The ILC Beam Delivery System Design and R&D Programme

T. Tauchi, EPAC 2008, Genoa, Italy, 26 June 2008

International Linear Collider (ILC)Acceleration with superconducting cavities and

~ 31 km total length Aug. 2004 Choice of super-conducting technologyMar. 2005 ILC GDE (Global Design Effort) establishedMar. 2006 BCD (Baseline Configuration Document) publishedAug. 2007 RDR (Reference Design Report) published2008-2010 Technical Design Phase 1 ( TDP1) - Interim report2010-2012 TDP2 - final report (the new baseline reference design)

Beam Delivery System

The ILC Baseline Design

Shaft Service Cavern(49x16x18m)

Main Linac

Service Tunnel (4.5m dia.)

320m

1266m

Laser Sight Hole

Dump Service Hall(35x20x4.5m)

Dump House(20x10x10m)

Personnel Crossover

Utilities Penetration( @ every 100m )

BDS Tunnel (4.5m dia.)

Muon Wall(15x7x6m)

Service Tunnel (4.5m dia.)

960m4452m, Beam Delivery System

BDS/IRService Shaft Cavern

(40x15x10m)

Beam Dump(10x10x20m)

Muon Wall(25x7x6m)

LaserSightHole

Process WaterShaft (0.8m dia.)

Dump Service Hall(35x20x4.5m)

BDS/IRService Shaft

(9m dia.)

IR Hall Shafts(16m dia.)

IR Hall(120x25x39m)

FIGURE 1.3-7. BDS layout, beam and service tunnels (shown in magenta and green), shafts, experimentalhall. The line crossing the BDS beamline at right angles is the damping ring, located 10 m above the BDStunnels.

• the final focus (FF) which uses strong compact superconducting quadrupoles to focusthe beam at the IP, with sextupoles providing local chromaticity correction;

• the interaction region, containing the experimental detectors. The final focus quadrupolesclosest to the IP are integrated into the detector to facilitate detector “push-pull”;

• the extraction line, which has a large enough bandwidth to cleanly transport the heavilydisrupted beam to a high-powered water-cooled dump. The extraction line also containsimportant polarization and energy diagnostics.

ChallengesThe principal challenges in the beam delivery system are:

• tight tolerances on magnet motion (down to tens of nanometers), which make theuse of fast beam-based feedback systems mandatory, and may well require mechanicalstabilization of critical components (e.g. final doublets).

• uncorrelated relative phase jitter between the crab cavity systems, which must be lim-ited to the level of tens of femtoseconds.

• control of emittance growth due to static misalignments, which requires beam-basedalignment and tuning techniques similar to the RTML.

• control of backgrounds at the IP via careful tuning and optimization of the collimationsystems and the use of the tail-folding octupoles.

• clean extraction of the high-powered disrupted beam to the dump. Simulations indicatethat the current design is adequate over the full range of beam parameters.

ILC Reference Design Report III-17

Layout of BDS tunnels

~ 2.2km / beam

Single IR for 2 detectors with push-pull scheme at Ecm=500GeV Upgradable to Ecm=1TeV in the same layout

MOPP004, -031 (IR - pushpull - MDI)

IR

Main LINAC

BDS parameters

Beam Delivery Systems

includes the MPS collimation system, skew correction section, emittance diagnostic section,polarimeter with energy diagnostics, fast extraction/tuning system and beta matching sec-tion.

-2200 -2100 -2000 -1900 -1800 -1700 -1600 -1500 -1400 -1300 -1200-2

-1

0

1

2

Z (m)

X (

m)

ILC e- BDS (500 GeV cm)

-1000 -800 -600 -400 -200 0 200-2

-1

0

1

2

Z (m)

X (

m)

MPScoll

skew correction /emittance diagnostics

polarimeterfast

kickers

betatroncollimation

fastsweepers

tuneupdump

energycollimation

energyspectrometer

betamatch

final transformer

final doublet

IP

polarimeter

energyspectrometer

fastsweepers

primarydump

FIGURE 2.7-2. BDS layout showing functional subsystems, starting from the linac exit; X – horizontalposition of elements, Z – distance measured from the IP.

