EXT Tuning 13th ATF2 Project Meeting, January 12 2012 M. Woodley

ATF / ATF2 Schematic Layout Emittance Measurement 5 × WS, 4 × OTR 10 μ W wires (x/y/+10°/-10°) Final Doublet Coupling Correction Final Focus β-match Dump Inflector Laserwire EXT Laserwire INJ PIP WS 10 μ W wires (x/y/45°) 5 μ C wires (y/+1.3°/-1.3°) IPBSM 10 μ W wires (x/y) 5 μ C wires screen Damping Ring Beam Transport FOBO XSR e- S-band RF Gun 1.3 GeV S-band Linac 120 m 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Outline EXT tuning (a recipe) emittance measurements with the OTRs calibration cross-check with WS 4D reconstruction results 4D emittance measurements lattices building a coupled beam matrix refresher on emittance growth Summary and Continuing Work 13th ATF2 Project Meeting, January 12 2012 M. Woodley

EXT Tuning Recipe load desired optics configuration standardize FF magnets (FS package) normally reset QS’s and QK’s to zero normally reset FF movers to zero check each shift that desired lattice is SET (FS “configCheck” function) after (roughly) steering beam to dump, do lattice diagnostics check verify BPM signs after calibration; look for focusing errors ZH/ZV response (FS package) “grid” scan (new FS package ... see Yves’ talk) establish horizontal extraction trajectory verify KEX1/KEX2 voltage (43.4 kV) use BS1X/BS3X/BH1X/ZH1X to center orbit in QF1X/QD2X/QF3X by hand steer EXT/FF using Yves’ code (FS package) expect steered orbit < 200 um DR orbit & extraction trajectory measure and correct dispersion (FS package) computer correction of DX/DPX using QF1X/QF6X manual correction of DY using QS1X/QS2X measure emittance and correct coupling multi-OTR emittance measurement (FS package) manually optimize projected vertical emittance with QK1X/QK2X/QK3X/QK4X ... or other (faster) techniques (see Javier’s and Glen’s talks) move to IP region check beta matching! need IP C-wires, PIP W- and C-wires, MSPIP all working at the same time! 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Emittance Measurement with OTRs 13th ATF2 Project Meeting, January 12 2012 M. Woodley

OTR2X beam tilt … is it real? Check measured response to ZH9X 13th ATF2 Project Meeting, January 12 2012 M. Woodley

OTR Vertical Emittance Measurement December 14, 2011 07:44 name sigt sigd sig ----- ------- ------- ------- OTR0X 17.00 2.54 16.80 OTR1X 13.44 2.90 13.12 OTR2X 19.18 5.77 18.29 OTR3X 17.53 3.26 17.22 Vertical emittance parameters at OTR0X ------------------------------------------------------- energy = 1.2817 GeV emit = 49.7560 +- 3.8167 pm emitn = 124.7989 +- 9.5732 nm emitn*bmag = 139.1183 +- 14.3102 nm bmag = 1.1147 +- 0.0582 ( 1.0000) bmag_cos = -0.0976 +- 0.0000 ( 0.0000) bmag_sin = 0.4310 +- 0.0000 ( 0.0000) beta = 6.2274 +- 0.6272 m ( 6.1903) alpha = 3.0722 +- 0.3470 ( 2.5763) chisq/N = 1.0000 Propagated vertical spot sizes ----------------------------------- OTR0X = 17.6 um ( 16.8 +- 1.4) OTR1X = 12.5 um ( 13.1 +- 0.9) OTR2X = 18.8 um ( 18.3 +- 1.3) OTR3X = 16.9 um ( 17.2 +- 1.3) 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Wire Scanner Vertical Emittance Measurement December 14, 2011 09:30 (MW1X σy value ignored) sigt sigd sigw sig ------- ------- ------- ------- 19.50 2.76 2.50 19.14 19.40 5.81 2.50 18.34 13.60 3.18 2.50 12.98 29.50 3.70 2.50 29.16 Vertical emittance parameters at MW0X ------------------------------------------------------- energy = 1.2817 GeV emit = 42.9533 +- 3.4254 pm emitn = 107.7395 +- 8.5918 nm emitn*bmag = 114.9045 +- 10.4024 nm bmag = 1.0665 +- 0.0409 ( 1.0000) bmag_cos = 0.3468 +- 0.0000 ( 0.0000) bmag_sin = -0.0229 +- 0.0000 ( 0.0000) beta = 8.8918 +- 0.9843 m ( 6.1903) alpha = 3.6762 +- 0.4276 ( 2.5763) chisq/N = 1.0000 Propagated vertical spot sizes ----------------------------------- MW0X = 19.5 um ( 19.1 +- 1.4) MW2X = 18.0 um ( 18.3 +- 1.4) MW3X = 13.5 um ( 13.0 +- 1.0) MW4X = 27.5 um ( 29.2 +- 2.2) 13th ATF2 Project Meeting, January 12 2012 M. Woodley

