ATF2ILC Final Focus Test Beam Line

at KEK-ATF

References :

ATF2 Proposal, KEK Report 2005-2

ATF2 Proposal Vol.2, KEK Report 2005-9

ホームページ：

http://atf.kek.jp/collab/ap/projects/ATF2/index.php

110 authors (25 reseach institutes) in the proposal

ATF2 Final GoalEnsure collisions between nanometer beams; i.e. luminosity for ILC

experiment

FACILITYconstructio

n,first result

ATF2/KEK2005-07-08?

FFTB/SLAC1991-93-94

Optics

Local chromaticity correction scheme; very short and longer L*

(β*y=100μm, Ltot=36.6m)

Conventional (separate) scheme; non-local and

dedicated CCS at upstream; high symmetry; i.e.

orthogonal tuning (β*

y=100μm, Ltot=185m)

Design beam size

34nm / 2.2μm, aspect=65

(γεy=3 x 10-8 m)

60nm / 1.92μm, aspect=32

(γεy=2 x 10-6 m)

Achieved ?70nm ( beam jitter remains !)

Reduction of Risk at ILCOptics and bean tuningStabilization

Mode-I A. Achievement of 37nm 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 20nm.)

B2) Establishment of beam jitter controlling technique at nano-meter level with ILC-like beam (2008 -?)

Optics v3.5, 1 July 2006

6m

reduction of dispersion

final focus

diagnostic

west テキスト

ATF2 beam line and ATF extraction line

ATF2 beam line ATF extraction line

ATF2 beam line and ATF extraction line

5 Wire Scanners or Laserwires5 Strip-line

BPMs

3 Screen Monitors

BSM

CLIC table

HVVHV

5 Steering (V,H) Magnets

SF5

H

53 m

22 Quadrupoles(Q), 5 Sextupoles(S), 3 Bends(B) in downstream of QM16

QM16

SD4 SF6B5B2B1QD0 QF1

SD0SF1

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

3.5m

IP

Shintake Monitor ( beam size monitor, BSM with laser interferometer )QBPMs (100nm ) and IPBPM ( 2nm ) at IPMONALISA ( nanometer alignment monitor with laser interferometer )Laserwire ( beam size monitor with laser beam )IP intra-train feedback system with latency of less than 150nsMagnet movers for Beam Based Alignment (BBA)High Available Power Supply (HA-PS) system for magnets

Magnets and Instrumentation at ATF2

Optics at ATF2

IP

electron beam

D

F

SF6

SF5

SD4

SF1

SD0

B1B2

B5

Q-magnet

Mover

Concrete Support

QBPM in a Q-magnet(IHEP, SLAC KEK)

(SLAC)

(KEK)

(KEK, PAL, SLAC)

• Example : a power system with Ethernet control that will provide 200A in a 4 out 5 redundant module configuration.

HA-PS system ( SLAC )

for a bend200ms

ΔB=-100GB=3.1kG

Voltage

Test result with 3+1 system (150A)switch off 1 module

short time : 2-3ppmlong time : 5ppmtemperature : 2.5ppm/℃

A.Jeremie

Bloc:61

Foot:26.5

Total:87.5

Length:240Width:90

Values are in cm and measured directly on the table with a tape-measure.Static load capacity per foot (there a 4) 182 kg to 1590 kg. Honeycomb bloc has a weight of 731kg.

CERN Stacis 2000 (CLIC) table currently in Annecy, France.

(LAPP, CERN)

IP-BPM

Wave guide

X Port

Y Port

Sensor Cavity

Beam PipeSlot

Rectangular cavity for X-Y isolation (-50dB)•2 Cavities in 1 block•2 Y ports and 2 X ports in 1 Cavity

11 cm

14 cm

14 cm

(61.45 x 48.58 x 6mm3)

(6 x 12 mm2)

Goal : 2nm position resolution

Residual vs TimeResidual of (Y2I – Y2Ipredicted)

1h

Preliminary beam test result :

Position resolution for 1 hour run

8.72 +- 0.28 (stat.) +- 0.35 (sys.) nm

( ICT = 0.68 x 1010 e-/bunch,

dynamic range = 4.96 um )

(KEK, KNU)

Schematics of Shintake MonitorMeasure beam size using phase (=position and period) of interference fringe

as a reference

Interference fringesas a reference

Electron beamto be measured

Scanning electron beam

γ-ray modulatedby interference fringes

(Univ. of Tokyo, KEK)

IP intra-train feedback system (Oxford)

Last line of defence against relative beam

misalignment

Measure vertical position of outgoing beam and hence beam-beam kick angle

Use fast amplifier and kicker to correct

vertical position of beam incoming to IR

FONT – Feedback On Nanosecond Timescales

( RHUL, Oxford)

Laserwire

MONALISA

• Need 2 tools, both with nm type resolutions over a few m.– Straightness Monitor measuring motion perpendicular to line of sight.

Main tool to measure the relative motion of objects

– Distance meter:• Frequency scanning interferometer

• Can also provide perpendicular measurements if several measurements are combined to do triangulation.

– Combine both measurements into one system! MONALISA

to monitor the relative displacement between QD0 and Shintake monitor at Nanometer

(Oxford)

Interference pattern sensitive to perpendicular motion of retro-reflector

distance meter

Retro-reflector

Monitoring of Alignment and Stabilization with high Accuracy

Cost Breakup, 26 Jan.07

magnets

power supplies

magnet

suppor

ts

includ

ing

moversalignmen

tvacuumcontrol

feedbac

kQ-BPMslaserwireShi

ntake

monito

r

CF :Infrastructure

CF:floor,shield etc.

Total 5.7 Oku-yen

commission

ing

tools

Monalis

a

ATF2 SchedulePresent ATF2 ON

1. International Construction and Operation; Mini-ILC 2. Forefront of Accelerator Technological R&D3. Human Resource Development for ILC4. Commissioning in October 2008