The ILC Reference Design Report Brian Foster Oxford

The ILC Reference Design Report Brian Foster (Oxford & GDE) Manchester EPS Meeting B. Foster - EPS 07/07 Global Design Effort 1

Overview h • This talk divided into two parts: • Today – Summary of progress on RDR – Brief glimpse of future • Tomorrow - in EPS/ECFA SESSION – Very brief summary of RDR – Details of future plans/timelines • For a full picture, come to both! Many thanks to L. Lilje & K. Yokoya B. Foster - EPS 07/07 Global Design Effort 2

ILC Parameters • Ecm adjustable from 200 – 500 Ge. V • Luminosity ∫Ldt = 500 fb-1 in 4 years (corresponds to 2*1034 cm-2 s-1 ) • Ability to scan between 200 and 500 Ge. V • Energy stability and precision below 0. 1% • Electron polarization of at least 80% • The machine must be upgradeable to 1 Te. V B. Foster - EPS 07/07 Global Design Effort 3

Overall Layout 1 st Stage: 500 Ge. V B. Foster - EPS 07/07 Global Design Effort 4

Basic Parameters Max. Center-of-mass energy Peak Luminosity 500 ~2 x 1034 Ge. V cm-2 s-1 Beam Current 9. 0 m. A Repetition rate 5 Hz Average accelerating gradient 31. 5 MV/m Beam pulse length 0. 95 ms 31 km ~230 MW Total Site Length Total AC Power Consumption B. Foster - EPS 07/07 Global Design Effort 5

Reprise - The Road to the RDR Jan 05 Frascati July Bangalore Vancouver Dec Valencia SLAC Feb 06 Aug Beijing Daegu Freeze Configuration Organize for RDR Review Design/Cost Methodology Review Initial Design / Cost Design and Costing B. Foster - EPS 07/07 Global Design Effort Review Final Design / Cost RDR Document Preliminary RDR Released RDR complete 6

ILC Reference Design Report ~700 Contributors from 84 Institutes The RDR is not a full engineering design - it is conceptual; some aspects require R&D. Forms reliable basis for detailed engineering design & costing. B. Foster - EPS 07/07 Global Design Effort 7

Electron Source System • ~2600 bunches, ~1 ms, 2 x 1010 at DR • >80 % polarization B. Foster - EPS 07/07 Global Design Effort 8

Positron Source • 3 possible positron generation schemes have been proposed A) Standard method: a few Ge. V electron on target B) Undulator scheme: use photons from >100 Ge. V electron through undulator C) Compton scheme: use photons from a few Ge. V electron through laser-Compton scattering • B) has been selected as the baseline – – B. Foster - EPS 07/07 C) is immature Cost saving by A) is not significant. Physics descoping (no positron polarization) Global Design Effort 9

Positron Source • Undulator scheme - Baseline – Electron beam at 150 Ge. V – Undulator • Helical, superconducting • length 147 m (longer for polarized e+) • K = 0. 92, l = 1. 15 cm, (B = 0. 86 T) – Needs ‘keep-alive source’ • 10 % intensity • Share 5 Ge. V linac B. Foster - EPS 07/07 Global Design Effort 10

DR Issues • Injection/extraction kickers • Instabilities – Electron-cloud, Fast Ion, … • Dynamic aperture • Tuning for low emittance Task Force S 3 has been established for DR R&D • Defining work packages • Available machines – KEK-ATF – KEKB, CESR, HERA B. Foster - EPS 07/07 Global Design Effort 11

Kicker System B. Foster - EPS 07/07 Global Design Effort 12

Electron Cloud • Secondary electrons attracted by positron beam causes an instability • Max. of Secondary Electron Yield (SEY) should be < 1. 1 • Possible cures – Coating with NEG – Solenoids in free field region – Grooves on chamber wall – Clearing electrode • Confident enough to baseline single e+ DR B. Foster - EPS 07/07 Global Design Effort 13

Main Linac Layout • 2 tunnels diameter 4. 5 m Penetrations: Cable & Plumbing Waveguide LLRF, Controls, Protection Racks Charger Main Modulator HV Pulse Transformer Horizontal Klystron LCW Chiller AC Switchgear Waveguide Distribution System Dwg: J. Liebfritz B. Foster - EPS 07/07 Global Design Effort 14

Main Linac RF Unit Overview • • Bouncer type modulator Multibeam klystron (10 MW, 1. 6 ms) 3 Cryostats (9+8+9 = 26 cavities) 1 Quadrupole at the center B. Foster - EPS 07/07 Global Design Effort 15

Cavities • Baseline: TESLA-type 1. 3 GHz – Identical to XFEL cavities • Only beamtubes shortened • Accelerating gradient – Vertical test • >35 MV/m, Q>0. 8 x 1010 – Average gradient in cryomodule • 31. 5 MV/m, Q>1 x 1010 • With the presently available technology – Average gradient lower than 31. 5 MV/m – Spread of gradient large – If uniform distribution in 22<G<34 MV/m, average 28 MV/m: Cost increase ~7 % B. Foster - EPS 07/07 Global Design Effort 16

