1. Emittance Diagnostics
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
June 7, 2005
ILC BDS Meeting

2. June 7, 2005
ILC BDS Meeting

3. FF Optics Modifications
From Tauchi-san’s ([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)
June 7, 2005
ILC BDS Meeting

4. β*x,y = 4,0.1 mm ΔL = 7.1 m (w.r.t. baseline) 30 cm offset
June 7, 2005
ILC BDS Meeting

5. Assembly Hall
optimal
baseline
June 7, 2005
ILC BDS Meeting

6. -1%
+1%
June 7, 2005
ILC BDS Meeting

7. Coupling Correction 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
1 See
June 7, 2005
ILC BDS Meeting

8. “Ideal” skew correction / ε diagnostic sectionSQ SQ SQ SQ WS WS WS WS
– x
– y
90°
180°
90°
90°
45°
45°
45°
See
June 7, 2005
ILC BDS Meeting

9. SQ SQ SQ SQ
2.0
2.0
2.0
2.0
2.0
2.0
2.0
1.3
1.3
1.3
1.3
2.0
2.0 WS WS WS WS WS
– x
– y
90°
180°
90°
90°
33°
57°
57°
33°
33°
57°
57°
33°
σ (μm)
59.2
10.8
108.0
5.9
59.2
10.8
108.0
5.9
59.2
10.8
For MAD files see
June 7, 2005
ILC BDS Meeting

10. new quadrupole (between QF3X and BH1X.3)
June 7, 2005
ILC BDS Meeting

11. A ‘Drift’ e-Diagnostic Section
from Paul Emma … b s L w1 w2 w3
3 wire scanners (or profile monitors)
June 7, 2005
ILC BDS Meeting

12. – x
– y
σmin = 3 μm
June 7, 2005
ILC BDS Meeting

13. 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
June 7, 2005
ILC BDS Meeting