Salzau 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

Salzau 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

Salzau 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

Salzau M. Körfer, DESY 4 Layout of Collimator System Start: m End: m Total length: 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

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

Salzau 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

Salzau 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

Salzau 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

Salzau 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

Salzau M. Körfer, DESY 10 Collimator a1a1 a2a2 a3a3 zz 100 mm  z[mm]a 1 [mm]a 2 [mm]a 3 [mm]  50  m reduction of uncorr. energy-spread by 50% Impact of wakefields at TTF2 Vacuum Pipe Conductivity Materialr[mm]   m [kV/nC/m] stainless steel 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

Salzau 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