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Primary Beam Lines for the Project at CERN

Primary Beam Lines for the Project at CERN. C.Bracco , F.M. Velotti , J. Bauche , A. Caldwell, B. Goddard, E. Gschwendtner , G. Le Godec , L.K. Jensen, M. Meddahi , P. Muggli , J.A. Osborne, A. Pardons, A. Petrenko. Outlines. AWAKE p+ beam line Present CNGS layout

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Primary Beam Lines for the Project at CERN

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  1. Primary Beam Lines for the Project at CERN C.Bracco, F.M. Velotti, J. Bauche, A. Caldwell, B. Goddard, E. Gschwendtner, G. Le Godec, L.K. Jensen, M. Meddahi, P. Muggli, J.A. Osborne, A. Pardons, A. Petrenko

  2. Outlines ACM @ Düsseldorf • AWAKE p+ beam line • Present CNGS layout • Needed lattice modifications for AWAKE beam • Optics • Beam instrumentation • AWAKE e- beam • Geometric layout and optics • Preliminary results on space charge effects

  3. AWAKE in the CERN Accelerator Complex CNGS AWAKE experiment will be installed @ the end of the CNGS beam line ACM @ Düsseldorf

  4. End of CNGS Proton Beam Line p+ Beam from SPS TARGET area Final focusing quadrupoles + trajectory correctors + Beam instrumentation ACM @ Düsseldorf

  5. End of CNGS Proton Beam Line Plasma cell p+ Beam from SPS TARGET area 7.16 % Final focusing quadrupoles + trajectory correctors + Beam instrumentation The end of the present CNGS line has to be modified to install the AWAKE plasma cell: new final focusing system + laser integration ACM @ Düsseldorf

  6. Lattice Modifications Present Layout (end of the line) FODO Final Focusing X X Plasma cell Future Layout • 2 quads (1 QTG + 1 QTS) are removed ACM @ Düsseldorf

  7. Lattice Modifications Present Layout (end of the line) FODO Final Focusing Plasma cell Future Layout • 2 quads (1 QTG + 1 QTS) are removed • 7 left quads are displaced and reshuffled for the new final focusing ACM @ Düsseldorf

  8. Lattice Modifications Present Layout (end of the line) FODO Final Focusing Plasma cell Future Layout • 2 quads (1 QTG + 1 QTS) are removed • 7 left quads are displaced and reshuffled for the new final focusing • 1 MBG is displaced + 4 B190 are added to create the chicane for laser integration (1.9 m long, 1.6 T max. magnetic field) ACM @ Düsseldorf

  9. Chicane for Laser Integration -2980 -3000 2 × B190 -3020 CNGS Tunnel wall Present Beam y [m] New Beam -3040 2 × B190 -3060 CNGS Tunnel wall Plasma cell -3080 -3100 4213 4214 4215 4216 4217 4218 x [m] MAD-X conversion of CERN Coordinate System ACM @ Düsseldorf

  10. Chicane for Laser Integration -2980 B190 1 mrad kick B190 1 mrad kick -3000 2 × B190 Laser -3020 CNGS Tunnel wall Present Beam y [m] New Beam -3040 2 × B190 p+ beam -3060 Offset between proton beam and laser axis = 24 mm @ Mirror: Beam size ~ 5 mm (6 sigma envelope + 3.5 mm mrademittance + 1 mm orbit + 1 mm mechanical misalignment ) Laser spot size ~ 4.3 mm (1 sigma) Mirror radius= 13.0mm (3 sigma, 0 angle, 9.2 mm for 45° angle) Mirror thickness= 6 mm (4.2 mm for 45° angle) Total needed offset ~ 18.4 mm CNGS Tunnel wall 12 m Plasma cell -3080 -3100 4213 4214 4215 4216 4217 4218 x [m] MAD-X conversion of CERN Coordinate System ACM @ Düsseldorf

  11. Final Focusing and Dispersion Matching Experiment requirements: round beam, beam size @ plasma cell entrance 1s = 200 ± 20mm  bx = by= 4.9m & Dx = Dy = 0 (400GeV, 3.5 mm mradnormalisedemittance, Dp/p =1 ‰) Achieved: bx=by= 4.9 m Plasma cell Dx= 0.029 m Dy= 0.029 m Plasma cell sx =sy= 224 mm ACM @ Düsseldorf

  12. Beam Instrumentation ACM @ Düsseldorf Existing CNGS beam instrumentation + suitable modifications due to different intensity and bunch structure: • Beam Position Monitors (BPM): • Exchange electronics • Add two high precision BPM (50mm) around the plasma cell to check the pointing precision (±100mm and ±20mrad, plasma and proton beam coaxial over the full length of the plasma cell)  interlock to stop extraction from the SPS if beyond tolerances • 2 Optical Transition Radiation (OTR) screens around plasma cell for p+ beam setup (out when TW laser on!) • Cable lengths and signal filtering optimisation for Beam Current Transformers (BCT) • Present Beam Loss Monitors (BLMs) Ok.

