Velo Upgrade for high
luminosity operation
Marina Artuso Syracuse University
Requirements
Technology choices
R&D Issues
Cost and timeline
1/12/2007
Marina Artuso LHCb High Luminosity
Upgrade Workshop
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LHCb Upgrade Goals
Upgrade LHCb detector such that it can operate
at 10 times design luminosity of ℒ ~ 2 x1033
cm-2s-1
z Upgrade LHCb detector to maximize sensitivity
to many interesting hadronic channels
z
Vertex trigger
z Optimization of photon detection
z
1/12/2007
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Upgrade Workshop
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Impact on vertex detector upgrade
requirements
Radiation resistance (>1015 1 MeV
neutroneq /cm2 )
z Fast and robust pattern recognition
capabilities ⇒ detached vertex criteria at
the lowest trigger level (L0 Vertex Trigger)
z Optimization of impact parameter resolution
z
Reduce detector inner radius
z RF foil modifications
z
z
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Material minimization for chosen solution
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Upgrade Workshop
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Additional considerations
z Resources
for this detector need to be
identified
z The chosen solution must be technically
achievable in the time scale envisaged
for the project (∼2013):
Coordinated R&D effort should start now
z R&D must demonstrate capabilities for large
scale production in a ∼3 years time span
z
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Upgrade Workshop
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Velo now
See T. Bowcock’s talk
z
rφ strip detector with
variable pitch:
z
z
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tradeoff between number of
channels and resolution
Quick rz tracking for triggering
purposes
Marina Artuso LHCb High Luminosity
Upgrade Workshop
VELO Module
Length determined by
angular acceptance and
minimum radius
requirement
“spare” system very close
in design to present system
is planned and is not the
upgrade discussed in this
talk
5
towards a LHCb Pixel Telescope
4 cm
2 cm
5 cm
10 cm
1.2 cm
Beam
5 cm
•Need to identify optimum geometry:
•Parametric study of telescope configuration
(number of stations, cell size…) as a function of
rmin
•Detailed study of vertex reconstruction algorithm
with full simulation
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Marina Artuso LHCb High Luminosity
Upgrade Workshop
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Why pixel?
z
thinned
8cm
Z Beam
1/12/2007
Measurement of 3D space
points, with very few
additional noise hits,
implies excellent pattern
recognition capabilies:
z Vertex reconstruction
in “real time” feasible
(see E. Gottshalk talk)
•Optimal radiation resistance (⇒inner
detector in all LHC devices):
•Allows operation with smaller rmin &
higher luminosity without
replacement for the duration of the
experiment
•Low noise (∼200 e- @ 25 ns) allows
more precise charge interpolation &
(in principle) thinner detectors.
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Upgrade Workshop
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The pixel module
z
Design choices:
z
z
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Sensor-front end
electronics
High density hybrid
Mechanical
support/cooling
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Upgrade Workshop
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Hybrid pixel devices
sensor module
z
Fully engineered solution
(ATLAS, CMS, BTeV)
z Allows separate R&D on
sensor and electronics
z Material needs to be
minimized (sensor-electronic
thinning-RF-overall system
design)
bump bonds
wire bonds
readout chips
high density interconnect
TPG substrate
BTeV
plane
0.22
0.12
1.11
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Well understood technology
z
z
z
z
Predictions from Monte
Carlo simulation
validated in extensive
test beam studies
Sensor design well
established (Atlas,
BTeV)
Lots of experience in
system issues during
CMS/ATLAS
commissioning
Front end design mature
(see D. Christian’s talk)
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Marina Artuso LHCb High Luminosity
Upgrade Workshop
MC
simulation
BTeV pixel
TB 1999
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Material minimization: wafer thinning
z
z
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BTeV/CMS R&D
achieved 200 μm backthinning of bump bonded
electronics (target
thickness) & FPIX2 dies
have been thinned down
to 150 μm (1 step) &
130 μm (2 steps)
We can capitalize on
advances in thinning
silicon wafer, hybrid
silicon wafer assemblies
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Upgrade Workshop
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R&D activities - sensors
z
Sensor-electronics technology:
z
Monolithic Pixel Devices (Liverpool)
z
z
z
z
Monolithic CMOS Active Pixel devices
Silicon on Insulator
3D sensors (Glasgow)
Substrate material to ensure maximum
radiation resistance (in collaboration with
RD50):
z
z
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p-type substrates (Liverpool, Syracuse)
Magnetic Czochralski (Glasgow)
Others….
