Development of the silicon microstrip supermodule prototype for the HL-LHC
8th "Hiroshima" Symposium on Development and Application of Semiconductor
Tracking Detectors (HSTD-8),
Taipei, Taiwan, December 3-8, 2011
Outline:
1. Background: HL-LHC and resulting tracking detector upgrades
2. A proposed silicon microstrip implementation for HL-LHC: module and
super-module design features
3. Where are we?
4. Comparison with HL-LHC requirements
5. Future design evolution
6. Feasibility for a construction and production success
University of Geneva: G. Barbier, F. Cadoux, A. Clark, Y. Favre, D. Ferrère, S. Gonzalez- Sevilla,
G. Iacoubucci, D. la Marra, M. Pohl, M. Weber
KEK:
Y. Ikegami, Y. Takubo. S. Terada, Y. Unno
University of Tsukuba: K. Hara
Osaka University:
M. Endo, K. Hanagaki
Probable schedule after Chamonix 2011 (1 year shift)
Machine and Detectors at HL-LHC
2012
2011
2012
2013
2018
2014
2019
2015
2020
2016
2021
2017
2022
Lpeak ~ 3.65 x 1033 cm-2s-1 Lint ~ 5 fb-1
Lpeak ~ 5 x 1033 cm-2s-1
2011
2012
√s=7 TeV
√s=8 TeV
2014 - 16
2018 - 20
√s=14 TeV Lpeak > 5 x 1033 cm-2s-1
Lpeak ~ 2-3 x 1034 cm-2s-1 Lint ~ 300 - 400 fb-1
> 2022
Lpeak ~ 5 x 1034 cm-2s-1 Lint ~ 3000 fb-1 (luminosity levelling)
– 25 nsec bunch spacing
– Tracking performance should be maintained with up to
~200 collisions per bunch crossing
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Benchmark layout and performance requirements (1)
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Benchmark layout and performance requirements (2)
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Prototype Module Design
Features:
• Detectors are mounted back-to-back, true stereo reconstruction
 Space point integrated by the module assembly with the precision of the jigs (~1 µm)
 Sensor 96 x 96 mm2, (short) strips 24 x 0.08 mm2
• Precise module location on the local structure
 Thanks to centering bushes: origin + alignment
• Bridge hybrid allows FE thermal path different from Si (stabilty consequences)
NB: Direct mounting save material and no show stopper in term of thermal performance
• Low CTE material and Good thermal conductivity: Si, TPG, CC, AlN
 Max Z deformation 1.4m @ -35°C
• Hybrid pigtails + connector for electrical connections (option)
Modularity and flexibility
• Module assembly known and simplified in term of procedure and QA: Inherited from SCT barrel
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Module Assembly Parts – low material budget
TPG and Ceramic facings
Populated hybrid with CC bridge
Sensor to baseboard assembly
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Module thermal FEA with and without CC bridge
Recent FEA calculations investigated by Franck
CO2 based
-35°C as coolant temp.
2mm ID pipe
Chip: 0,3W
Bridge hybrids
Hybrid glued on the Si-sensor
No wire bonds connected here…
Some gap in here…
Sensor temperature
[-22, -24 °C]
Sensor temperature
[-19, -22 °C]
Temperature offset and distribution is slightly larger but acceptable as compared with the bridged FEA
Recall: Thermal run-away was found to be around a factor 4 to the LHC Si power density for bridged design
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Module Electrical Performance
Modules constructed
Module made at KEK
Additional modules are under
industrialization process with
local Japanese companies
Essential to survey for future
production evaluation
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Module Electrical Performance
Module Performance
Typical noise results from the 4 module test box
Hybrid 0
564 to 590e-
Col
0
Col 1
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Hybrid 1
Col 0
Col 1
Identical noise inside a
single module test box
or when combined in
the 4 module test box
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Module Electrical Performance
Module Irradiation
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Super-module Design Features
• Modular concept. All parts decoupled from module design and are modular:
• cooling, local support, service bus, powering units, SMC
• during prototyping, flexibility of evolutions: electronics, service bus, cooling, mechanics versions
•parallel assembly at all stages: components prototyping & procurement, fabrication & QA
• Full module coverage in Z
• Space points: distance to the stereo side of 400 microns: space point resolution equivalent to SCT
• Rework : ability to easilyrework up to the commissioning after integration
• End-insertion: >1m20 stiff Local Support allows simple support structure and service modularity
• Low thermo-mechanical stresses:.service bus almost free, cooling pipe uses sliding joins.
