The SLHC
Centre de rencontre de Cartigny
D. Ferrère, 14 septembre 2007
Team: G. Barbier, A. Clark, D. Ferrère, D. Lamarra,
S. Pernecke, E. Perrin, M. Pohl
Cartigny, le 14 Septembre 2007
SLHC, Didier
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The European Strategy for Particle Physics
 Draft Strategy Document Initiatives:
http://council-strategygroup.web.cern.ch/council-strategygroup/
“The LHC will be the energy frontier machine for the foreseeable future,
maintaining European leadership in the field; the highest priority is to fully exploit
the physics potential of the LHC, resources for completion of the initial program
have to be secured such that machine and experiments can operate optimally at
their design performance. A subsequent major luminosity upgrade (SLHC),
motivated by physics results and operation experience, will be enabled by
focused R&D; to this end, R&D for machine and detectors has to be vigorously
pursued now and centrally organized towards a luminosity upgrade by around
2015.”
SLHC status:
• R&D towards a realistic Upgrade scenario is active (Machine and Detectors)
• SLHC is not approved yet!
• Exact time schedule is unknown
• Machine scenarios exist but not frozen
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The ATLAS ID current status at LHC
 All services (pipes, cables, fibers,..) Installed
 TRT barrel & Endcap cabled and connected - 1.8% problematic channels out of 105K,
noise figure as on surface – Cosmics collected in M4 runs
 SCT barrel and Endcap signed off on surface - < 0.3% problematic channels out of 6.3
M, >99% efficiency on cosmics. Commissioning in Progress, ongoing delays due to cooling
and environmental gas.
Pixel signed off on surface and installed and waiting for connection and tests
… towards the end …
December 07: End of the ATLAS Installation
Jan-Feb 08: Overall ATLAS commissioning
March/April 08: Close Access
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Machine and Scenarios
3 phases considered:
Phase 0: Push the machine to its maximum performance without hardware change
Luminosity of 2.3x1034 cm-2s-1. and ultimate energy 7.54 TeV (dipole field @ 9T)
Phase 1 (SLHC): Interaction Region (IR) quadrupoles life expectancy < 10 years
 Modify the insertion quadrupoles and their layout b*
Phase 2: Rebuild the SPS with superconducting magnets, the transfer line to inject
into LHC at 1 TeV and new 15T dipoles  proton energy of 12.5 TeV
LHC
SLHC - Phase1
Parameters
Scenario 1
Scenario 2
25
25
50
25
Proton/bunch Nb[1011]
1.15
1.7
4.9
b* at IP1&5 [m]
0.55
0.5
0.25
Gaussian
Gaussian
Flat
Gaussian
7.55
7.55
11.8
7.55
1
2.3
10.7
15.5
0.56
1.15
3.5
3.6
19
44
403
294
Wire comp.
Crab + D0
(+ Q0)
Bunch spacing [ns]
Longitudinal profile
Rms bunch length sz[cm]
Peak luminosity [1034 cm-2s-1]
Effective luminosity (5h) [1034 cm-2s-1]
Peak events per crossing
Comments
1.7
0.08
Alternative
Ultimate
Baseline
Nominal
NB: Original scenario of 12.5 ns excluded since exceed the max local cooling capacity
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Physics Benchmarks
Ideally it is desired to increase
the luminosity and get a better
detector performance
Luminosity should be 10 times higher
& Upgrade is considered for the detectors
The future observations at LHC should drive physics investigations at SLHC
•Higgs:
- H couplings to bosons and fermions
- WW scattering and resonances
• SUSY spectroscopy:
- mass reconstruction, sparticle ID, BR measurements, …
- performances for heavy SUSY (> 2 TeV) – impact and statistics
• EW physics:
- Boson self-couplings: focus on those for which the sensitivity is close to ILC
• Super-heavy stuff:
- Multi-TeV region: light Higgs decay to new gauge bosons Z’, W’
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ATLAS Upgrade
Due to increase of radiation level, pile-up, background
each sub-detectors has to think of the consequences in
term of detector performance, aging, radiation hardness!
Inner Detector (ID):
Completely new design and detectors – No TRT, more pixel and strips:
 New detector and ASICs technologies to withstand the radiation level
 Simulations drive optimal geometry (Strawman layers) and occupancies
LAr Calorimeter:
FCAL: To be replaced with smaller gap size and special cooling close to the beam pipe.