2.7.3.1.1 MPS collimation At the exit of the main linac is a short 90! FODO lattice,composed of large bore quadrupoles, which contains a set of sacrificial collimators of decreas-ing aperture. The purpose of this system is to protect the 12 mm aperture BDS from anybeam which develops an extremely large trajectory in the 7 cm aperture main linac (thee!ective aperture is R/!1/2, which is 3–4 times smaller in the BDS than in the linac). Thissection also contains kickers and cavity BPMs for inter- and intra-train trajectory feedback.

2.7.3.1.2 Skew Correction The skew correction section contains 4 orthonormal skewquadrupoles which provide complete and independent control of the 4 betatron couplingparameters. This scheme allows correction of any arbitrary linearized coupled beam.

2.7.3.1.3 Emittance Diagnostics The emittance diagnostic section contains 4 laserwires which are capable of measuring horizontal and vertical RMS beam sizes down to 1 µm.

ILC Reference Design Report III-91

Functional subsystems in BDS

Muon wall

Crab cavity (14mr crossing)

IR - Machine Detector Interface (MDI)

Major Issues in BDS1. Chromaticity correction of final doublet chromaticity (ξ) : Δσ* = ξδσ* , δ=(E-Eo)/Eo ξ ~ L*/β*y ~10,000 corrected by sextupoles2. Beam diagnostic and tuning beam size, energy, polarization measurements

3. Beam-beam effect in interaction point (IP) background (e+e- pairs) - flat beam extraction of disrupted beam to dump - crossing

4. Beam halo from main LINAC robust collimation for synchrotron radiations muon wall (spoiler) for created muons

MOPP007, -016

MOPP021

MOPP032, -033 MOPP005 (2mr)

MOPP027 (fast feedback)

MOPP024 (de-polarization)

Optics design choice(1) Non-local correction

A plan of KEK-ATF Final Focus Test Beam Line (ATF2)∗

Shigeru Kuroda, J.Urakawa, H.Hayano, K.Kubo, T.Okugi, S.Araki, N.Toge, T.Matsuda and T.Tauchi

High Energy Accelerator Research Organization(KEK), 1-1 Oho, Tsukuba-shi, Ibaraki, Japan

Abstract

This report describes one of the possible programs which

is being investigated as the near-future extension of Ac-

celerator Test Facility (ATF) at KEK. In this program, a

36.6m long final focus test beam line, which we call ATF-

2, adopts the new final focus optics proposed by P. Rai-

mondi and A. Seryi. The goal of ATF-2 will be to test ex-

perimentally this new optics and to realize the beam size

of 50nm or less for the E = 1.5GeV beam extracted

from ATF. We present in this short report the basic design

of ATF-2, results of tracking simulation and a simulation

study of a possible beam tuning procedure.

1 INTRODUCTION

ATF [1] was built to investigate the feasibility of future Lin-

ear Collider (LC), in particular, the feasibility to provide

an extremely-flat multi-bunch beam to the LC main linac

[2]. Recently we focus on the development of beam-tuning

techniques and the stabilization of key machine compo-

nents to extract the small emittance beam from the ATF

damping ring. Table 1 summarizes the accelerator parame-

ters so far achieved at ATF.

With the successful demonstration of the production of

ultra-low emittance beams, the ATF group has initiated in-

vestigations on its next-stage research programs, which are

collectively called ATF-II. One possibility is called ATF-

1, where a bunch compressor will be added in the beam

extraction line of ATF, followed by a short X-band linac

unit. This allows ATF-II to serve as a complete test injec-

tor for an LC. Another possibility is called ATF-2, where

the issues associated with the final focus system at linear

colliders will be studied. The ATF-2 takes advantage of the

ultra-low emittance beam at ATF, which offers a unique

opportunity to experimentally study the LC final focus sys-

tem. Fig. 1 shows a proposed plan view for ATF-II.

In the following we present the basis of the LC final fo-

cus system, the new final focus optics recently proposed,

the current design of ATF-2 and finally a short summary.

2 BASIS OF LC FINAL FOCUS SYSTEM

The LC final focus system is to squeeze electron and

positron beams from the main linacs to obtain maximum

luminosity. The vertical size of the beams at the interaction

point (IP) must be a few nm. One of the critical issues in

designing the final focus optics is how to suppress the beam

size growth due to the energy deviation δ = (E −E0)/E0.

