April 5, 2005 ILC BDS Meeting 1

Coupling Correction and Emittance Diagnostics for the ATF2 Extraction Line

nBPM (SLAC)nBPM (KEK)

FONT

Compton / laserwireODR

ATF Extraction Line

Coupling Correction /Emittance Diagnostics

April 5, 2005 ILC BDS Meeting 2

• ideally

–correction section with 4 independent skew quadrupoles, followed by

–2D (4 wire scanner) emittance measurement section–optics for orthogonal control of the 4 coupling phases–minimize εy once with each skew quadrupole

• in present ATF extraction line

–non-optimal optics in EXT straight section–wire scanners and skew quads interspersed–each wire scanner has x, y, and “u/v” (small angle, ~10°) wires

• one attempt at full 4D beam matrix measurement and correction was inconclusive4

Coupling Correction

4 See http://atfweb.kek.jp/atf/Reports/ATF-99-01.pdf

April 5, 2005 ILC BDS Meeting 3

“Ideal” skew correction / ε diagnostic sectionSQ SQ SQ SQ

WS WS WS WS

90°90°

180°90°

90°90°

45°45°

45°45°

45°45°

– x– y

See http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-8581.pdf

April 5, 2005 ILC BDS Meeting 4

– x– y

5°8°

13°20°

30°36°

SQ SQ SQ SQ

WS WS WS WS WS

L = 11.43 m

April 5, 2005 ILC BDS Meeting 5

SQ SQ SQ SQ

L = 20.58 mΔL ≈ 10 m

WS WSWS WS WS

32°48°

51°21°

32°58°

58°32°

– x– y

1.1 1.11.3 1.10.9 0.9 0.9 0.7 1.31.2 1.2 1.7 1.7

σWS > 5 μ

April 5, 2005 ILC BDS Meeting 6

L = 15.80 mΔL ≈ 5 m

SQ SQ SQ SQ

WS WSWS WS WS

31°40°

41°13°

32°58°

58°32°

– x– y

0.6 0.60.8 0.5 0.5 0.5 0.3 0.8 0.60.8 0.7 1.7 1.7

April 5, 2005 ILC BDS Meeting 7

sL

w1 w2 w3

N

L 2

min02

nnc 1cot

cc 120

0

00 2

1 2

L

3n

A ‘Drift’ A ‘Drift’ -Diagnostic Section-Diagnostic Section

3 wire scanners (or profile monitors)

00 ,

20

0min

1

00 ,

from Paul Emma …

April 5, 2005 ILC BDS Meeting 8

– x– y

σmin = 3 μ

April 5, 2005 ILC BDS Meeting 9

Emittance Growth in ILC Upstream Polarimeter/Spectrometer Chicanes

1.4 m

April 5, 2005 ILC BDS Meeting 10

γε/γε0 = 9.610-6 η5

April 5, 2005 ILC BDS Meeting 11