ilc accelerator

ILC Accelerator

Kaoru Yokoya (KEK)2013.12.13 KIAS

2013/12/13 KIASWS Yokoya 1

TDR• Global TDR Event on Jun.12.2013• TokyoCERNFNAL• TDR handed to LCC Director Lyn Evans


Site Down-selection• Down selection to

Kitakami site announded in August end


ILC Layout

• Electron source• Positron source• Damping Rings


• RTML• Main linacs• BDS

ILC Parameters (TDR Executive Summary)L Upgrade

A BCenter- of- mass energy ECM GeV 250 350 500 500 1000 1000Collision rate frep Hz 5 5 5 5 4 4Electron linac rate Hz 10 5 5 5 4 4Number of bunches nb 1312 1312 1312 2625 2450 2450Bunch population nb x1010 2 2 2 2 1.74 1.74Bunch separation Dtb ns 554 554 554 366 366 366Pulse current Ibeam mA 5.8 5.8 5.8 8.8 7.6 7.6Main linac average gradient MV/ m 14.7 21.4 31.5 31.5Average total beam power Pbeam MW 5.9 7.3 10.5 21 27.2 27.2Estimated AC power PAC MW 1221) 121 163 204 300 300RMS bunch length sz mm 0.3 0.3 0.3 0.3 0.25 0.225Electron RMS energy spreadDp/ p % 0.19 0.158 0.124 0.124 0.083 0.085Positron RMS energy spreadDp/ p % 0.152 0.1 0.07 0.07 0.043 0.047Electron polarization P- % 80 80 80 80 80 80Positron polarization P+ % 30 30 30 30 20 20Horizontal emittance gex

mm 10 10 10 10 10 10Vertical emittance gey nm 35 35 35 35 30 30IP horizontal beta function b*

x mm 13 16 11 11 22.6 11IP vertical beta function b*

y mm 0.41 0.34 0.48 0.48 0.25 0.23IP RMS horizontal beam sizes*

x nm 729 683.5 474 474 481 335IP RMS vartical beam size s*

y nm 7.7 5.9 5.9 5.9 2.8 2.7Luminosity L x1034/ cm2s 0.75 1 1.8 3.6 3.6 4.9Fraction of L in top 1% L0.01/ L % 87.1 77.4 58.3 87.1 59.2 44.5Average energy loss dBS % 0.97 1.9 4.5 4.5 5.6 10.5Number of pairs/ bunch crossing x103 62.4 93.6 139 139 200.5 382.6Total pair energy/ bunch crossing TeV 46.5 115 344.1 344.1 1338 3441

1) 129MW for 250GeV machine

Baseline 500GeV Machine Energy Upgrade


Main Linac• Key area of ILC

– ~2/3 of the total cost• TDR specification

– Gradient at vertical test• Average 35MV/m• Accept cavities > 35 -20% = 28MV/m• Q0 > 0.8x1010 at 35MV/m• yield > 90% (Up to 2 surface treatment passes)

– Average operating gradient 31.5MV/m• Accept the range +/- 20%• Q0 > 1xx1010 at 31.5MV/m


Main Linac Parameters


MAIN Linac RF Parameters

Cavity (9- cell TESLA elliptical shape)Average accelerating gradient 31.5 MV/ mQ factor Q0 1.00E+10Effective length 1.038 mR/ Q 1036 W

Accepted operational gradient spread +/ - 20 %Cryomodule

Total slot length 12.652 mType A 9 cavitiesType B 8 cvities incl. 1 SC quadML unit A+B+ANumber of units (e+/ e- ) 282/ 285

Total component countsCryomodule type A 564/ 570Cryomodule type B 282/ 2859- cell cavities 7332/ 7410SC quad 282/ 285

Total linac length (flat site) 11027/ 11141 mTotal linac length (mountain site) 11072/ 11188 mEffective average accelerating grad 21.3 MV/ m

