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PS2 Injection/Extraction Layout

PS2 Injection/Extraction Layout. Wolfgang Bartmann PS2 Meeting, 23-May 07. Outline. Aims Optics in LSS Space Requirements – Injection H - -Injection – Lorentz stripping and Septum geometry Space Requirements – Extraction/Beam dump Conclusion of space requirements

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PS2 Injection/Extraction Layout

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  1. PS2 Injection/Extraction Layout Wolfgang Bartmann PS2 Meeting, 23-May 07

  2. Outline • Aims • Optics in LSS • Space Requirements – Injection • H--Injection – Lorentz stripping and Septum geometry • Space Requirements – Extraction/Beam dump • Conclusion of space requirements • Fitting Injection/Extraction together • Next steps PS2 Meeting: Inj/Extr Layout

  3. Aims • Injection: • Fast Injection • H--Injection • Extraction: • Fast Extraction • Resonant Extraction • Low-loss 5 turn continuous transfer • Beam dump (assumed internal) PS2 Meeting: Inj/Extr Layout

  4. FODO Lattice - LSS Betafunctions and Dispersion in the LSS: • betx, bety < 42 m • Dx < 10 cm PS2 Meeting: Inj/Extr Layout

  5. Space Requirements: Injection (1) • Fast Inj. needs one cell. We see no special issues with this system. • H--Inj. is limited due to Lorentz Stripping: For energies up to 3.5 GeV, the field strength in dipoles must not exceed 0.14 T (2.4 · 10-5 loss/m) which corresponds to a maximum deflection of ~ 9 mrad/m; Field at 75 mm offset in quadrupoles does not exceed these limits (at injection energies!). PS2 Meeting: Inj/Extr Layout

  6. H- -Inj: Lorentz stripping… • Can parameterize formula for lifetime in magnetic field • t = a/E x exp(b/E) Where t = lifetime, a~4x10−14 s-MV/cm, b~44 MV/cm and E is Lorentz-transform of the magnetic field B (E [MV/cm] = 3.20 p [GeV/c] x B [T]). • Rule of thumb : p x B ≤ 0.6 - 0.7 GeV/c x T • More exactly: for PS2 injection at 4.8 GeV/c (4 GeV kinetic) should keep fields below 0.13 - 0.15 T (corresponds to about 10-3 loss per m of field)…gain x10 in loss at fixed B at 3.5 GeV! PS2 Meeting: Inj/Extr Layout

  7. H--Inj: Lorentz Stripping –total losses • Need to aim for 10-3 total loss • Few 10-4 per element/system • Bend angles were assumed at 200 mrad… • Maximum bend about 9 mrad/m (3.5 GeV) • Would need ~20 m of injection septum!!!! • In one FODO ½ cell have ~ 10 m free drift • Assume 8 m magnetic length for septum • Maximum deflection is then ~ 70 mrad. PS2 Meeting: Inj/Extr Layout

  8. Space Requirements: Injection (2) H--Inj. in FODO structure: • Injecting in one halfcell (~11.3 m free drift) with several septa reaches a displacement of about 0.57 m at the quadrupole. • Going through the coil window of the enlarged quadrupole avoids large septum kicks but needs one halfcell more. • H--Inj. occupies 1.5 to 2 cells • Space requirement for injection: 2.5 to 3 cells PS2 Meeting: Inj/Extr Layout

  9. H--Inj: Injection septum geometry 570 mm 60 mm 2.0 m, 18.0 mrad Difficult (but maybe not impossible!) to get past upstream quad yoke and into the downstream quad aperture. PS2 Meeting: Inj/Extr Layout

  10. H--Inj: Injection septum geometry‘coil window’ alternative 300 mm 60 mm 2.0 m, 7.5 mrad Less bending angle, but the first meters of the halfcell before are needed, too. PS2 Meeting: Inj/Extr Layout

  11. Space Requirements: Extraction • the three extraction systems need 4.5 cells according to the conceptual design (Jan 07) • rearrangement of the elements in the extraction and placing the extraction kicker in the dispersion suppressor gives a requirement of three cells in the LSS Problems: • larger apertures in the dipoles • less flexibility in the design of the dispersion suppressor S S PS2 Meeting: Inj/Extr Layout

  12. Space requirements: Beam dump ~2 m Vertical plane… Internal dump block at about 40 mm aperture Dump kickers filling one half-cell (~ 2.5 mrad needed at 50 GeV) Vertical has some advantages: - smaller beam size at injection means block closer to orbit  lower kick Needs to fit into long injection/extraction straight section…. - infrastructure, radiation PS2 Meeting: Inj/Extr Layout

  13. Conclusion of space requirements • Injection: 2.5 to 3.0 cells • Extraction: 3.0 cells (4.0 total) • Dump: 1.0 cell • Total: 6.5 to 7.0 cells PS2 Meeting: Inj/Extr Layout

  14. Optimum (?) fitting togetherwith present lattice Fast Injection H--Injection Extraction DS InjK InjS H0S H-InjS MTEBK MS2 MS1 ES MTEBK ExtK 6 cells • No room for beam dump • Kicker in Dispersion Suppressor PS2 Meeting: Inj/Extr Layout

  15. Options for inj/extr straightwithout using the DS Fast Injection H--Injection Extraction Beam Dump InjK InjS H0S H-InjS MTEBK MS2 MS1 ES MTEBK BD DuK ExtK InjK InjS H0S H-InjS MTEBK MS2 MS1 ExtK MTEBK BD DuK ES 7 cells PS2 Meeting: Inj/Extr Layout

  16. Next steps: Iterate Inj/Extr Layout Versions • Designing the arc as an achromat saves one cell per arc (cell length is shorter)  7 LSS cells • Use different cell structure in the LSS, e.g. Doublet • Increase dipole strength in the arc in order to gain one cell more for the LSS (7 cells) for same circumference • More detailed H- -injection design! PS2 Meeting: Inj/Extr Layout

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