R.Bailey, March 2008 Beam plans for Accelerator Systems R.Bailey, F.Zimmermann eLTC Summary March...

R.Bailey, March 2008R.Bailey, March 2008

Beam plans for Accelerator SystemsBeam plans for Accelerator Systems

R.Bailey, F.ZimmermannR.Bailey, F.Zimmermann

eLTC SummaryeLTC Summary

March 2008March 2008


Overall commissioning strategy for protons (estOverall commissioning strategy for protons (estdd. 2005). 2005)

Hardware commissioning

Machine checkout

Beam commissioning

43 bunch operation

75ns ops

25ns ops IInstall Phase II and MKB

25ns ops II

Stage A B C

No beam Beam

D

A.A. Pilot physics runPilot physics run First collisionsFirst collisions 43 bunches, no crossing angle, no squeeze, moderate intensities43 bunches, no crossing angle, no squeeze, moderate intensities Push performancePush performance Performance limit 10Performance limit 103232 cm cm-2-2 s s-1-1 (event pileup) (event pileup)

B.B. 75ns operation75ns operation Establish multi-bunch operation, moderate intensitiesEstablish multi-bunch operation, moderate intensities Relaxed machine parameters (squeeze and crossing angle)Relaxed machine parameters (squeeze and crossing angle) Push squeeze and crossing angle Push squeeze and crossing angle Performance limit 10Performance limit 103333 cm cm-2-2 s s-1-1 (event pileup) (event pileup)

C.C. 25ns operation I25ns operation I Nominal crossing angleNominal crossing angle Push squeezePush squeeze Increase intensity to 50% nominalIncrease intensity to 50% nominal Performance limit 2 10Performance limit 2 103333 cm cm-2-2 s s-1-1

D.D. 25ns operation II25ns operation II Push towards nominal performancePush towards nominal performance

*

bk

N

Optimise

Pileup

Losses

Beampower

Complexity

Minimise

)( *


Stage A: Commissioning procedures (LHCCWG)Stage A: Commissioning procedures (LHCCWG)

Web based with EDMS approval http://lhccwg.web.cern.ch/lhccwg/overview_index.htm

http://lhccwg.web.cern.ch/lhccwg/overview_index.htm

http://lhccwg.web.cern.ch/lhccwg/overview_index.htm


Stage A: Commissioning PhasesStage A: Commissioning Phases

Phase

A.1 First turn Injection commissioning and threading

A.2 Circulating pilot Establish circulating beam, closed orbit, tunes, RF capture

A.3 450 GeV initial commissioning System commissioning (instrumentation, beam dump)

A.4 450 GeV optics Beta beating, dispersion, coupling, non-linear field quality, aperture

A.5 450 GeV, increasing intensity Prepare the LHC for unsafe beam

A.6 450 GeV, two beam operation Handle 2 beams together

A.7 450 GeV, collisions If requested by experiments

A.8 Snap-back and ramp Single beam, 2 beams

A.9 Top energy checks Single beam, 2 beams

A.10 Top energy Collisions

A.11 Squeeze Commissioning the Betatron squeeze in all IP’s

A.12 Experimental magnets Beam commissioning with experimental magnets


Stage A: Phase 3 – Initial system commissioningStage A: Phase 3 – Initial system commissioning

Phase

A.1

A.2

A.3

A.4

A.5

A.6

A.7

A.8

A.9

A.10

A.11

A.12

Phase Step Activity Who (OP +)

A.3

A3.1 Final RF commissioning with Pilot Intensity RF

A3.2 BCTFR and BPM checks with Pilot Intensity BI

A3.3 First Commissioning of Beam Dumping System (pilot) BT BI ATB

A3.4 Commission systems with higher intensity (3 x 1010) BT BI RF

A3.5 Establish cycling machine (3 x 1010) OP

A3.6 Lifetime optimisation (3 x 1010) OP

A3.7 Further commissioning of beam instrumentation (3 x 1010) BI

A3.8 Basic optics checks in addition to LOCO Results (3 x 1010) AP BI RF

A3.9 Further commissioning of beam dumping system (3 x 1010) BT BI ATB

A3.10 Commission feedback systems (3 x 1010) RF BI

A3.11 Rough Setting up of the TDI (3 x 1010) BT ATB

Phase Will be working with Max beam Who (OP +)

A.3

RF systemsBeam dump with pilotTDIBCTTune meter and PLLWire scannersSynchrotron lightRest Gas Ionisation monitorMulti turn acquisitionFeedback systems

3 1010

RFATBBIBT


Stage A: The view from the expertsStage A: The view from the experts

Phase

A.1

A.2

A.3

A.4

A.5

A.6

A.7

A.8

A.9

A.10

A.11

A.12 BT RF Etc BIEtc

Etc Etc


Session 4 – Beam plans for accelerator systemsSession 4 – Beam plans for accelerator systems

Taking the Beam Commissioning Procedures as a basis, each Taking the Beam Commissioning Procedures as a basis, each presentation should elaborate the details of how the presentation should elaborate the details of how the accelerator system in question is commissioned with beam accelerator system in question is commissioned with beam through the various phases of the established plan. through the various phases of the established plan.