RF requirements (for average gradient)Beam current 5.8 mAbeam (peak) power per cavity 190 kWMatched loaded Q (QL) 5.40E+06Cavity fill time 924 msBeam pulse length 727 msTotal RF pulse length 1650 msRF- to- beam power efficiency 44 %

Progress in 1.3 GHz ILC Cavity Production


• Progress in EXFEL (800 cavity construction as of 2012/10): (courtesy by D. Reschke: the 2nd EP at DESY)

– RI: 4 reference cavities with Eacc > 28 MV/m, (~ 39 MV/m max.)– Zanon: 3 reference cavities with Eacc > 30 MV/m ( ~ 35 MV/m max.)

year # 9-cell cavitiesqualified

Capable Lab. Capable Industry2006 10 1

DESY2

ACCEL, ZANON

2011 41 4 DESY, JLAB, FNAL, KEK

4 RI, ZANON, AES, MHI,

2012 (45) 5 DESY, JLAB, FNAL, KEK,

Cornell

5 RI, ZANON, AES, MHI,

Hitachi

A. Yamamoto, May2013, ECFA13

9

Global Cavity Gradient Results - EU

2013/12/13 KIASWS Yokoya

DESY data, D. Reschke et al., SRF2009, TUPPO051.

3 slides from R.Geng, LCWS12

10

Global Cavity Gradient Results - Americas


JLAB data, R.L. Geng et al., IPAC2011, MOPC111.

11

Global Cavity Gradient Results - Asia


KEK data, Y. Yamamoto et al., IPAC2012, WEPPC013.

High Gradient Accelerating Cavity


Production yield: 94 % at > 28 MV/m,Achieved Average gradient: 37.1 MV/m

> 16000 cavities needed for 500GeV

13

System Viability Proof

DESY: FLASH• SRF-CM string + Beam,

– ACC7/PXFEL1 < 32 MV/m >• 9 mA beam, 2009• 800ms, 4.5mA beam, 2012

KEK: STF• S1-Global: complete, 2010

– Cavity string : < 26 MV/m> • Quantum Beam : 6.7 mA, 1 ms, • CM1 & beam, 2014 ~2015

FNAL: NML/ASTA• CM1 test complete• CM2 operation, in 2013• CM2 + Beam, 2013 ~ 2014


ILC Spec: 5.8mA, 1ms

A. Yamamoto, JPS meeting, Mar.2013

E.Kako, 2013/12/05, KEK

Euro-XFEL Status


As of 11.09.2013

Num. of cavities:vendor 1 23vendor 2 56

Europe - XFEL cavity production

2nd pass: additional high-pressure rinse

usable gradient: X-ray limited (dark current)Maximum gradient

2013/12/13 KIASWS Yokoya D. Reschke, LCWS13 15

US – Fermilab CM-2


CM-2 features all high gradient cavities (> 35 MV/m)Cryomodule is installed and cold. Commissioning has started – no results yet

New 500 W 2K refrigerator operational

16

M.Harrison, LCWS13

17

US FY 2014 2015 2016 2017 2018 2019

CDR

Q_0 recipe

CM testing

CM Prod.

First X-rays

High Q_0 cryomodule with reduced cryogenics operating costs:

Improved cooling capabilityNew cavity surface processing recipeImproved magnetic shieldingAdiabatic cool-down process

