report from the gde

Report from the GDE

Barry BarishACFA Workshop

EXCO, Daegu, Korea 11-July-05

11-July-05 ACFA Workshop - Barish 2

The Energy Frontier


The Third ACFA Statementon

International Linear Collider

issued on Nov. 3, 2004 at the 9th Plenary ACFAIn August 2004, ICFA has decided on superconducting technology for the future linear collider (LC), by endorsing the resolution of the international technology recommendation panel (ITRP) created by ILCSC under ICFA. The ITRP report emphasizes the importance of world-wide unified approach as a single team to design the international linear collider (ILC).

ACFA has discussed various issues relating to ILC in the plenary meeting of ACFA at VECC, Kolkata in India on 2-3 Nov. 2004, and ACFA came to the following conclusions

ACFA welcomes the truly international nature of the decision on technology for the ILC. This sets the stage for international collaboration in the design efforts for the ILC.

ACFA reaffirms that the ILC, the next major high-energy physics project, should be realized by world-wide efforts. In such International collaboration ACFA and scientists in ACFA countries should play crucial and leading roles.

ACFA reconfirms the importance of hosting ILC in Asia, which will make high energy physics and accelerator science truly global.


The Third ACFA Statementon

International Linear Collider

ACFA urges the Japanese Government to fully support the efforts of KEK and Japanese scientists to host the ILC in Japan.

ACFA reconfirms that KEK is the best suited institute in Asia for hosting the Central Team of GDI.

ACFA urges KEK to establish the Asian Regional Center for R&D in GDI and encourages other Asian countries to actively participate in GDI.

With ILC entering this important phase, ACFA urges Governments of Asian countries to support participation of their scientists in GDI.

ACFA feels that Asia has wide expertise in accelerator technology which can be directed to develop SCRF technology required for the ILC, and large trained manpower which can make major contributions to the ILC. Because ILC will pose major scientific and technical challenges, there will be several technological fallouts. ACFA therefore feels that by participating in the ILC not only the scientific community of the participating country but also its industry will benefit.


The Community then Self-Organized

Nov 13-15, 2004


The First ILC Meeting at KEK

There were 220 participants divided among 6 working groups

Working Group 1: Overall Design Working Group 2: Main Linac Working Group 3: Injector, including damping rings Working Group 4: Beam Delivery Systems, including collimator, final focus, etc. Working Group 5: Cavity design: higher gradients, ..Working Group 6: Strategic communication

Each working group had three convenors, one from each region

The Global Design Effort

Formal organization begun at LCWS 05 at Stanfordin March 2005 when I became director of the GDE

Technically Driven Schedule


GDE – Near Term Plan

• Staff the GDE– Administrative, Communications, Web staff– Regional Directors (one per region)– Engineering/Costing Engineer (one per region)– Civil Engineer (one per region)– Key Experts for the GDE design staff from the world

community– Fill in missing skills (later)

Total staff size about 20 FTE (2005-2006)



• Organize the ILC effort globally– First Step --- Appoint Regional Directors within the

GDE who will serve as single points of contact for each region to coordinate the program in that region. (Gerry Dugan (North America), Fumihiko Takasaki (Asia), offered to Brian Foster (Europe))

– Make Website, coordinate meetings, coordinate R&D programs, etc

• R&D Program– Coordinate worldwide R & D efforts, in order to

demonstrate and improve the performance, reduce the costs, attain the required reliability, etc. (Proposal Driven to GDE)



• Schedule• Begin to define Configuration (Aug 05) • Baseline Configuration Document by end of 2005

-----------------------------------------------------------------------• Put Baseline under Configuration Control (Jan

06) • Develop Reference Design Report by end of 2006

• Three volumes -- 1) Reference Design Report; 2) Shorter glossy version for non-experts and policy makers ; 3) Detector Concept Report


main linacbunchcompressor

dampingring

source

pre-accelerator

collimation

final focus

IP

extraction& dump

KeV

few GeV

few GeVfew GeV

250-500 GeV

Starting Point for the GDE

Superconducting RF Main Linac


Some Key Near-Term Design Choices

• Accelerating Gradient• Positron Production mechanism• Design of Damping ring• Site-specific considerations: One or two tunnels?

Shallow or deep?, etc

• Total cost will be a key determining factor in our ability to get the ILC built. Therefore cost optimization of all systems is of primary importance


Towards the ILC Baseline Design


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


rf bands:

L-band (TESLA) 1.3 GHz = 3.7 cm

S-band (SLAC linac) 2.856 GHz 1.7 cm

C-band (JLC-C) 5.7 GHz 0.95 cm

X-band (NLC/GLC) 11.4 GHz 0.42 cm

(CLIC) 25-30 GHz 0.2 cm

Accelerating structure size is dictated by wavelength of the rf accelerating wave. Wakefields related to structure size; thus so is the difficulty in controlling emittance growth and final luminosity.

Bunch spacing, train length related to rf frequency

Damping ring design depends on bunch length, hence frequency

Specific Machine Realizations

Frequency dictates many of the design issues for LC


Cost Breakdown by Subsystem

cf31%

structures18%rf

12%

systems_eng8%

installation&test7%

magnets6%

vacuum4%

controls4%

cryo4%

operations4%

instrumentation2%

Civil

SCRF Linac


What Gradient to Choose?