Super-Module
1.2 m long with 960 ABCN readout chips
Made of 12 double-sided modules assembled on a local support
Coolant tube structure
Hybrids & FE ABCN
Super-Module
Controller
Local Support
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Super-module Mechanical Structure Design
CAD view of the SM2.0 (Modules have been removed for clarity)
Cross beam x7
(in T300 prepreg)
Cooling Plates x6
(prototyped in
aluminum…
CC2D at the end)
Central pipe in T300
(key part!)
Every sub part assembled with DP490 glue
(with jig and centering pieces)
Cross beam
(or « wings »)
Guiding pipe
(T300)
Cooling pipe
Cover (T300)
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Modules
(TPG, Si, Hybrid,…)
Joint pieces in plastic
(polycarbonate for proto)
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Super-module Mechanical Structure Design
End Insertion as a reminder
Safe handling
The SM slides w/o stress into the
structure (locking in 3 positions)
End Insertion using a
Removable inner guide rail
Guide rail
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End Insertion also developed for “stave” concept
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Super-module Mechanical Prototype
Concept validated with endinsertion interfacing dummy
barrel locking system
Module + Cooling plate and
loop independent from LS
Light CFRP local support structure
(UniGe – Composite Design)
Total support 0.18 X0
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Easy handling…
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Super-module Load Tests and FEA
FEA’s outcome on a 1200mm SM
1G
Carbon fiber
Layup (M55J)
Load case
Deflection
(micron)
Max Stress
(Mpa)
16°
77
11
Vertical
80
12
Horizontal
11
10
Eigenvalue
f1: 57 hz
-
Module material
assembly
Modal shape
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Major load and distortion measurements
underway to compare/input in FEA, and aid next
design iteration
Results very positive
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Cooling and Mechanical Performance
Measurements of thermal conductivity
cross-checked with FEA (K. Streit)
Grease Sample
Th. Cond. [W/mK]
Comments
DC340
0.7
Used on SCT
DC340 irradiated
0.8
Polymerized @ 1.1015 1Mev neq/cm2
WLPG
1.2
Colza oil with graphite. Leaking oil…
WLPG irradiated
1.05
Pasty but ok after irradiation
WLPF
0.5
Non-silicone + metal oxyde
Electrolube HTCP
1.5
Non-silicone + Zinc oxyde
Focus – IBL baseline
Samples of HTCP irradiated up to 1.2x1016 1MeV neq/cm2 for IBL
Samples drying and dryer but OK with SCT fluences
F
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F
• 2.3mm OD Ti-pipe with ~50-70 micron
• Grease area ~70mm2 per pipe
•Irradiated at 1x1015 1MeV neq/cm2
•Thermal conductivity satisfactory
•Young Modulus increases from ~40 Mpa to 160 Mpa
•Very positive result, being input into FEA calculations
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Super-module Electrical Prototype
Module removed from 4 Module Box
Module support jig
Modules with wiggly service buses, BCC boards and DC-DC
1st module mounted on the structure
4 mounted modules
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Super-module Electrical Prototype Performance
See talk of Sergio Gonzalez
Sevilla at this conference
Aim: study of 8-module readout
Status: 4 modules so far read out
successfully
Hybrid noise versus
chip id
Hybrid noise versus
col
Noise is uniform
ENC/hybrid < ~ 600e-
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S. Gonzalez Sevilla, Y. Takubo) +
collaboration for r/o between “supermodule” and “stave” R&D projects
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Comparison with HL-LHC Requirements
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Next Steps
Status:
Close to demonstrating feasibility and practicability of super module solution
for ATLAS Phase II tracking detector
Will allow technical comparison with competing technologies
Evolution: Evolution of sensor design
Development of front-end electronics (ABCN 130 nm design)
Evolution and implementation of read-out architecture
Members of Super Module R&D strongly involved in all these developments
Next steps: 2012: Thermal and electrical measurements on 2nd iteration LS with modules
and dummy thermal modules (CO2 cooling)
: 2nd iteration module design studies
: 2013: Development of pre-production LS and module prototypes optimized for
material, electrical (ABCN 130) and thermo-mechanical performance after
irradiation, and construction simplicity
: issues: adapt to layout criteria
: optimization of the service bus
: LV services (DC-DC or SP powering)
: HV services (4 module per HV line?, 1 HV line per LS?)