HEC: Cold electronics may have to be replaced (no need to get HEC wheels apart)
Others: More R&D require about the Ion buid-up
Tile Calorimeter:
Front-end electronics and Low Voltage Power Supplies
Muon System:
MDT: Chambers and readout electronics are radhard at LHC or can stand 10 times the
max nominal flux but further studies need to be performed in SLHC environment
 2008: detail upgrade plan based on some tests and R&D
TGC: Thick GEMs can possibly replace forward chambers due to high occupancy.
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Radiation Background in ATLAS at SLHC
•With safety factor of two,
Simulation using FLUKA2006
design short microstrip layers to
withstand 1015neq/cm2 (50%
neutrons)
Outer layers up to
4×1014neq/cm2 (and mostly
neutrons)
•
Issues
Thermal management and shot
noise. Silicon looks to need to be at
~ -25oC (Thermal runaway).
Si power: 1W @ -20°C
4W @ -10°C
10W @ 0°C
 High levels of activation will
require careful consideration for
access and maintenance.
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1 MeV equivalent neutron fluences assuming an
integrated luminosity of 3000fb-1 and 5cm of
moderator lining the calorimeters (reduces
fluences by ~25%)
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Inner Detector Upgrade - Layout
The goal for b-layer replacement is fall 2012
Actual b-layer is expected to survive 3 years at LHC design luminosity (~300fb-1)
The Upgrade of the entire tracker should take place in 2016
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Silicon Sensors
Choice of adequate material thanks to RD50 collaboration
Pixel b-layer: 3D technology is an option
Pixel and Strips: n-in-p (planar technology)
(should be ready for b-layer replacement in 20012)
Exist in single and double column type
 No type inversion, full depletion is on structured side
 Collection of electrons (faster than p-in-n)
ionizing particle
Still ~15000e- at 1.1015 cm-2s-1 (FZ or MCZ)
signal [electrons]
25000
3D FZ Si, 235 m, (laser injection, scaled!), pad [Da Via 2006]
n-FZ Si, 280 m, (-10oC, 40ns), n-in-n pixel [Rohe et al. 2005]
p-FZ Si, 280 m, (-30oC, 25ns), strip [Casse 2004]
p-MCZ Si, 300 m, (-30oC, s), pad [Bruzzi 2006]
n-epi Si, 150 m, (-30oC, 25ns), pad [Kramberger 2006]
n-epi Si, 75 m, (-30oC, 25ns), pad [Kramberger 2006]
20000
p-Si
sCVD-Diamond, 770m, (RT, s), [RD42 2006] (preliminary data, scaled)
pCVD-Diamond, 500m, (RT, s), strip, [RD42 2002-2006] (scaled)
15000
SiC, n-type, 55 m, (RT, 2.5s), pad [Moscatelli et al. 2006]
10000
3D FZ 235m
5000
0
0
n+-columns
P-FZ 280m
20
40
60
80
eq [1014 cm-2]
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M.Moll 2007
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electrons swept away
by transversal field holes drift in
central region and
diffuse towards p+
contact
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Electronics for Strips
Goal: Prepare a design of the FE ASIC in deep submicron radiation tolerant.
Design and evaluation with 250 nm towards 130 nm technology
Minimum requirements:
 Implementation of an on-chip shunt regulation to allow any
powering scheme (Serial or DC-DC)
ABC-N Readout architecture
 Increased data bandwidth of 160 Mb/s
 Compatibility with existing ATLAS SCT DAQ ROD
hardware
Front-end for two signal polarities, 3 to 12 cm long silicon
strips
 Minimum power circuit techniques
 Delay adjustment for control and data signals
Similar “core” functionality as for the present silicon strip
tracker: signal amplification, discriminator, binary data
storage for L1 latency, readout buffer with compression logic,
and data serializer.
• Daniel La Marra, Sebastien Pernecker, Geneva University
• Wladek Dabrowski, Krzysztof Swientek, AGH-Cracow
Design team: • Jan Kaplon, Karolina Poltorak, Francis Anghinolfi, CERN
• Mitch Newcomer, Pennsylvania University
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Module Integration
Focus on the most challenging modules with Short-Strips, 80 chips (24W), 4
hybrids, 160MHz clocking to FE chips, and readout by group of 10 modules.
