Transcript No Slide Title

D. Lissauer
Brookhaven National Laboratory
Presentation to:
HEPAP Future Facilities Subcommittee
U.S. Participation in LHC Upgrade
1
•
LHC – Upgrade: Schedule and Options
•
Physics Motivation
•
Detector Upgrades
•
Machine Upgrade Options
•
Conclusions
•
Questions/Answers
D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
LHC Schedule & Upgrade Options
•LHC Schedule
•First Beams
April
2007
•Physics Run
July
2007
•LHC Upgrade Options
• Luminosity upgrade – SLHC : L = 1035 cm-2 s-1
--extends LHC mass reach by ~ 20-30%
--modest changes to machine
--very challenging for experiment
--time scale
~ 2014
• Energy Doubled LHC - EDLHC: s ~ 25 TeV L = 1034-1035 cm-2 s-1
--extends LHC mass reach by ~ 1.5-2 for L=1034-1035
--requires new machine (e.g. 15 T magnets …)
--very expensive option
--time scale
> 2020
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Physics Potential of SLHC
integrated luminosities :
• LHC 100 fb-1/year
• SLHC 1000 fb-1/year
L  2 x 1034
L = 1035
* Detector Performance at SLHC
needs to be similar to LHC.
• Higgs physics
• rare decay modes
• Higgs self-couplings
• Higgs couplings to fermions and bosons
• Supersymmetry
• Heavy Higgs bosons of the MSSM
• Mass reach up to 3 TeV
• New Gauge Bosons
• Strongly-coupled vector boson system
• WLZL g WLZL WLWL g WLWL , ZLZL
• Extra Dimensions
• Quark substructure
• Electroweak Physics
• production of multiple gauge bosons (nV .ge. 3)
• triple and quartic gauge boson couplings
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Strongly Coupled Vector Boson System
If no Higgs, expect strong VLVL scattering (resonant or non-resonant) at
sˆ  TeV
q
q
VL
VL
q
Difficult at LHC
VL At SLHC
• degradation of fwd jet tag and central jet veto due to pile-up
VL • BUT : factor ~ 10 in statistics  5-8 excess in W+L W+L scattering
q
 other low-rate channels accessible
Fake fwd jet tag (|| > 2) probability
from pile-up (preliminary ...)
ATLAS full simulation
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Indicative Physics Reach
Units are TeV (except WLWL reach)
Integrated luminosities correspond to 1 year of running at nominal
luminosity for 1 experiment
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PROCESS
LHC
14 TeV
100 fb-1
Squarks
WLWL
Z’
Extra-dim (=2)
q*
 compositeness
2.5
2
5
9
6.5
30
SLHC
EDLHC
14 TeV
28 TeV
1000 fb-1 100 fb-1
3
4
6
12
7.5
40
4
4.5
8
15
9.5
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Detectors: General Considerations
s
L
Bunch spacing t
pp (inelastic)
N. interactions/x-ing
(N=L pp t)
dNch/d per x-ing
<ET> charge particles
Track density
Pile-up noise in cal
Dose central region
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LHC
SLHC
14 TeV
1034
25 ns
~ 80 mb
~ 20
14 TeV
1035
12.5 ns
~ 80 mb
~ 100
~ 150
~ 450 MeV
1
1
1
~ 750
~ 450 MeV
10
~3
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
ATLAS
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
CMS
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Inner Tracking
The inner tracker will need to be re-built using higher granularity detectors in
a harder radiation environment in order to preserve the current pattern
recognition, momentum resolution, b-tagging capability.
a
a
Radiation increase by ~ 10.
To keep Occupancy constant granularity has to increase
by a factor 10.
Small Radius Region: Vertex detector (r < ~20cm)
• aim for a pixels size factor ~ 5-8 smaller than today
(50x400 mm2 g ~ 50 x ~ 50 mm2) g benefit b-tagging, t-tagging
R&D:
Pixels Sensor Technologies
Super rad-hard electronics to achieve small pixel sizes.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Inner Tracking
Intermediate Radius: ~20<r<~60 cm
•Aim for cell sizes 10 times smaller than conventional Si strip
detectors.
benefit: momentum-resolution and pattern recognition
R&D:
• Lower cost/channel compared to present Si strip detectors
• Si macro-pixels of an area ~1mm2 : pads or shorter strips ?
• Single sided two dimensional readout (new concepts)
Large Radius: ~60<r
Large area Si detectors.
Could use present day ‘radiation resistant’ strip technology,
or new single sided technology
R&D:
Similar to intermediate radius – less demanding except for cost.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Inner Tracking
Engineering/Integration:
Aim at a factor of ~10 more channels but with less material.
This means that the System aspects have to be integrated and
understood from the start.