!Correponding author: J.Urakawa, email:junji.urakawa@kek.jp

ATF- II

50.4

m

L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 L11 L12 Lec2 L13 L14 L15 L16Lec1

120m

X-band Section

Bunch Compressor

1.54 GeV S-band Linac

1.54 GeVDamping RingControl Room

Final Focus

ATF1 ATF2

(compress from 30ps to 3ps)

Figure 1: Layout of ATF-II

The growth is approximately expressed as;

∆σ∗ = ξδσ∗0 (1)

where ξ and σ∗0 are the chromaticity and the linear-optics

beam size, respectively. For the standard final focus optics

the chromaticity ξ is in the order of 103 ∼ 104. Thus, even

with the small energy spread δ of ∼ 10−3, the beam size

easily grows by a factor of 10. The chromaticity can be

corrected by introducing sextupole magnets (sextupoles) in

the dispersive regions. The sextupoles, however, have non-

linear magnetic field that also causes the beam size growth.

This nonlinear effect, the geometric aberration, can be can-

celled by the magnet configuration shown in Fig. 2. Only

IIII PPPP

- I -

I

SSSS FFFF 1111

SSSS

FFFF

2222

SSSS

DDDD

1111

SSSS

DDDD

2222

QQQQ

FFFF

QQQQ

DDDD

Figure 2: Cancellation of the Geometric Aberration

sextupoles and final quadrupole magnets (quadrupoles) are

shown in the figure. Between them there are many other

quadrupoles that are not shown. The two pairs of sex-

tupoles are required for the correction of horizontal and

vertical chromaticity. The transfer matrix between the two

sextupoles of each pair is set to be −I so that the nonlinear

kick by the first sextupole may be cancelled by the sec-

ond. This scheme of the geometric aberration cancellation

(2) Local correction

Table 1: Achieved and design parameters of ATF.

Items Achieved Values Design

Maximum Beam Energy 1.28GeV 1.54GeV

Circumference 138.6 ± 0.003m 138.6mMomentum Compaction 0.00214 0.00214Single Bunch Population 1.2 ! 1010 2 ! 1010

COD(peak to peak) x " 2 mm, y " 1 mm 1 mmBunch Length " 9 mm 5 mmEnergy Spread 0.08% 0.08%Horizontal Emittance (1.7 ± 0.3) ! 10−9 m 1.4 ! 10−9 m

Vertical Emittance (1.5 ± 0.75) ! 10−11 m 1.0 ! 10−11 m

Multibunch(M.B.) Population 12 ! 1010 m 20 ! 1010 m

M.B. Vertical Emittance (1 " 3) ! 10−11 m 1.0 ! 10−11 m

has been applied, with some modifications, to the JLC fi-

nal focus system [3] and also in the JLC Design Study [4].

The scheme was verified experimentally at the Final Fo-

cus Test Beam (FFTB) at SLAC, where beam was success-

fully squeezed to σy " 60nm [5]. A simple extrapolation

from FFTB, which takes only the physical emittance into

account, predicts the beam size of 36nm for ATF-2.

Recently P.Raimondi and A.Seryi has proposed a new

final focus optics [6]. With this optics that squeezes beam

as small as the standard optics does, the final focus beam

line for JLC or NLC can be as short as 500 m, much shorter

than those by the conventional design [7]. Therefore it is

very important to verify this new optics experimentally and

here ATF-2 will provide a unique opportunity.

3 NEW FINAL FOCUS SYSTEM

The new final focus system is shown schematically in

Fig. 3. In Fig. 3 some quadrupoles upstream of SF2 are

IIII PPPP

SSSS FFFF 1111

SSSS

DDDD

1111

SSSS

FFFF

2222

QQQQ

FFFF

SSSS

DDDD

2222

QQQQ

DDDD

PPPP

MMMM

QQQQ

NNNN

TTTT

rrrr

aaaa

nnnn

ssss

ffff

eeee

rrrr

MMMM

aaaa

tttt

rrrr

iiii

cccc

ssss

Figure 3: New Final Focus Optics

not shown. P, M, Q and N represent the transfer matri-

ces as shown in the figure. The chromaticity is corrected

by the sextupoles. Two of them are placed close to the final

quadrupoles that are major chromaticity sources because of

large beta-function there. The second order geometric aber-

ration is cancelled by other two sextupoles with the transfer

matrix given below;

MP =

F 0 0 0F21

1F 0 0

0 0 F 00 0 F43

1F

(2)

QM =

D 0 0 0D21

1D 0 0

0 0 D 00 0 D43

1D

(3)