Each presentation should cover Each presentation should cover what needs to be done at the various stages of commissioningwhat needs to be done at the various stages of commissioning how it will be donehow it will be done who will do itwho will do it how long it is expected to takehow long it is expected to take

As a minimum, each presentation should cover commissioning As a minimum, each presentation should cover commissioning up to the performance levels attainable in phase A. A look up to the performance levels attainable in phase A. A look forward into later stages is left to the discretion of the speakerforward into later stages is left to the discretion of the speaker


Session 4 – Beam plans for accelerator systemsSession 4 – Beam plans for accelerator systems

Accelerator system Speaker Time

Beam Commissioning Procedures R.Bailey 20+10

Injection and associated protection devices V.Kain 30+10

Power converters (tracking between sectors) F.Bordry 20+10

coffee

RF acceleration systems P.Baudrenghien 30+10

Beam dump and associated protection devices B.Goddard 20+10

2h+1h

lunch

BI systems R.Jones 30+10

RADMON T.Wijnands 20+10

Transverse damper W.Hofle 20+10

coffee

Collimators R.Assmann 30+10

Machine protection J.Uythoven 20+10

2h+1h


Power converters’ biblePower converters’ bible


Power convertersPower converters

Tracking between the 8 main dipole convertersTracking between the 8 main dipole converters 20ppm accuracy after calibration gives 0.7mm20ppm accuracy after calibration gives 0.7mm OKOK

Tracking between the dipole and quadrupole convertersTracking between the dipole and quadrupole converters 20ppm accuracy gives tune change 0.0320ppm accuracy gives tune change 0.03 OKOK

Tracking between the quadrupole convertersTracking between the quadrupole converters 20ppm accuracy gives very small 20ppm accuracy gives very small beating beating OKOK

Above reachable after calibration (automatic procedure)Above reachable after calibration (automatic procedure)

Sector 45 tests show very good performance (no triplet)Sector 45 tests show very good performance (no triplet)

LHC Power Converters performance will be measured and improved mainly without dedicated beam time

Periodic calibration will be required

PC experts should be very close to beam operation, for issues like Offsets between sectors Tracking measurement and correction Ramp


Injection and associated protection devicesInjection and associated protection devices

TDIMKI +90˚

TCDD

TCLIBTCLIA

KickerMKI

LEFT OF IP2 (H plane)

RIGHT OF IP2 (H plane)

TCLIM

SeptumMSI

TCDI


Injection and associated protection devicesInjection and associated protection devices

Phase A1 (First turn)Phase A1 (First turn) First to TDIFirst to TDI Then beyond and into threadingThen beyond and into threading

Phase A2 and A3 (Circulating pilot++)Phase A2 and A3 (Circulating pilot++) Injection oscillationsInjection oscillations Re-steer injectionRe-steer injection

Phase A4 (450GeV optics)Phase A4 (450GeV optics) Stability (1000 shots inject and dump)Stability (1000 shots inject and dump) Aperture in injection regionAperture in injection region MKI waveformMKI waveform Injection matchingInjection matching

Phase A5 (Increase intensity)Phase A5 (Increase intensity) Multi bunch injection and Protection devicesMulti bunch injection and Protection devices

1-2 shifts/beam

1-2 shifts/beam

1-2 shifts/beam

1-2 shifts/beam

1313

R1

Low-levelLoops

Processor

Radial PUFront-end

VCXO

Phase Discri

F RF Prog 1

Radial loop

Phase loop

Synchro loop

DDS1 DDS2

Sync

F1,P

1

F2,P

2

F1 F2

1/h divider

Master F rev

To Ring 1 Cavity Controllers (fibers)

Dual Frequency Program and

Rephasor FPGA

Function Gen. Function Gen.

F RF Prog 2

DUAL FREQUENCY

PRGM

Master F RF

Beam 1Rad. PU

Beam/Vt phase

RF/Fprog phase

F out

Rad

Pos

.

