradiation at
benchmark fluence.
ATLAS IBL Overview
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Overall Layout
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Cylindrical layer formed by
14 staves, with sensors at
an average radius of 3.3
cm.
Stave length: 72 cm.
Staves loaded with pixel
modules: sensor-chip(s)
assemblies.
12 millions 50 × 250 µm2
pixels.
F. Djama
ATLAS IBL Overview
7
The Stave Assembly
wing
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Carbon foam (light weight, thermal conductivity).
Foam is surrounded by carbon fiber laminate (omega shell) for
stiffness.
Foam houses a titanium cooling pipe (0.1 mm wall thickness and 1.5
mm inner radius).
14 circuits of CO2 evaporative cooling. Fluid temperature at -40° C,
for a sensor temperature of -25° C.
Services and signals are routed using a polyimide-aluminium-copper
multilayer circuit, the stave flex, glued on the stave. It is connected
to each front-end chip by « wings ».
F. Djama
ATLAS IBL Overview
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Sensors on the Stave
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F. Djama
IBL to be inserted earlier than forseen in the begining.
Only « mature » technologies among the candidate
could make it: n-on-n planar silicon sensor with slim
edge, and double-sided thin edge 3D silicon sensors.
3D sensors placed at high pseudorapidity (η around
2.8), to benefit from the vertical orientation of
electrodes in measuring z coordinates, especially after
heavy irradiation.
ATLAS IBL Overview
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Slim Edge Planar Silicon Sensors
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Manufactured by CiS (Erfurt, Germany).
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n-in-n design, moderate p-spray isolation.
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Read by 2 FE-I4 Chips (2 × 80 columns × 336 rows).
Physical dimensions: 41.3 × 18.54 mm2.
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200 µm thick, 250 × 50 µm pixels except:
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The two central rows, between the 2 FE: 450 × 50 µm2.
The two external rows have their pixel extended beyond the
guard ring and have 500 × 50 µm2. This is the slim edge
concept:
Figure: S. Grinstein in ATL-INDET-PROC-2102-004
F. Djama
ATLAS IBL Overview
10
3D Silicon Sensors
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Manufactured by CNM (Barcelona, Spain) and FBK (Povo di
Trento, Italy).
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p-type bulk, two different flavor designs (same geometry and
same performance).
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Read by one FE-I4 chip (20.5 × 18.8 mm2).
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230 µm thick, p-n distance of ~ 70 µm.
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More in G.-F. Della Betta Talk.
CNM design
F. Djama
ATLAS IBL Overview
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20.2 mm
Front End Chip FE-I4
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18.8 mm
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FE-I4 Manufactured in IBM 130
nm CMOS process.
26880 channels, 150 µm thick.
FE-I4A/B
DC coupling, electron
collection.
Each pixel: Amplification,
shaping, discrimination at a
tuned threshold.
Digital processing (buffering,
trigger, encoding) shared by 2
x 2 pixels region.
4 bits dynamic range, 256
cycles latency, 160 Mb/s
bandwidth.
2.0 mm
Bump-bonded to sensors by
silver-tin solder.
F. Djama
ATLAS IBL Overview
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Leakage Current and Breakdown
Voltage
Batch:
Wafer:
ATLAS10
1
ATLAS10 - W1 - FEI4 sensor total current
230
value
# of good detectors
6
# of ~ good detectors
# of bad detectors
0
2
Class
S1
S2
S3
S4
S5
S6
S7
S8
NOK
OK
NOK
OK
OK
OK
OK
OK
CiS
sorting thresholds
o
Current @
20V
[nA]
2.00E+06
2.42E+02
2.00E+06
1.94E+02
2.15E+02
1.64E+02
1.69E+02
2.93E+02
o
1
0
1
0
0
0
0
0
"slope"
(15÷20)V
[#]
1.000
1.384
1.000
1.215
1.284
1.447
1.211
1.331
0
0
0
0
0
0
0
0
Breakdown
Voltage
[V]
8
38
6
38
39
46
47
42
1E+04
1
0
2
2.5
1E+03
1
0
0
0
1E+02
o
FBK
0
0
25
30
0
10
20
30
40
50
60
70
V_rev [V]
Notes
S4 OK S7 OK
Confortable
plateau before breakdown.
Similar
irradiation.
S1 after
S3
S6 OK S8 OK
NOK
3D sensors:S2 OK
o
S1
S2
S3
S4
S5
S6
S7
S8
1E+01
2000
5000
NOK
F. Djama
1E+05
Planar sensors:
o
o
1E+06
(nominal value/measured value)
(measured value/not available)
I [nA]
Wafer thickness [µm]
Wafer bow [µm]
S5 OK
Modest depletion voltage.