High Gradient Reproducibility: S 0 S 1 Program • Task Force created and R&D program set up • S 0: establish 35 MV/m in low power tests – Single-cell program • optimise final surface preparation (e. g. short electr polishing, alcohol rinse, ultrasound gegrease) – Tight-loop process • repeated surface treatment with small number of cavities including exchange of cavities among Asia-US-Europe in 2007 – Production-like process • Many cavities with the same recipe • Large data set is (will be) available from the XFEL project – experience with TTF and FLASH – pre-production runs » includes industrialisation e. g. Electropolishing at Industry • Time line – Establish high yield well before EDR • S 1: Establishing 31. 5 MV/m operational in accelerator modules B. Foster - EPS 07/07 Global Design Effort 17

Current status 2006 2005 2007 B. Foster - EPS 07/07 KEK single cell results: 2005 – just learning 2006 – standard recipe 2007 – add final 3 μm fresh acid EP Note: multi-cells harder than singles Global Design Effort 18

Module Test – Goal • Intermediate goal – Achieve 31. 5 MV/m average operational accelerating gradient in a single cryomodule as a proof-of-principle. In case of cavities performing below the average, this could be achieved by tweaking the RF distribution accordingly. – Auxiliary systems like fast tuners should all work. • Final goal – Achieve > 31. 5 Me. V/m operational gradient in 3 cryomodules. – The cavities accepted in the low power test should achieve 35 MV/m at Q 0 = 1010 with a yield as described above (80% after first test, 95% after re-preparation). – It does not need to be the final cryomodule design B. Foster - EPS 07/07 Global Design Effort 19

S 1 RF Performance: Compare Acceptance Test with Module Operational Accelerating Gradient • • This is the main motivation for S 1 Improvement on assembly procedures needed – Addressed in studies with industry also B. Foster - EPS 07/07 Global Design Effort 20

XFEL assets: Module Test at DESY • High gradient modules have been assembled – For installation in FLASH • Test in dedicated test stand possible e. g. – – Cavity performance Thermal cycles Heat loads Coupler conditioning – Fast tuner performance – (LLRF tests) • Part of the ongoing preparation work for XFEL B. Foster - EPS 07/07 Global Design Effort 21

Module Test DESY B. Foster - EPS 07/07 Global Design Effort 22

Alternatives: • LL-type cavity – Lower max. magnetic field at same accelerating gradient • Potentially higher gradient > 40 MV/m – Under development at KEK and JLab • Single-cell test successful with max. over 50 MV/m • But 9 -cell cavities are still poor with max. 29 MV/m without HOMs • Nb material: Large grain – Started at JLab – Single-cells • comparable performance to standard material – Full nine-cells fabricated XFEL preparation phase • so far only etched (BCP) • EP underway B. Foster - EPS 07/07 Global Design Effort 23

Large Grain Material: EP and BCP D. Reschke et al. B. Foster - EPS 07/07 Global Design Effort 24

Modulator • Baseline – Bouncer-type modulator • Design at FNAL – Has been working for >10 years at TTF at DESY – No major technical issues – XFEL choice – Design improvements (within XFEL industrialisation) • More cost-efficient design under way • Redundancy of internal components for higher availability • Alternative: – Marx Modulator • • B. Foster - EPS 07/07 Under development at SLAC Smaller size No step-up transformer Potentially high cost saving Global Design Effort 25

Klystrons • • • Requirements: – 10 MW – 1. 6 ms – 5 Hz – lifetime for full power >40000 hrs Baseline solution: Multi-beam klystron – Use multiple beams of low charge – Lower space-charge effects – Lower voltage (120 k. V) – Higher efficiency (~65 %) Prototypes from 3 manufacturers for the European XFEL (higher repetition rate: 10 Hz) – Thales and Toshiba MBKs being successfully tested at DESY at full spec • for > 1000 hrs • Several klystrons under varying operating conditions at FLASH, PITZ and test stand Horizontally mounted klystron needed for small tunnel diameter – XFEL develops this with industry More lifetime testing going on (eventually also at SLAC) – At DESY all tubes now in operation show no sign of degradation B. Foster - EPS 07/07 Global Design Effort 26

Cryogenics System • 1 cryogenic plant covers 2. 5 km linac length. – Installed power ~4. 5 MW • Total 10 plants – ~45 MW – comparable to LHC cryogenics system B. Foster - EPS 07/07 Global Design Effort 27

BDS (Beam Delivery System) • From main linac exit to IP (Interaction Point) and to the beam dump • Roles of BDS – Focus the beam to the desired spot size for collision – Remove beam-halo to minimize the background events – Protect the beamline and detectors against mis -steered beam – Diagnostics of the linac beam – Safely dump the spent beams B. Foster - EPS 07/07 Global Design Effort 28

