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04/10/2013 New injection system - concept

LIU-SPS 50 ns Pb ion injection system review. 04/10/2013 New injection system - concept

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04/10/2013 New injection system - concept

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  1. LIU-SPS 50 ns Pb ion injection system review 04/10/2013 New injection system - concept B.Goddard, O.Aberle, B.Balhan, J.Borburgh, E.Carlier, K.Cornelis, L.Ducimetière, L.K.Jensen, T.Kramer, D.Manglunki, A.Mereghetti, V.Mertens, D.Nisbet, B.Salvant, L.Sermeus, J.Uythoven, F.Velotti

  2. Motivation • Strong request from LIU-ION to study improving injection rise time, to 50 ns • For Pb ions only • Keeping existing injection energy for ions (rigidity of 60 Tm) • Not impacting negatively on injection for p+ or other ions • Flat top to allow injection of 4 bunches at 50 ns spacing (i.e. ~160 ns) • “Acceptable” emittance growth (can assume damper) – so 2-98% rise-time to respect in B field

  3. SPS injection • LHC p+ injection (26 GeV/c) uses all kickers, at 52.0 kV (225 ns) • CNGS p+ injection (14 GeV/c) uses MKPA/C, at 49.2 kV (< 1000 ns) • Pb82+ ion injection (17 GeV/c per charge) • used MKPA/C, at 52 kV for Q26 (200 ns) • uses all kickers at ~40 kV for Q20 (225 ns) • TBSJ is injection dump (use MDSH119 to improve centering) MSI TBSJ MKP MKPAC

  4. Present ion injection • Present “ion” kickers type MKP-S • Were designed to reach 115 ns (with PFLs, never installed…) • Measured at <150 ns (2-98%) with present PFNs • Need also to use “LHC p+” MKP-L kickers for Q20 • Imposes 225 ns rise-time • Look at split tunes, or back to Q26 for ions, to reach 150 ns with present layout • Addition of PFLs to the present MKP-S magnets is possible (already foreseen in BA layout) • Will give 125 ns for sure, maybe 100 ns • No additional tunnel equipment • Kick strength then only sufficient for ≤13 GeV/c depending on optics

  5. MKP usage for ions(from discussion with Django) • 2011 • Q26 optics, use first three tanks only (MKP-S) • Pushed voltage to 52 kV and tweaked trajectories and orbits to make a 17 GeV/c be injected in a system which was designed for 13 GeV/c • Rise time used was 200 ns • The MKP-S measured rise time 2 % - 98 % is 148 ns. See later slide from 2000. • 2012 • Q20 optics – less help from quad in front of MKP • Used the fourth tank (MKP-L) as well, which was not modified 13 years ago • Rise time used, as for LHC protons: 225 ns, due to the slower MKP-L

  6. Concepts studied • Rebuild entire injection kicker system • Add thin pulsed septum and rebuild entire injection kicker system • Add separate new ion kicker and new thin pulsed septum, for ion injection only • Add PFLs to existing kickers, with new thin pulsed septum • Do nothing to existing kickers, either with or without new thin pulsed septum

  7. Option (i) • Rebuild existing magnets completely • Higher impedance (16.6 -> 25 Ohm) • Much shorter magnets (0.6-0.7 -> 0.28 m) • Many more individual magnets (12 -> 48) • Much longer magnetic length needed (8 -> 12 m) • No aperture for dumping p+ beam • Extremely expensive even if possible • Discarded: does not look feasible • Many integration issues • Many technical issues • No aperture for dumped beam • Huge cost and investment even if solutions could be found

  8. Option (ii) • Add thin in-vacuum septum and rebuild existing MKP, with rearrangement of layout • Only need to rebuild a subset of the MKP • Same issues with very short 28 cm magnets • More issues with magnet aperture (vertical gap not enough) • No solution found to dump p+ beam cleanly • Discarded: does not look feasible • Some integration issues • Some technical issues • Aperture limits in vertical plane • No way to dump p+ beam • Large cost and investment

  9. Option iii: the minimalist • Don’t change anything and we can probably go down to 150 ns rise time (2 – 98 %) • If we want to have more margin / less tweaked orbits and trajectories one can install the MSI-V, but might not be strictly necessary • In this case the installation of an ion injection dump might be nice to keep it ‘clean’ • Without MSI-V Q20 clearly makes things more difficult – try split tunes? • More work on the MKP-S front cells in the PFN might make it possible to go down to 125 ns rise time • Would be available for tests after LS1

  10. Option iv: the intermediate • To go below 125 ns kicker rise time, aiming for 100 ns kicker rise time (2 – 98 %): install a PFL in parallel to the present PFNs on the MKP-S system. • No kicker magnets to be installed in the tunnel • This reduces the maximum voltage on the PFL to 40 kV and the installation of the MSI-V becomes obligatory • With MSI-V no problems with Q20 optics • The switching between PFN and PFL requires development and lab tests • Injection dump for ions would be nice, to control losses

  11. Option v: the full monty • Install the new MKP-I magnets & MSI-V • If all works well this would allow for a rise time of 75 ns (2 – 98 %). But not easy and a lot of work • Adds impedance to the machine – beam dynamics, and risk of kicker heating • Not sure that impedance shielding is possible with this rise time • New kickers and cables needed in highly radioactive zone downstream of TIDVG • Ion injection dump again needed, to stay clean

  12. Option v Layout in SPS MSI-V MKP-I

  13. Option v 17 GeV/c/u Pb82+ ionswithout injection bump

  14. Option v 14 GeV p+ (as done today)

  15. Option v • Could conceivably have a dump block in a new location just upstream QD.121 • Could misalign MBB.12070/90 by -10 mm in H ~1.4 m available

  16. Option v

  17. Considerations • Performance reach is one important aspect • Others are • Required effort level (resources, cost) vs. benefit • Radiation doses for installation, operation and maintenance • Technical risk • Compatibility with injection of p+ beams (aperture) • Compatibility with HL-LHC beams (impedance)

  18. LSS1 is a very active area… MSI-V MKP-I TBS-I TIDVG

  19. Summary of performance/costs

  20. fin

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