Small leakage current.
ATLAS IBL Overview
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80
Beam Test : Edge Efficiency
Planar
3D
Figure: I. Rubinsky in ATL-INDET-PROC-2102-007
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Sensors scanned with 120 GeV pion beams at CERN.
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Both technologies managed to reduce the inefficient
edge to about 200 µm.
F. Djama
ATLAS IBL Overview
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Beam Test: Cell Efficiency
• Planars:Some loss of efficiency after high radiation dose under the bias grid
even for large bias voltage.
• 3D: Losses at position of electrodes, reduced for tilted tracks.
• Both technologies within the specifications.
F. Djama
ATLAS IBL Overview
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Cluster Properties of CNM 3D Sensors
Normal incidence, 1.6 T magnetic field
F. Djama
ATLAS IBL Overview
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Cluster Properties of 3D FBK Sensors
15° incidence, no magnetic field
F. Djama
ATLAS IBL Overview
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Cluster Size for High Pseudorapidity
Tracks (η1.7) in 3D Sensors
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F. Djama
120 GeV pions incident at 80° along the long pixel
dimension: a pseudorapidity of 1.7 in ATLAS.
Naive projection gives a cluster width of 6.
Cluster width still at 4.5 after irradiation.
Spacial resolution analysis on going.
Tests at higher pseudorapidity forseen.
ATLAS IBL Overview
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Spacial Resolution
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F. Djama
120 GeV pions incident at 15°.
2-pixel clusters.
ATLAS IBL Overview
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IBL Simulation in ATLAS: Pixel hits
F. Djama
ATLAS IBL Overview
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ATLAS B-tagging performance with IBL
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F. Djama
Simulation of t t events in
ATLAS.
IBL will bring rejection of
light jets with phase 0
pileup at its level without
pileup, with the present
ATLAS Pixel Detector.
Performance will improve
when using a neural
network based clustering.
It will improve resolution
on close tracks in jet cores
(see T. Peres poster).
ATLAS IBL Overview
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Production status
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F. Djama
Sensors: 100 % delivered, including spares. Yield
of 89 and 62 % for planar and 3D respectively.
FE-I4B chips: 70 % delivered. Yield of 62 % up to
now. Already have 672 IBL quality chips (448
needed, excluding spares).
Module flex: To be received end of July 2012.
Staves: 2 in hands, last delivery in October 2012.
Stave flex: Last delivery November 2012.
Stave 0 demonstrator loaded with test modules
using FE-I4A version:
ATLAS IBL Overview
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IBL schedule overview
Activities
Starting
Ending
FEI4-B
Sept 11: Submission
Dec 11 chips received, testing
1st batch complete end Feb
2012.
Bump bonding
Aug 11: pre-production
Nov 12: Completion (incl.
Spares)
Module
assembly
End May 12: 1st modules
ready for loading
Feb 13 (spare and contingency
incl)
Module loading
Aug 12:  4 staves to be
ready by Oct 12
May 13: Completion (spare and
contingency incl)
Stave loading
Mar 13: starting with the
June 13: Completion
1st large batch of available
staves
Final tests and
commissioning
July 13
F. Djama
Sept 13: IBL Installation
(Nov 13 with contingency)
ATLAS IBL Overview
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Conclusions
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F. Djama
ATLAS will have a 4-hits Pixel Detector after the first
long LHC shutdown.
R&D efforts converged towards an achievable new
layer within the allocated time.
Tests under beam and laboratory measurements
showed that required performance is met, including
after irradiation.
Detailled ATLAS simulation showed significant
improvement in tracking, vertexing and heavy flavor
tagging. New specific developments are expected soon.
Sensors and front-end chips already secured.
Stave loading will start in august 2012.
ATLAS IBL Overview
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Backup
DBM
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F. Djama
DBM: Diamond Beam Monitors: 4 telescopes of 3
diamond pixel sensors on each side of the ATLAS
interaction point.
Sensors have the FE-I4 size.
Will be installed if the IBL is inserted on surface.
Decision on December 2012.
ATLAS IBL Overview
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nSQP
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F. Djama
SQP: Service Quarter Panel: holds connections and
services for the present Pixel Detector.
Significant mortality of VCSEL in the optical boards.
Need to bring optoboards from inside the tracker
volume to the first patch panel outside it (PP1).
Construction of new SQP (nSQP).
Will be installed only if the IBL is to be inserted on
surface.
ATLAS IBL Overview
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