Single IR with Push-Pull Detectors • Large cost savings compared with 2 IR – ~200 M$ compared with 2 IR with crossing angles 14 + 14 mrad - much more if one IR has “small angle” crossing. • Push-pull detectors – Task force from WWS and GDE formed – Conclusion is • No show-stoppers • But need careful design and R&D works • 2 IR should be left as an `Alternative’ B. Foster - EPS 07/07 Global Design Effort 29

IR Hall for push-pull may be accessible during run The concept is evolving and details being worked out accessible during run B. Foster - EPS 07/07 detect or A detector B Global Design Effort detector B Platform for electronic and services (~10*8*8 m). Shielded (~0. 5 m of concrete) from five sides. Moves with detector. Also provide vibration isolation. 30

BDS (Beam Delivery System) • Single IR and pushpull detector • Total length 4. 45 km • 1 Te. V upgrade by inserting some components (no geometry change) B. Foster - EPS 07/07 Global Design Effort 31

BDS Layout B. Foster - EPS 07/07 Global Design Effort 32

Interaction Region • Crossing angle 14 mrad • Final quadrupole magnets – Superconducting (QD 0 in detector magnetic field) – Out-going beam goes outside B. Foster - EPS 07/07 Global Design Effort 33

Crab Crossing • Large crossing angle 14 mrad • Need to deflect head and tail oppositely • Crab cavity – 3. 9 GHz SC – phase tolerance ~60 fs – prototype fabricated B. Foster - EPS 07/07 Global Design Effort 34

Layout of BDS+DR Elevation different between DR and BDS is ~10 m B. Foster - EPS 07/07 Global Design Effort 35

Value Estimate • From Bangelore to Beijing – LCWS 06 Bangalore, March 9 to 13, 2006 Value Estimate and Costing Rules – VLCW 06 Vancouver, July 19 to 22, 2006 First Cost Estimate – ILC 06 Valencia, November 6 to 10, 2006 Cost Reduction – BILCW 07 Beijing, February 4 to 7, 2007 Release of Draft Reference Design Report with Reliable Costs B. Foster - EPS 07/07 Global Design Effort 36

RDR Cost reduction Further cost reduction ideas deferred to engineering phase B. Foster - EPS 07/07 Global Design Effort 37

ILC COST Summary RDR “Value” Costs Total Value Cost (FY 07) 4. 80 B ILC Units Shared + 1. 82 B Units Site Specific + 14. 1 K person-years (“explicit” labor = 24. 0 M person-hrs @ 1, 700 hrs/yr) 1 ILC Unit = $ 1 (2007) Σ Value = 6. 62 B ILC Units B. Foster - EPS 07/07 The reference design was “frozen” on 1 -12 -06 for RDR production, including costs. Important to realise this is a snapshot; design will continue to evolve, due to R&D, accelerator studies & value engineering. The value costs have already been reviewed many times. Global Design Effort 38

ILC Value – by Area Systems Main Cost Driver Conventional Facilities Components B. Foster - EPS 07/07 Global Design Effort 39

ILC Value – by Technical Systems B. Foster - EPS 07/07 Global Design Effort 40

Reviewing the RDR • Reviews (5 major international reviews + regional) – The Design: “The MAC applauds that considerable evolution of the design was achieved … the performance driven baseline configuration was successfully converted into a cost conscious design. ” – The R&D Plan: “The committee endorses the approach of collecting R&D items as proposed by the collaborators, categorizing them, prioritizing them, and seeking contact with funding agencies to provide guidelines for funding. ” – International Cost Review (Orsay): - “The Committee believes that the GDE is doing an excellent job of designing the ILC under the conditions that currently exist. The costing methodology is as good as can be done at the present time. For more accuracy on some items, further R&D and a designated site location for the ILC is needed. ” - “… sees further possible cost savings based on expected R&D results and further optimization. . ” B. Foster - EPS 07/07 Global Design Effort 41

Future - Technically Driven Timeline 2006 2010 Engineer Design BCD RDR 2014 Construction Startup EDR Begin Const Siting Plan being Developed Site Prep 2018 Site Select End Const Detector Construct Detector Install All regions ~ 5 yrs R & D -- Industrialization B. Foster - EPS 07/07 Global Design Effort 42

Summary and Outlook • RDR Draft published in February 2007 • Final RDR to be published in August and presented to ILCSC - represents enormous effort over last 18 months. • Many R&D and engineering design issues still remain. – The next document will contain much more technical detail: Engineering Design Report due 2010 - for details see my ECFA talk • Our job in the GDE is two-fold: - produce the EDR, a blueprint for ILC construction containing and hopefully reducing cost so that governments have to act. - mount political and scientific campaign to convince them and the general public that the ILC is a good investment. • We all had better do a good job the future health of world HEP depends on it. B. Foster - EPS 07/07 Global Design Effort 43