# Presentation: 475644

## International Linear Collider Overview

- Shekhar Mishra
- ILC R&D
- Fermilab

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Activities WorldwideInternational Framework

- Organization
- Global Design Effort (GDE) to develop CDR and then engineering design
- Reliance on (three) regional design centers
- Regional Efforts
- ILC-Americas collaboration forming with multi-institutional participation
- Construction and operation based on host lab/international project model
- ECFA Study on governance (“host lab/international project”)
**http://committees.web.cern.ch/Committees/ECFA/Cern03KalmusReport.pdf**
- Support
- Several meetings of the regional funding agencies
- Need increase in resources starting in FY2006
- Timelines
- GDE established (w/ Director) in early 2005
- “CDR” complete 1-2 years later
- Construction timeline likely to be paced by the political path

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## International Linear Collider View

- An internationally constructed and operated electron-positron linear collider, with an initial center-of-mass energy of 500 GeV, has received strong endorsement by advisory committees in North America, Europe, and Asia as the next large High Energy Physics facility beyond LHC.
- An international panel, under the auspices of ICFA, has established performance goals as meeting the needs of the world HEP community. The performance document is available at:
- http://www.fnal.gov/directorate/icfa/LC_parameters.pdf
- The International Technology Recommendation Panel has recommended, and ICFA has accepted the recommendation, that the International Linear Collider (ILC) design be based on superconducting rf technology.

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## International Performance Specification

- Initial maximum energy of **500 GeV**, operable over the range 200-500 GeV for physics running.
- Equivalent (scaled by 500 GeV/s) integrated luminosity for the first four years after commissioning of **500 fb****-1**.
- Ability to perform energy scans with minimal changeover times.
- Beam energy stability and precision of 0.1%.
- Capability of **80%** electron beam **polarization** over the range 200-500 GeV.
**Two interaction regions**, at least one of which allows for a crossing angle enabling  collisions.
- Ability to operate at **90 GeV** for calibration running.
- Machine upgradeable to approximately **1 TeV**.

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Overview The Last Year

- Cold technology selection
- ILC Collaboration formed
- GDE established
- B. Barish named director
- Near term goal is CDR by the end of 2006
- ILC-Americas getting organized: G. Dugan, Director
- SMTF collaboration formed and proposal submitted to Fermilab
- Consistent with Fermilab as lead lab on SRF technology development within the Americas region
- DOE identification of Fermilab as preferred U.S. site
**“****This (ILC) is the highest priority initiative for the laboratory.”**
**      **P. Oddone to EPP2010 (5/16/05)

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## The Global Design Effort: The early Phase

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC OverviewGDE Organization

- International

- Regional

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Activities WorldwideNational

- USLCSG established and functioning
**http://www.slac.stanford.edu/~hll/USLCSG/**
- Development and implementation of a strategy for bringing an international linear collider to reality
- Coordination of U.S. R&D activities
- Preparation of the U.S. bid to host
- Identification of LC as highest mid-term priority in the Office of Science 20-year plan
- On-shore ILC will probably require Presidential Initiative
- Formation of ILC-Americas collaboration underway with first meeting held at SLAC, October 14-16.
- Broad participation from DOE and NSF support laboratories and universities.

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC OverviewAmericas R&D Program 

- Major initiatives & test facilities (US)
- Significant presence within all major subsystems
- Superconducting Module Fabrication and Testing Facilities
- Industrialization (more advanced in Europe than US/Asia)
- Integrated systems test (linac)
- Modeling/simulations
- Site Development

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## International Linear Collider:Physical Layouts and Configurations

- TESLA TDR

- USLCSG Study

- Two concepts developed to date:
- TESLA TDR
- USLCSG Study
- Possible considerations:
- Energy/luminosity tradeoffs at “500” GeV
- Undulator vs. conventional e+ source
- Upgrade energy
- Head on vs. crossing angle IR
- Upgrade injector requirements
- One vs two tunnels

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Performance Parameters

- ILC collaboration would have a new parameter set by Sept 05.

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Parameters

- parameterspace

- peak luminosity

- 21034

- Define baseline at relaxed goal of21034 cm-2s-1
- consistent with WWS 500fb-1 in first 4 years
- Now have several possible parameter sets (parameter ‘plane’)
- Operational flexibility
- Sub-system experts to evaluate trade-offs between relevant parameters

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Requirements and ChallengesEnergy: 500 GeV, upgradeable to 1000 GeV

- RF Structures
- The accelerating structures must support the desired gradient in an operational setting _and_ there must be a cost effective means of fabrication.
- 24-35 MV/m  20 km
- ~21,000 accelerating cavities/500 GeV
- RF power generation and delivery
- The rf generation and distribution system must be capable of delivering the power required to sustain the design gradient
- 10 MW  5 Hz  1.5 msec
- ~600 klystrons and modulators/500 GeV
- The rf distribution system is relatively simple, with each klystron powering 30-36 cavities.
-  Demonstration projects: TTF-I and II(DESY); SMTF(USA-FNAL) in conceptualization phase

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Towards the ILC Baseline Design

- Decisions to be Made!