  13. Electron Beam Line: Geometry • 12.2 m long e- beam line from RF gun to plasma cell (tunnel for e-beam) • e- beam impinging perpendicularly w.r.t. plasma cell window RF Gun Plasma Cell e- beam 7.16 % Line design based on Fermi@ELTTRA magnets MAD-X conversion of CERN Coordinate System ACM @ Düsseldorf

  14. Electron Beam Line: Geometry • 12.2 m long e- beam line from RF gun to plasma cell (tunnel for e-beam) • e- beam impinging perpendicularly w.r.t. plasma cell window V bends e- beam 7.16 % Line design based on Fermi@ELTTRA magnets MAD-X conversion of CERN Coordinate System ACM @ Düsseldorf

  15. Electron Beam Line: Geometry • 12.2 m long e- beam line from RF gun to plasma cell (tunnel for e-beam) • e- beam impinging perpendicularly w.r.t. plasma cell window H bends e- beam 7.16 % Line design based on Fermi@ELTTRA magnets MAD-X conversion of CERN Coordinate System ACM @ Düsseldorf

  16. Electrons Merging Point • Ideally possible to move merging point (2-5 m) and angle (5-20mrad)  movable dipoles ? • 30 cm max. aperture !! • ~13 G m (1 m long dipoles, for 20 mrad) • To be studied! Plasma cell Diagnostics * Studies shown in the following refer to 16 MeV ** Emittance blowup in plasma 2 mm mrad @ merging point *** Bunch compression option to be studied ACM @ Düsseldorf

  17. Electron Beam Optics V bends H bends Quads Experiment requirements: Round beam, Beam size 1s < 250mm, Dp/p < 1% Achieved @ merging point (waist 5 m after beginning of plasma cell): sx = 126mm sy = 126mm (0.5 mm mrad norm. emittance) sx = 251mm sy = 253mm (2mm mrad norm. emittance) Plasma cell Merging dipole not considered to match the optics, if dipole ON (with this optics)  Dx = 2 cm and beam size 8% larger for Dp/p = 0.1% and 80% larger for Dp/p= 1% ACM @ Düsseldorf

  18. Matched Optics with Merging Dipole Merging dipole V bends H bends Quads Experiment requirements: Round beam, Beam size 1s < 250mm, Dp/p < 1% Achieved @ merging point (waist 5 m after beginning of plasma cell): sx = 199mm sy = 198mm (2 mm mrad norm. emitt. Dp/p = 0.1%) sx = 379mm sy = 370mm (2 mm mrad norm. emitt. Dp/p = 1%) Plasma cell At the entrance of the plasma cell: sx= 1.07 mm sy = 1.16 mm (0.5mm mrad norm. emitt. Dp/p = 0.1%) ACM @ Düsseldorf EAAC2013 4/06/2013

  19. Matched Optics @ Entrance of Plasma Cell V bends H bends Quads Experiment requirements: Round beam, Beam size 1s < 250mm, Dp/p < 1% Achieved @ plasma cell entrance: sx = 200mm sy = 200mm (0.5 mm mrad norm. emitt. Dp/p = 0.1%) Dispersion explodes (only way of keeping b reasonably low)  momentum spread must be kept @ 0.1% level! Plasma cell ACM @ Düsseldorf EAAC2013 4/06/2013

  20. Matched Optics @ Entrance of Plasma Cell Additional quad. V bends H bends Quads Experiment requirements: Round beam, Beam size 1s < 250mm, Dp/p < 1% Achieved @ plasma cell entrance: sx = 200mm sy = 200mm (0.5 mm mrad norm. emitt. Dp/p = 0.1%) Dispersion explodes (only way of keeping b reasonably low)  momentum spread must be kept @ 0.1% level! Plasma cell Additional focusing (k = 2.5 m-2 ) around plasma cell @ 4 m from cell start (conflict with moving dipoles…) sx = 943mm sy = 990mm (2mm mrad norm. emitt. Dp/p = 0.1%) sx = 243mm sy = 179mm (0.5 mm mrad norm. emitt. Dp/p = 0.1%) ACM @ Düsseldorf EAAC2013 4/06/2013

  21. Space Charge Studies: Assumptions p Dp f Df Df = 2p for full bucket  Dt ~ 1 ns ACM @ Düsseldorf • Tracking simulations: • Code: PTC-ORBIT (ORBIT for SC, FFT method to calculate force on the grid using the binned particle distribution) • Initial distribution: • Transverse plane: Gaussian (1 s cut) x-x’, y-y’ • Longitudinal plane: uniform in Df and Gaussian in Dp/p • 200 000 Macroparticles • Assumed RF frequency wRF= 3 GHz: • 10ps ~ Df= 188.5mrad • 0.3ps ~ Df= 5.7mrad • Filled bucket area Df×Dp/p = constant (Dp/p = 1%@ 0.3 ps)

  22. Space Charge Effects Beam distribution @ merging point (5 m from beginning of plasma cell) Preliminary results 10ps, 0.3‰ Dp/p 0.3ps, 1% Dp/p ACM @ Düsseldorf

  23. Space Charge Effects Beam distribution @ merging point (5 m from beginning of plasma cell) Expected emittance growth when increasing e- beam intensity Preliminary results 10ps, 0.3‰ Dp/p 0.3ps, 1% Dp/p ACM @ Düsseldorf

  24. Conclusions ACM @ Düsseldorf • AWAKE p+ beam line: • Experiment at the end of CNGS beam line • Minor modifications of existing lattice to fit plasma cell and fulfill geometric and optics requirements • Existing magnet hardware and beam instrumentation can be used (suitable changes due to different intensity and bunch structure) • AWAKE e- beam line • Geometric layout defined • Optics requirements fulfilled (matching for different optics needed): where shall the waist be? • New hardware needed + dedicated studies for magnets around plasma cell (feasible changing merging point and angle? precision?) • Very preliminary studies for space charge effects but effect seems to be real! • Other codes for benchmarking (TRACE-3D, ASTRA?) • To evaluate effect of Coherent Synchrotron Radiation (CSR) • Additional external focusing? • Bunch compression....

  25. THANK YOU FOR YOUR ATTENTION

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