R&D:
new light weight materials for stable structures,
Power
Multiplexing of readout
cooling,
alignment
installation and maintenance aspects
Activation: 250 mSv/h – implications for access and maintenance
Timescale : Need ~ 8-10 years from launch of R&D
~ 4-6 years of R&D and prototyping , ~4 years to build,
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Calorimeter
Increased Luminosity will increase the contribution of the pile up to the
noise by a factor of ~ 3.
Increased radiation will imply moderate changes to the detectors
mostly in the forward direction.
R&D:
Endcap: find an alternative to plastic scintillator (CMS)
Long term irradiation effects on crystals. (CMS)
Readout electronics – some will need to be upgraded for
increased radiation level.
E.g: ATLAS Front end board should be redesigned either by
making components more radiation resistant,and/or use analog
optical links to bring the signals out.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Muon System
Current ATLAS/CMS Muon systems have a safety factor of 3-5 with respect
to background estimations.
Background has strong geometric dependence –
aDetectors that now function at high- at LHC will function at low- in
SLHC
aRadio-activation at high , of shielding, supports and nearby detectors
may limit maintenance access
aStrategy:
Balance robust detectors vs. shielding and reduced high- acceptance
R&D:
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Study limits of current detectors – possible use of CSCs at lower .
At high- - higher rates – higher granularity CSCs, GEMs?
D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Level-1 Trigger/DAQ
Increased LHC Luminosity up to SLHC means trigger and
DAQ needs to evolve in time.
Reduced Bunch crossing to 12.5 n-sec will have an impact
on the Level –1 trigger architecture.
R&D:
– Study Required modifications to LVL1 trigger and detector front end
electronics.
–Data transfer for processing at 80 MHz sampling.
– Synchronization (TTC, etc) becomes an issue for short bunch crossing
period.
–How to handle bandwidth (rate  size); is an issue both for readout and
for event building.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
LHC Upgrade Options
• SLHC Luminosity upgrade to 1035:
-- increase bunch intensity to beam–beam limit  L ~ 2.5 x 1034
-- halve bunch spacing to 12.5 ns (electron cloud limitation?)
--Reduce * to 0.25 m (from 0.5 m)
--Increase crossing angle.
--Reduce bunch length. (new RF)
--Super Bunch option being investigated.
• EDLHC  s upgrade to 25 TeV :
-- ultimate LHC dipole field : B= 9 T  s = 15 TeV
 any energy upgrade requires new machine & Injector
-- present magnet technology up to B ~ 10.5 T
small prototype at LBL with B= 14.5 T
-- magnets with B~17 T may be reasonable target for operation
in >2020 provided intense R& D
on new superconductors (e.g. Nb3Sn)
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moderate
hardware changes
time scale  2014
major
hardware changes
time scale  2020
D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
U.S. Role in Machine R&D
LHC R&D by the U.S. Labs will focus on increasing the luminosity.
•Understand the limitations of the current machine configuration,
particularly the IRs, and develop proposed modifications.
• Low * insertion sections: (separation dipoles, triplet quads)
• Develop high-field Nb3Sn magnets for new low * insertion
… * ~15-20 cm seems possible.
• Next Generation Machine Instrumentation and feedback systems.
Other luminosity upgrade R&D to be addressed by CERN, e.g.
• r.f. upgrades – for halving bunch length or handling superbunches
• collaborate with U.S. labs on R&D on luminosity upgrade magnets
R&D for EDLHC adequately covered by U.S. base program.
• High-field Nb3Sn dipole R&D and BNL, FNAL and LBNL
addresses either EDLHC or VLHC.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Conclusions
• Physics reach of LHC can be extended significantly by
increasing the Luminosity by a factor of 10 or by doubling the
energy of the machine.
• Luminosity upgrade can be achieved by ~ 2014
• Detectors must preserve (the expected LHC) performance to
realize the physics potential.
• R&D for both machine and detectors upgrades needs to start
soon. (Note that many present ATLAS/CMS detectors
started R&D in ’87) Assuming sufficient funds, this is covered
by the LHC Research Program.
•US Machine R&D projects are well suited to the capabilities at
the three national labs. (FNAL, BNL & LBNL)
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Conclusions
•Tracking system upgrade is the most challenging. The system
will need to be almost completely rebuilt. Significant R&D is
needed covering the full spectra from generic new materials
to system integration.
•Calorimeters and Muon systems should be able to perform
well with moderate upgrades.This will involve mostly
increasing the radiation hardness of the readout electronics.
•Trigger,DAQ will be upgraded – benefiting from commercial
developments.
Strong US involvements in the SLHC will ensure significant
U.S. presence at the physics frontier for the coming decades.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Questions from the Committee
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1.
What is the estimated cost of the tracking upgrade, given
the greatly increased channel count associated with the
Luminosity upgrade?
2.
Can you give more information on the scope and cost of
the Nb3Sn magnet R&D for the luminosity upgrade?
More generally , what would be the scope of the U.S.
part of the accelerator upgrade?
3.
What is the scope and cost of the U.S. part of the
detector upgrades?