Fiber Optic TX

BEAM CONTROL

LOOPS MODULE

Radial steering with radial loop

Coarse F1

LF switch

Phase Discri

7 TeV synthesizer

Phase shifter

180 deg hybrid

a b

BEAM POS

MODULE

FPGAA

DC

SYNCHROMODULE

Ib RF Summing Network

Vt

Phase PU

AD

C

CORDIC (+ AGC?)

Bunch/RF phase

CORDIC (+ AGC?)

Vt/RF phase

Phase Difference

and Averaging

BEAM PHASE

MODULE

AD

C

Cavities

Analog I/Q demod

Analog I/Q demod

Master FrfMaster Frf

AD

C

AD

C

Delay adjust

Function Gen.

fsync

fphase

A function sets the RF frequency on the injection plateau and through the ramp

Injection frequency, injection phase and stable phase will be adjusted by observing these two signals

The VCXO generates the RF sent to the Cavity Controllers

This synthesizer replaces the frequency program during physics

Low level RFLow level RF


RF acceleration systemsRF acceleration systems

Phase A1 (First turn)Phase A1 (First turn) RF OFFRF OFF

Label buckets (Numerology and cogging)Label buckets (Numerology and cogging) Signal tuningSignal tuning

Phase A2 (Circulating pilot++)Phase A2 (Circulating pilot++) RF ONRF ON

Adjust RF frequencyAdjust RF frequency Commission phase loop and synchro loopCommission phase loop and synchro loop Capture and check phasing of cavities with beamCapture and check phasing of cavities with beam Adjust positions of bunches for collisions in IRsAdjust positions of bunches for collisions in IRs

Phases A3 onwardsPhases A3 onwards As and when needed by commissioning programAs and when needed by commissioning program

Commission radial loop for the rampCommission radial loop for the ramp Commission multi bunch injectionsCommission multi bunch injections Commission multi batch injectionsCommission multi batch injections RampingRamping Rephasing on the flat topRephasing on the flat top

1 shift

8 shifts

8 shifts


Beam dump and associated protection devicesBeam dump and associated protection devices


Beam dump and associated protection devicesBeam dump and associated protection devices

Phase A3 (Circulating pilot++)Phase A3 (Circulating pilot++) First controlled extractionsFirst controlled extractions

Phase A4 (450GeV optics)Phase A4 (450GeV optics) IR6 aperture and IR6 aperture and TCDQTCDQ

Phase A5 (Increase intensity)Phase A5 (Increase intensity) Abort gap cleaningAbort gap cleaning Extraction trajectoriesExtraction trajectories

Phase A8 (Ramp)Phase A8 (Ramp) Energy trackingEnergy tracking

Phase A9 (Top energy)Phase A9 (Top energy) IR6 aperture and IR6 aperture and TCDQTCDQ Abort gap cleaningAbort gap cleaning

Phase A11 (Squeeze)Phase A11 (Squeeze) Different opticsDifferent optics TCDQTCDQ

3-4 shifts

1-2 shifts

6-10 shifts

1-3 shifts

4-6 shifts

1 shift


Beam InstrumentationBeam Instrumentation

Phase A1 (First turn)Phase A1 (First turn) Screens, BPM in asynchronous mode, fast BCT, BLMScreens, BPM in asynchronous mode, fast BCT, BLM Check polarity errors while threading (stage the repairs)Check polarity errors while threading (stage the repairs)

Phase A3 (Circulating pilot++)Phase A3 (Circulating pilot++) BPM in synchronous mode and systematic calibration (BPM, COD)BPM in synchronous mode and systematic calibration (BPM, COD) DC BCT & lifetimeDC BCT & lifetime Tune meter with beam excitation Tune meter with beam excitation

Via transverse damper easiestVia transverse damper easiest Via MKQVia MKQ

Head tail monitor for ChromaticityHead tail monitor for Chromaticity Wire scanner, SL (needs undulator), BGI (needs gas injection)Wire scanner, SL (needs undulator), BGI (needs gas injection) Abort gap monitor (needs undulator)Abort gap monitor (needs undulator)

Phase A8 (Ramp)Phase A8 (Ramp) Continuous orbit, tune, coupling and chromaticity (+ feedbacks)Continuous orbit, tune, coupling and chromaticity (+ feedbacks) Continuous emittance monitoring (SL from D3 above 2TeV)Continuous emittance monitoring (SL from D3 above 2TeV)

