Extended Coupling Correction and Emittance Diagnostic Section for “optimal” ATF2
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June 7, 2005 ILC BDS Meeting 1 Extended Coupling Correction and Emittance Diagnostic Section for “optimal” ATF2 nBPM (SLAC) nBPM (KEK) FONT Compton / laserwire ODR Existing ATF Extraction Line Coupling Correction / Emittance Diagnostics
description
Extended Coupling Correction and Emittance Diagnostic Section for “optimal” ATF2. Coupling Correction / Emittance Diagnostics. FONT. nBPM (KEK). nBPM (SLAC). Compton / laserwire. Existing ATF Extraction Line. ODR. FF Optics Modifications. From Tauchi-san’s email ([bds 117] June 2, 2005): - PowerPoint PPT Presentation
Transcript of Extended Coupling Correction and Emittance Diagnostic Section for “optimal” ATF2
June 7, 2005 ILC BDS Meeting 1
Extended Coupling Correction and Emittance Diagnostic Section for “optimal” ATF2
nBPM (SLAC)nBPM (KEK)
FONT
Compton / laserwire
ODR
Existing ATF Extraction Line
Coupling Correction /Emittance Diagnostics
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FF Optics ModificationsFrom Tauchi-san’s email ([bds 117] June 2, 2005):
5. Optics modifications:
(1) concentrate on "optimal" design (straight) … done (2) change bends from sector bends to rectangular … done (3) use 0.8 m bends (as used in ATF) instead of 1 m for better field
stability and more space … done (4) remove octupoles (do not use them, and they are tight) … done (OC0
removed; OC1 moved away from SF1) (5) extend diagnostics section (use up to ~10 m additional space) … done (6) QM14 is the strongest quad, and is close to max field of BT quads,
need to check if its strength can be reduced by reoptimizing the matching section … done (QM14[K1L] = -1.1 m-1)
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30 cm offset
ΔL = 7.1 m (w.r.t. baseline)
β*x,y = 4,0.1 mm
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baseline
optimal
Assembly Hall
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-1% +1%
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• 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 inconclusive1
Coupling Correction
1 See http://atfweb.kek.jp/atf/Reports/ATF-99-01.pdf
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“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
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90°90°
180°90°
90°90°
– x– y
33°57°
57°33°
33°57°
57°33°
SQ SQ SQ SQ
WS WS WS WS WS
59.210.8
108.05.9
59.210.8
108.05.9
59.210.8σ (μm)
2.0 2.0 2.0 2.0 2.0
2.0 2.0 2.0 2.0
1.3 1.3 1.3 1.3
For MAD files see http://www.slac.stanford.edu/~mdw/ATF2/optimal
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new quadrupole (between QF3X and BH1X.3)
1 2
-1 0 0 0
-0.52 -1 0 0
0 0 -1 0
0 0 1.37 -1
K KR
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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 …
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– x– y
σmin = 3 μm
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Continuing Work
• optimize system bandwidth and performance
• add BPMs and dipole correctors• simulate steering and dispersion/coupling
correction with machine/diagnostic errors• verify what space is needed for diagnostic
equipment in chicane• investigate drift ε–diagnostic section• writeup for ATF2 proposal document
