The ILC Global Design Effort
Barry Barish
SPC Meeting
CERN
13-Aug-05
Why a TeV Scale e+e- Accelerator?
• Two parallel developments over the past few
years (the science & the technology)
– The precision information from LEP and other data
have pointed to a low mass Higgs; Understanding
electroweak symmetry breaking, whether
supersymmetry or an alternative, will require
precision measurements.
– There are strong arguments for the complementarity
between a ~0.5-1.0 TeV LC and the LHC science.
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Electroweak Precision Measurements
Winter 2003
6
theory uncertainty
(5)
had =
0.027610.00036
0.027470.00012
4
LEP results strongly point
to a low mass Higgs and
an energy scale for new
physics < 1TeV
W ithout NuTeV
2
0
Excluded
20
Preliminary
100
400
mH GeV
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Why a TeV Scale e+e- Accelerator?
• Two parallel developments over the past few
years (the science & the technology)
– The precision information from LEP and other data
have pointed to a low mass Higgs; Understanding
electroweak symmetry breaking, whether
supersymmetry or an alternative, will require
precision measurements.
– There are strong arguments for the complementarity
between a ~0.5-1.0 TeV LC and the LHC science.
13-Sept-05
Scientific Policy Committee - CERN
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LHC/ILC Complementarity
The 500 GeV Linear Collider Spin Measurement
LHC should discover the
Higgs
The Higgs must have spin zero
The linear collider will
measure the spin of any
Higgs it can produce.
The process e+e–  HZ can
be used to measure the
spin of a 120 GeV Higgs
particle. The error bars are
based on 20 fb–1 of
luminosity at each point.
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LHC/ILC Complementarity
Extra Dimensions
Linear collider
New space-time dimensions can
be mapped by studying the
emission of gravitons into the
extra dimensions, together with
a photon or jets emitted into the
normal dimensions.
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Why a TeV Scale e+e- Accelerator?
• Two parallel developments over the past few years (the
science & the technology)
– Two alternate designs -- “warm” and “cold” had come
to the stage where the show stoppers had been
eliminated and the concepts were well understood.
– A major step toward a new international machine
requires uniting behind one technology, and then
make a unified global design based on the
recommended technology.
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TESLA Concept
• The main linacs based on 1.3
GHz superconducting
technology operating at 2 K.
• The cryoplant, is of a size
comparable to that of the LHC,
consisting of seven subsystems
strung along the machines every
5 km.
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GLC
GLC/NLC Concept
• The JLC-X and NLC are
essentially a unified single
design with common
parameters
• The main linacs are based
on 11.4 GHz, room
temperature copper
technology.
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Which Technology to Choose?
– Two alternate designs -- “warm” and
“cold” had come to the stage where the
show stoppers had been eliminated and
the concepts were well understood.
– A major step toward a new international
machine requires uniting behind one
technology, and then make a unified
global design based on the recommended
technology.
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The ITRP Recommendation
• We recommend that the linear collider be based
on superconducting rf technology
– This recommendation is made with the
understanding that we are recommending a
technology, not a design. We expect the final design
to be developed by a team drawn from the combined
warm and cold linear collider communities, taking
full advantage of the experience and expertise of
both (from the Executive Summary).
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SCRF Technology Recommendation
• The recommendation
of ITRP was presented
to ILCSC & ICFA on
August 19, 2004 in a
joint meeting in Beijing.
• ICFA unanimously
endorsed the ITRP’s
recommendation on
August 20, 2004
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The Community Self-Organized
Nov 13-15, 2004
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KEK Workshop Organization
Birth of the GDE
and Preparation for
Snowmass
•
•
•
•
•
•
WG1 Parms & layout
WG2 Linac
WG3 Injectors
WG4 Beam Delivery
WG5 High Grad. SCRF
WG6 Communications
13-Sept-05
•
•
•
•
•
•
•
WG1 LET beam dynamics
WG2 Main Linac
WG3a Sources
WG3b Damping Rings
WG4 Beam Delivery
WG5 SCRF Cavity Package
WG6 Communications
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Global Design Effort
– The Mission of the GDE
• Produce a design for the ILC that includes a
detailed design concept, performance
assessments, reliable international costing,
an industrialization plan , siting analysis, as
well as detector concepts and scope.
