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:[email protected]
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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5@A0
6::7=&?#",8=7=B=1C
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F)((( GHH)I/G'
ICTH1
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.