D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Tracking Cost estimate
The estimate is very preliminary and is based on the
following assumptions: The active components of the
tracker are all Si. The inner radius has upgraded Si Pixel
detectors, followed by Si Strip detectors, in the outer
radius we use single sided 2-D Si detectors.
The estimate was done by scaling the cost of the ATLAS Si
detector as well as information from CMS, and the
CDF/D0 upgrade cost.
In scaling the costs we had to make assumptions on how
the main cost drivers will scale with the number of
channels, the area and the expected time evolution.
The R&D and final design will have to be driven by
optimizing the cost to performance of the overall system.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Tracking Cost estimate
– Mechanics: The mechanics does not scale with the number of channels.
One has to keep the services and the total weight to a minimum.
The cost estimate assumes there is added complexity due to light weight:
– Si Detectors: Scale with the detector area and only marginally with the
granularity.
The optimization of the number of layers and exact location has not
been finalized. The total amount of Si will be factor of ~ 5-10 greater
than the present ATLAS detector.
Possible cost reduction:
Si detectors: Cost is driven to a large extent by the size of the
wafers and industry is moving toward larger wafers.
Minimize the the amount of Si: by using advances in detector
technology. For example single sided 2D readout can be used in the
medium and larger radii where the segmentation needs are dominated by
tracking accuracy rather than occupancy.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Tracking Cost estimate
– On detector read out electronics:
The readout electronics cost is driven by the number of channels.
Take advantage of the reduction in the feature size of the electronics.
(ATLAS design used ATMEL/DMILL rad hard technology that has a
conservative feature size of 1.2 Micron in the Strips. CMS and
ATLAS pixels are using sub micron technology of 0.25 micron)
Present industry standard is 0.18 moving toward 0.13 microns. We
expect that by the time we go into production the standard feature size
will be as low as 0.08 microns. Allowing for a substantial reduction in
the power and space needed for the electronics and allowing for finer
granularity without an increase in power and space needed.
The reduction in power has important implication also on the cooling
and services that will be needed.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Tracking Cost estimate
– Module integration:
Module integration costs include costs of Hybrids and the components
assembly.
In the case of the Pixel detectors the cost of bump bonding Si is a
significant part of the module integration.
Significant cost reductions are possible assuming one of the integrated
developments matures in time. They integrate the readout and the active
detector on the same wafer eliminating the need for individual bonds.
–
Cables & Data Links:
Assumed a higher level of multiplexing compared to the present
solutions. In particular the amount of power cables that need to be
reduced for physics (reduced mass), space and cost reasons.
– Power Supplies:
Power supplies will need to be optimized and serve a larger number of
modules. This has implication on coherent noise and very detailed system
integration will be needed to achieve this.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Tracking Cost estimate
– Cooling: (Additional) The needed cooling capacity will scale with the
number of channels, but we have taken advantage of the lower power
requirements of the lower feature size electronics. A large part of the
external cooling can be reused.
– Off detector electronics: (Read out Drivers) We have to take advantage of
advances and reduction in the cost of electronics. We assume that a factor
of 10 more data 10 years from now will cost factor of ~ 1.5 more than
present cost.
The Tracker cost for one detector thus estimated to be between
150-180 M$. (assuming the full detector is built in the US)
These numbers are only given as a rough estimate. We are not
ready for an engineering estimate, which will have to be done after
R&D has progressed and better optimization done.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
U.S. Machine R&D
See note from Jim Strait
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
Scope and cost of U.S. involvement.
• Scope:
The U.S. has ~ 20% of the Physicists on both experiments and
contributes close to 20% toward the construction of ATLAS & CMS.
In the R&D phase of the LHC program the U.S. contributions have been
more significant. The U.S. participation in electronics development and
production is significantly higher than 20% .
We expect this to hold true also in the SLHC era.
We note that the Upgrade will take place while the LHC will be fully
operational and a large maintenance and operations effort will be in place.
The maintenance and operation will be concentrated at CERN. In
principle this responsibility will be shared equally between all collaborators.
The division of responsibility for the upgrade has not been finalized.
We assume the U.S. Share will be the same as during the construction of the
experiments. (~20%).
There is a good possibility that the U.S. will trade off some of the M&O
responsibility for additional responsibility in the Upgrade.
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D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.
U.S. cost for SLHC experiments.
•
•
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•
•
•
•
•
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Cost:
The total cost estimate of the upgrade is hard to predict.
We expect the main cost to be in the tracking upgrade.
The exact scope of the upgrade for the different systems is
not clear and will be somewhat different in the two
experiments.
The split between the different systems and what upgrade
will be done will have to be a result of optimization –
based on actual LHC experience.
One can only make a “straw man” upgrade model for the
detector upgrade.
This cost does not include R&D that we expect to be
covered from the ongoing LHC Research Program.
We expect that the experiments share will be more than 2/3
and the rest for the accelerator.
D. Lissauer, BNL, HEPAP –Subcommittee , Feb. 15 2003.