NLC work for ILC BDS design

review what has been done by O.Napoly, J.Payet,

D. Angal-Kalinin et. aland what we can do

A.S., September 7, 2004

1) Study collimator survivability of NLC BDS with 3.5m L* for ILC parameters, determine minimum beam sizes at spoilers in ILC BDS - Lew

2) Study existing ILC BDS optics and crossing schemes solutions- A.S., Tom

3) Design optimized ILC optics (based on NLC) with optimal collimators, L* 4.2 and 5m and tail folding - A.S.

4) Accommodate Geant model of SiD and/or LD detectors to ILC IR parameters, find or build Geant model of ILC/Tesla detector - Takashi

5) Study halo performance of new ILC BDS with Turtle and Geant - Lew, Takashi

6) Optimize collimator gaps and photon masks location in new ILC BDS- Lew, Takashi

7) Study collimator wake-field performance of ILC BDS - P.T. 8) Review Brett's linac dump design, if acceptable and no redesign needed, modify to

include second order dispersion correction - Mark9) Design 30m FFS optics for demonstration at ATF - Mauro, A.S. 10) Start work on pair monitor distribution analysis with realistic beams and various

crossing angle (continue work of Achim Stahl) - Glen11) Study realistic ILC BDS tuning with errors and misalignment - Yuri12) Continue fast feedback optimization (s-shaped bunch question), and include

collimator and resistive wakes - Glen13) Extraction line design - Yuri14) ILC Detector solenoid field optimization and compensation - Yuri, A.S.

Saclay, Daresbury work

• BDS optics design – NLC style– Hybrid style (NLC style for Y, traditional for X)– Design for L* of 3,4,5m– Collimation requirement evaluation– Constraint to preserve head on option => ~250m free

straight path till beamstrahlung dump– Collimation redesign (2nd energy slit) – Opposite FD acceptance => FF w. Final Quadruplet– Octupole folding being designed? (not reported yet)

Next: Slides from O.Napoly, J.Payet, April 2003 and January 2004

0

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s (m)

x1/2

HCCSHorizontal correction

z1/2

Vertical correctionDx

Dx (m)

Hybrid Correction, l*=5m

SH SH

SV1 SV2

Beamstrahlung Dump

IP angular dispersion, D’x* = 2.6 mrad

NLC type correction, l*=5m

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SF1, SD1

SF2

SD2

SF3

Beamstrahlung Dump

IP angular dispersion D’x* = 10 mrad

Collimationrequirementsfor• l* = 5m• Φ = 48 mm • inner mask

- s = 4 m- Φ = 24 mm

l* [m] smask [m] Nx Ny

TDR 3 2 13 81

New FF 5 2 10 48

New FF 5 4 7.8 42

new collimation section required with tail folding by octupoles

1st order transport

The collimation sectionWe use the TDR collimation section with some changes :

• Reverse the first

dispersion bump

• Introduce a second

energy spoiler

(ΔΨx =2 between

the 2 energy spoilers)

-1,25E-03

-7,50E-04

-2,50E-04

2,50E-04

7,50E-04

1,25E-03

400 500 600 700

x (m)

s (m)

1st Order d=+.6 %All Orders d=+.6 %All Orders d=+.52 %All Orders d=-.39 %

Energy Spoilers

-1,25E-03

-7,50E-04

-2,50E-04

2,50E-04

7,50E-04

1,25E-03

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1st Order d=+.6 %All Orders d=+.6 %All Orders d=+.52 %All Orders d=-.39 %

x (m)

s (m)

Energy Spoilers Betatron Spoilers

NLC-like optics : Central trajectories

Betatron spoilers : gx = 1.8 & 1.3 mm gy = 0.7 mmEnergy spoilers : gx = 0.8 mm

NLC-like optics

Momentum acceptance : -0.39 % , +0.52 %

Betatron spoilers : gx = 1.8 & 1.2 mm gy = 0.7 mmEnergy spoilers : gx = 0.9 & 0.7 mm

Hybrid optics

Momentum acceptance : -0.42 % , +0.57 %

Spoiler d SpoilerH/V (mm) (mm)

3.01.0

1.8 , 1.20.7

1.8 , 1.30.7

l* (m) h 'x (mrad) L/L0 @ 0,4% d Acc. (%) L (m)type

TDR 3 0.0 0.73 6.6 10-14 4.0

Dex (m.rad) H/HTDR

2.0 10-13 0.9 , 0.7 0,57

-

Hybride 5 2.6 0.70 662-0.42 , +0.57

1,00 630

NLC 5 10.0 0.86 5995.6 10-14 0.8 0,56-0.39 , +0.52

all δ-order transport

Next: Compilation from O.Napoly, J.Payet, April 2003, R.Appleby, D.Angal-Kalinin,O.Napoly, J.Payet, LCWS 2004

New:Daresbury group modified FF optics to use Final Quadruplet => improve extracted line acceptance for head on or small vertical x-ing.Some consideration of small horizontal x-ing.

Beam Extraction

φ*

Final doublet acceptance Θ*max (E, φ*)with• l* = 5m• Φ = 48 mm • Solenoid BS = 4 T

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HorzVertDispersion

Final Focus Optics for L*=5m with quadruplet

Beam Sizes for –40% energy tail particles at MSEP (~50 m from IP) in the extraction line:

With doublet

[R. Brinkmann]

With quadruplet

Could this be used for TESLA ?

Next: Slide from K.Busser, LCWS 2004

IR design for L* > 4.05m

Last week A.Stahl was suggesting that > 4.2m is needed?

Proposed Design for l* ≥ 4.05 m

Design by Achim Stahl

End of quoted slides

• Impression on optics– Hybrid optics may be unusable with tail folding– Present NLC-like design may be not optimized for tail

folding • What seem to be missing (perhaps work is

ongoing) – detailed analysis of collimation performance– design and performance of tail fording – collimator wakes analysis – detailed analysis of small H or V crossing angle

• Impression on x-ing angle schemes – small horizontal x-ing has less chances than small

vertical x-ing– the latter depends on crab cavity and electrostatic

separator experimental tests

• BDS design work, assumption– head-on remain an option until experiments show

performance of crab cavity and electrostatic separator

• Design two BDS versions with head-on constraints and without– complete design, with collimator and tail folding and

performance study – design two version of collimation – passive survival

and consumable ?

• Study IR background with small and large x-ing schemes

• Extraction schemes…

The NLC b-collimation is optimized for consumable spoilers. Beam size in SP1,3 and SP2,4 cannot be increases simultaneously. To achieve passive survival, would need to change to 45deg and twice more cells

90deg.