Cryomodule Production– Fermilab & JLAB

M.Harrison, LCWS13 2013/12/13 KIASWS Yokoya

US – LCLS II


CM01 CM2,3 CM04 CM15 CM16 CM35BC1

E = 250 MeVR56 = -55 mmsd = 1.4 %

BC2E = 1600 MeVR56 = -60 mmsd = 0.46 %

GUN0.75 MeV

LHE = 98 MeVR56 = -5 mmsd = 0.05 %

L0j= *

V0=97 MVIpk = 12 A

Lb = 2.0 mm

L1j =-22°

V0=220 MVIpk = 12 A

Lb =2.0 mm

HLj =-165°

V0 =55 MV

L2j = -21°

V0=1447 MVIpk = 50 A

Lb = 0.56 mm

L3j = 0

V0=2409 MVIpk = 1.0 kA

Lb = 0.024 mm

LTUE = 4.0 GeV

R56 = 0sd 0.016%

2-km

100-pC machine layout: Oct. 8, 2013; v21 ASTRA run; Bunch length Lb is FWHM

3.9GHz

Linac and compressor layout

4 GeV CW SRF Linac based FEL based on ILC cavities at SLAC• 35 cryomodules – 280 cavities• Gradient 16 MV/m; Q0 2e10 at 1.8K• Beam power 1.2 MW max• Cryogenic power 5.5 MW• Located in the upstream end of the existing 3km tunnel

550 m~ LCLS-II

Length

18

M.Harrison, LCWS13

10 year Evolution of STF at KEK

2013/12/13 KIASWS Yokoya 19E.Kako, 2013/12/05, KEKup to ~ 420MeV

Remaining Technical Issues for Main Linac

• Cavity production yield as high as possible• Improvement of cavity performance in

cryomodule• Finalize the coupler design (TTF3/XFEL or STF2

type)• Confirmation of the reliability in long term

operation (coupler, tuner)• Further cost reduction in mass production• Higher cavity gradient for Ecm>500GeV


Positron Source

• Undulator method (adopted in ILC baseline)


3 possible shemes of positron beam generation

• Conventional Method– Hit a few GeV electrons on a target, and collect the generated positrons– adopted in many accelerators, well established– Issues in the application to ILC

• Survivability of the target OK • Emittance of the generated positron OK (improved DR optics)• Transport to DR entrance under study• No polarized positron

• Laser-Compton method (far future)

ILC Design (undulator method)• Electron energy >150GeV


• Undulator– At the end of the electron linac– Helical, superconducting– Length ~150m (~230m when highly poloarized positron is needed)– K=0.92, l=1.15cm, (B=0.86T on the axis)– beam aperture 5.85mm （直径）

• Target: rotating titanium alloy• Flux Concentrator for positron capture• Normal-conducting accelkeration up to 400MeV• Polarization ~30% (~60% with photon collimator and longer undulator)

Positron Yield• Undulator aT the end

of electron l;inac• positron yield

depends on the electron energy (=center-of-mass energy / 2)


• Positron insufficient for Ee < 150GeV

• To restore the luminosity, the electron linac is operated at 10Hz: 5Hz for positron

production 5Hz for collision

Target• Wheel of Titanium alloy,

diameter 1m• Must rotate at 100m/s

(2000 rpm) in vacuum• Under test at LLNL using

Ferromagnet seal• Still unsatisfactory

– Outgassing spikes still being observed

• More works needed– market products don’t work


Positron Capture• Baseline : Capture by flux concentrator

– No change since RDR– But lower the max field 5T3.5T

(simulation showed sufficient)• Problem: pulse duration 1ms

– Also being tested at LLNL• Can be replaced with QWT (Quarter Wave Transformer)

– But requires longer undulaort (x1.6 倍 )– Heavier load on the target


20 triplets, rep. = 300 Hz • triplet = 3 mini-trains with gaps • 44 bunches/mini-train, Tb_to_b = 6.15 n sec

DRTb_to_b = 6.15 n sec

2640 bunches/train, rep. = 5 Hz • Tb_to_b = 369 n sec

e+ creation go to main linac

Time remaining for damping = 137 m sec

Booster Linac5 GeV NC300 Hz

Drive LinacSeveral GeV NC300 Hz

TargetAmorphous Tungsten

Pendulum or Slow Rotation 2640 bunches60 mini-trains

Conventional e+ Source for ILCNormal Conducting Drive and Booster Linacs in 300 Hz operation


T.Omori

Bunch Pattern

<-- the 100 ns gap is required to cure an e- cloud problem in e+ DR.

