Achieving Nominal Ion Beam PS Ion Progress

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