Here the strength of the sextupoles must be chosen as

k2SF1 = #F 3k2SF2 and k2SD1 = #D3k2SD2. With

this conditions, however, still remains the 3rd order geo-

metric aberration that can be given by the coefficients of

polynomial expansion of the nonlinear map including the

sextupole actions. In the thin lens approximation, it is ex-

pressed as;

U3444 $ N234Q12(N33Q34 + N34Q44)2 (4)

U1244 = U3224 $ N234Q12 + N2

12Q12(NQ)234# 4N12N34Q34(NQ)12(NQ)34 (5)

The indices 1, 2, 3 and 4 represent x, px, y and py , respec-

tively. Thus the 3rd order geometric aberration is deter-

mined only by the two transfer matrices Q and N. With

adequate choice of the strength of the final quaduapoles,

U1244 = U3224 becomes zero and thus U3444 becomes

small.

4 DESIGN OF ATF-2

As we have discussed above, it is important to test exper-

imentally the new final focus optics at ATF-2. We here

propose a design of ATF-2. All the calculation in this sec-

tion was done by the computer program SAD developed at

KEK [8].

Before we discuss the design, we summarize in Table 2

the parameters of the extracted beam from ATF. The beam

emittance is same with that of the JLC design. The energy

geometric aberration cancellation and ξ correction at far upstream in exclusive sections

P.Raimondi and A.Seryi, Phys. Rev. Lett. 86 3779 (2001)

; Conventional and tested at FFTB/SLAC

; ILC choice and to be tested at ATF2/KEK

ξ correction at FDgeometric aberration cancellation

CompactLarge IP bandwidthSmall aberration for beam halohigher order

aberration cancellation

Problem :Large aberrations for off-momentum particles (beam halo)

Bend

Bend

IP

Sextupoles

Bend

Quadrupole

η

∆x′ =K1

(1 + δ)(x + ηδ) ! K1("δx " ηδ2)

∆x′ =K2

2(x + ηδ)2 → K2η(δx +

ηδ2

2)

Quadrupole:

Sexupole:

Horizontal Chromaticity, 2nd Order Dispersion Correction

geometric aberration(x2 term of Sx) canceled by M=-1the higher order one by optimizing transfer matrix

∆x′ =K1

(1 + δ)(x + ηδ)2 +

Kβ−match

(1 + δ)x → 2K1(−δx −

ηδ2

2)

Kβ−match = K1 K2 =2K1

η

Quadrupole pair:

chromaticity2nd order dispersion

δ =!E

E

Beam with energy spread of

Test Facilities1. ESA at SLAC , for 2006 - 2008 ILC-BDS instrumentation experiments

2. ATF2 as scaled-down model of LC-BDS final focus All the elements will be developed and tested.

3. Proposed facility of FACET at SLAC“Facilities for Accelerator Science and Experimental Test Beams” - Accelerator Science Facility (ASF) , 24GeV and focused beam plasma wakefield accelerators (PWFA) - ESA (12GeV) and ASF ILC-BDS instrumentation and ILC/LHC detector R&Ds

1

End Station A Test FacilityEnd Station A Test FacilityFor Prototypes of Beam Delivery and IR ComponentsFor Prototypes of Beam Delivery and IR Components

UCL

U. of Cambridge

UC Berkeley

U. of Bristol

U. of Oregon

UMass Amherst

Notre Dame U.

Manchester U.

Lancaster U.

LLNL

U. of Birmingham

TEMF TU Darmstadt

SLAC

QMUL

KEK

DESY

CERN

CCLRC

http://www-project.slac.stanford.edu/ilc/testfac/ESA/esa.html

Collimator design, wakefields (T-480)

BPM energy spectrometer (T-474)

Synch Stripe energy spectrometer (T-475)

IP BPMs, kickers

Other (ex. Linac) BPM test stations

EMI (electro-magnetic interference)

IR Mockup

PAC05 paper/poster: SLAC-PUB-11180, e-Print Archive: physics/0505171 Collaborations for ESA experiments

Beam Tests for 2006 - 20085 weeks in each of 2006 and 20073-4 weeks in 2008

28.5GeV

M. Woods (SLAC)

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Energy spectrometer R&D at ESA/SLAC Goal : 100ppm -resolution ; MOPP021

Position monitoring system (laser interferometer) at μm levelWakefields box at ~8m upstream of first BPM for collimator damage