=132 bunches

T.Omori

Moving target still needed but much slower


Issues of the Positron System

• Undulator Scheme– Rotating target and flux concentrator development at LLNL– Photon collimator for higher polarization

• Conventional Source– “conventional” but still needs some more R&D– High current, high rep rate driver linac– Moving target (<~ 5m/s)– Flux concentrator– Overall simulation

• Confirm the positron yield• Including capture, bunch compression, beamloading & energy compression

• Choice of undulator/conventional will not affect the tunnel shape– The driver electron linac for Conventional Source can be installed in the

space for undulator+photon drift in the ubdulator scheme– Therefore, we have some couple of years to the deadline of the choice


Moving Target• <~5m/sec required (1/20 of undulator scheme)• 2 possible schemes being developed at KEK


bellows seal

vacuum

airferromagneticfluid seal

air vacuum

5Hz pendulum with bellows seal rotating target with ferromagnetic seal

main issue: life of bellows main issue: vacuum

First step prototype being tested

Damping Rings• Requirements

– gex = 5.5 mm, gey = 20nm– Time for damping 100ms– First step 1312 bunches, maximum 2625 bunches– bunch-by-bunch injection/extraction


quadrupole section

dipole section

• Circumference ~3km• 1 ring for each of electron and positron

in the first step bunch interval ~6ns

• (if necessary) add one more positron ring when going to 2625 bunches• depends on electron cloud• 1 electron ring in any case (bunch

interval 3ns)

Damping Ring Configuration


Damping Ring Requirements


Beam energy 5 GeVTrain repetition rate 5 nsMain linac bunch separation 554 nsNumber of bunches per train 1312Buncg population 2.00E+10Injection requirements

Normalized betatron amplitude (Ax+Ay)max 0.07 m.radEnergy range (full) 75 MeVBunch length (full) 66 mm

Extracted beamNormalized horizontal emittance 5500 nm.radNormalized vertical emittance 20 nm.radRms relative energy spread 0.11 %Rms bunch length 6 mmMaximum allowed transfer jitter 0.1 sx, sy

Damping Ring Parameters


Low powerHigh lumi positron electronCircumference kmNumber of bunches 1312 2625Bunch population 2.00E+10 2.00E+10Maximum bunch current mA 389 779Transverse damping time ms 12.86 17.5Longitudinal damping time ms 6.4 8.7Bunch length mm 6.02 6.01Momentum compaction factor 3.30E- 04 3.30E- 04Normalized horizontal emittance mm 6.4 5.6Horizontal chromaticity - 50.9 - 51.3Vertical chromaticity - 44.1 - 43.3Wiggler firld T 2.16 1.81Number of wigglersEnergy loss per turn MeV 8.4 6.19RF frequency MHzNumber of cavities 10 12Total voltage MV 14 22 17.9Voltage per cavity MV 1.4 1.17 1.83 1.49RF synchronous phase deg 18.5 21.9 20.3Power per RF coupler kW 176 294 272 200

38923.95

12650 6504.554

1.51- 43.3- 51.35.7

3.30E- 046.0212

54

2.00E+10

5Hz mode 10Hz mode

3.238 3.2381312

Electron Cloud Instability

• Has been studied at CESR-TA by international team• Gave recommendation for the mitigation method (table below)

– Arc and wiggler sections requires antichamber– Full power in 3.2km ring needs aggressive mitigation plan

• No significant difference between 6.4km with 2600 bunches and 3.2km with 1300 bunches

EC Working Group Baseline Mitigation RecommendationDrift* Dipole Wiggler Quadrupole*

Baseline Mitigation I TiN Coating Grooves with

TiN coating Clearing Electrodes TiN Coating

Baseline Mitigation II

Solenoid Windings Antechamber Antechamber

Alternate Mitigation NEG Coating TiN Coating Grooves with TiN

CoatingClearing Electrodes

or Grooves

ECLOUD`10 (October 13, 2010, Cornell University)342013/12/13 KIASWS Yokoya

Damping Ring Vacuum Chamber• Following the recommendation by CESR-TA team, ILC adopts the

following chambers• Other instabilities are less serious in positron damping ring• FII (Fast Ion Instability) is the most important in the electron ring