• Coordinate worldwide prioritized proposal
driven R & D efforts (to demonstrate and
improve the performance, reduce the costs,
attain the required reliability, etc.)
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GDE Members
Chris Adolphsen, SLAC
Jean-Luc Baldy, CERN
Philip Bambade, LAL, Orsay
Barry Barish, Caltech
Wilhelm Bialowons, DESY
Grahame Blair, Royal Holloway
Jim Brau, University of Oregon
Karsten Buesser, DESY
Elizabeth Clements, Fermilab
Michael Danilov, ITEP
Jean-Pierre Delahaye, CERN,
Gerald Dugan, Cornell University
Atsushi Enomoto, KEK
Brian Foster, Oxford University
Warren Funk, JLAB
Jie Gao, IHEP
Terry Garvey, LAL-IN2P3
Hitoshi Hayano, KEK
Tom Himel, SLAC
Bob Kephart, Fermilab
Eun San Kim, Pohang Acc Lab
Hyoung Suk Kim, Kyungpook Nat’l Univ
Shane Koscielniak, TRIUMF
Vic Kuchler, Fermilab
Lutz Lilje, DESY
Tom Markiewicz, SLAC
David Miller, Univ College of London
Shekhar Mishra, Fermilab
Youhei Morita, KEK
Olivier Napoly, CEA-Saclay
Hasan Padamsee, Cornell University
Carlo Pagani, DESY
Nan Phinney, SLAC
Dieter Proch, DESY
Pantaleo Raimondi, INFN
Tor Raubenheimer, SLAC
Francois Richard, LAL-IN2P3
Perrine Royole-Degieux, GDE/LAL
Kenji Saito, KEK
Daniel Schulte, CERN
Tetsuo Shidara, KEK
Sasha Skrinsky, Budker Institute
Fumihiko Takasaki, KEK
Laurent Jean Tavian, CERN
Nobu Toge, KEK
Nick Walker, DESY
Andy Wolski, LBL
Hitoshi Yamamoto, Tohoku Univ
Kaoru Yokoya, KEK
Americas 16
Europe 21
Asia
12
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49 members
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Participation in Snowmass
670 Scientists
attended two week
workshop
at
Snowmass
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GDE Organization for Snowmass)
•
•
•
•
•
•
Provide input
Global Group
•
•
•
•
•
•
WG1 LET bdyn.
WG2 Main Linac
WG3a Sources
WG3b DR
WG4 BDS
WG5 Cavity
Technical sub-system
Working Groups
GG1 Parameters
GG2 Instrumentation
GG3 Operations & Reliability
GG4 Cost & Engineering
GG5 Conventional Facilities
GG6 Physics Options
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The GDE Plan and Schedule
2005
2006
2007
2008
2009
2010
CLIC
Global Design Effort
Baseline configuration
Reference Design
Project
LHC
Physics
Technical Design
ILC R&D Program
Expression of Interest to Host
International Mgmt
Starting Point for the GDE
pre-accelerator
few GeV
source
KeV
damping
ring
few GeV
few GeV
bunch
compressor
13-Sept-05
250-500 GeV
main linac
extraction
& dump
final focus
IP
collimation
Superconducting RF Main Linac
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Parameters for the ILC
• Ecm adjustable from 200 – 500 GeV
• Luminosity  ∫Ldt = 500 fb-1 in 4 years
• Ability to scan between 200 and 500 GeV
• Energy stability and precision below 0.1%
• Electron polarization of at least 80%
• The machine must be upgradeable to 1 TeV
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Higgs Coupling and Extra Dimensions
ILC precisely measures Higgs
interaction strength with standard
model particles.
•
• Straight blue line gives the
standard model predictions.
• Range of predictions in models
with extra dimensions -- yellow
band, (at most 30% below the
Standard Model
• The models predict that the effect
on each particle would be exactly
the same size.
• The red error bars indicate the
level of precision attainable at the
ILC for each particle
• Sufficient to discover extra
dimensional physics.
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Design Approach
• Create a baseline configuration for the machine
– Document a concept for ILC machine with a complete
layout, parameters etc. defined by the end of 2005
– Make forward looking choices, consistent with attaining
performance goals, and understood well enough to do a
conceptual design and reliable costing by end of 2006.