Module #1
Cooling
TTC, Data &
DCS fibers
Module #2
Module #10
Opto
BGT
DCS env. IN
PS cable
DCS
interlock
Service bus
SMC
3 flavors are considered: Staves, Super-Modules, Modules
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Power Distribution
Services are clearly an issue for the material budget as well as for the system design
Tracker Upgrade should leave with the existing ID services and optimize the
power distribution: Serial Powering or DC-DC (Individual Powering is abandoned)
SCT - 4mW/ch  24 kW (excl. cable losses)
Strip Upgrade - 2mW/ch  90 kW only for FE (45 Mch)
Short-Strip Super-Module configuration
n is hybrid number = 20; VH (0.13m)=1.2V
SP
IPS=IH=4.2A
VPS=nVABCN=24V
1
2
3
4
5
6
n-1
n
PP
g= GAINDC-DC=20
IPS=n/g.IH=2A
VPS=gVABCN=24 V
NB: Here only 2 cables/SM needed but for IP it would be 40 cables
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Cooling
Cooling System is one of the key points for ID operation
Heat density is 4-7 times higher than the current SCT module
3 candidates for the cooling:
• CO2 (~100 bar)
• C2F6 (Low pressure)
• C3F8 (Low pressure)
Pressure [bar]
Detector thermal runaway impose to operate the silicon wafer below -20ºC
Tsensor = Tcoolant + DTHeat_Path
 Coolant: Less than -30 C is considered for the pipe temperature
 Module design and choice of material is critical – Thermal FEA
Existing pipes are considered:
-SCT & Pixel (ok for C2F6, C3F8)
-TRT (ok for CO2 but limited number)
1g of evaporation @ -30ºC ~280 J
(Where for C3F8 it is 100 J/g)
CO2
Enthalpy [kJ/kg]
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Status in the various working groups
Pixel:
3D sensors:
-ATLAS geometry evaluated: Laser and capacitance measurements
- proton and neutron irradiations will soon come
- H8 TB will be in September/October 2007
Readout chips: Prototyping activity in 0.13 m technology – chip FE 14
Powering: Promising results for SP – Using current ATLAS Pixel modules
Strips:
Sensors: 10X10 cm2 short strip sensors ordered (15 units for UniGe)
Readout chips ABC-n: Specification document created and under design. The
submission is foreseen at the beginning of 2008
Powering: Promising results for SP – Using current ATLAS SCT modules on
staves and with individual modules. DC-DC is also investigated!
Module Integration:
- Concept proposed and some Thermal FEA showed
- Prototypes with ABC-n and new n-in-p sensors in 2008
- TB and irradiation will follow
Structure and Services: On going discussions and specifications expected soon
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UniGe Involvements
Asics: Digital Architecture & Simulation: pipeline, Derandomizer, Data
Compression Logic, Readout Logic and Control; Check after place and route!
 250nm submission January 2008
 130nm design from January 2008
Detectors: 135 sensors of size10X10cm2 ordered to Hamamatsu
UniGe ordered 15 sensors: 12 p-stop and 3 p-spray
Sensor characterization will be made and compared with other institutes
Module Concept: UniGe investigated 2 concepts module directly mounted on
barrel or mounted on an intermediate local support!
UniGe operates 3D Thermal FEA to evaluate and optimize the design
Strategy is to make prototype modules in 2008 with above detectors and Asics
DCS: Involvement in the strategy and decision for the detector safety. DCS will be
part of the system design to optimize the service and resource issues.
Mechanical Engineering: Involvement in the structure and service design.
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Important Milestones Drafted
1. Beam off – start decommissioning
2. Ready for beam:
•
•
•
•
•
•
•
•
•
•
1/7/2014 (18 month for installation)
1/1/2016
Straw man Layout December 2006
(Modification/changes to be made in
term of performance /Risk/Cost etc.)
TDR Feb/2010
Cooling PRR
April/2010
Mechanical Support Design complete Oct/2010
Sensor PRR
July/2010
FE-electronics
Sept/2010
Surface Assembly
March/2012
 B-Layer replacement 
Ready for Installation
August/2014
Barrel Installation
Feb/2015
B-layer/beam pipe
August/2015
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Conceptual Design R&D
Prototypes
Pre-Series
Production
Assembly & Installation
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Conclusions
 SLHC is clearly in the continuity of the machine and detector operation
 Phase 1 will be to increase the luminosity up to a factor 10 (1035 cm-2s-1 )
 ATLAS and CMS are considering options to Upgrade the detectors in
2016
 The ATLAS Inner Tracker will be completely renewed (no TRT) and is in
a design and specification phase
 The B-layer replacement is foreseen already in 2012 using 3-D sensors
 The major challenges are: Service and material reductions, Cooling,
Powering scheme
 The time scale is short and there is almost no time for R&D
 Working groups start smoothly to grow and to be active
 UniGe involved in various topics and keep an eye on the B-layer
replacement activities
 Next events:
• Pixel Upgrade Workshop 28-29 September at CERN
• ID Upgrade Workshop 12-14 Dec 2007 in Valencia
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Back-up slides
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Appendix - Tracker Organizational Structure
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new upgrade bunch structures
nominal
25 ns
ultimate
& 25-ns upgrade
25 ns
50-ns upgrade,
no collisions @S-LHCb!