black circles = WS blue circles = OTR OTR Vertical Emittance Measurement December 14, 2011 07:44 Wire Scanner Measured Vertical Beam Sizes December 14, 2011 09:30 (MW1X σy value ignored) black circles = WS blue circles = OTR 13th ATF2 Project Meeting, January 12 2012 M. Woodley

4D Coupling Measurement & Emittance Reconstruction 13th ATF2 Project Meeting, January 12 2012 M. Woodley

simulation 13th ATF2 Project Meeting, January 12 2012 M. Woodley

2D projected (Gauss fit) measurement: 2D projected (Gauss fit) 4D lsqnonlin analysis 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Ideal Coupling Correction with 4D Emittance Measurement SQ WS coupling correction measurement emittance x y x' y' setting σ13 to zero at first 4 WS using SQs is equivalent to minimizing εy with the SQs ref: “Zeroth order design report for the Next Linear Collider: Volume 2”, section 11.3 http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-r-474.pdf 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Ideal Coupling Correction with 2D Emittance Measurement SQ WS coupling correction emittance measurement x y x' y' setting σ13 to zero at 4 WS using SQs is not equivalent to minimizing εy with the SQs 13th ATF2 Project Meeting, January 12 2012 M. Woodley

ATF2 Coupling Correction with 2D Emittance Measurement SQ OTR coupling correction emittance measurement x y x' y' setting σ13 to zero at 4 WS using SQs is not equivalent to minimizing εy with the SQs 13th ATF2 Project Meeting, January 12 2012 M. Woodley

“Irwin” Coupling Parameters: Generating Coupled Beam Matrices Lie algebra generator: Define D: Define g and h (two alternate forms): Define β1,2 and α1,2 to be the uncoupled x,y Twiss parameters, and ε1,2 to be the uncoupled (intrinsic) x,y emittances. Then can construct coupled beam matrix (σ) from arbitrary mixtures of the 4 coupling phases (a,b,c,d). ref: “Expanded Studies of Linear Collider Final Focus System at the Final Focus Test Beam”, Appendix A, section A.3 http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-r-475.pdf 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Matlab script for generating function sig=e4d2sig(X) % % sig=e4d2sig(X) % Compute 4x4 beam matrix from 10 "4D" beam parameters % (see SLAC-R-95-475 (December 1995), pp 258-259) % Input: X(10) = 4D beam parameters (emit1,emit2,beta1,beta2,alpha1,alpha2,a,b,c,d) % Output: sig(4,4) = computed beam matrix % download 4D beam parameters e1=X(1);e2=X(2); b1=X(3);b2=X(4); a1=X(5);a2=X(6); a=X(7);b=X(8);c=X(9);d=X(10); sig=zeros(4,4); % compute g and h D=b*c-a*d; t=sqrt(abs(D)); if (D>0) g=cosh(t); h=sinhc(t); % sinhc(t)=sinh(t)/t else g=cos(t); h=sinc(t); % sinc(t)=sin(t)/t end % horizontal 2x2 sub matrix sig(1,1)=b1*(g^2*e1+h^2*(c^2+d^2)*e2); sig(2,1)=-g^2*a1*e1-h^2*(c*(a+a1*c)+d*(b+a1*d))*e2; sig(2,2)=(g^2*(1+a1^2)*e1+h^2*((a+a1*c)^2+(b+a1*d)^2)*e2)/b1; sig(1,2)=sig(2,1); % vertical 2x2 sub matrix sig(3,3)=b2*(g^2*e2+h^2*(b^2+d^2)*e1); sig(4,3)=-g^2*a2*e2-h^2*(b*(a+a2*b)+d*(c+a2*d))*e1; sig(4,4)=(g^2*(1+a2^2)*e2+h^2*((a+a2*b)^2+(c+a2*d)^2)*e1)/b2; sig(3,4)=sig(4,3); % coupling 2x2 sub matrix sig(3,1)=sqrt(b1*b2)*g*h*(b*e1+c*e2); sig(3,2)=sqrt(b2/b1)*g*h*((d-a1*b)*e1-(a+a1*c)*e2); sig(4,1)=sqrt(b1/b2)*g*h*((d-a2*c)*e2-(a+a2*b)*e1); sig(4,2)=g*h*((a*a1-d*a2+b*a1*a2-c)*e1+(a*a2-d*a1+c*a1*a2-b)*e2)/sqrt(b1*b2); sig(1,3)=sig(3,1); sig(2,3)=sig(3,2); sig(1,4)=sig(4,1); sig(2,4)=sig(4,2); Matlab script for generating coupled beam matrices (I still need to figure out how to use the coupled matrix (4x4) to populate particle distributions for tracking … ) 13th ATF2 Project Meeting, January 12 2012 M. Woodley