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Main Linac: The Cost Driver

- Biggest single cost item
- 10 years of R&D by the TESLA Collaboration has produced a mature technology
- But still lots to do...

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Main Linac: The Cost Driver

- Primary focus of future R&D *should* be
- successful tech. transfer to industry
- cost reduction through industrialisation
- need extensive effort to achieve _high reliability_ !!!
- Euro XFEL project is already doing much of this within Europe
- Asia and US should follow
- One important question: “What should the design gradient be?”

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Gradient

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Gradient versus Length

- Higher gradient gives shorter linac 
- cheaper tunnel / civil engineering
- less cavities
- (but still need same # klystrons)
- Higher gradient needs more refrigeration 
- ‘cryo-power’ per unit length scales as *G*2/*Q*0
- cost of cryoplants goes up!

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Simple Cost Scaling

- Relative Cost

- Gradient MV/m

- general consensus that 35MV/m is close to optimum
- However Japanese are still pushing for 40-45MV/m
- 30 MV/m would give safety margin

- C. Adolphsen (SLAC)

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Technology StatusAccelerating Structures

- Vertical (low power test)

- Comparison of low and high power tests (AC73)

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Technology StatusAccelerating Structures

- Recent results from AC70
- First cavity processed in DESY EP facility

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## TESLA Cavity Design

- 9-cell 1.3GHz Niobium Cavity
- Reference design: has not been modified in 10 years

- ~1m

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Possible Minor Enhancement

**Low Loss** Design
- Small modification to cavity shape reduces peak B field.
- Increase operation margin.
- Increases peak E field (field emission)
- Mechanical stability ??(Lorentz force detuning)

- KEK currently producing prototypes

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Cryomodule Variants

- TESLA CM already 3rd generation

- 	     **TTF****	****  ILC**
- # cavities   8	  12?spacing	     3/2	  /2?quad loc.    end	  centre?

- Main emphasis is on- industrialisation - reliability- cost optimisation

- EURO XFEL

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Cavity Auxiliaries

- TTF TYPE-IIIHP Coupler

- INFN blade tuner

- SACLAY tuner (type III)

- industrialisation – cost – reliability

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Technology StatusRF Sources

- Three Thales TH1801 Multi-beam klystrons fabricated and tested.
- Efficiency = 65%
- Pulse width = 1.5 msec
- Peak power = 10 MW
- Repetition rate = 5 Hz
- Operational hours (at full spec) = 500 hours
- Operational hours (<full spec) = 4500 hours
- Independent MBK R&D efforts now underway at CPI and Toshiba
- 10 Modulators have been built
- 3 by Fermilab and 7 by industry
- 7 modulators are in operation
- Based on Fermilab design
- 10 years operation experience

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Example: Klystron Development 

- THALUS

- CPI

- TOSHIBA

- 10MW 1.4ms Multibeam Klystrons
- 	~650 for 500 GeV
- 	+650 for 1 TeV upgrade

- Other ideas being considered (e.g. sheet beam klystrons)

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Global SCRF Test Facilities

- TESLA Test Facility (TTF)currently unique in the worldVUV-FEL user facilitytest-bed for both XFEL & ILC
- US proposed SMTFCornell, JLab, ANL, FNAL, LBNL, LANL, MIT,MSU, SNS, UPenn, NIU, BNL, SLACcurrently requesting fundingTF for ILC, Proton Driver (and more)
- STF @ KEKaggressive schedule to produce high-gradient(~45MV/m) cavities / cryomodules

- All facilities will be discussed at **TESLA Collaboration**** ****Meeting**
- 30/3-1/4 at DESY

- Others (UK proposals?)

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Towards the ILC Baseline Design

- More Decisions to be Made!

- Not cost drivers
- But can be *L* performance
- bottlenecks
- Many challenges!

