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Primary beam production: progress - Extraction from LSS2 - Switching from TT20 at 100 GeV. B.Goddard F.Velotti , A.Parfenova , R.Steerenberg , K.Cornelis , W.Bartmann, V.Kain, E.Carlier, A.Alekou , M.Meddahi, L.Jensen V.Mertens , Magdalena Kowalska
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Primary beam production: progress- Extraction from LSS2- Switching from TT20 at 100 GeV B.Goddard F.Velotti, A.Parfenova, R.Steerenberg, K.Cornelis, • W.Bartmann, V.Kain, E.Carlier, A.Alekou, M.Meddahi, L.Jensen V.Mertens, Magdalena Kowalska A.Kosmicki, J.Osborne, I.Efthymiopoulos
Extraction from LSS2 • Another test made on 3rd October with 100 GeV fast extraction, using MKP in LSS1. • Emittances of around 3.0 um (parasitic MD) • No losses in arc, even with ±10 mm bumps added at QFs • Next test planned 22nd October using LSS6 MKE kickers with 440 GeV beam • Cycle deployed, new working point tested, simulations made and settings defined
LSS6 -> LSS2 at 440 GeVAntiphase bump through LSS1 New SPS working point with H tune of 26.87 for 2012 test (will eventually reuse Q_split to adjust this)
LSS6 -> LSS2 at 440 GeVSimulation with aperture and envelopes 2.3 km
LSS6->LSS2 at 440 GeVExtraction point More clearance than 100 GeV beam
Switching from TT20:MBS magnets with open C-core 3.0 m magnetic length 1.65 T max field 70 mm H good field region
MBS magnet cross-section 56 mm
For TT20 switch • Only one spare 3.0 m MBS magnet exists • New series of ~10 probably required for AWAKE • For TT20 switch, need 3 new MBS magnets • 1.65 T field is possible (field quality not really any issue here) • Geometry already looks reasonable with ‘standard’ intermagnet drifts (for bellows and pumping ports)
TT20 optics and geometry changes • Can manage by removing 1 MBE (211524) from the upper bending chain MBE.211524 removed
Switch detail Will probably need to reorganise layout of MDLV and BSGV to gain ~30 cm longitudinally – no major issue
Impact of removing MBE dipole • Remove one vertical MBE dipole (8.4 mrad) • To arrive at same position in splitter for NA beams, need to trim strengths of remaining 12 dipoles in this bend (total k *13/12): • Option 1: arrange as 2+10 • One family at 74.1%, one family at 115.1% (2.096 T). New cabling and one by-pass convertor needed • Option 2: arrange as 6+6 • One family at 98.4%, one family at 118.3% (2.154 T). New cabling and 2 bypass convertors needed • Only Option 1 looks possible (MBE field maximum 2.1 T) • Unless reduce slightly beam energy for NA to keep same peak B as for SPS MBA/B (2.0475 T) • 2+10 then limits energy to 390 GeV • 6+6 then limits energy to 380 GeV
TT20 Trajectory changeUp to ~80 mm vertical realignment neededover 120 m (larger for 2+10 split) 6+6 2+10
Optics changes with new dipole layout Only visible in DY, and this negligible (advantage of keeping bend in same location) Beta functions Dispersion
More Dy perturbation with 2+10 dipoles 2+10 6+6 2+10 6+6 2012 2012
XY plane coordinates TT20 SBL
Vertical coordinates With SBL switch, arrive in similar vertical plane as top of TT20 (vertical angle compensated by rolling slightly 2nd H bend family) TT20 SBL SBL TT20
Junction considerations Splitters • A. Geometry with junction cavern • Beam angle about 130 mrad into new tunnel • Access possible between all tunnels (2 vacuum chambers to remove) • Long cavern (35 m)
Junction considerations Splitters • B. Geometry with ‘core’ • Beam angle about 115 mrad at the tunnel wall • Access along TT20 blocked • Separate access needed for new SBL line
Conclusions to date • 100 GeV LSS2 fast extraction tested: works with low intensity, large emittance. Still seems feasible. • 440 GeV to test next week from LSS6. • Switching from near top of TT20 looks possible at 100 GeV • We can use 3x MBS magnets (which need to be built) • May need to slightly rearrange MDLV corrector and BI • 1 MBE then needs to be removed from TT20 • Trajectory can be recovered without (significant) impact on optics • Needs 1(2) new power convertor(s) and recabling for remaining 12 magnets, into two new families • Vertical realignment needed of 120 m of TT20 • Other switch options/optimisations could also be possible • Coordinates for junction and start of SBL line defined • Options for cavern or parallel tunnel and core – transport?
Next steps • Extraction from LSS2 • Beam tests on 23rd October for 440 GeV extraction (LSS6 -> LSS2) • Documentation of studies and MD results • Switch zone • Check of MBE maximum fields – 2.1 T may be OK, which points to 2+10 split and 400 GeV, but might need magnet tests at 6000 A. • Develop realistic junction civil engineering (cavern better for transport) • Iterate switch if needed to fit CE constraints • TT20 transfer line • Rematching of present TT20 optics to something more reasonable for low-loss beam transport • Checks of TT20 aperture with 100 GeV FT beam • Instrumentation inventory and upgrade requirements • New SBL transfer line • Finalisation of target coordinates needed! • Design of new 100 GeV line (new student just started working with ABT)