ATF/ATF2STF

KEKB

KEK High Energy Accelerator Research Organizationin Tsukuba site, Japan

PF

J.Urakawa, KNU-KEK ATF2 collaboration meeting, 16-19 Mar.2008

BELLE

KEKB/PFinjector

Main Gate

ATF International Collaboration

KEKWaseda Univ.Nagoya Univ.Tokyo Univ.Kyoto Univ.Hiroshima Univ.PAL (Korea)IHEP (China)

Foreign Researchers visiting KEK (2006/4~2007/7)23 institutes,71 people, total 2085 people・day

（full-year researchers are excluded）

CERNDESYIN2P3 ( LAL, LAPP, LLR )Tomsk Polytechnic Univ.INFN, FrascatiUniversity College LondonJohn Adams Ins., Oxford Univ. Royal Holloway Univ. of London

SLACLBNLFNALCornell Univ.

N.Ternuma, LC project committee, 7 Aug.2007

with MOU since Aug.2005

Damping Ringultra low emittance beam (2pm)dynamics -fast ion instability

beam instrumentation(BPM,LW)

Extraction line :utilization of low emittance beambeam instrumentation, collimator damage

RF Gunmulti-bunch beam

S-band Linac ( 70m )multi-bunch acceleration

Pulsed Laser Wire Scannerfor beam size monitor ( μm )

Fast kickerrise time < 3ns

CSR

Cavity BPMnanometer res.

Energy: 1.28 GeVElectron bunch:

2x1010 e/bunch1 ~ 20 bunches/train3 trains/ring1.56 Hz

XSR

ATF Accelerator Test Facility, KEK

FONTfast feedback ( ns )

1997-2008

Beam Dynamics

LW, Cavity Compton

ODR, OTR single shot meas.

N.Ternuma, LC project committee, 7 Aug.2007

Collimation damagephase-1

MOPP003, - 047

MOPP018, -066

MOPP024

iii

Boris Ivanovich Grishanov, Pavel Logachev, Fedor Podgorny, Valery Telnov(BINP SB RAS, Novosibirsk)

Deepa Angal-Kalinin, James Jones, Alexander Kalinin(CCLRC/DL/ASTeC,Daresbury, Warrington, Cheshire)

Olivier Napoly, Jacques Payet(CEA/DSM/DAPNIA, Gif-sur-Yvette)

Hans-Heinrich Braun, Daniel Schulte, Frank Zimmermann(CERN, Geneva)

Robert Appleby, Roger Barlow, Ian Bailey, Leo Jenner, Roger Jones, German Kourevlev(The Cockcroft Institute, Daresbury, Warrington, Cheshire)

Eckhard Elsen, Vladimir Vogel, Nick Walker(DESY, Hamburg)

Nikolay Solyak, Manfred Wendt(Fermilab, Batavia, Illinois)

Tohru Takahashi(Hiroshima University, Higashi-Hiroshima)

Jie Gao, Weibin Liu, Guo-Xi Pei, Jiu-Qing Wang(IHEP, Beijing)

Nicolas Delerue, Sudhir Dixit, David Howell, Armin Reichold, David Urner(John Adams Institute at Oxford University)

Alessio Bosco, Ilya Agapov, Grahame A. Blair1, Gary Boorman, John Carter, Chafik Driouichi,Michael Price

(John Adams Institute at Royal Holloway, Univ. of London)

Sakae Araki, Hitoshi Hayano, Yasuo Higashi, Yosuke Honda, Ken-ichi Kanazawa, Kiyoshi Kubo,Tatsuya Kume, Masao Kuriki, Shigeru Kuroda, Mika Masuzawa, Takashi Naito,

Toshiyuki Okugi, Ryuhei Sugahara, Toshiaki Tauchi,1 Nobuhiro Terunuma,Nobu Toge, Junji Urakawa, Hiroshi Yamaoka, Kaoru Yokoya

(KEK, Ibaraki)

Yoshihisa Iwashita, Takanori Mihara(Kyoto ICR, Uji, Kyoto)

Maria Alabau Pons!, Philip Bambade, Olivier Dadoun(LAL, Orsay)

!LAL, Orsay and IFIC, Valencia

ATF2 Proposal, Volume 2, 2005

iv

Benoıt Bolzon, Nicolas Ge!roy, Andrea Jeremie, Yannis Karyotakis(LAPP, Annecy)