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Upgrade Workshop
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Monolithic Pixel Devices
z
Advantages:
z Easier to reduce module
material
z Eliminate one interconnection
step: bump bonding of sensor
and electronics
z In general, no separate
development path for sensor and
electronics
z No large scale production
experience
RALLiverpool
prototype
wafer
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Front end
electronics
Sensor: epitaxial
layer (Variation:
silicon on insulator
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3d silicon sensors
z
Combine VLSI processing
and MEMs (Micro Electro
Mechanical System)
technology
z Variant of the sensor
implementation in hybrid pixel
systems
z Advantages:
z Very low depletion
voltage
z Very low capacitance
z The edge is an electrode:
dead volume near the
edge < 5μm
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Radiation hard technologies
z
charge collection efficiency as detector lifetime
predictor
Liverpool
GlasgowCERN
Czochralski
1/12/2007
n-on-p
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Front-end electronics
z
Must provide digitized
data to trigger processor
in real time:
Time stamping
z On chip sparsification
z On chip digitization
z Ideal option: adapt fully
engineered solution to our
application
z New smaller feature size
technologies may allow
smaller “long pixel
dimension”
z
FPIX2
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Upgrade Workshop
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R&D activities – front end electronics
z Optimization
of the front-end device:
noise, speed, power.
z Choice of optimal data flow architecture
z Technology: proved radiation hardness,
must be available throughout the
duration of the project, development and
production cost.
z Much more on D. Christian’s talk
1/12/2007
Marina Artuso LHCb High Luminosity
Upgrade Workshop
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Signal connections
From R. Yarema
Vertex2005
1/12/2007
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Upgrade Workshop
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The vacuum tank
z
Critical issue: can we reduce the material in
front of the first measuring point?
z
z
A drastic solution: vertex detector in the machine
vacuum.
Issues:
z
z
z
z
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Is it feasible?
Is it allowed?
Necessary to fully understand outgassing
properties of each material used in the pixel
module, redundancy and safety margin in vacuum
components, effect of beam image currents (beam
simulator)
The prize is well worth the R&D effort
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Summary of R&D needed
z
Physics case + geometry optimization simulation work (23FTE): define geometry and prioritize choices among various
R&D options described:
z
z
z
z
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rad hard sensors
Data driven front-end electronics
interconnection technologies
mechanical issues
Synergistic interactions with R&D effort with similar goals
z Sensor RD50 (already in progress: Glasgow, Liverpool,
Syracuse)
z Submicron technology, other implementations of data
push architecture (Syracuse-Fermilab)
z Other SLHC upgrade efforts
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Construction cost & manpower projection (assuming a pixel
telescope)
Material cost
FTE
Sensor Hybridization (sensors, bump
bonding…)
2.1M$
9
Front electronics
1.0M$
7
Services (LV/HV/Cables)
1.7M$
5
Mechanics, cooling and vacuum
1.6M$
25
Integration and testing
0.8M$
57
total
7.2M$
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Marina Artuso LHCb High Luminosity
Upgrade Workshop
<FTE>=26 over 5 years, ramping up
Projected construction time 4-5 years
(depending upon time contingency assumed)
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Conclusions
z
z
z
z
A vertex detector suitable for a fast L0 vertex trigger is
critical to achieve the goals of an LHCb upgrade.
A pixel technology with self triggering readout
electronics is an important element of such a system.
Additional R&D items include low mass and reliable
interconnections and mechanical system aspects such
as vacuum design, RF shielding …
Construction expected to last 4-5 years based on
experience on similar projects: R&D should start soon
to achieve desired timeline
1/12/2007
Marina Artuso LHCb High Luminosity
Upgrade Workshop
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