– Technical and cost considerations will be an integral part
in making these choices.
– Baseline will be put under “configuration control,” with a
defined process for changes to the baseline.
– A reference design will be carried out in 2006. I am
proposing we use a “parametric” design and costing
approach.
– Technical performance and physics performance will be
evaluated for the reference design
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Parametric Approach
• Parametric approach to design
– machine parameters : a space to optimize the machine
– Trial parameter space, being evaluated by subsystems
– machine design : incorporate change without redesign;
incorporates value engineering, trade studies at each
step to minimize costs
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Approach to ILC R&D Program
• Proposal-driven R&D in support of the baseline
design.
– Technical developments, demonstration experiments,
industrialization, etc.
• Proposal-driven R&D in support of alternatives to the
baseline
– Proposals for potential improvements to the baseline,
resources required, time scale, etc.
• Develop a prioritized DETECTOR R&D program aimed
at technical developments needed to reach combined
design performance goals
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The Key Decisions
Critical choices: luminosity parameters & gradient
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Cost Drivers
cryo operations
4%
4%
instrumentation
2%
controls
4%
cf
31%
vacuum
4%
Civil
magnets
6%
installation&test
7%
systems_eng
8%
rf
12%
structures
18%
SCRF Linac
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What Gradient to Choose?
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How Costs Scale with Gradient?
2
Relative Cost
alin
G
$
 bcryo
G
Q0
35MV/m is
close to
optimum
Japanese
are still
pushing
for 4045MV/m
30 MV/m
would give
safety
margin
C. Adolphsen (SLAC)
13-Sept-05
Gradient MV/m
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Cavity Fabrication
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single-cell measurements (in nine-cell cavities)
Gradient
Results from
KEK-DESY
collaboration
must reduce
spread (need
more statistics)
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Improved Fabrication
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Improved Processing
Electropolishing
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Electro-polishing
(Improve surface quality -- pioneering work done at KEK)
BCP
EP
• Several single cell cavities at g > 40 MV/m
• 4 nine-cell cavities at ~35 MV/m, one at 40 MV/m
• Theoretical Limit 50 MV/m
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Baseline Gradient
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Improved Cavity Shapes
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Large Grain
Single Crystal Nb Material
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ILC Siting and Civil Construction
• The design is intimately tied to the features of the
site
– 1 tunnels or 2 tunnels?
– Deep or shallow?
– Laser straight linac or follow earth’s curvature in
segments?
• GDE ILC Design will be done to samples sites in
the three regions
– North American sample site will be near Fermilab
– Japan choosing between three final sites
– Europe sample sites --- CERN and DESY
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1 vs 2 Tunnels
• Tunnel must contain
– Linac Cryomodule
– RF system
– Damping Ring Lines
• Save maybe $0.5B
• Issues
– Maintenance
– Safety
– Duty Cycle
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Possible Tunnel Configurations
•
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One tunnel of two, with variants ??
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ILC Civil Program
Civil engineers from all three
regions working to develop
methods of analyzing the
siting issues and comparing
sites.
The current effort is not
intended to select a potential
site, but rather to understand
from the beginning how the
features of sites will effect the
design, performance and cost
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Baseline Klystrons
Available today: 10 MW Multi-Beam Klystrons (MBKs) that operate
at up to 10 Hz
Thales
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CPI
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Toshiba
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Improved Klystron ?
5 MW Inductive Output
Tube (IOT)
10 MW Sheet Beam
Klystron (SBK)
Low Voltage
10 MW MBK
Parameters similar to
10 MW MBK
Voltage e.g. 65 kV
Current 238A
More beams
Output
Klystron
SLAC
13-Sept-05
Perhaps use a Direct
Switch Modulator
IOT
Drive
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KEK
CPI
43
RF Distribution
BASELINE DESIGN
Similar to TDR and XFEL scheme.
POSSIBLE IMPROVEMENT?
With two-level power division and proper phase lengths, expensive circulators
can be eliminated. Reflections from pairs of cavities are directed to loads.
Also, fewer types of hybrid couplers are needed in this scheme. There is a
small increased
risk to klystrons.
(Total reflection from a pair of cavities sends
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< 0.7% of klystron power back to the klystron.)