50 ns
50 ns
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25 ns
Cartigny, D. Ferrere
50-ns upgrade
with 25-ns
collisions
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in LHCb
Two scenarios Luminosity Upgrade
25 ns scenario
50 ns scenario
Merits
•Negligible long-range collisions,
•No geometric luminosity loss,
•No increase in beam current
beyond ultimate
•No elements in detector,
•No crab cavities,
•Lower chromaticity,
•Less demand on IR quadrupoles
(NbTi possible)
Challenges
•D0 dipole deep inside detector (~3
m from IP),
•Q0 doublet inside detector (~13 m
from IP),
•Crab cavity for hadron beams
(emittance growth),
•4 parasitic collisions at 4-5s
separation,
•“Chromatic beam-beam”
Q’eff~sz/(4pb*sd),
•Poor beam and luminosity lifetime
~b*
•Operation with large Piwinski
parameter unproven for hadron
beams,
•High bunch charge,
•Beam production and acceleration
through SPS,
•“Chromatic beam-beam”
Q’eff~sz/(4pb*sd),
•Larger beam current,
•Wire compensation (almost
etablished)
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Per Grafstrom
CERN
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Heat load
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B-Layer Replacement
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B-Layer Replacement & Tracker Upgrade
•
ATLAS considers to have a B-layer replacement after ~3 year of integrated full
LHC luminosity (2012) and replace completely the Inner Tracker with a fully
silicon version for SLHC (2016).
•
The B-layer replacement can be seen as an intermediate step towards the full
upgrade. Performance improvements for the detector (here some issues more
related to FE chip):
– Reduce radius and design for > 1034cm-2s-1 luminosity  Improve radiation
hardness ( 3D sensor, p-type bulk materials)
– Reduce pixel cell and architecture related dead time ( deign FE for
higher luminosity)
– Reduce material budget of the b-layer (~3% X0  <2.5% X0)  stave
replaces module as the basic building block.
– increase the module live fraction ( increase chip size, > 1214 mm2),
optimize inactive chip periphery, use “active edge” technology in the sensor.
– Use faster R/O links, move MCC at the end of stave
– FE chip technology will use 0.13 µm 8 metal CMOS.
•
The B-layer for the upgrade will push even more technological/ design/
architectural issues of the FE chip  radiation hardness (1015  1016 neq/cm2)
and detector occupancies ( 15)
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Reference (r, Z)
+ fixation
LSR on Barrel
(UniGe Concept)
Intermediate
support bracket
+ insertion guide
10-Module Structure
Half barrel
Barrel end
Reference (r,f)
+ alignment
End view
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EC disks – Petal option
C. Lacasta
SS disks
SS+LS disks
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Data Transmission
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Low evaporation pressure limit
12
• Limit from return line impedance and
compressor suction pressure.
p [bara]
10
• Mostly of concern for C3F8
C3F8
8
7.6 bara
6
4
– TRT pipes would give ~70% more flow →
return pipe Δp would have to increase (α
2
1.1 bar
~P2),
0
– Heaters/HEXs (diameter) need to be bigger, -60
-40 -35 -20
– Alternative pev control: cold condenser
T [°C]
(needs development),
– Surface condensers to reduce compression SCT return p budget
ratio → allows to reduce suction p.
Heaters & HEXs
– Mix with C2F6:
Return pipes
a
• Allows to tailor saturation properties,
• Lower HTC to wall (~50%),
• Mixture control by measurement of vsound.
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0
20
40
Δp [bar]
~0.2
~0.1
Back pressure regulators
~0.5
Compressor suction p
p ~ 0.7
Total
p ~ 1.5
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Coolant properties
Run conditions @ -35C
C3F8
C2F6
CO2
Pevaporation
1.1 bar
6 bar
12 bar
ΔT for ΔP=+-0.1bar
+2 C / -2 C
+0.2 C / -0.2 C
ΔT for ΔP=+-1.0bar
+20 C / ~-44 C
+1.8 C / -1.9 C
ΔH for evaporation
100 J/g
100 J/g
280 J/g
Flow for 100 W
1.0 g/s
1.0 g/s
0.4 g/s
Volume flow
0.6 cm3/s
0.6 cm3/s
0.4 cm3/s
HTC [W/cm2/K]
3000 W/cm2/K
Major difference for CO2 with respect to C3F8
cooling is the increase by a factor of 10 of the
evaporation pressure for T=-35C.
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8000 W/cm2/K
Advantages….
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