: tradeoff between performance (material, noise pickup) and robustness
(next slides)
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Module Design Evolution
1st draft layout with ABCN130, HCC under investigation
Cooling plates and tubes
GND AC coupling with HVret
Flexible pigtail with
connector and stiffener
Input Filtering
Stiffener linking the 2
sides possibly free from
the local support
HCC
Power
Card
CC + hybrid flex
“U” bridge
HCC
D. Ferrere
S. Gonzalez Sevilla
Comments:
- Symmetry between the two rows is quite important
- Power card (DC-DC or SP) implantation is quite challenging and needs study
- Pigtail flexibility is essential to pass over the cooling plate
- EMI investigation is essential when considering DC-DC
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Super-Module Design Evolution
Module #1
Cooling In
Module #2
Module #8
TTC, Data &
DCS
SMB
Cooling In
Service bus
DCDC
BCC board
DCDC
DCDC
Cooling In
BCC board
DCDC
DCDC
BCC board
DCDC
PS cable
HV cable
Extrapolated version with ABCN130 & HCC
Module #1
Cooling In
TTC, Data &
DCS fibers
Module #2
Module #12
P
S
P
S
Opto
SMC
DCS, Interlock
GBT SCA
P
S
Cooling Out
PS cable
HV cable
SMC
Hybrid
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HCC
HCC
HCC
HCC
Service bus
F. Cadoux, Y. Favre, D. Ferrere
HCC
HCC
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Design Evolution – 3D Models
1st version of new module
design using 3D
Will serve as input for thermal
and thermo-mechanical FEA
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Integration of modules on the cooling plates
and optimized LS
Integration of supermodule with Local Support
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Material Budget Estimation
Item
Rad. length [% X0]
Module with CC bridge (12mm width)
-
1.59
Module without CC bridge
1.49
-
Local support
0.18
0.18
Cooling plates
0.25
0.25
Bracket, inserts (interface to cylinder)
0.08
0.08
Cooling pipe (Ti 2mm)
0.04
0.04
Cable bus Al/Cu
0.19
-
-
0.31
2.23
2.45
Cable bus Cu only
Total
From Y. Unno (evolving)
NB:
• The sensor thickness is considered 320 m. If 250 m one gains 0.15%!
• The list above does not include the power cards: serial power interface or DC-DC card
• Module without CC bridge means that the hybrid flex is directly glued on top of the Si-sensor. This
must be investigated.
• Al/Cu bus is a multilayer flex which is the IBL baseline.