Beamsize Growth Study
(cumulative after feedback)
30 min
ground.
13-Sept-05
+
Undulator
+
Component
jitter
+
5 Hz
ground.
Scientific Policy Committee - CERN
+
Kicker, current,
energy jitter,
BPM resol.
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Availability Studies
1 vs 2 tunnels
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Improving
Mean Time Between Failures
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Damping Rings: Three variants
6km
3km
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17 km ‘dogbone’
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Beam Delivery, MDI
Strawman solution (BCD recommendation)
Appears to work for nearly all suggested parameter sets:
Exceptions:
• 1 TeV high-luminosity (new parameter set suggested for 20mrad)
• 2 mrad extraction has problems with high disruption sets
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Industrial Studies
•
Industrial studies in three regions are essential.
–
–
–
–
–
–
Important to understand industrial costs
Important to examine potential cost reductions
Need to think about what studies are needed and when
Focus on the cost drivers for ILC, important for cost estimate
Focus on places where there is technical risk to the project goals
ILC need a point-of-contact and a plan for industrial studies
2nd ILC Industrial Forum Meeting is scheduled to be held at
Fermilab Sept. 21st and 22nd, 2005.
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Detector Concepts and Challenges
• Three concepts under study
• Typically requires factors of
two or so improvements in
granularity, resolution, etc.
from present generation
detectors
• Focused R&D program
required to develop the
detectors -- end of 2005
• Detector Concepts will be
used to simulate
performance of reference
design vs physics goals
next year.
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Accelerator Physics Challenges
• Develop High Gradient Superconducting RF systems
– Requires efficient RF systems, capable of accelerating high
power beams (~MW) with small beam spots(~nm).
• Achieving nm scale beam spots
– Requires generating high intensity beams of electrons and
positrons
– Damping the beams to ultra-low emittance in damping rings
– Transporting the beams to the collision point without
significant emittance growth or uncontrolled beam jitter
– Cleanly dumping the used beams.
• Reaching Luminosity Requirements
– Designs satisfy the luminosity goals in simulations
– A number of challenging problems in accelerator physics and
technology must be solved, however.
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Creating an International Project
• Several Studies and Plans for ILC
– OECD (Organization for Economic Cooperation and
Development)
• “A template for Establishing, Funding and Managing an
International Scientific Research Project Based on an
Agreement Between Governments and Institutions”
– Features a template that covers all aspects of creating
agreements for an international collaboration, in
particular formal agreements, funding arrangements,
central structure and using existing institutions
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OECD International Project Template
Participants
Participants
Host Country
Participants
Memorandum of Understanding
Country
Agreement
Governing
Board
Scientific and
Technical
Advisory Bodies
(optional)
Host
Agreement
Secretariat
Host
Director
Staff
The Collaboration
13-Sept-05
Secretariat
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Creating an International Project
• Several Studies and Plans for ILC
– TESLA proposed plan for Project Organization
• “Organization and Management of an International
Collaboration on the TESLA Linear Collider”
– Features a “Global Accelerator Network”, which is
basically a collaboration between institutions where as
much as possible the participation is treated as an
extension of the laboratory programs and even the
accelerator is to be run locally from the collaborating
laboratories.
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TESLA Proposed Project Organization
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Creating an International Project
• Several Studies and Plans for ILC
– ECFA EUROPEAN COMMITTEE FOR FUTURE
ACCELERATORS subcomittee EUROPEAN LINEAR
COLLIDER STEERING GROUP
• “Report of the Sub-group on Organizational Matters”
– Features a detailed breakdown of top level governance
and project management, how they relate to each other.
It is based on regional organizations; mostly in-kind
contributions; shared central management, oversight,
responsibility. It is concerned with Europe and how to
do it within European Labs (CERN) and structures
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ECFA ILC Governance and Management
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Conclusions
Remarkable progress in the past two years toward realizing
an international linear collider:
important R&D on accelerator systems
definition of parameters for physics
choice of technology
start the global design effort
funding agencies are engaged
 Many major hurdles remain before the ILC becomes a
reality (funding, site, international organization, and most
importantly, a technical design and construction plan)
 The time scale for ILC project readiness is consistent
with early results from LHC and CLIC feasability studies.
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