1 / 12

Achieving Nominal Ion Beam PS Ion Progress

Achieving Nominal Ion Beam PS Ion Progress. C. Carli and D. Manglunki on behalf of the I-LHC team. Status: LEIR PS SPS In view of the Early LHC Ion Beam: Actions In view of the Nominal LHC Ion Beam: Actions Present Planning. Status (LEIR). Comments on the autumn 2006 run:

nellis
Télécharger la présentation

Achieving Nominal Ion Beam PS Ion Progress

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Achieving Nominal Ion BeamPS Ion Progress C. Carli and D. Manglunki on behalf of the I-LHC team • Status: • LEIR • PS • SPS • In view of the Early LHC Ion Beam: • Actions • In view of the Nominal LHC Ion Beam: • Actions • Present Planning C. Carli & D. Manglunki

  2. Status (LEIR) • Comments on the autumn 2006 run: • Vacuum leaks during preparations for the run: • (leak of high voltage feed through, exchange of electron cooler gun, bake-out incident, leak on cooler collector, … finally fixed with UHV varnish), • Thanks for all the efforts (workshop, AT/VAC teams, e-cooler team) • Magnetic cycle generation: temp. difficulties to make new lattice data available • Solved thanks to efforts from the LSA team. • Low level RF • re-commissioning (during “normal” start-up, had been considered an issue), • continuous development during run. • Very limited support from OP • AD run extended throughout PS commissioning • Strong perturbations of the start-up (and the run). • Early beam available without particular difficulties: • Apart injection efficiency fluctuations due to PS stray field (-> LEIR performance depending on PS cycle) • Some diagnostics missing/difficult: • ionisation profile monitors, profiles in ejection line, “old” system for Schottky diagnostics…. C. Carli & D. Manglunki

  3. Status (LEIR) • 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 C. Carli & D. Manglunki

  4. Status (LEIR) • 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 some 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 ? …) C. Carli & D. Manglunki

  5. PS status • Planned (Aim at Early Beam, but hope to produce “quasi-nominal” beam): • 21 days of parallel MD time (daytime only) • 5 (out of 6 requested) periods of 8 dedicated hours • Achieved: • 15 days of parallel MD time • In spite of difficult startup, LEIR beam only delayed by 2 days • 4 days lost by subsequent breakdowns/faults from LINAC 3, LEIR, MPS • 5 periods of 6 dedicated hours • Interventions inside PS (+30’ cooldown) needed for PI.SMH26 cooling and outside PS for F16.QFO205 control at beginning and end of each MD (see below) • Issues and Problems encountered: • SEMgrids in PS and TT2 (OK now) • Doubt on stripper movement (see shutdown work) • Recheck quadrupole polarities in TT2 (done during MD) • Insufficient current from one power supply (F16.QFO205) for low-b scheme440A needed, 330A available, 400A available for dedicated MDs (see shutdown work) • New extraction optics from 2007 onwards (no PE.QKE58) • Java console Manager problems with PPMcopy, polluted CCVs • No Automatic Beam Steering (ABS) in TT2 • Only 2 users (LHCION and MDION), 3 needed (Early, Nominal , Flat) • Resources mobilised by LHC proton beamS C. Carli & D. Manglunki

  6. PS status: Early beam [1] • Injection (in parallel) • First time right with computed currents • Lifetime measurements (in parallel) • Excellent vacuum + ion species => t>>700ms • LEIR-PS matching (2 dedicated MDs) • Still some V mismatch • Acceleration/Transition/Synchro • Only losses (25-50%) at field rise • All done in parallel whilst providing MD&OP beams • Ejection with old then new optics C. Carli & D. Manglunki

  7. PS status: Early beam [2] • (Limited) Low-b validation and Matching to TT2 (3 dedicated MDs) • Bonus: Transport through TT10 at the end of last dedicated MD • Thanks to LSA, no instrumentation • Design parameters practically achieved for Early Beam, but more stability needed H=10.2 m V=6.9m C. Carli & D. Manglunki

  8. PS status: Nominal beam (RF) • Reminder: same intensity/bunch as Early, but lots of gymnastics: • Batch expansion H16 -> H14 -> H12 • Splitting H12 -> H24 • Batch expansion 24 -> H21 • Transition crossing, synchro to SPS and rebucketing at H169 as for Early Beam • Insufficient pick-up sensitivity to permit the radial loop to be closed until ~100ms after injection. • One 80MHz cavity is required for rebucketing, tuned to a different frequency from that for LHC protons. (i.e. no spare cavity for p+) • Sampled measurement of harmonic number did not work at the very lowest energies (realtime task?). • Splitting difficult at chosen energy (short bunches due to proximity to transition ). Good measured lifetime indicates we can lower it for the next attempts in 2007 • Control of the relative phasing between the different harmonic components of the 10MHz system is an issue that must be addressed • Several more MDs will be required to complete the work on the nominal beam. C. Carli & D. Manglunki

  9. SPS Status • Early beam was sent to the entrance of the machine in November • Commissioning of the LHC ion beam planned for autumn 2007 • Early LHC ion beam seen just upstream from SPS injection • Issues: • Complete the low level RF system on time for next autumn • Resources: time and manpower for ions while preparing LHC proton startup C. Carli & D. Manglunki

  10. In view of the Early LHC Ion Beam(List of Actions) • The Early beam has been produced in LEIR • Improve intensity reliability/reproducibility • Upgrades in the PS (planned for shutdown 06-07): • RF: radial loop pick-up sensitivity boost by 12dB (most probable cause of the ~30% losses seen at the start of acceleration) • Controls: ABS, PPM copy • Power supply for F16.QFO205 in TT2 • Cooling water for PI.SMH26 • Modification of stripper movement acquisition (outside vacuum) • SPS: beam knocked at the door but everything remains to be done; extensive dedicated MD period scheduled for autumn 2007 • Inject on flat bottom, measure lifetimes • Accelerate through transition, synchronize on external frequency • Extraction C. Carli & D. Manglunki

  11. In view of the Nominal LHC Ion Beam(List of Actions) • Produce the Nominal beam in LEIR: • Improved diagnostics: • Renovate emittance measurement in the ring (ionization profile monitors), • Renovate emittane measurements of the LEIR to PS transfer line, • Verification of transverse dampers (and maybe other systems), • Increased Linac 3 current will help • Thorough (needs sufficient resources) optimizations (electron cooling, injection ……) and investigations to: • Produce the nominal LEIR beam and/or, • Understand and cure limitations. • Nominal scheme in the PS: • Complete the setting-up of the RF gymnastics (many harmonic number changes, “re-bucketing”, bunch splitting): • Can mostly be done with lower intensity, • Verification that it works with the nominal parameters (measure ejected beam). • SPS: • Investigate limitations (tune spreads, IBS) as soon as possible (autumn 2007) with “early beam” (nominal bunch population, just a longer plateau needed), • Leaves time to implement cures, in case limitations are encountered, • Setting up of accumulation of up to 52 LHC ion bunches of the nominal beam. C. Carli & D. Manglunki

  12. In view of the Nominal LHC ion Beam (Present Planning …) • Autumn 2007: • In draft 2007 Accelerator Schedule: • Commissioning of the early beam in the SPS • MDs to investigate limitations of the SPS (IBS, DQSC) with the nominal beam scheduled • MDs to investigate limitations of the LHC (collimators) with the nominal beam proposed/scheduled. • In addition: • Studies in view of the nominal LHC Ion beam in LEIR, • Work on nominal scheme in the PS (resources ?) • MDs to be planned for 2008 • First LHC ion run with early scheme in 2009 C. Carli & D. Manglunki

More Related