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

PS2 Meeting: Inj/Extr Layout 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 23-May 07 PS2 Meeting: Inj/Extr Layout

PS2 Meeting: Inj/Extr Layout Aims Injection: Fast Injection H--Injection Extraction: Fast Extraction Resonant Extraction Low-loss 5 turn continuous transfer Beam dump (assumed internal) 23-May 07 PS2 Meeting: Inj/Extr Layout

PS2 Meeting: Inj/Extr Layout FODO Lattice - LSS Betafunctions and Dispersion in the LSS: betx, bety < 42 m Dx < 10 cm 23-May 07 PS2 Meeting: Inj/Extr Layout

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!). 23-May 07 PS2 Meeting: Inj/Extr Layout

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! 23-May 07 PS2 Meeting: Inj/Extr Layout

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. 23-May 07 PS2 Meeting: Inj/Extr Layout

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 23-May 07 PS2 Meeting: Inj/Extr Layout

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. 23-May 07 PS2 Meeting: Inj/Extr Layout

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. 23-May 07 PS2 Meeting: Inj/Extr Layout

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 23-May 07 PS2 Meeting: Inj/Extr Layout

Space requirements: Beam dump 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 23-May 07 PS2 Meeting: Inj/Extr Layout

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 23-May 07 PS2 Meeting: Inj/Extr Layout

Optimum (?) fitting together with 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 23-May 07 PS2 Meeting: Inj/Extr Layout

Options for inj/extr straight without 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 23-May 07 PS2 Meeting: Inj/Extr Layout

PS2 Meeting: Inj/Extr Layout 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! 23-May 07 PS2 Meeting: Inj/Extr Layout