Injection and Extraction

• Reporting on work of many, many people who have helped design, build and commission these systems. In particular

Etienne, Jan, Jörg , Ilya, Lars, Laurent, Malika, Mike, Thomas, Verena

thanks, folks

TL and injection BI• All working well, from the very start

• One issue: could do with more BPMs through the TLs– OK when there are no problems, but complicates TI 8 studies– Propose already (this shutdown?) cabling H&V for all BPMs– Think about adding more monitors (at least in matching section)

Lars and the BI guys, plus applications

TL and injection apertures

• Thorough checks made during sector tests for injected beam• Found serious limit in LHC at VMANF.5L2• 10 mm error on valve corrected by VAC• Now looks as expected in H/V in both P2 and P8• Still checks to make with circ. beam (MSI, TDI, …)

aperture limitat VMANF.5L2

I.Agapov and madx online

TL optics matching• Main focus on dispersion mismatch from TI 8• Investigations continuing – many obvious candidates ruled out

– Presently checking ‘normal’ errors + traj correction as possible cause.– New match to better initial conditions from SPS

• Response data (until TED) and screen matching data also being used

Malika, Volker & co

MKI performance: spark on MKI.D2 (07/09/2008)

Breakdown in Magnet D : beam trajectory shows ~20% over-kick at 4:42hrs, i.e. consistent with breakdown ~60% thru magnet D.

• No beam loss before magnet spark.• Valve at exit of Q5 was first one to interlock, with a pressure rise of >1e-6, at 04:42hrs. • Valves upstream and downstream shut to isolate 2 sectors around the valve. Valve closure causes out-gassing…..

Vacuum rise @ 4:42hrsPressure in magnet D >7e-7 mbar….

• Conclusion: magnet D spark caused the vacuum rise: bunch spacing was 48s, and the bunch was over-kicked – therefore magnet broke-down before bunch arrived. • Shows real need for TDI system and for good injection protection! ~5-6 kick

Mike Barnes & BT

Injection sequencing and procedure

• Injection sequences well-sorted out

• Synchronisation and timing now looks ~stable

• Still a lot of conditions to get ready for OP beforehand– Injection kicker SoftStart– Beam permit loops– SPS and LHC modes– LBDS arming– Beam extraction from SPS– Kicker-beam synchronisation check– Beam to TED, TDI and into LHC– …

Verena, Reyes & Delphine

Steering and stability

• First steering done for B2, several mm off in vertical– Nice convergence of autopilot algorithm– To revisit to include MSI and MKI, and check apertures

• Short-term (1 h) stability looks OK at injection point on screens– P8 - measure RMS jitter of 0.27 / 0.13 nominal (cf ±1.5 spec)– Still to check P2 and long-term effects

2.1 2.15 2.2 2.25 2.3 2.35 2.4 2.45 2.5

x 104

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

Time (local)

Pos

ition

[mm

]

Beam position

LHC.BTVSI.A5R8 HLHC.BTVSI.A5R8 V

-2 -1.5 -1 -0.5 0 0.5 1 1.5 20

2

4

6

8

10

12

14

LHC.BTVSI.A5R8Positions

Position [mm]

H: rms 0.15426 mmV: rms 0.051263 mm

Jorg, Verena

Injections - present status

Beam 1 (TI2/P2) Beam 2 (TI8/P8)Transfer line optics OK Dispersion mismatchInjected beam aperture OK (after vac. re-alignment) OKKicker synchronisation OK OKInjection element strengths OK OKBeam instrumentation checks OK OKCheck injection stability Started (data to evaluate) OKInterlocks Started StartedCirculating beam aperture To do Started (TDI moved in)Injection steering To do StartedKicker waveform measurement To do To doDetailed optics matching to LHC To do To doInjection protection systems setup To do To doInjecting onto Xing/sep bumps To do To doAbort gap keeper To do To do

Extraction and dump BI• No major problems seen – BLMs, BTVs working straight away

– No time yet for systematic checks– BCT performance with kicker noise to be looked at

Lars and the BI guys

“Loss-free” B2 extraction

Logged lossesBTVSE

BTVD

BTVDD

Dump BTVs

Strengths and setttings

• In sector test #3 quickly found 200 urad error in MSD strength– V. trajectory from BTVs, losses at MKB– Corrected for 10/09 and now looks good at first sight– Still to check details with beam, and update BETS tables

MSD +200 urad

MKB

Mike & LSA

Kickers

• No problems seen so far• MKD strength looks OK at present

– Will need to sort out orbit before final checks• MKB sweep has been seen on BTVDD already

– Debunched beam extracted in a few cases– Systematic checks still to make

Inject inject and dump mode Dump with RF off

Etienne, Jan & BT

Sequencing and synchronisation• Dump sequences well-sorted out

– Arming, Inject and dump, circulate and dump• “Inject and dump” and “circulate and dump” modes work OK

– Still to check “C&D” for B1– Can try to speed up to get every injection…not yet.

• Beam is kicked out OK– Detailed synchronisation between kick and bunch 1 still to do

Verena, Reyes & Etienne

MKD kick and beam

Dumps - present Status

Beam 1 (TD/UD68) Beam 2 (TD/UD62)Inject and dump setup OK OKCirculate and dump setup To do OKDump region aperture To do To doDetailed kicker synchronisation To do To doExtraction element strengths Started (corrected MSD) Started (corrected MSD)Beam instrumentation checks Started StartedInterlocks (BPMSA, TCDQ, …) To do To doSweep waveform measurement To do To doDump protection systems setup To do To doPM and XPOC Started StartedTracking tests Started (to test 4 sectors) Started (to test 4 sectors)Abort gap keeper To do To do

Injection: summary

• Looking pretty good at the moment

• Main issue still unresolved is to find unambiguous cause for TI 8 D mismatch, and then to define and test the correction strategy

• Still plenty of work to be done over the next weeks– TI8 to LHC optics matching (dispersion and betatron).– Measurements of injection mismatch and blowup– Re-visit injection steering – MSI, MKI, aperture, …– Setting-up and validation of injection protection systems– MKI kick waveform measurement– Commissioning of abort-gap keeper– Tests of injecting into different buckets

• MKI flashover happens – use protection

• Basic functionality demonstrated for B1 and B2– Synchronisation, kickers, septum, BI, beam on TDE

• Still all systematic checks with beam to make in next weeks– Aperture with extracted and circulating beam– Detailed synchronisation– Settings and strengths– MKB sweep measurement– Beam related interlocks (BPSA, TCDQ, BLMs, …)– Full BI checks– PM and XPOC systems – Setting-up and validation of dump protection systems– Commissioning of abort-gap keeper

Dumps: summary

First “Emergency Dump” on Thurs 11th at 22:45:08