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LEIR Status

LEIR Status. C. Carli and M. Chanel on behalf of the LEIR and I-LHC team. General Comments on the Autumn 2006 LEIR Run What has (not) been achieved: Early LHC ion Beam Matching LEIR -> PS In view of the Nominal Beam Low level RF Schottky Diagnostics at high energy Conclusions Lessons

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LEIR Status

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  1. LEIR Status C. Carli and M. Chanel on behalf of the LEIR and I-LHC team • General Comments on the Autumn 2006 LEIR Run • What has (not) been achieved: • Early LHC ion Beam • Matching LEIR -> PS • In view of the Nominal Beam • Low level RF • Schottky Diagnostics at high energy • Conclusions • Lessons • Detailed “To do list” (for completeness) LEIR Status

  2. General Comments on the Autumn 2006 LEIR Run • Vacuum leak(s) before and at the beginning: • Leak on a high voltage feed through (ion pump) detected on August 28th, • Preparation to exchange the electron cooler gun (known problem in this sector), • Bake-out between weeks 37 and 38, • Incident (heating of the cooler collector to >400 deg.) on September 19th, • Vacuum leak on collector – differential pumping (no varnish precaution) -> vacuum o.k., but sparks at the outside, • All PCs available on September 25th (should start with beam), • “Definite” fix (saving the run) with UHV varnish on October 4th by the SPS vacuum team (several leaks detected), • Thanks for all the efforts (workshop, AT/VAC teams, e-cooler team) • Magnetic cycle generation: • Test started at beginning of September, • Difficulties to make new lattice data available -> restart with old “LSA-supercycles” (system still in development !), • Efforts from the LSA team were crucial for us (thanks !). LEIR Status

  3. General Comments on the Autumn 2006 LEIR Run • Circulating beam again on September 26th (but no electron cooling !!). • Low level RF (new generation fully digital, by M.E. Angoletta & Co) • re-commissioning (during “normal” start-up, had been considered an issue), • continuous development during run. • Electron cooling: • Available on October 5th (after fix of the collector leak) only, • Cooling observed immediately. • LEIR beam circulated for the first time in PS on Thursday, October 12th: • almost on time – a miracle !! (planning: LEIR beam available on October 9th). • Until the end of the run (November 20th): • operational machine providing ion beam (h=1 AND later h=2) to the PS, • various machine studies in parallel. • Very limited support from OP LEIR Status

  4. What has (not) been achieved • Early beam: • Obtained (after sorting out technical problems – vacuum, cycle generation …) relatively easily, without too much readjustments, • LEIR is reproducible (like e.g. the PSB) apart injection line in PS tunnel, • One Linac 3 shot (> 22 mA) just sufficient. OASIS acquisition on October 9th LEIR Status

  5. What has (not) been achieved • Matching LEIR -> PS (and transverse emittances): • difficult due to the state of the instruments, • dedicated PS MD on Oct. 18th: “large” dispersion mismatch, • dedicated PS MD on Oct. 25th: almost perfect in horizontal, but strong vertical mismatch !! Vertical Profiles in PS ring (October 18th) Horizontal Profile on ETL.MSF10 (November 17th) LEIR Status

  6. What has (not) been achieved • In view of the nominal beam (schedule: “first exploratory studies”): • Nominal intensity accumulated, • Losses (not understood) at beginning of ramp, emittances NOT measured !! • Further studies (availability of measurements) required !! • Best we could obtain with the available resources. 80% of nom. intensity accelerated on Oct. 13th Nom. intensity at end of accumulation on Oct. 13th LEIR Status

  7. What has (not) been achieved • Low Level RF system: • “Pilot system” for a new generation of fully digital systems, • After re-commissioning, h=1 and h=2 operational beams provided for PS • “In the shadow”, continuous development of the system, • System very well advanced (close to completion), • Still to do: completion (diagnostics …) and transfer to operations. PU and transformer traces of a correctly synchronized h=2 beam LEIR Status

  8. What has (not) been achieved • Schottky diagnostics at high energy: • Special cycle: debunched beam on “long ejection plateau”, • Clear Schottky spectra with present (no cryogenics) system in all 3 planes. Vertical Schottky spectrum at high energy (average over ~20 shots) (courtesy J. Tan) Special cycle for Schottky measurements at high energy LEIR Status

  9. ConclusionsLessons • LEIR operational status • reasonably reproducible (say like the PSB), • apart technical problems (vacuum ..), reasonably smooth start-up, • “early” beam for the PS provided without particular problems, • vacuum upgrades successful: studies on nominal beam not limited by life-time (small margin? – intensity saturated at less than twice the nominal one), • electron cooler works well (gun/collector spare situation is a concern). • Needs for consolidation/completion (emittance and other measurements, hardware, RF low level …) • Still a long way to have the nominal LEIR beam available: • we did the best we could with the resources and time available, • (probably) not exhaustive list of issues: • improve accumulation rate (injection, Linac 3 current …), • better understanding of transverse damper, • understand losses at beginning of ramp (acceptances/emittances in all three planes, tune spreads ? …) LEIR Status

  10. Conclusions(detailed “to do list” for completeness) Detailed and (may-be still) not exhaustive “to do list”: LEIR Status

  11. Conclusions(detailed “to do list” just for completeness) LEIR Status

  12. LEIR Status

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