Low Emittance Tuning (LET) . Through Dispersion Free Steering .

1. Low Emittance Tuning (LET).Through Dispersion Free Steering.

2. Lowemittance:requirments for SuperB SuperBe+e- collider luminosity is: This requires very low emittances for both rings: LER e− εx = 2.5nmrad εy = 6.2pmrad HER e+ εx = 2nmrad εy= 5pmrad Within the reach of 3rd generation light sources Low Emittance Tuning (LET) Algorithm S.M.LiuzzoPhDat LNF-INFN

3. SVD inversion of RESPONSE MATRIX M determines the Correction L.E.T. • CORRECTORS USED • V & H steerers • Skew quad • gradients • Bpm Tilts-Gains • (in progress) DFS Pis the orbitH or V dispersion Coupling • Matrix M simulated from Model • SVD inversion for simultaneous minimization of dispersion coupling and β-beating 1 Off-diagonal block ORM column β-beating Only few measurements: 1 to ~10 RM columns , orbit (P) and dispersion (η) TOTAL TIME: 5 min 1 diagonal block ORM column Time

4. LET compared to ORM and DFS Vertical Emittance and vertical correctors rms as a function of the eigenvalues cut used in SVD pseudo-inversion. Vertical alignment errors corrected with: Orbit Response Matrix Dispersion Free Steering Low Emittance Tuning Vertical Correctors rms grows while vertical emittance is reduced for all correction algorithms ORM DFS εy LET rms V cor. [Slide 4] S.M.Liuzzo PhD at LNF-INFN

5. Simulations of correction SuperB HER V12 Arcsrmsmisalignments: Quadrupoles [0 300]μm ∆H, ∆V [0 300]μrad ∆φ Sextupoles [0 300]μm ∆H, ∆V BPM Offsets [0 300]μm 168 H-V correctors 168 H-V BPM Produced table of tolerances for SuperB S.M.LiuzzoPhDat LNF-INFN

6. Comparison between LET and LOCO Simulations for Diamond Simulations: 50 machine with random misalignments and bpm offsets, corrected using DFS and LET R.Bartolini DFS εy =5.28 10-12 LET Correction applied in two iterations using H and V steerers only. No BPM Tilts εy =3.27 10-13 S.M.LiuzzoPhDat LNF-INFN

7. Comparison between LET and LOCO Measurements at Diamond Decay mode 900 bounches 150 mA Current[mA] H emittance [nm] Lifetime [h] Coupling [%] Initial conditions 21.1 h After 2 LOCO iterations with skewquad and quad 5.9 h 5.5 h After 4 LET iterations with skewquad FinalLifetimemeasurementspreformedafterinjection LOCO LOCO LET BPM Tilt estimate by LOCO S.M.LiuzzoPhDat LNF-INFN

8. Couplingestimated from lifetime: εy =1.6 10-12 m rad (LET) Same measurements. Parametersvs iteration number LET Vertical dispersion [m] LET RED LOCO BLUE Lifetime [h] 350 μm (LOCO:700 μm) 5.5 h 5.9 h Residual Vertical orbit Coupling from Lifetime [h] 0.06 % 32 μm (LOCO: 1 μm) 0.07 % Residual Vertical orbit + H corr Current*Lifetime [mAh] 818 mAh 881mAh

9. Measurements at SLS Measurements aimed to achieve low vertical emittance SWISS LIGHT SOURCE 2.4 GeV, 288m, 12 beamlines, 400 mA, 5.4 nm Hor. Emit. Resolution Same Tool used for Diamond, modified for direct access to Control System Vertical beamsizemeasurementsperformed usingverticallypolarizedSyhnchrotron Light Monitor TUPB27 Proceedings of DIPAC 2007, Venice, Italy S.M.LiuzzoPhDat LNF-INFN

10. Measurements at SLS Top-up mode 400 mA Normal user operations Beam size measurement for 3 subsequent correction performed using only VERTICAL STEERERS Best observed σy=6.8 μm 400 μmresidual vertical orbit. SLS best σy=4.9 μm isobtianedusingskewquadrupoles Testedalso Horizontalcorrection and Skewquadrupolescorrection, butstill work is in progress. S.M.LiuzzoPhDat LNF-INFN

11. Summary Conclusion • Developed and appliedLow Emittance TuningTool for SuperB. • Testedand comparedalgorithm to LOCO at Diamond (skewquarupoles) • Testedalgorithmat SLS with promisingstartingresults. (sametoolasdimond) • LET Algorithmperformingwellbutstillnotreachingsimulationexpectedresults. • Need to further test and debug to control H corrections and Tilt detection • Future application in DAΦNE S.M.LiuzzoPhDat LNF-INFN