Damping Wigglers in PETRA III

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1 Damping Wigglers in PETRA III WIGGLE2005, Frascati Winni Decking, DESY-MPY Introduction Damping Wiggler Parameters Nonlinear Dynamics with DW Operational Aspects Summary

2 DESY and its Accelerators HERA: 6.3 km 27 GeV e + / 920 GeV p TTF-2: 300 m 1 GeV PETRA: 2.3 km 12 GeV e + / 40 GeV p DORIS: 300 m 4.7 GeV e +

3 PETRA III Parameters: - energy: 6 GeV - current: 100 ma - emittance: 1 nmrad - straight sections: 9 - undulators: 13 - undulator length: 2, 5, 20 m

4 PETRA II - Overview Circumference: 2304 m octant Undulator

5 PETRA III Parameters Without Wiggler With Wiggler Tune Nat. Chromaticities / / -47 I2 Energy Loss/turn Hor. Emittance Energy Spread Bunch length 6.3e MeV 4.65 nm rad % 8.3 mm 2.6e MeV 1.2 nm rad % 12.7 mm Damping times Rev. Frequency Acceptance 80/80/40 ms 10400/5200 turns khz 20/20/10 ms 2600/1300 turns 30 µm / 2.2 µm / 1.5 %

65 nm rad 0.083 % 8.3 mm 2.6e-1 4.66 MeV 1.2 nm rad 0.0126% 12.7 mm Damping times Rev.

6 PETRA III Optics

7 ε Emittance Constituents I 5 H 1, I5 = dl I dl I I, 2 = 3 ρ ρ Optics Ring Geometry 1 ε x, ring = 2, A x, A 2, N x, N 2, W x, W + I + I + I + I 2, A 2, N 2, W 2, U For small emittance you need: Large bending radius Small bending angle per cell Small horizontal beta-functions ( I ε + I ε + I ε I ε ) 2, U x, U Given by user constraints

2, U For small emittance you need: Large bending radius Small bending angle per cell

8 2, A 2, N Total field integral: B 2 m: 98 T 2 m Maximum field and period length B 3 λ 2 : 0.2 Wiggler Requirements 1 ε x, ring = 2, A x, A 2, N x, N 2, W x, W + I + I + I + I 2 I W B dl 2, 2, W 2, U ε x ( I ε + I ε + I ε I ε ) 2 3 2, W Bmaxλ β depends on wiggler field shape 2, U x, U [ nm]

9 PETRA 3 Damping Wigglers Period: 20 cm Field amplitude: 1.56 T Field 1 cm: <10-3 Total length: 80 m Total radiation power:887 kw

10 Wiggler Magnet Design (P. Vobly, BINP) Blue - iron, Green permanent magnets Magnetic symmetry leads to magnetic potential of wedge-like plate equals zero No coupling between poles

11 Wiggler Field

12 Wiggler Treatment Linear Optics, Emittance Calculations, Closed Orbit Simulations: Hard-edge dipole model in MAD Linear 6 6 matrix based on field data Nonlinear dynamics Field calculations with RADIA, Field fitting (Halbach formulae) with usually 9 harmonics Symplectic integration of analytical field description Generating function (G. Wüstefeld) for tracking studies End field not yet implemented Field errors as additional multipoles based on field integral measurements

formulae) with usually 9 harmonics Symplectic integration of analytical field description Generating function (G.

13 Nonlinear motion after 1 wiggler/7 undulator periods 0 x x 10-6 y' [rad] e e e e e e e e y [m] 3 x e e e e e e e e-15 y' [rad] x [m] x e e e e e e e e-18 x' [rad] 1 x' [rad] y [m] e e e e e e e e x [m]

15e-15 y' [rad] 0-2 -4-6 0 0.01 0.02 0.03 x [m] -0.5 0 x 10-5 -2.02e-01 7.70e-04-1.61e-11 1.25e-14 1.70e-04-1.71e-12 6.86e-15-5.

14 Wiggler and Undulator No Wiggler Wiggler Wiggler + Undulators

15 Resonances tune scan with initial status x=5mm y=1mm delta=0.1% Wigglers and undulators No Wigglers and undulators

16 DA with/without all insertion devices Transverse Longitudinal

17 Operational Issues: Emittance Control No. of Events No. of events No. of events Horizontal rms orbit (mm) Vertical rms orbit(mm) Combined orbit & dispersion correction No. of events No. of events RMS Vertical Dispersion(mm) Golden Orbit Vertical rms orbit(mm) Horizontal rms orbit(mm)

Combined orbit & dispersion correction No. of events No. of events 0 2 3 4 5 6 7 8 80 70 60 50 40 30 20 10 0 0.03 0.

18 Operational Issues: Wiggler SR Power Absorbers (BINP) ma, E c =36 kev Opening angle: 5 mrad horizontal, mrad vertical 70 kw 200 kw 15 kw Cu, 200 W/cm

kev Opening angle: 5 mrad horizontal, 0.

19 Schedule 2004: TDR published : Finalize technical design Procure hardware Continue machine studies at PETRA II 2007: End of HERA HEP Reconstruction of PETRA 2008: Commissioning of PETRA III 2009: Beam to users

20 Summary PETRA III closes the gap between DESY s DORIS III and existing high energy 3 rd generation light sources, Ideal partner for the X-FEL project Ideal test bed for LC damping ring issues Wiggler dominated Large injected beam with frequent injection Small vertical emittance State of the art beam stability State of the art diagnostics e + /e - possible BUT: Synchrotron radiation facility

Wiggler dominated Large injected beam with frequent injection Small vertical emittance State of

Frequency Map Experiments at the Advanced Light Source. David Robin Advanced Light Source

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