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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 1

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 2008-2009 – Source + Linac 3 (2008) – PS, SPS (2008 or 9?) LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 2

Reminder: key parameters (Nominal beam)

Output energy 208 Pb charge state Output B r [Tm] bunches/ring ions/pulse

ions/LHC bunch

bunch spacing [ns] e * (norm. rms) [ m m] e ( phys., rms) [ m m] Repetition time [s]

ECR Source

2.5 KeV/u 29+ 9 10 9

1.1 10 10.

Linac 3

4.2 MeV/u 29+  54+ 2.12  1.14

1.15 10 9

1.45 10 9 LEIR

72.2 MeV/u 54+ 4.80

2 (1/8 of PS) 9 10 8

2.25 10 8

0.07

30 0.2-0.4

0.25

2.6

0.2-0.4

0.7

1.75

3.6

PS

5.9 GeV/u 54+  82+ 86.7  57.3

4 4.8 10 8

1.2 10 8

100 1.0

0.14

3.6

SPS LHC 177 GeV/u 82+ 1500

52 4.7 10 9

9 10 7

100

1.2

0.0063

~50 2.76 TeV/u 82+ 23350 592 4.1 10 10

7 10 7

100 1.5

0.0005

~10’fill/ring LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 3

Reminder: Nominal scheme (L=1E27cm

-2

s

-1

)

LEIR 4 injections (9 10 8 Pb ions / 3.6 s) 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 b

* = 0.5 m -> L = 10 27 cm -2 s -1

Pb ions / (future) LHC bunch 12 10 7 9 10 7 7 10 7 2.25 10 8 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 4

Harmonic number / Frequency 2 16–14-12-24 24-21 -169-423 200 MHz 200 MHz 400 MHz

Reminder: Early scheme (L=5E25cm

-2

s

-1

)

LEIR 1 injection ( 2.5

10 8 Pb ions / 2.4

s) Nb of bunches 1 Pb ions / (future) LHC bunch 2.5 10 8 PS at injection and acceleration 1 PS at extraction 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 1 3 (4) 3 (4) about 60 b

* = 1 m -> L = 5 10 25 cm -2 s -1

1.2 10 8 9 10 7 10 7 7 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki

Harmonic number / Frequency 1 16 16 + 169 200 MHz 200 MHz 400 MHz

5

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) e L e H = 40meVs/n >> 25meVs/n ~0.5

m m, e V ~0.18

Extraction efficiency > 80% synchronized to PS energy matched m m, LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 6

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: Resistive wall pick-up Ch2: Phase discriminator Ch3: B-train up Ch4: B-train down Ch1: Radial position Ch2: Phase discriminator Ch3:Beam current transformer Ch4: Resistive wall pick-up LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 7

Done in 2007 in view of the Early Beam (List of Actions LHCMAC 20) • PS

– Controls  ABS  PPM copy ABS reactivated PPM copy works – Power supply for F16.QFO205 in TT2 – Cooling water for PI.SMH26

– Modification of stripper movement acquisition (outside vacuum) Upgraded to 450A for full low beta Modified, no intervention needed any more prior to dedicated MDs Modified, easier maintenance LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 8

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 ~1.0-1.5mg/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 m 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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 9

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   No synchronization – IBS & space charge studies  Extraction at low intensity data still under analysis  Alternate schemes under study for nominal beam – Collimation: loss maps at 17 & 270 Z GeV/c  Partly at low intensity LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 10

SPS MDs in 2007

• Achieved/Planned MD time: – 12 days (vs ~35) parallel – 7x24h (ok) + 1x8h (vs 3x8h ) dedicated • Issues and Problems encountered: – Linac 3 – PS   Source Quad in transfer line – LEIR  RF cavities     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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 11

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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 12

Early beam at SPS injection

Parameter I

e *

H

e *

V

e

//

t

B

D

p/p Design 9.8

1.0

1.0

0.05

4 1.2

Achieved 8.9 (*) 0.8

0.8

0.03

3.6

0.9

Unit E9 charges

m

m

m

m eVs/u ns E-3

• Up to 4 injections • Lower intensity but brighter than expected • D Q SC = 0.092 on flat bottom (!) • Transverse IBS growth times ~ 3 minutes • Stable IBS longitudinal (growth time ~ -2 minutes) LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 13

Flat bottom

• New working point Qh = 26.20 (26.13) ; Qv = 26.25 (26.19) • VRF dips from 3.5Mv to 2.6 MV at each injection • Bunch shortening observed during flat bottom LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 14

Flat bottom and acceleration

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

Flat Top

LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 16

Extraction to TT60

• 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

I Parameter N

e

H

e

V

e *

H

e *

V Design 30 3.6

6E-3 6E-3 1.2

1.2

Achieved 6 (*) 0.7 (*) 6E-3 6E-3 1.2

1.2

Unit E9 charges E8 ions

p

.mm.mrad

p

.mm.mrad

m

m

m

m

LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 17

0.08

X 0.06

0.04

0.02

0.02

0.04

0.06

0.08

Collimation studies

• 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 5250 x m 0.08

0.06

0.04

0.02

5275 0.02

0.04

0.06

0.08

5300 5250 5275 5325 5300 5350 5325 5350 5375 5375 5400 5400 LHC Machine Advisory Committee, Dec 7 th , ‘07 S m S D. Manglunki 0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.12

0.14

AX AX 18

Collimation studies: 17 Z GeV/c

Zoom on sector 5 Zoom on BLMs after collimator, ions Sim. # nucl. lost close to BLM (norm.) Measured signal Ions Protons • Good qualitative agreement, but exact ratio not matching.

• Could be because the amount of material between loss and BLM differs!

• More simulations needed LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 19

Collimation studies: 270 Z GeV/c

Zoom on sector 5 ions Zoom on BLMs after collimator Sim. # nucl. lost close to BLM (norm.) Measured signal ions protons (nov. 2006) LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki protons 20

Space charge and IBS studies on front porch

• 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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 21

Space charge and IBS studies on front porch

• Transverse emittance: – No dramatic blow-up seen on good coasts at injection energy – Need better fitting than in online program • Longitudinal Profiles: – Bunch typically loses half intensity in about 1-1.5 minute (actual movie time = 2’) LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 22

Space charge and IBS studies on front porch

• 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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 23

Progress towards nominal beam: LEIR

• • • • • I~ 4x10 10 charges accelerated h=2 bunches<200ns e l <50meVs/n/b e h ~0.5

m m, e v ~0.18

m m LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 24

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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 25

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) LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 26

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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 27

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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 28

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 LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 29

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) LHC Machine Advisory Committee, Dec 7 th , ‘07 D. Manglunki 30