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Module Production and Organization
Integration
Collaborating Institutes
Operations
SM shipment
Assm Sites
Operations
CERN
Module assembly
Individual component QA and checks
Module assembly
Module metrology
Wire bonding
Thermal cycling
Module metrology
Electrical QA and inspection
Storage
SM reception tests
Barrel structure assembly
Structure alignment survey
SM end insertion
Commissioning the full barrel
SM assembly
Next
LS inspections and basics checks
Pipe checks
Service checks
SMC hybrid functionality checks
Module assembly on LS with pipe
Service assembly
SMC hybrid assembly
SM metrology
SM QA
Storage until shipment
Parallel prototyping, procurement, assembly possible for all parts of the supermodules
•
•
•
Modules/supermodules replaceable at all stages, even when assembled on barrel
Simplification and flexibility of prototyping (e.g. prototype changes to SMC-GBT, service bus, LS, pipe)
Flexibility to layout and production changes
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From D. Ferrere
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Conclusions
1. The double sided-module program is close to demonstrating feasibility for HL-LHC
•
•
•
•
The noise performance on single module test box, combined module test box or on the
super-module prototypes using DC-DC is as expected and below ~600eExpected good mechanical stability for modules, and supermodules on LS (design is
optimised for thermal stability)
Flexibility in design (true stereo space-points, possibility of z-overlaps etc)
Some key questions remain, independent of super module (services, layout, trigger …)
2. New layout considering a realistic “pre-production” design has started
•
•
ABCN130, HCC and a dedicated service
competitive material budget (service material is one of the keys material to be workedout)
1. Assembly parallelism and flexibility
•
•
Possible at all stages of prototyping, assembly and integration
Maximizes quality, minimizes risks
2. Much still to be done ……
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Module Thermo-mechanical FEA Checks
Max stress in the TPG ~16 MPa  much lower
than the TPG tensile strength (40 MPa)
Von Mises stresses in TPG plane
A module elongation of ~10 microns is probed
at the opposite side of the module origin
Deflection in the module
Max deformation / bow is less than 1.5micron in the sensor baseboard
Z deformation top side
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Z deformation bottom side
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Super-module Load Tests and FEA
Load testing applied to the Prototype (several weight, locations,…)
SM onto the granite table @ Unige (+ its assembly jig)
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F. Cadoux, G. Barbier
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Super-module Load Tests and FEA
Same Load testing applied to the Prototype but “FEA wise” (several weight, locations,…)
F1
C2
C1
Pretty good agreement!
(FEA : 0,5-0,6mm / Test: 0.65mm)
F1
How does it compare with tests??
 Only check / one F1 location
 C1: OK while… C2: NOK so far!
 Fine tune the wing stiffness
 wing rotation (F applied on bridge end)
under evaluation…
F. Cadoux, G. Barbier
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Service Bus Development
Inputs for future design:
• HCC integrated on the hybrid together with ABCN130
• Direct hybrid pigtail connection to service bus – 1 connector for 2 hybrids
• Mass optimization to be considered: LV traces (Al vs Cu), connectors, bus dimension
• Multi-drop LVDS to think (without LVDS fanout)
• Steer the CTE mismatch between service bus and super-module local support
• HV line insulation: via + open pads and connectors
• Impedance adaptation for LVDS lines: Point-to-point and multi-drop
• Shield plane for LVDS and HV. EMI investigation (simulation, measurements, …)
• Service bus temperature should be estimated and stay homogenous
• DC-DC or SP interface to hybrid, bus and cooling?
• Fabrication issue to be investigated: Al mixed with Cu versus service bus length
Two types identified:
• Multilayer flex with Al-layers for LV supply and Cu-traces for the other lines (Like IBL)
• Multi-stack of 2-layers: 1 with Al for LV supply assembled via connectors to two-layers Cu.
NB: Assembly precision need to be better than ~ ¼ of the connector pitch
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References
Super-module:
• ATLAS public note: ATL-UPGRADE-PUB-2011-002
“Design and assembly of double-sided silicon strip module prototypes for the ATLAS
upgrade strip tracker”
• TWEPP Poster (S. Gonzalez Sevilla): 2011 JINST 6 C11002
http://iopscience.iop.org/1748-0221/6/11/C11002/
Thermal grease:
• ATLAS public note: ATL-UPGRADE-PUB-2010-002
“Thermal Grease Evaluation for ATLAS Upgrade Micro-Strip Detector”
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