TESLA Cavity

9-cell 1.3GHz Niobium Cavity

Reference design: has not been modified in 10 years

~1m


(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

Electro-polishing


Gradient

Results from KEK-DESY collaboration

must reduce spread (need more statistics)

single

-cell

measu

rem

ents

(in

nin

e-c

ell

cavit

ies)


How Costs Scale with Gradient?

Relative

Co

st

Gradient MV/m

2

0

$ lincryo

a Gb

G Q

35MV/m is close to optimum

Japanese are still pushing for 40-45MV/m

30 MV/m would give safety margin

C. Adolphsen (SLAC)


Evolve the Cavities Minor Enhancement

Low Loss Design

Modification to cavity shape reduces peak B field. (A small Hp/Eacc ratio around 35Oe/(MV/m) must be designed).

This generally means a smaller bore radius

Trade-offs (Electropolishing, weak cell-to-cell coupling, etc)

KEK currently producing prototypes


New Cavity Design

More radical concepts potentially offer greater benefits.

But require time and major new infrastructure to develop.

28 cell Super-structure

Re-entrant

single-cell achieved45.7 MV/m Q0 ~1010

(Cornell)


Fermilab ILC SCRF Program


Experimental Test Facility - KEK

• Prototype Damping Ring for X-band Linear Collider

• Development of Beam Instrumentation and Control


Final Focus Test Faclity - SLAC


TESLA Test Facility Linac - DESY

laser driven electron gun

photon beam diagnostics

undulatorbunch

compressor

superconducting accelerator modules

pre-accelerator

e- beam diagnostics

e- beam diagnostics

240 MeV 120 MeV 16 MeV 4 MeV


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 and Europe are to determine sample sites by the

end of 2005


Fermilab ILC Civil Program

A Fermilab Civil Group is collaborating with SLAC Engineers and soon with Japanese and European engineers 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


Draft 27-May-05

Conventional Facilities Site Considerations

1 Site impacts on critical science parameters 5 Construction Cost Impacts (cont.)

1AConfiguration (Physical Dimensions and

Layout)5

CClimate

.1 Usable Length and Width.

1Snowfall

.2 Flexibility for Adjustment of Alignment.

2Average Ambient temperature

.a Adaptable to Laser Straight.

3Average underground temperature

.b Adaptable to Earth Curvature.

4No of days rainfall

.3 Depth of Tunnel 5

DEnvironmental Restrictions

.4 Depth of Interaction Halls5

EAccessibility

.5 Accessibility to Tunnels5

FSite Utility Support & Installation

1BPerformance (Vibration and Stability

5GProximity of Soil Borrow and Disposal Areas

.1 Natural Vibration/Noise Sources5

HLocal Labor

.a Geologic Dynamic Properties.

1Construction Rate Index


Parameters of Positron Sources

rep rate# of bunches per pulse

# of positrons per bunch

# of positrons per pulse

TESLA TDR 5 Hz 2820 2 · 1010 5.6 · 1013

NLC 120 Hz 192 0.75 · 1010 1.4 · 1012

SLC 120 Hz 1 5 · 1010 5 · 1010

DESY positron source

50 Hz 1 1.5 · 109 1.5 · 109


B=0.75 T5 mm gap

Conventional source

Undulator-based source

Positron source


Laser Compton Source


Beam Delivery Systems -- Challenges

• Transport the high-energy beam from the end of the main linac to the interaction point

• Transport the post-collision spent beam and beamstralung to the dumps

• Provide collimation for control of backgrounds

• Provide machine protection systems for errant beams

• Provide collision point maintenance through the use of fast feedback systems (inter-train and intra-train)


20 mrad ILC FF9 (x 4)

tuneupdump lines

ILC Strawman Layout

Mark Woodley


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.


Test Facility at KEK


Test Facility at SLAC


TESLA Test Facility Linac - DESY

laser driven electron gun

photon beam diagnostics

undulatorbunch

compressor

superconducting accelerator modules

pre-accelerator

e- beam diagnostics

e- beam diagnostics

240 MeV 120 MeV 16 MeV 4 MeV


Fermilab ILC SCRF Program


• “Our task is to continue studies on physics at the linear collider more precisely and more profoundly, taking into account progresses in our field, as well as on developments of detector technologies best suited for the linear collider experiment. As we know from past experiences, this will be enormously important to realize the linear collider.”

• Akiya Miyamoto

ACFA Joint Linear Collider Physics and Detector Working

Group


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.


Beam Detector Interface

TauchiLCWS05


• The Machine

• Accelerator baseline configuration will be determined and documented (BCD) by the end of 2005

• R&D program and priorities determined (proposal driven)

• Baseline configuration will be the basis of a reference design done in 2006

• The Detector(s)

• Determine features, scope: one vs two, etc (same time scale)

• Measure performance of the baseline design

• Beam delivery system and machine detector interfaces

• Define and motivate the future detector R&D program

The GDE Plan

report from the gde

Documents

acfa countries

acfa statement

plenary meeting of acfa

following conclusions

ilc meeting

importance of hosting

overall design working

working groups