Beam Delivery SystemReview of RDR(draft)

1.Overview2.Beam parameters3.System description 3.1 diagnostic, tune-up dump, machine protection 3.1.1 MPS collimation 3.1.2 Skew correction 3.1.3 Emittance diagnostcs 3.1.4 Polarimeter and energy diagnostics 3.1.5 Tune-up and emergency extraction system

3.2 Collimation system 3.2.1 Muon suppression 3.2.2 Halo power handling 3.2.3 Tail-folding octupoles

3.3 Final focus 3.4 IR design and integration to detector 3.5 Extraction line

4.Accelerator components 4.1 Crab cavity system 4.2 Feedback system and stability 4.2.1 Train-by-train feedback 4.2.2 Intra-train IP position and angle feedback 4.2.3 Luminosity feedback 4.2.4 BDS entrance feedback( ‘train-straightener’) 4.2.5 Hardware implementation for intra-train feedbacks

4.3 Energy, luminosity and polarization measurements 4.3.1 Energy measurements 4.3.2 Luminosity measurements 4.3.3 Polarization measurements

4.4 Beam dumps and collimators 4.5 BDS magnets 4.5.1 BDS magnets: tail-folding octupoles

4.6 Vacuum system 4.6.1 Wakes in vacuum system 4.6.2 Beam-gas scattering 4.6.3 Vacuum system design

4.7 IR arrangements for two detectors 4.8 Diagnostic and correction devices

RDR contentsS.Kuroda

1.Overview• Single IP(14mrad) and push-pull detector

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• measure the linac beam and match it into the final focus; • protect the beamline and detector against mis-steered beams from the main linacs; • remove any large amplitude particles (beam-halo) from the linac to minimize background in the detectors;• measure and monitor the key physics parameters such as energy and polarization before and after the collisions;

Squeeze beam at IP to x=639nm, y=6.7nm

RDR

IR14 mrad

14 mrad ILC FF9 hybrid (x 2)

14 mrad (L* = 5.5 m) dump linesdetector pit:

25 m (Z) × 110 m (X)

e- e+hybrid “BSY” (x 2)

2226 m

ΔZ ~ -650 m w.r.t. ILC2006c

M.Woodley

2.Beam Parameters

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RDR

3.System Description

polarimeterskew correction /emittance diagnostic

MPScoll

betatroncollimation

fastsweepers

tuneupdump

septa

fastkickers

energycollimation

β-match

energyspectrometer

finaltransformer

finaldoublet

IP

energyspectrometer

polarimeter

fastsweepers

primarydump

MainLinac

ILC2006e electron BDS schematic

energycollimation

M.Woodley

3.1 Diagnostic, Tune-up Dump,

Machine protection

polarimeterskew correction /emittance diagnostic

MPScoll

β-match

MainLinac

betatroncollimation

extraction

angle = 0.837 mrad

LB =2.4 m (×3)ΔLBB = 0.3 m

Compton IP250 GeV

x = 20 mm

76.9 m

MPSEcoll±10%

8 m

3 m

laserwiredetector

16.1 m

35 GeV

25 GeV

Cerenkovdetector

2 m

12.3 cm

18.0 cmΔE/EBPM

optics

Polarimeter chicane

M.Woodley

3.2 Collimation SystemTo remove Halo particles( BG of detector ) SR which hits detectorBetatron Collimator Spoiler/Absorber pair at high beta pointsEnergy Collimator Single spoiler at high dispersion pointCollimation depth 8-10x, 60-80y

Muon suppression 5m long magnetized iron filled in tunnelTail-folding octupole Non-linear focusing of halo particles Core part of the beam unaffected

3.3 Final Focus

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RDRLocal chromaticity correctionCorrection of geometric aberration, 2nd order dispersion and higher order aberration

3.4 IR Design and Integration to Detector

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FD: compact superconducting magnet inside detectorFirst cryostat is attached to detector

Solenoid effect to beam anti-solenoid, DID, anti-DID

RDR

3.5 Extraction Line

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RDR

Transport beam to dumpDiagnostics Energy measurement at 1st v-chicane Polarimetry at 2nd IP( R22=-0.5 )

4. Accelerator Components4.1 Crab Cavity SystemTo make head-on collisionTwo 3.9GHz SC 9-cell cavities

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Crab cavity prototype(RDR)

4.2 Intra-train FeedbackMeasurement of beam-beam deflection stripline kickerFONT4: R&D with digital board processor Test is on-going at ATF. Goal latency is 140ns

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P.Burrows et al

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4.3 Polarization Measurement

RDR

ILC physics requiresPolarization measurement with 0.25% accuracy

4.4 IR Arrangements for two detectors

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RDR

Detector Hall surface assemblyDetector self-shield/shielding wall between detectors maintenance when off beam-line

5. Solenoid Effect

Orbit change at IP( in y )Accuracy in polarization measurement For correction, Detector Integrated Dipole(DID)At higher energy, back-scattered e+e- pair huge BG for detector DID with reversed polarity( anti-DID ) which align orbit to out-going beam line

DID/anti-DID

A.Seryi, B.Parker

Anti-Solenoid

Overlapping of solenoid field with FD produces hugebeam size blow-up. Anti-solenoid can correct the beam size growth excellently.The effect is independent on x-ing angle.

With antisolenoids and linear knobs, y = 0.9%

Y. Nosochkov, A. Seryi

6. Beam TuningBeam tuning method is being studied by computer simulation BBA, Luminosity(beam size) tuning,…

Example. BBA+Luminosity tuning with traditional method; Linear knob of SX mover + higher order knob Errors dx/dy for magnets=200um, roll=300urad, field error-1e-4, ……..

0 10 20 30 40 500

20

40

60

80

100

Tuning Iteration

% Seeds > 100% Nominal Luminosity

Disp, Waist, <x’y>, <xy>

tilt

dK

Luminosity

G.White

7. Issues for further StudyHardware Crab cavity system Feedback system SC magnets Monitors( LW,…) …….Study of beam tuning, beam dynamics, BG,…

Alternative design e.g. small x-ing angle/head-on collision including ES separator, large bore magnets for EXT

Test facility ESA, ATF/ATF2,…..