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LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki1 Ion commissioning in the SPS D. Manglunki presenting the work of M.Albert, G.Arduini, Ph.Baudrenghien,

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Presentation on theme: "LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki1 Ion commissioning in the SPS D. Manglunki presenting the work of M.Albert, G.Arduini, Ph.Baudrenghien,"— Presentation transcript:

1 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki1 Ion commissioning in the SPS D. Manglunki presenting the work of M.Albert, G.Arduini, Ph.Baudrenghien, G.Bellodi, P.Beloshitsky, E.Benedetto, Th.Bohl, C.Bracco, H.Braun, R.Bruce, C.Carli, E.Carlier, M.Chanel, H.Damerau, B.Dehning, S.Gilardoni, S.Hancock, B.Holzer, D.Jacquet, J.Jowett, L.Jensen, V.Kain, D.Küchler, M.Martini, E.Métral, S.Maury, L.Normann, S.Pasinelli, G.Papotti, S.Redaelli, M.Schokker, R.Scrivens, J.L.Vallet, B.Vandorpe, J.Wenninger, U.Wehrle, Th.Weiler, C.Zamantzas, and Linac, LEIR, PS & SPS operations teams

2 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki2 Outline Reminders: Parameters, Nominal scheme, early scheme Actions performed on injector chain since last December (LHCMAC20) SPS commissioning –Injection, acceleration, extraction of Early beam –Collimation studies –Issues on front porch Progress towards nominal beam –LEIR –PS –SPS Beam requests for –Source + Linac 3 (2008) –PS, SPS (2008 or 9?)

3 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki3 Reminder: key parameters (Nominal beam) ECR Source Linac 3LEIRPSSPSLHC Output energy2.5 KeV/u4.2 MeV/u72.2 MeV/u5.9 GeV/u177 GeV/u2.76 TeV/u 208 Pb charge state Output B [Tm] bunches/ring 2 (1/8 of PS) ions/pulse ions/LHC bunch bunch spacing [ns]100 (norm. rms) [ m] phys., rms) [ m] Repetition time [s] ~50~10fill/ring

4 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki4 Reminder: Nominal scheme (L=1E27cm -2 s -1 ) LEIR PS after splitting SPS at injection (43.2 s flat-bottom), after 13 (12, 8) transfers from PS SPS at extraction, after 13 (12, 8) transfers from PS LHC at injection, after 12 transfers from SPS ( Pb ions / 3.6 s) Pb ions / (future) LHC bunch * = 0.5 m -> L = cm -2 s -1 Harmonic number / Frequency – MHz 400 MHz 4 injections

5 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki5 Reminder: Early scheme (L=5E25cm -2 s -1 ) LEIR PS at injection and acceleration TT2 after stripper SPS at injection (7.2 s flat-bottom), after 3 (4) transfers from PS SPS at extraction, after 3 (4) transfers from PS LHC at injection, after 16 transfers from SPS ( Pb ions / 2.4 s) 1 1 Nb of bunches 1 3 (4) about 60 * = 1 m -> L = cm -2 s -1 Harmonic number / Frequency MHz 400 MHz Pb ions / (future) LHC bunch PS at extraction 1 injection

6 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki6 Done in 2007 in view of the Early Beam (List of Actions MAC Dec 2006) LEIR –Improve intensity reliability/reproducibility Intensity OK (1.2E10 charges/ 2.2E8 ions) Run routinely from CCC (LEIR OP daytime, SPS OP nights & week-ends) L = 40meVs/n >> 25meVs/n H ~0.5 m, V ~0.18 m, Extraction efficiency > 80% synchronized to PS energy matched

7 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki7 Done in 2007 in view of the Early Beam (List of Actions LHCMAC 20) PS –RF: radial loop pick-up sensitivity boost by 12dB (most probable cause of the ~30% losses seen at the start of acceleration) Done; but also other debugging helped improve losses: - frequency programme - crosstalk from synthesizer dedicated to ions 30dB attenuation Ch1: Radial position Ch2: Phase discriminator Ch3:Beam current transformer Ch4: Resistive wall pick-up Ch1: Resistive wall pick-up Ch2: Phase discriminator Ch3: B-train up Ch4: B-train down

8 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki8 Done in 2007 in view of the Early Beam (List of Actions LHCMAC 20) PS –Controls ABS PPM copy –Power supply for F16.QFO205 in TT2 –Cooling water for PI.SMH26 –Modification of stripper movement acquisition (outside vacuum) ABS reactivated PPM copy works Upgraded to 450A for full low beta Modified, no intervention needed any more prior to dedicated MDs Modified, easier maintenance

9 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki9 Also done in 2007 Source –improved performance and stability –operation with Pb 29+ reduced radiation from the linac tanks –operation with two ovens not as effective as expected (factor 1.5 instead of 2 in operation time) –reduced lead consumption to ~ mg/h But lack of oven spare parts gave some troubles during the last oven refills –hexapole and complete set of solenoids ordered (most critical spare parts concerning delivery time) Linac 3 –new performance record: 31 e A of Pb 54+ out of the linac (but needs more stability) –read back of ramping/debuncher cavities installed (was write-only) –remote reset installed for tank2 and 3 (no more car trip needed from CCC) – modified stripper mechanism (no more losses of stripper frames) TT2/TT10 –Complete rematching with full low beta scheme