DR Orbit & Extraction Trajectory Emittance & Coupling DR Orbit & Extraction Trajectory 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Combined EXT 4-wire Horizontal Emittance Measurement (Nave=3, Nmeas=3, May 18 2010) sigt sigd sigw sig ------- ------- ------- ------- 126.23 3.54 2.50 126.16 86.37 2.52 2.50 86.29 179.43 3.75 2.50 179.38 100.17 1.22 2.50 100.13 Horizontal emittance parameters at MW1X ------------------------------------------------------- energy = 1.2817 GeV emit = 1904.8575 +- 78.4143 pm emitn = 4777.9375 +- 196.6858 nm emitn*bmag = 5174.7263 +- 144.2612 nm bmag = 1.0830 +- 0.0261 ( 1.0000) bmag_cos = -0.3570 +- 0.0000 ( 0.0000) bmag_sin = -0.1415 +- 0.0000 ( 0.0000) beta = 8.3788 +- 0.3057 m ( 12.0320) alpha = 1.1391 +- 0.1068 ( 1.8558) chisq/N = 0.0519 Propagated horizontal spot sizes ----------------------------------- MW1X = 126.3 um ( 126.2 +- 4.4) MW2X = 86.1 um ( 86.3 +- 2.9) MW3X = 181.7 um ( 179.4 +- 11.1) MW4X = 100.1 um ( 100.1 +- 1.7) 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Combined EXT 5-wire Vertical Emittance Measurement (Nave=3, Nmeas=3, May 18 2010) sigt sigd sigw sig ------- ------- ------- ------- 13.63 5.31 2.50 12.30 10.47 4.57 2.50 9.08 23.07 9.20 2.50 21.00 8.97 3.89 2.50 7.68 10.30 3.00 2.50 9.53 Vertical emittance parameters at MW0X ------------------------------------------------------- energy = 1.2817 GeV emit = 11.7381 +- 2.2922 pm emitn = 29.4427 +- 5.7495 nm emitn*bmag = 42.2019 +- 1.9205 nm bmag = 1.4334 +- 0.2490 ( 1.0000) bmag_cos = 0.0448 +- 0.0000 ( 0.0000) bmag_sin = -0.7150 +- 0.0000 ( 0.0000) beta = 12.6951 +- 2.0753 m ( 8.4774) alpha = 3.5809 +- 0.4296 ( 3.0756) chisq/N = 7.9155 Propagated vertical spot sizes ----------------------------------- MW0X = 12.2 um ( 12.3 +- 0.6) MW1X = 9.6 um ( 9.1 +- 0.5) MW2X = 18.3 um ( 21.0 +- 1.1) MW3X = 7.8 um ( 7.7 +- 0.2) MW4X = 8.6 um ( 9.5 +- 1.2) 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Observed that first 2 EXT vertical correctors (ZV1X and ZV2X) needed to be strong to properly launch into EXT (since before EXT rebuild for ATF2 … ) hypothesize that correctors are compensating for a kick error in extraction channel simulate error kick by rolling individual elements; use ZV1X and ZV2X to correct orbit find error that gives best fit to actual ZV1X/ZV2X values → BS3X septum magnet roll BS3X was physically rolled ~ -4 mrad (March 17, 2010) to relieve ZV1X and ZV2X projected vertical emittance in EXT before coupling correction was improved (~20-40 pm before → ~10-20 pm after) BS3X roll = 4.66 mrad Izv1 = -6.918 (-6.976) amp Izv2 = 1.270 ( 0.965) amp chi2 = 0.3102 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Horizontal EXT Emittance Measurements Vertical EXT Emittance Measurements Date Nwire Emit (nm) BMAG Dec 14 2010 4 1.784 ± 0.130 1.10 ± 0.04 Dec 9 2010 1.686 ± 0.102 1.08 ± 0.05 Nov 2010 (?) EXT kicker controller replaced May 18 2010 1.905 ± 0.078 1.08 ± 0.03 Apr 21 2010 1.212 ± 0.065 1.26 ± 0.03 Mar 17 2010 BS3X rolled ~4 mrad (CCW) Feb 25 2010 1.868 ± 0.336 1.15 ± 0.12 Feb 17 2010 negative Feb 3 2010 1.626 ± 0.095 1.10 ± 0.06 Jan 28 2010 Date Nwire Emit (pm) BMAG Dec 14 2010 5 27.6 ± 1.8 1.09 ± 0.04 Dec 9 2010 4 29.3 ± 3.1 1.05 ± 0.02 Nov 2010 (?) EXT kicker controller replaced May 18 2010 11.7 ± 2.3 1.43 ± 0.25 Apr 21 2010 15.4 ± 2.0 1.78 ± 0.17 Mar 17 2010 BS3X rolled ~4 mrad (CCW) Feb 25 2010 22.08 ±0.9 1.19 ± 0.03 38.33 ± 1.1 1.10 ± 0.02 Feb 17 2010 22.6 ± 1.4 1.15 ± 0.04 Feb 3 2010 16.1 ± 0.7 1.06 ± 0.03 Jan 28 2010 31.6 ± 1.2 1.03 ± 0.01 13th ATF2 Project Meeting, January 12 2012 M. Woodley

