Dämpfungswigglerstrecken Markus Tischer, 18.11.08 Damping wiggler sections BINP / DESY cooperation on Damping wiggler Vacuum system Absorber

Prinzip Abstrahlung von SR  Impulsverlust innerhalb Abstrahlkonus K/ und Nachbeschleunigung entlang Ausbreitungsrichtung  GGW mit kleinerer Emittanz („Strahlungs-Dämpfung“) 92m Damping section elements: P3 – Nord

Komponenten

Specification – damping x = 4 nmrad  1 nmrad requires damping integral wiggler-induced emittance total wiggler length ~ 80m  wig = 20cm, B0 = 1.5 T Court. W.Decking

Specification – apertures Vertical acceptance: 3 mm mrad for max = 25m (inj~300nmrad, =10%)  vertical aperture = 17 mm absorber 1+1 2 mm vac. chamber 2+2 4 mm tolerance 1 mm  magnetic gap = 24 mm Horizontal at least 30 mm aperture, defined by maximum absorption power of regular absorbers

Wiggler – Design Parameters Magnet structure Peak field B0 1.52 T Magnetic gap 24 mm Period length 0.2 m Number of poles 38 + 2½ Magnet volume / period 2200 cm3 Field quality at x0 = 10 mm < 10−3 Damping integral / segment 3.9 T2m Overall length / segment 3.97 m Number of wiggler segments 20 SR characteristics SR critical energy 35.8 keV K -Parameter 28.4 Wiggler SR power* 42.1 kW Vertical SR spread 170 µrad Horizontal SR spread 4.84 mrad * I=200mA NdFeB magnets Br = 1.3T Hcj = 1430kA/m (17.9kOe)

Wiggler – Magnetic Design End plate Pole Non-magnetic spacer Long. magnet

Magnet Quality Magnet characterization of 180 blocks: good integral properties high remanence with small scatter (~0.7%) small systematic angular error (~0.2°) with a narrow distribution (<1°)

Measurement Equipment Field integrals reproducible within 30Gcm after dis-/reassembling

Magnetic Measurements – Hall probe Vertical field (after peak field tuning, before setting finger corr.) • By = 15.6kG, 10-4 variation • transverse profile in By due to ~20µm protrusion in pole

Magnetic Measurements – Λ-Coil Horizontal field : • after assembling: large transverse integrals, large horizontal multipoles, due to - inhomogeneities - mechanical imperfection  locate faulty poles • after adjustment by: - transverse shift of poles - magic fingers 1. Field Integral [Gcm]

Magnetic Tuning – Magic Fingers • vertical correction with 10 magnets, 6x6mm2, gapmin=24mm • horizontal correction with 12 magnets, 7x18mm2, gapmin=65mm (no other space) • adjustment range : ~600 …1000Gcm Transverse dependence of horizontal integrals: measured data, modelled signature for selected configuration, on top (sign and strength), expected residual after correction.

Field Integrals vertical 1. Field Integral [Gcm] horizontal +1000 -1000 vertical horizontal • 1st integrals tuned to about ±30Gcm (vertical) ±50Gcm (horizontal) 1. Field Integral [Gcm] • 2nd integrals flat within ±30kGcm2

Vakuumsystem Quadrupolkammer (VA) Wigglerkammer (Alu) Absorber (Cu) Mehrere Sonderkammern Wiederholte Optimierung der Apertursprünge wg. Absorberlayout und Impedanz-Budget BPM Bellows Quad

Vakuum – Wigglerkammern Extrudierte Aluminumkammern Sprengplattierter Alu-VA-Übergang NEG-beschichtet Wasserkühlung vorgesehen Maximum expected heat load (COD=1mm) on wiggler chamber (#9): PowerDens. ~1mW/mm2 Ptot<100W

Absorbers Total power: ~400 kW / DW section 8 regular absorbers: < 26 kW each … 2 long absorbers: à ~90 kW Lumped absorber: ~120 kW Total power: ~400 kW / DW section

Regular Absorber Design Odd absorber (vertical aperture 9mm) Even absorber (vertical aperture 17mm) Vacuum chamber A B Absorber body (upstream part) Absorber mask (downstream part) X [mm] Z [mm] General design Body, body,… Mask e- Abs. No. A [mm] Zmax [mm] B [mm] Abs. body load [kW] Abs. mask load [kW] 1 30 4.5 34.4 3.3 1.3 2 8.5 36.8 7.4 5.2 3 31.5 35.7 16.6 4.1 4 31.1 36.4 18.1 5.0 5 39.7 40.0 12.5 2.1 6 36.2 41.8 19.7 5.8 7 56.7 48.2 9.2 2.4 8 43.7 49.3 19.6 5.6

Absorber Layout SR-Leistungsberechnungen für COD mit 1mm Amplitude für alle COD-Phasen jeden Absorber Leistungsdichteverteilungen für schlechtesten Fall vollständige FE-Simulation aller Absorber (Temp., Spg.) aufwendiger Iterationsprozess  empfindliche Komponenten  Überwachnung durch MPS notwendig COD phase projected power density map temperature map stress analysis

(Layout of all absorbers for I = 200mA) Power Load Regular Absorbers maximum acceptable power load: 20kW for body 6kW for mask  200W/cm maximum linear power density Apertures of all absorbers have to be optimized individu- ally, unification of design not possible No. 7 is most delicate and very sensitive to closed orbit distortions Max. load Long & Final Absorbers Same mechanical concept Power uptake 90kW (Long) 120kW (Final) (Layout of all absorbers for I = 200mA)

2 Long Absorbers 4.5m length 90kW power deposition several segments, brazed to a single piece last wiggler

Final Absorber … to come : Final absorber hinter dem Dipol am Ende der geraden Strecke Dipol gedreht, neue Kammern für Dipol, Q9N Fertigung von Auslaßkammer- system und Final Absorber bis Ende Nov.08, Einbau Mitte Jan.09 L=6m, ausgelegt für P~120kW 4 Segmente, gelötet, Schraubverbindung vor dem letzten Segment (ggf. spätere SR-Auskopplung in Beamline)

Inbetriebnahme der DW-Strecken Ausheizen der Wigglerkammern (wg. NEG-Beschichtung) Inbetriebnahme der Maschine ohne Dämpfungswiggler Positionierung der Wiggler auf Strahlachse Betrieb mit Wigglern bei kleinem Strom  Ausgasen der Absorber Wiggler auf Parkposition fahren, NEG-Beschichtung der Wigglerkammer aktivieren, Wiggler in Strahlposition bringen vermessen Inbetriebnahme der Maschine mit Dämpfungswigglern

Ausheizen der Wigglerkammern T=140°C für 24h neues Ausheizsystem samt Steuerung und Überwachung Magnetstrukturen: Tmax<50°C ist gewährleistet

Wiggler – Gap separation Position for vacuum chamber activation 1. 2. 3. Open the gap Remove side wall Slide in wiggler Vacuum chamber support arm Aux. support Gap drive mechanics 4. Wiggler in operation position

Wiggler – Gap separation 16 to

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