10 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki10 SPS commissioning programme Planned: –Injection, acceleration, extraction of Early beam –IBS & space charge studies on front porch at 17 Z GeV/c with nominal intensities –Collimation studies at 270 Z GeV/c with nominal intensities –Slow extraction to North Area for crystal channeling studies Achieved: –Early Beam: Injection of 4 bunches, capture, acceleration, extraction Extraction at low intensity No synchronization –IBS & space charge studies data still under analysis Alternate schemes under study for nominal beam –Collimation: loss maps at 17 & 270 Z GeV/c Partly at low intensity

11 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki11 Achieved/Planned MD time: –12 days (vs ~35) parallel –7x24h (ok) + 1x8h (vs 3x8h ) dedicated Issues and Problems encountered: –Linac 3 Source Quad in transfer line –LEIR RF cavities –PS New ion cycle PFWs & W8L trips Stuck beam stopper Vacuum leak on dump 48 –TT2 QDE207 (wrong polarity, frequent trips) –SPS Late delivery of RF hardware (priority of LHC protons) Injection kicker prepulse distribution, conflicts with LHC p+ & CNGS) 2 main magnets exchanges Long setting up for each cycle, only 1 user for 3 cycles SPS MDs in 2007

12 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki12 3 SPS Cycles / 1 user Parallel MD cycle –allowed to perform first injection, debug hardware, prepare acceleration –Single injection flat bottom –acceleration through transition (up to 70 Z GeV/c) EARLY LHC filling cycle (dedicated) –1-4 injections –acceleration to 450 Z GeV/c –extraction –with coastable flat bottom Loss maps studies cycle (dedicated) –1-4 injections –270 Z GeV/c coastable plateau

13 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki13 Up to 4 injections Lower intensity but brighter than expected Q SC = on flat bottom (!) Transverse IBS growth times ~ 3 minutes Stable IBS longitudinal (growth time ~ -2 minutes) Early beam at SPS injection ParameterDesignAchievedUnit I (*) E9 charges H m V m // eVs/u B 43.6 ns p/p E-3

14 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki14 New working point Qh = (26.13) ; Qv = (26.19) VRF dips from 3.5Mv to 2.6 MV at each injection Bunch shortening observed during flat bottom Flat bottom

15 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki15 81% transmission 23% total front porch loss 12% uncaptured beam (capture loss, loss along flat bottom) Flat bottom and acceleration

16 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki16 Flat Top

17 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki17 Benefited from TI2 test the preceding week-end –Same magnetic rigidity etc… first time right! –Allowed to measure extracted beam properties No synchronization of extracted beam (yet) (*) Extracted beam was ~20% of design value due to vacuum leak in PS, but 90% design intensity had been accelerated 2 weeks before extraction Extraction to TT60 ParameterDesignAchievedUnit I 30 6 (*) E9 charges N (*) E8 ions H 6E-3.mm.mrad V 6E-3.mm.mrad H 1.2 m V m

18 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki18 LHC secondary collimator prototype installed in SPS (2 independent carbon jaws in horizontal plane) Jaws moved in and out during operation BLM signals recorded from all 216 monitors in the ring September 2007: LHC BLMs installed on predicted ion- specific loss locations Collimation studies

19 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki19 Collimation studies: 17 Z GeV/c Ions Protons Zoom on sector 5 Zoom on BLMs after collimator, ions Measured signal Sim. # nucl. lost close to BLM (norm.) Good qualitative agreement, but exact ratio not matching. Could be because the amount of material between loss and BLM differs! More simulations needed

20 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki20 Collimation studies: 270 Z GeV/c protons (nov. 2006) Zoom on sector 5 protons ions Zoom on BLMs after collimator Measured signal Sim. # nucl. lost close to BLM (norm.) ions

21 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki21 Method: coasts at injection energy and measure: –Emittances with wire scanner Alternating planes manually, every cycle Correct for blowup by multiple scattering in each wire scan –Longitudinal bunch profiles –Beam Current Transformer (DC and fast) Scanned horizontal and vertical tunes Varied intensity (once) at LEIR level Correlation of different instruments not straightforward => Long analysis process => Preliminary data Space charge and IBS studies on front porch

22 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki22 Transverse emittance: –No dramatic blow-up seen on good coasts at injection energy –Need better fitting than in online program Space charge and IBS studies on front porch Longitudinal Profiles: –Bunch typically loses half intensity in about minute (actual movie time = 2)

23 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki23 Lifetime seems adequate for Early scheme, not so clear for Nominal Loss mechanisms not yet clearly identified (RF noise?) Analysis continuing for emittance Correction of measurements for multiple scattering on wire Space charge and IBS studies on front porch

