CLIC Beam Delivery System R. Toms Thanks to H. Braun, A. Latina, J. - - PowerPoint PPT Presentation

CLIC Beam Delivery System

• R. Tomás

Thanks to H. Braun, A. Latina, J. Resta and

• D. Schulte

April 2007

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.1/18

Contents

• Status of the CLIC BDS:
• The new diagnostics section
• FFS optimization and shortening overview
• Impact of new parameters on:
• FFS optimization
• Collimation
• Luminosity with beam jitter

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.2/18

Goals & Requisites of Diagnostics

Goals:

• Coupling correction
• Emittance measurement
• Energy measurement (placed in collimation

section to save space) Requisites:

• 4 skew quadrupoles
• 4 laser wires either or:
• located at

(present technology)

• able to measure
• ✁

• Photon detector
• Precise dipoles and BPMs

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.3/18

Diagnostics optics & layout

0.0 200. 400. 600. 800. 1000.

Momentum offset = 0.00 % s (m) Diagnostics section

0.0 100. 200. 300. 400. 500. 600.

βx (m), βy (m)

β x β y

SQ1 SQ2 SQ3SQ4 LW1 LW2LW3 LW4

This is for existing laser wire technology

• ✁

If new BSM measures > 0.4

, length

• 400m.

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.4/18

Full BDS

100 200 300 400 500 600 500 1000 1500 2000 2500 3000 3500 βx,y

1/2 [m1/2]

Longitudinal location [m] βx βy

Diagnostics Energy collimation Betatron collimation FFS

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.5/18

Layout & photon collection

• 0.1
• 0.05

0.05 0.1 400 500 600 700 800 900 1000 1100 1200 Horizontal displacement [m] Longitudinal location [m] Beam diagnostics beam line Laser wire photons Dipoles for energy col. photon detector

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.6/18

PLACET simulations, Andrea Latina

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1 10 100 1000 10000 σy [µm] σroll [µrad] beam size at laser wire 1 before correction after correction

Realistic simulations:

• Quadrupole rolls (

)

• Radiation

Correction works up to

• ✂

• 6e-05
• 4e-05
• 2e-05

2e-05 4e-05 6e-05 8e-05 1e-04 1 10 100 1000 K1SL [m-1] Strength of the skew quadrupoles as a function of σroll SKEW1 SKEW2 SKEW3 SKEW4

Maximum strength

• ☎

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.7/18

FFS shortening and optimization I

Advantages of a shorter FFS:

• Shorter tunnel
• Lower beta peak (better stability)
• Lower chromaticity (smaller aberrations)
• Shorter L
• Disadvantages:
• Shorter L
• (detector and solenoid constrains)
• Stronger focusing (quad field)

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.8/18

FFS shortening and optimization II

4 5 6 7 8 340 360 380 400 420 440 460 480 500 520 540 560 Total luminosity [a.u.] FFS Length [m] FFS shortening and optimization chart Adding one sextupole (2007) Removing one dipole, adding one octupole, adding one decapole Sextupole optimization Full non-linear and disp optim. (2006) Nominal FFS

L

• =4m

L

• =2.6m

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.9/18

New parameters and FFS optimization

2 4 6 8 10 12 14 16 3 3.2 3.4 3.6 3.8 4 Luminosity per interaction [a.u.] σx [10-8m] factor 1.8 ± 0.2 factor 1.6 ± 0.2 N=5.8 109, σz=75µm N=5.2 109, σz=62µm N=4.0 109, σz=35µm

Close to linear Lumi Vs. charge and Lumi Vs.

• Rogelio

Tom´ as Garc´ ıa CLIC Beam Delivery System – p.10/18

New parameters and Collimation I

Survival plot from CLIC note 477 and J. Resta’s thesis for different materials:

• ✁

154 bunches/train 0.666 ns

311 bunches/train 0.667 ns New parameters rule out Be collimators!

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.11/18

New parameters and Collimation II

Possible solutions:

• Carbon collimator

largest impedance

• larger betas

longer system (

• 1 km more)
• non-linear collimation system

slightly lower luminosity

• lower charge

lower luminosity

• consumable collimators

technologically complex

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.12/18

New parameters and Collimation II

Example of a rotary consumable collimator designed for NLC:

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.13/18

Vertical jitter, Andrea Latina & Daniel

0.75 0.8 0.85 0.9 0.95 1 1.05 1.1

• 0.6
• 0.4
• 0.2

0.2 0.4 0.6 L/L0 Y offset / σy Vertical Beam Jitter at the entrance of the BDS NO COLL, CHARGE= 5.8e9 * 0.9 0.7 COLL, CHARGE = 5.8e9 * 0.9 0.7

Higher charge enhances the luminosity loss with beam jitter due to beam-beam disruption and collimator wakefields.

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.14/18

Summary

• FFS optimization is charge independent (so far)
• BDS length with Diagnostics section and short

FFS:

• Existing laser wire technology
• 3.2 km
• Assuming better BSM
• 2.7 km
• Be collimators do not survive

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.15/18

ILC beam diagnostics section

50 100 150 200 250 300 350 100 200 300 400 500 600 700 βx,y [m] Longitudinal location [m] βx βy

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.16/18

FFS optimization

1e+34 2e+34 3e+34 4e+34 5e+34 6e+34 7e+34 8e+34 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 Luminosity [a.u.] σx

*σy * [10-15m2]

CLIC machines 1/x example path

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.17/18

Optics table

Element Location

• ✁

• ✁

• ✁

SQD1 130 27 138 SQD2 217 27 138 90 90 SQD3 341 27 138 270 180 SQD4 428 27 138 360 270 LW1 462 49 312 LW2 594 141 302 39 45 LW3 647 139 302 64 54 LW4 855 101 393 123 120

• ✁
• ✆

= 1

m

Rogelio Tom´ as Garc´ ıa CLIC Beam Delivery System – p.18/18