Chamonix 2009 – LHC Performance Workshop · Etienne and team, Laurent and team, Eric, Ilya, Jan, Jörg, Lars, Malika, Mike, Thomas, Verena The great efforts of the BI, CO and OP

Chamonix 2009 – LHC Performance Workshop

Injection and beam dump

B.Goddard TE/ABT

On behalf of everyone involved

B.Goddard Chamonix 2009 - LHC Performance 1

Acknowledgement

The work described here is that of many peopleThe work described here is that of many people

In particular the following were instrumental in preparing and commissioningIn particular, the following were instrumental in preparing and commissioning the systems, and have also supplied material directly for this talk

Etienne and team, Laurent and team, Eric, Ilya, Jan,

Jörg, Lars, Malika, Mike, Thomas, Verena

The great efforts of the BI, CO and OP groups, together with all the other groups and teams involved at CERN are also warmly acknowledgedgroups and teams involved at CERN, are also warmly acknowledged

B.Goddard Chamonix 2009 - LHC Performance 2B.Goddard Chamonix 2009 - LHC Performance 2

Outline of talk

• Preamble

• Beam Injection j– Strengths and synchronisation checks– Local aperture measurements

I j ti t bilit– Injection stability – Beam losses on MKI and flashover

• Beam Dumping• Beam Dumping– Strengths and synchronisation– Local aperture measurements– Dump diagnostics

• SW, sequencing and operational aspects

• Lessons and changes for 2009 and beyond

• Conclusions


Injections – what was done

Beam 1 (TI2/P2) Beam 2 (TI8/P8)Beam 1 (TI2/P2) Beam 2 (TI8/P8)Transfer line optics OK Still question of dispersion matchInjected beam aperture OK (after vac. re-alignment) OKKicker synchronisation OK (rough) OK (rough)I j ti l t t th OK OKInjection element strengths OK OKBeam instrumentation checks OK OKCheck injection stability Started (data to evaluate) OKInterlocks Started StartedCi l i b T d T d (TDI d i OK)Circulating beam aperture To do To do (TDI moved in - OK)Injection steering To do Started (rough)Kicker 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

• Maybe 40-50% through initial (pilot) beam commissioning


Injection element strengths and sychronisation

• MKI kicker strengths look perfect – No trims needed at this stage

MSI t t th l k f t• MSI septum strengths look perfect– But! Effect of pulsed leakage field found by Ralph S on circulating orbit (0.5 mm)– Investigating powering in MSI DC (magnet, PC, controls, interlocks, …)

• SPS extraction and LHC injection kicker timing-in worked fine– Dynamic destination implemented

Rough injection kicker timing OK– Rough injection kicker timing OK– Noise on TL BCT signal made adjustment procedure tricky - upgraded for 2009

-MKI kick waveform- BCT (beam and kicker noise)


Injection region aperture measurements• Single pass measurement using unclosed oscillations at various phases

– Very useful tools with madx online for preparation and visualisation

All as expected except at one location VANMF 5L2 between MSI and Q5• All as expected, except at one location – VANMF.5L2 between MSI and Q5– Hot-spot with radiation survey (3 μSv/h) - 10 mm vertical realignment made– 20/22 mm aperture of MSI protection device / MSI septa confirmed

• Still to check potential limits in vertical at D1 with MKI off (using RCBYV.4)

Vertical aperture IR2 Vertical aperture IR8 (before vertical injection steering)

Still to check potential limits in vertical at D1 with MKI off (using RCBYV.4)

• Still to make circulating beam measurements at MSI & TDIB.Goddard Chamonix 2009 - LHC Performance 6

Injection steering and stability• First steering done for B2, was initially several mm off in vertical (last slide)

– Nice convergence of autopilot algorithm– To revisit including MSI and MKI strengths, and rechecking apertureso e s c ud g S a d s e g s, a d ec ec g ape u es

• Short-term (1 h) stability v. good at injection point (using screens in LHC)– P8: measured RMS jitter for B2 of 0.27 / 0.13 nominal σ H/V (c.f. ±1.5 spec)– Upper limit on MKI kicker instability of about 1.7 × 10-3 (c.f. 5 × 10-4 spec)