Andy Wolski(LBL, Berkeley, California)

Je! Gronberg(LLNL, Livermore, California)

Stewart Takashi Boogert, Alexey Liapine, Stephen Malton, David J. Miller, Matthew Wing(University College London, London)

Masayuki Kumada(NIRS, Chiba-shi)

Samuel Danagoulian, Sekazi Mtingwa(North Carolina A&T State University, North Carolina)

Eric Torrence(University of Oregon, Eugene, Oregon)

Jinhyuk Choi, Jung-Yun Huang, Heung Sik Kang, Eun-San Kim, Seunghwan Kim, In Soo Ko(Pohang Accelerator Laboratory)

Philip Burrows, Glenn Christian, Christine Clarke, Anthony Hartin, Hamid Dabiri Khah,Stephen Molloy, Glen White

(Queen Mary University of London, London)

Karl Bane, Axel Brachmann, Thomas Himel, Thomas Markiewicz, Janice Nelson, Yuri Nosochkov,Nan Phinney, Mauro Torino Francesco Pivi, Tor Raubenheimer, Marc Ross, Robert Ruland,

Andrei Seryi1, Cherrill M. Spencer, Peter Tenenbaum, Mark Woodley(SLAC, Menlo Park, California)

Sachio Komamiya, Tomoyuki Sanuki1, Taikan Suehara(University of Tokyo, Tokyo)

1The Editorial Board

ATF2 Proposal, Volume 2, 2005

110 authors (25 research institutes)ATF2 Proposal Vol.1 and 2

6m

Final Focus System

テキスト

DiagnosticReconfiguration of extraction linefor reduction of dispersion

ATF - DR

ATF2 beam line

Injection LINAC (S-band, 1.3GeV)

β mat-ching

LW (μm-size)Ultra low β* (CLIC, proposed)

Collimation damage(phase-2)

ATF2 Project in the ATF collaborationMOPP030, - 039, TUPP016 (tuning, BBA, flight simulation)

3.1 ATF2 FF optics and comparison with the ILC-FF 21

order of 104. Thus even with a small energy spread !E = 10!3 the beam size may easily grow by an or-der of magnitude. The chromaticity is corrected introducing sextupole magnets in dispersive regions.Most of the chromaticity comes from the final focus quadrupole magnets, therefore it is most effectiveto have the sextupoles in the final doublet, providing local compensation of chromaticity. The secondorder dispersion, arising from sextupoles, can be compensated simultaneously with chromaticity ifone allows that half of the total horizontal chromaticity would come from upstream of FD. Higherorder aberrations cancelled by proper beam transport relations with the upstream sextupoles. Thelocal chromaticity compensation for ILC optics is beneficial, because then the optics is less sensitiveto synchrotron radiation, can be reasonably short, even for TeV energy and can have large bandwidth(of about a percent or higher).

3.1.2 Proposed optics designs

The final focus beam line of the ATF2 is extending the existing ATF extraction line as shown inFig. 1.1. The optics of the ATF2 final focus with the new diagnostics section is shown in Fig. 3.3.The FF optics has L" = 1 m (distance from last focusing quadrupole to IP), "# = −0.14 (derivativeof dispersion at IP) with IP beta-functions #"

x/y = 4/0.1 mm. The total chromaticity of this optics isapproximately the same as in the ILC FF. The vertical beam size will be focused to 37 nm with theaspect ratio of about 100:1 similar to the ILC. The ATF2 beam parameters are compared with ILCparameters in Table 3.1.

The ATF2 proposal was originally considered with an alternative final focus optics proposed by Kurodaet al. in [5]. We have compared performance of both proposed designs and found that the optics sug-gested in [5] has fewer magnets and would be less expensive, however in this optics the chromaticitycorrection is not purely local, the tolerances on magnet strength and position are tighter, the band-width is narrower and scaling to TeV energy is more difficult. Therefore, the NLC-like optics waschosen as a baseline design for the ATF2. A detailed report on comparison of these two optics optionsis in preparation [8].