24 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki24 Progress towards nominal beam: LEIR I~ 4x10 10 charges acceleratedI~ 4x10 10 charges accelerated h=2h=2 bunches<200nsbunches<200ns l <50meVs/n/b l <50meVs/n/b h ~0.5 m, v ~0.18 m h ~0.5 m, v ~0.18 m

25 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki25 Progress towards nominal beam PS: No effort possible on nominal beam in 2007 (priorities) SPS : Current studies to get rid of 43.2s plateau –Nominal beam in LEIR and PS –Shorter flat bottom in SPS 10.8 s for 4 injections 18.0 s for 6 injections –Up to 80% of Nominal current with same LHC filling time ~650s/ring –ALICE studying 75ns possibility

26 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki26 Summary 2007 LEIR –Improved diagnostics –Reliably run from CCC –Progress towards nominal beam PS: –New cycle with lower intermediate plateau –Lots of debugging, improved transmission –Finalized low-beta optics; complete rematching of transfer line –No effort possible on nominal beam (priority to proton and early beams) –Vacuum leak at end of run SPS: –RF hardware late delivery; first 2 dedicated MD sessions replaced by magnet repair –Injection, acceleration, extraction of early beam –Loss maps studies at 17 and 270 Z GeV/c –Studies of beam behaviour on injection plateau –No time for slow extraction in North Area (crystal channeling)

27 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki27 Requests for 2008: 4 -6 weeks source & Linac 3 Source –Commission 18GHz –commissioning of the source with the 18 GHz generator – to better understand the source behaviour need of a more elaborate source development programme (oven, bias disk) –improve radiation shielding –improve situation of spare parts –replacement of both source extraction turbo molecular pumping systems (no more spares for the controllers available), –the pumps will be exchanged if they fail Linac 3 –replacement of the Bruker power converter (ITL, ITM) by a modular –solution, budget not yet approved –new vacuum control system to be implemented during the shutdown 2007/08 –prepare remote reset of RFQ and tank1 –finish work on the software/hardware of the ramping cavity –if possible emittance measurements with pepper pot system from KVI/Groningen in the ITL

28 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki28 Requests for 2008 (or 2009?) 8 weeks for LEIR LEIR –Injection studies mismatch, acceptances –Digital Low level RF –Voltage feedback –Finalise nominal beam –Better understanding of machine chromaticity, lattice deviations, tests of different tunes… –Cooling not fully tested and measured lifetime and cooling rate depending on current, electrons distribution; systematic measurements needed –Understand extraction efficiency –Study betatron matching with PS –Full control of Linac3 ramping & debuncher cavities, bumper parameters. –Many applications to write for improving operation spectra analysis, BIPM measurements, ecool beam trajectory, tune measurement, … –Transformers acquisition for beam survey and vistar –Add transfer lines in LSA?? –RF HV Power supplies: finalise solution

29 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki29 Requests for 2008 (or 2009?) >3 weeks PS (party in parallel with LEIR?) PS RF: –Second iteration for frequency programme –Test new hardware (being built this shutdown) for 423-divider ejection synchronization –RF gymnastics for nominal beam

30 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki30 Requests for 2008 (or 2009?) 6 weeks for SPS SPS RF: (4 weeks parallel + 4 dedicated sessions) –reproduction of results of 2007 with definitive hardware and software –synchronization with LHC at flat top –longitudinal emittance blow-up Full extraction of early beam to both TI2 and TI8 Slow Extraction to North Area for crystal channeling studies Note: ALICE is still requesting 2 weeks of ions at the end of the first p+ run –… and is interested in a low energy run in any case! (highest collision energy for heavy ions, even at injection)

31 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki31 Spare slides :

32 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki32 In view of the Nominal LHC Ion Beam (List of Actions MAC 2006) 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.

33 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki33 Alternative schemes LEIR PS after splitting Nominal SPS at injection: 10.8 (18.0) s flat-bottom, after 4 (6) transfers from PS LHC at injection, after 30 transfers from SPS ( Pb ions / 3.6 s) Pb ions / (future) LHC bunch injections –Nominal beam in LEIR and PS –Shorter flat bottom in SPS 10.8 s for 4 injections 18.0 s for 6 injections –Up to 80% of Nominal current with same LHC filling time ~650s/ring –ALICE studying 75ns possibility

34 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki34 SPS commissioning period Planned: –29/8 - 12/11 in parallel –3x8h + 7x24h dedicated Used: –< 12 days parallel –1x8h + 7x24h dedicated

35 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki35 New PS Cycle B =21.7 Tm h= splitting h 24 h=24 21 (10MHz) 4 bunches B =86.7 Tm h= (80MHz) 4 bunches 0.05 eVs/n ions total T [ms] B [Tm] B =4.8 Tm, h=16, 2 bunches, 0.05 eVs/n ions total An intermediate plateau is required for the rf gymnastics of the nominal scheme. For beam lifetime reasons, this was introduced at the highest possible energy.

36 LHC Machine Advisory Committee, Dec 7 th, 07D. Manglunki36 Schedule 2008 (?) Accelerate and extract full EARLY beam Synchronize to external frequency (LHC) Crystal collimation studies in North Area More collimation studies at 270 Z GeV/c


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