• Still to measure MKI waveform with kick delayBeam position

LHC.BTVSI.A5R8Positions

1

1.5

2Beam position

10

12

14Positions

H: rms 0.15426 mmV: rms 0.051263 mm

-0.5

0

0.5

Posi

tion

[mm

]

6

8

2 1 2 15 2 2 2 25 2 3 2 35 2 4 2 45 2 5-2

-1.5

-1

LHC.BTVSI.A5R8 HLHC.BTVSI.A5R8 V

0

2

4

2.1 2.15 2.2 2.25 2.3 2.35 2.4 2.45 2.5

x 104Time (local) -2 -1.5 -1 -0.5 0 0.5 1 1.5 2

0

Position [mm]


MKI flashovers on MKI.C2 and MKI.D2• First flashover during SoftStart, after aperture measurements (MKI off)

– Pilot beam lost on aperture limit upstream Q5 (total of about 5e10)– Subsequently added BLMs directly on MKIsSubseque y added s d ec y o s

• Second flashover during beam passage (MKI on)– Different type of incident – no preceding beam loss in the region– Injected trajectory showed clear overkick of about 20% (40 μrad or 10 σ)– Demonstrates perfectly need for TDI….and for SoftStart– Breakdown about 60% along magnet consistent with observations

• Still to decide interlocking strategy with BLMs

MKI FrankMKI FrankZimmermann

Breakdown in Magnet D


Dumps – what was done

Beam 1 (TD/UD68) Beam 2 (TD/UD62)Beam 1 (TD/UD68) Beam 2 (TD/UD62)Inject and dump setup OK OKCirculate and dump setup To do OKDump region aperture To do Started (some phases)D t il d ki k h i ti T d T dDetailed kicker synchronisation To do To doExtraction element strengths Started (corrected MSD) Started (corrected MSD)Beam instrumentation checks Started StartedInterlocks (BPMSA, TCDQ, …) To do To doS f T d T d ( i i l k OK)Sweep waveform measurement To do To do (parasitic looks OK)Dump protection systems setup To do To doPM and XPOC Started StartedTracking tests Started (2 sectors only) Started (2 sectors only)Abort gap keeper Started Started

• Maybe 10-20% through initial (pilot) beam commissioning


Dump element strengths and sychronisation

• MSD septum strengths looked OK after initial 200 μrad error corrected– Required tunnel access to update lookup tables in Energy Tracking System

MKD ki k t th l k d OK• MKD kicker strengths looked OK – Extracted first attempts with correctors not MKD – but complexity for TD line BI

• MKB dilution kicker strengths looked OKMKB dilution kicker strengths looked OK – parasitic sweep data taken for many dumps

• TSU locking and arming fine - Injection prepulse- TSU RF lock

• Rough timing in and synch. doneTSU RF lock

- MKD trigger- MKD current

TSU DPLLs locked to LHC b1 revolution frequency

- Beam current- MKD current


Inject and dump synchronisation

Dump region aperture measurements

• Performed first measurements from 00:00 to about 04:00 on 19/10– Did not finish them…problems with arming LBDS…then other problems

O l f h h k d f B1– Only a few phases checked for B1– 6.5 σ horizontal limit at TCDS to revisit (orbit, bunch timing in kick waveform)

• No obvious problems so far – and “loss free” extractions performedNo obvious problems so far and loss free extractions performed

Aperture Scan TD68

30Vertical

0 02

0.04

0.06

-30-900306090MKB

Phase sigma location sigma location0 12 Q4

30

+ve -veVertical

-0.02

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x [m

]TCDS

VDDA

MKDHorizontal

306090 15 MKB 15 MKB

-0.06

-0.04MSD

Phase sigma location sigma location0 12.5 Q4 6.5 TCDS

30 13.5 Q4 6.5 TCDS

+ve -ve

2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500-0.08

s [m]

60 13.5 TCDS90 7.5 TCDS 13.5 MSDC


Dump diagnostics - XPOC Analysis

• Automatic XPOC analysis for MKD and MKB kickers now mature– Throughout 2008 for reliability run, dry runs and commissioning

P d d d lt i l di fi di f di t d t i bl– Produced good results, including finding of some disconnected trigger cables

• Analysis of BI systems started with beam – mainly BTVDD screen– Analysis results and references agree well – MKD/MKB strengths look OKy g g– Extended and updated for 2009 (see Jan’s talk)