BDS(Beam Delivery System)

• Ultimate role of BDS is to focus the beam at the IP, but there lots of devices to do this

• Machine Protection System• Tune-up/emergency dump• Collimator• Beam diagnostics section (beam energy, emittance,

polarization)• Muon absorber• Crab cavity• Feedback system• Beam diagnostics after IP (beam energy, polarization)• Main beam dump


BDS Layout


BDS Main Parameters


BDS Parameters

Length per side 2254 mLength of main extraction line 300 mLength of tune- up extraction line 467 mMaximum beam emnery 250 GeVMaximum beam energy (with more magnets) 500 GeVDistance from IP to first quad (ILD/ SiD) 3.51/ 4.5 mCrossing angle at IP 14 mradNormalized emittance (horizontal) 10000 nmNormalized emittance (vertical) 35 nmNominal bunch length 300 mm

39120 m

50 mLINAC

DR

ATF2

The ATF2 has been designed, constructed and operated under the international collaboration.

ATF2: Beam Focusing Test Facility at KEK


ATF2 Goals

• Beam size at 1.3GeV– Goal 37nm– ~65nm

achieved • Beam

positron stabilization to a few nm by feedback


IP Feedback• Bunch interval is long enough for

intra-train digital feedback– Advantage of SC collider

• Large disruption parameter– Dy = 25


Issues on BDS• ATF2

– Beam focus by another factor 2– Stabilization to ~2nm

• Design check – beam dumpline– impedances

• Commissioning strategy– Is the IP beam size monitor needed?

• Access to IR hall– Access slope in TDR (mountain region) but, is vertical shaft

possible?


Access Tunnel Access Hall(Slope <10%)

Damping RingDetector HallRing To Main Linac (RTML)

e- Main Linac (ML)

e+ ML

RTML turn-around

e- Source

e+ Source (Slope <7%)Existing surface road

Existing road

(The background photo shows a similar site image, but not the real site.)

Surface Structures

PM-13PM-12

PM-10PM-8

PM-ab PM+8PM+10 PM+12 PM+13

(Center Campus)PX

Kitakami-site cross section

Site Specific Design


43

CFS Plan Towards the Construction Start


2013 2014 2015 2016 2017 2018 2019

A.Enomoto, LCWS13

9-year Construction Schedule


From the LCWS Conclusion on CFS

• The selected site satisfies the TDR conventional designs without any fundamental issues

• The remaining issues yet to be worked out (such as the path length and positron scheme) will not affect the underground construction and surface facility layout

• Intensive geotechnical study of the detector hall by a Japanese company. This will be checked with the previous European IR hall analysis



LCC Pre-IL Accelerator Organization

Electrical SupportJapan

Mechanical SupportJapan

Cryogenic SupportJapan

SRFww

Conventional Facilitiesww

LC Project Office (KEK)

Controls & ComputingJapan

SafetyJapan

Accelerator Design & Integrationww

Electron Sourceww

Positron Sourceww

Damping Ringsww

RTML & bunch compressor

ww

Main Linacww

Beam Deliveryww

Machine-Detector Interface

ww

Domestic Programs &System Tests

Project Management Baseline, ScheduleCost, EDMS

Technical Board

LCWS13 Mike Harrison

48

Summary• Site down-selected to Kitakami, Japan• Site-specific design going to start• There are some remaining issues

– positron– Final focus (ATF2)

• New organization under LCC-ILC box (chaired by Mike Harrison) is being formed


ilc accelerator

Documents

kiasws yokoya8progress

kiasws yokoya13ilc spec

ilc cavity production

high gradient cavities

cavity string

ma beam

mvm quantum beam

cavity construction