1. Salzau 21.01.2003 M. Körfer, DESY 1 Layout and Functionality of Collimator System Purpose of the Collimator System Layout Sub-Systems Transversal/ Energy Collimation Fast Orbit Correction System Matching Sections Diagnostic Concept

2. Salzau 21.01.2003 M. Körfer, DESY 2 Layout and Functionality of Collimator System Purpose: Protection of Permanent Magnet Undulator transversal collimation  beam halo separation energy collimation  dark current separation TTF2 Design for high average beam power 72 kW average beam power 1 nC, 800  s, 9 MHz, 10 Hz, 1 GeV Collimator Scheme Energy & Transversal Collimation Beam Design take into account: beam dynamics material science interaction of e- and collimator

3. Salzau 21.01.2003 M. Körfer, DESY 3 Experience of the TTF1 collimator 1) energy collimation needed  absorption of dark current 2) offset of collimator and undulator axis  secondary particle (mostly low energy photons !) escaping the absorber system should not hit the undulator Additional Functionality : saves tunnel length by including a) fast orbit correction system and b) optics matching Layout and Functionality of Collimator System

4. Salzau 21.01.2003 M. Körfer, DESY 4 Layout of Collimator System Start: 143.35 m End: 166.11 m Total length: 22.76 m TCOL: 9.02 m ECOL: 6.95 m MATCH: 6.79 m Dipole: 3.5 ˚ horizontal Offset: 400 mm Bypass TCOL ECOL MATCH Beam

5. Salzau 21.01.2003 M. Körfer, DESY 5 Diagnostic Concept Beam Quad+BPMDark CurrentDipoleKickerCollimatorToroidOTR-Wire Steerer MATCH ECOLTCOL

6. Salzau 21.01.2003 M. Körfer, DESY 6 Transverse Collimation Beam TCOL TQA Kicker Steerer TQA Kicker Bypass Dipole Toroid DCM Copper versus Titanium: better temperature conductivity better electrical conductivity better Collimator efficiency less stress limit  T=180º Copper Collimator total length: 500 mm mover support:hor./vert. position accuracy:15  m TCOL

7. Salzau 21.01.2003 M. Körfer, DESY 7 Energy Collimator Beam ECOL TQB+BPM TQB TQB+BPM TSB Steerer TDH ECOL TDH ECOL  dispersive Section  at the end D = 0, D` = 0  Quadrupoles inbetween Dipoles  compensation of higher order dispersion by sextupoles  orbit at the undulator entrance independent of energy within  5% due to quadrupoles ECOL  400 mm beam path offset avoids direct photon shower into the undulator

8. Salzau 21.01.2003 M. Körfer, DESY 8 CSR-Effect and Slice-Emittance Growth Collimator Dogleg Input:  l =50  m  n =2 mm mrad E=1.0 GeV Output:  l =50  m  slice =2.2 mm mrad  proj. =2.8 mm mrad  E/E corr = 0.05 % Trafic 4 Beam ECOL TQB+BPM TQB TQB+BPM TSB Steerer TDH ECOL TDH

9. Salzau 21.01.2003 M. Körfer, DESY 9 capture particle max. aperture at minimum energy bandwidth for R=2 mm (without interaction with pipe) Collimator Efficiency: calculated with gaussean beam profile back scattering secondary particle Collimation and Efficiency Undulator Chamber Dark Current Module blue curve Collimator Aperture

10. Salzau 21.01.2003 M. Körfer, DESY 10 Collimator a1a1 a2a2 a3a3 zz 100 mm  z[mm]a 1 [mm]a 2 [mm]a 3 [mm]  rms[kV/nC] @ 50  m 02--17153 20024.517113 reduction of uncorr. energy-spread by 50% Impact of wakefields at TTF2 Vacuum Pipe Conductivity Materialr[mm]  rms @50  m [kV/nC/m] stainless steel1712.2 copper173.1 TESLA Cavity399.6 Consequence: 1.copper coated vacuum pipes 2.avoiding steps inside the pipes 3.Bellow RF-shielding Longitudinal Wakefields und Energy Spread

11. Salzau 21.01.2003 M. Körfer, DESY 11 Matching Section MATCH Fast orbit correction system: H-Kicker >  3  h V-Kicker >  2  v at undulator entrance Optic Matching with downstream section Beam Kicker TQB+BPM Steerer Phasemonitor, Toroid, OTR TQB