Reference trajectoryRaw data from BTVDD

Processed trace

j y

XPOC


Sweep characterisation and “asynchronous” dumps• Already an interesting rogues gallery of different dumps

– Uncaptured beam, sweeps, different parts of kicker waveforms, unstable beams...– Used XPOC analysis to check MKB sweepUsed OC a a ys s o c ec s eep

• In process of correlating with losses at extraction elements and around LHC– Will give experimental data for some of the simulations on failure cases– Huge data sets - available tools for browsing logged BLM data are not adequate

12th Sept 02h34BTVDD XPOC

BLMs


Sequencing and special machine modes• All sequences developed and tested for injection and dump systems

– Injection, SoftStart, arming, inject and dump, circulate and dump– Improved versions now available (exception handling and error messages)p ( p g g )– Question of unskippable tasks etc. for MP critical systems to address

• Need to maintain, load and unload all required timing tables– susceptible to error – any way to improve this?– susceptible to error – any way to improve this?

• Inject and dump mode worked well– Could dump both beams on 0th turn

OK f b h 1 i b h 1 d i f h b h b ( i l l b2)– OK for bunch 1 in batch 1 – needs testing for other bunch numbers (particularly b2)– Conceptual issue to fix on PM suppression (limits to ~20 turns instead of 1000)– All implications of RF prepulse to be tested (e.g. rephasing for bucket selection)

• Circulate and dump mode worked well– Dumped with timing event, up any time (in ms)– Find better way to adjust injection – dump delay (presently clunky)


Other operational aspects

• These are complicated systems with a lot of dependencies

• Injection requires a lot of preparation for OPj q p p– Injection kicker SoftStart– Beam permit loops– SPS and LHC modesSPS and LHC modes– LBDS arming– Beam extraction from SPS

Kicker beam synchronisation check– Kicker-beam synchronisation check– Beam to TED, TDI and into LHC

• OP frequently stressed or thwarted with SoftStart seconds running out

• Improved where possible for 2009 (‘better’ SoftStart - shorter, no ‘cheats’, improved arming and sequences, operator training planned)

• MKI application SW updated

• Will have first version of injection quality checks for 2009– Checking kickers BLMs filling patternChecking kickers, BLMs, filling pattern


Preparation in 2009

• In 2008 we hit the ground running in Sector Tests and finally on September 10th

• Need to repeat this in 2009– Changes to systems to be checked and rendered operational– Scheduling of TL beam tests already being discussed (June/July?)– Dry runs should already be starting – will be late compared to 2008– No reliability run in 2009 – but a lot of updates/modifications/new HW/SW to validate– Same people, teams and organisation (at our level…)

• Formalise interlock testing and/or acceptance?• Formalise interlock testing and/or acceptance?– Any proposals for this wrt 2008?

• Schedule time for critical systems tests (energy tracking, BIS→LBDS link)?y ( gy g )– Machine checkout time for this evaporated under the 10/09 floodlights

More details in Jan’s talk


Conclusions

• LHC injection and beam dump systems so far perform as expected– Some concern about MKI flashovers with beam – devise strategy for operation

Improvements made (sequencing arming SW) to make operations’ life easier– Improvements made (sequencing, arming, SW) to make operations’ life easier– Full XPOC and Injection quality check deployment needed– All HW/SW changes since 2008 need thorough validation

• Commissioning measurement programs with beam started well– To date no major issues found…but a lot of work here still to do– Increasing intensity, abort gap cleaning and setting up of protection devices willIncreasing intensity, abort gap cleaning and setting up of protection devices will

be some of the main challenges

• Tools, techniques and teams have performed wellK ti ll i ti f 2009– Keep essentially same organisation for 2009

– Some minor improvements of diagnostic and analysis tools needed

• TL and injection beam tests in 2009 will speed up ring beam commissioningj p p g g– Get these in schedule now (many dependencies: sort out impact)– Systems Integration and Dry Runs being organised and scheduled– Presently behind schedule wrt 2008 preparation (shutdown work impact)Presently behind schedule wrt 2008 preparation (shutdown work impact)


Documents

Chamonix 2009 – LHC Performance Workshop · Etienne and team, Laurent and team, Eric, Ilya, Jan, Jörg, Lars, Malika, Mike, Thomas, Verena The great efforts of the BI, CO and OP