Table 3.1: ATF2 proposed optics IP parameters in comparison with ILC.params ATF2 ILCBeam Energy [GeV] 1.28 250L" [m] 1 3.5 – 4.2$ %x [m-rad] 3e-6 1e-5$ %y [m-rad] 3e-8 4e-8#"

x [mm] 4.0 21#"

y [mm] 0.1 0.4"# (DDX) [rad] 0.14 0.094&E [%] ∼0.1 ∼0.1Chromaticity Wy ∼ 104 ∼ 104

The ATF2 optics was designed primarily using codes MAD, Transport, Turtle and DIMAD. However,

ATF2 Project, 2005

(f*)

σy(nm)

!x(µm) 2.8 0.655

34 5.7

! L!/!!

y

σx/σy 82 115

5

3

Mode-I A. Achievement of 34nm beam size A1) Demonstration of a new compact final focus system; proposed by P.Raimondi and A.Seryi in 2000, A2) Maintenance of the small beam size (several hours at the FFTB/SLAC)

Mode-II B. Control of the beam position B1) Demonstration of beam orbit stabilization with nano-meter precision at IP. (The beam jitter at FFTB/SLAC was about 40nm.) B2) Establishment of beam jitter controlling technique at nano-meter level with ILC-like beam (2008 -?)

ATF2-FF (30m)

ILC-FF (660m)

SF6

SF5

SD4

SF1

SD0

B1 B2 B5

IP DF

B1 B2 B5

SD4

SF5

SF6

SF1

SD0

electron beam

electron beam

m

mQM11

QM11

QM16

QM16

ATF2 FeaturesThe same number of magnets as the ILC-FF.

The tuning knob, methods are the same,too.

Beam instrumentation has been developed with the ILC specifications; BPMs, BSMs, movers, magnet support, laserwires, HA power supplies, FONT-feedback system etc. .

International participation in the commissioning and operation

Strip-line BPM 3 Screen Monitors

Hardware System at ATF2

Correctors for feedback

22 Quadrupoles, 5 Sextupoles, 3 Bends in downstream of QM16

5 Wire Scanners, Laserwires

BSM(IPBPM)

LAPP table

H9 V10V11H10

V1SF5

16

SD4

SF6B5B2B1

QD0

QF1

SD0SF1

焦点

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feedback

QF21X

QD20X

QK4X

feedbackQM11 12 13 14 15

QD10B

QD10A

QF9B

QF9A

QD8

QF7

QD6

QF5B

QF5A

QD4B

QD4A

QF3

QD2B

QD2A

QF19X

QD18X

QF17X

MW

0X

MW

1X

MW

2X

MW

3X

MW

4X

LW signal

BSM signal

LW1X(1um

)

LW2X(3D)

54m

MFB1

MFB2

(10nm)

nBPMsMONALISA

ICT

IP

MDUM

P

RC1

RC2

RC3

RC1X

30m

All Q- and S-magnets have cavity-type beam position monitors(QBPM, 100nm).

Shintake Monitor ( beam size monitor, BSM with laser interferometer ):Tokyo univ.MONALISA ( nanometer alignment monitor with laser interferometer ):Oxford univ.Laserwire ( beam size monitor with laser beam for 1μm beam size, 3 axies):RHULIP intra-train feedback system with latency of less than 150ns (FONT):Oxford univ.Magnet movers for Beam Based Alignment (BBA):SLAC - MOPP039High Available Power Supply (HA-PS) system for magnets:SLAC - THPP127

(IHEP, China, MOPP014) (SLAC) (SLAC, IHEP)

(PAL, Korea)

Floor structure for ATF2 beam line

Refurbishment from Jun to Sep 2007

Structure is same as that of DR.

20th August 2007 4th September 2007

A 0.6m thick concrete slab of 396m3 is supported by 0.6m thick beams and 38 piles with 0.7m diameter and 13m height.

29th November 2007 Q-manets installation, 10th January 2008

Beam Dump, 31st March 2008 Shintake mon. optics start, 14th May 2008

cabling and piping, 14th May 2008 HA-PS installation, 14th May 2008

Laser hut construction(LW), 14th May 2008 QBPM phase fine-adjustment, 21st May 2008

ATF2 Construction Schedule

Not changed since Dec. 2006. ATF2 Schedule

ATF2 will be commissioning in this October.

ConclusionILC BDS has been designed by large international collaboration in framework of ILC-GDE since 2005.There are R&Ds of critical subsystems such as final doublet, crab cavity, laser wire, collimation etc. Close collaboration between machine and physics people is essential in the design, and it has been successful; i.e. IR Interface Document.Test facilities ( ESA, ATF2 and FACET) will assure stable collisions of nanometer beams at future linear colliders.