SET-file History (Apr-Dec, 2010) εy = 27.6 pm Apr 21 εy = 15.4 pm May 18 εy = 11.7 pm KEX controller replaced Dec 9 εy = 29.3 pm fast kicker fast kicker 13th ATF2 Project Meeting, January 12 2012 M. Woodley

2010 Result 13th ATF2 Project Meeting, January 12 2012 M. Woodley septum 2010 Result 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Summary & Continuing Work 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Summary more time is needed for analysis of existing data and simulations (MDW) EXT setup and maintenance is well understood, relatively fast, and stable mostly automated procedures … “recipe” for the rest we have good BBA offset values for most quadrupoles and sextupoles BPM system (striplines, C-band cavities, S-band cavities, IPBPMs) is working well multi-OTR system is working well we’re still plagued with vertical emittance growth between DR and EXT diagnostics section up to a factor of 10! appears to be strong x-y coupling ... maybe (at least partly) nonlinear we have seen emittance measurements (May 2010) from the WS that show virtually no vertical emittance growth from DR to EXT diagnostics section (and no coupling correction required) no empirical fudge factors required need to figure out: how to optimally correct the vertical emittance that we have (QK scan or “quick” methods) what is causing the observed emittance growth and where does it happen? are there other coupling sources between EXT diagnostics section and IP? 13th ATF2 Project Meeting, January 12 2012 M. Woodley

Continuing Work coupling measurement / 4D beam reconstruction and ... revisit emittance measurement and 4D reconstruction simulations generate coupled beams at all phases (adjust coupling magnitude for εy = 60-100 pm) simulate QK scans … can we deduce ε2? OTR and MSPIP tilt angles vs coupling phase … what should we expect to see? simulate coupling correction schemes … what works? under what conditions? and ... 13th ATF2 Project Meeting, January 12 2012 M. Woodley