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Damping Rings

- bunch train compression
- 300km  20km

- smaller circumference
- (faster kicker)

- higher Iav

- 

- 

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## see A. Wolski’s talk: http://lcdev.kek.jp/ILCWS/Talks/14wg3-10-WG3-10_DR_Wolski.pdf

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## see A. Wolski’s talk: http://lcdev.kek.jp/ILCWS/Talks/14wg3-10-WG3-10_DR_Wolski.pdf

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## see A. Wolski’s talk: http://lcdev.kek.jp/ILCWS/Talks/14wg3-10-WG3-10_DR_Wolski.pdf

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ATF @ KEK

- emittance tuning
- wiggler dynamics
- collective effects
- multi-bunch
- fast kicker technology
- diagnostics test bed

- E	1.28 GeV
- N 	21010 e/bunch
- bunches	1-20
-  x/y 	1.5nm / 4pm
- 20 weeks/year
- 2 weeks/month

- wiggler magnets

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Technology StatusDamping Rings

- The required emittances, x/y = 8.0/.02 m, have been achieved in the ATF at KEK
- Performance is consistent with IBS, however,
- Single bunch, e-
- Circumference = 138 m

**ILC Design**

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Technology StatusDamping Rings

- The total length of the ILC beam pulse is:
- 2820337 nsec = 950 sec = 285 km (!)
- This creates many unique challenges in the ILC damping ring design:
- Multiplexing the beam (16 in the TELSA TDR)
- Requires fast (~20 nsec rise/fall time kicker for single bunch extraction)
- Circumference is still ~285/16 = 18 km
- Space-charge is an issue because of the large C/y (a first for an electron storage ring).
- X/Y “transformer” used to mitigate.
- A number of ideas exist for reducing the circumference and associated challenges.

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Technology StatusEmittance Preservation

- Emittance growth budget from DR to IR is:
- 1.2 (horizontal),  2.0 (vertical)
- Sources of emittance growth include:
- Wakes
- Single bunch controlled by BNS damping
- Multibunch controlled by HOM dampers and tune spread

- Alignment and jitter
- Vertical dispersion   momentum spread = emittance growth
- Controlled by alignment and correction algorithms (feedback)
- Alignment tolerances ~300 mm, 300 mrad; BPM resolution ~10 mm
- Maintaining beams in collision
- Intra-train feedback

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## BDS Issues

- very active (international) group!

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## BDS Strawman Model

- Discussion on angles between the Linacs:
-  Multi-TeV upgradeability argument is favoured by many
-  Small crossing angle is disfavoured by some

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ATF-2: FFTB @ ATF

- Test of local correction FF optics
- 35nm IP beam size
- Test facility for stabilisation techniques (beam-based feedback and mechanical: goal 2nm at IP)
- Long term stability studies
- ...

- International Collaboration
- (ongoing discussions)
- Begin construction 8.2006
- Begin operation 1.2007

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Positron Source

- Hotly debated subject.

- Large amount of charge to produce
- Three concepts:
- undulator-based (TESLA TDR baseline)
- ‘conventional’
- laser Compton based

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Parameters of existing and planed 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 |

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Undulator-Based

- 6D e+ emittance small enough that (probably) no pre-DR needed [shifts emphasis/challenge to DR acceptance]
- Lower *n* production rates (radiation damage)
- Need high-energy e- to make e+ (coupled operation) Makes commissioning more difficult
- Polarised positrons (almost) for free 

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Conventional

- Extrapolation of existing methods
- SLC e+ source
- Extremely challenging for ILC pulse structure
- feasibility still a question
- Requires thick target(s)
- High(er) n production – radiation damage a primary issue
- Large e+ emittance probably means pre-DR needed.
- Completely de-couples e+ from e- machine 
- greater flexibility 
- operability 
- commissioning 

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Reliability / Operability

- A major issue for ILC – needs much more workCurrent state-of-the-art is Tom Himel study for USCWO

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## ILC Technology StatusExamples of Outstanding Issues

- RF Structures and Source
- Establish gradient goal
- Develop US capability for fabricating high gradient cavities
- Coupler design
- Controls/LLRF
- Industrialization
- Particle Sources
- Conventional e+
- Damping Rings
- Length of the current design
- Common tunnel
- Commissioning
- New design concepts to reduce circumference

- Emittance Preservation
- Alignment of structures inside cryomodules
- Instrumentation and feedback systems
- Maintaining Beams in Collision
- Feedback
- Head-on IR?
- Machine Protection
- Collimation systems
- Civil
- 1 tunnel vs. 2
- Near surface vs. deep

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005

## Summary

- The ILC is ambitious project which pushed the envelope in every subsystem:
- Main SCRF linac
- sources
- damping rings
- beam delivery
- Still many accelerator physics issues to deal with, but _**reliability**_ and _**cost issues**_ are probably the greater challenges
- Probably in excess of 3000 man-years already invested in design work.
- but still plenty for _you_ to do if you want to join us 

*L *performance bottleneck

- cost driver $$$

- Talk at the Organizational Meeting of USLCIF

- 6/6/2005