Phase A10 (Collisions)Phase A10 (Collisions) Luminosity (BRANA (ionisation) in 1&5, BRANB (CdTe in 2&8)Luminosity (BRANA (ionisation) in 1&5, BRANB (CdTe in 2&8) SchottkySchottky


Beam Instrumentation issuesBeam Instrumentation issues

Chicken and Egg situationChicken and Egg situation Good measurements needed to get good beamGood measurements needed to get good beam Good beam needed to get good measurementsGood beam needed to get good measurements

BTV images in LSS3 and LSS4BTV images in LSS3 and LSS4 Single shot OK but not turn by turnSingle shot OK but not turn by turn Need fast camerasNeed fast cameras Not for 2008 (resource issues)Not for 2008 (resource issues)

BPM in Intensity modeBPM in Intensity mode Requires intensity for precision better than 50%Requires intensity for precision better than 50% Complicated software mapping (B1 position Complicated software mapping (B1 position ↔↔ B2 intensity) B2 intensity) Have auto trigger anywayHave auto trigger anyway

Fast BCT on single bunchFast BCT on single bunch BGIBGI

Needs gas injection for low intensitiesNeeds gas injection for low intensities Considered risky by AT/VACConsidered risky by AT/VAC

BRANBRAN Ionisation monitors arrive just in time at best Ionisation monitors arrive just in time at best

Hence iterative. Heavily interleaved with the commissioning program

Time estimates difficult


Radiation monitoring systemsRadiation monitoring systems

Several systems, various groups, different objectivesSeveral systems, various groups, different objectives RAMSESRAMSES BLMBLM RADMONRADMON BCM/BSCBCM/BSC

Collaborative approach proposed to observations at key stagesCollaborative approach proposed to observations at key stages Increase in beam intensityIncrease in beam intensity Increase in energyIncrease in energy Change of opticsChange of optics CollisionsCollisions

Distinguish betweenDistinguish between Simulations, shielding and monitoringSimulations, shielding and monitoring Radiation damage effectsRadiation damage effects

Need to define a system commissioning team for these systems

No dedicated beam time requested. In the shadow of other activities


Transverse damperTransverse damper

Pick-up 1

Kicker

Signal processing

beam

signal

Pick-up 2

gain g

Need real-time digitalsignal processing

Match delays: t signal = t beam + MT 0

T0 : beam revolution time

M=1: very common -> “One -Turn-Delay” feedbackBut M>1 also possible

phase and delay adjustments

• feedback: curing transverse coupled bunch instabilities

• excitation: of transverse oscillations for beam measurements & other applications

• damping: of transverse injection oscillations


Transverse damperTransverse damper

Damper essential to avoid increase of transverse emittance already in phase A (1-156 bunches)

shot-to-shot reproducibility with single bunch, kicker ripple effect with 43 to 156 bunches

Between now and first beam a lot of hardware commissioning, delay adjustments, calibrations in order to minimize time needed to get damper operational with beam

Damper commissioning can start from phase A1 with observations

Dedicated time required from phase A3 onwards (after RF capture) to set-up the system

Injection damping available from phase A4 onwards

Commissioning of abort gap cleaning from phase A5-A6 onwards

Commissioning damper during ramp in A8 to prepare for higher intensity of phase B

1-2 shifts/beam

1-2 shifts/beam

1-2 shifts/beam

MD: few ramps


CollimatorsCollimators

Not needed until Phase A5 (Increase intensity)Not needed until Phase A5 (Increase intensity)

Strategy proposedStrategy proposed Beam based setup to startBeam based setup to start Observable is beam loss signalsObservable is beam loss signals Establish reference positions thereafter (reproducibility as issue)Establish reference positions thereafter (reproducibility as issue) Need orbit feedback to be workingNeed orbit feedback to be working Need to this forNeed to this for

450GeV (phase A5)450GeV (phase A5) Ramp (phases A8 A9)Ramp (phases A8 A9) Squeeze (phase A11)Squeeze (phase A11)

1.1. Start from end of ramp settingsStart from end of ramp settings

2.2. Squeeze to 6mSqueeze to 6m

3.3. Measure and correct tail populationMeasure and correct tail population

4.4. Adjust dump protection TCDQAdjust dump protection TCDQ

5.5. Set collimators for next step (5m, 4m, 3.5m, 2.5m, 2m, …)Set collimators for next step (5m, 4m, 3.5m, 2.5m, 2m, …)

6.6. Squeeze to next step (5m, 4m, 3.5m, 2.5m, 2m, …)Squeeze to next step (5m, 4m, 3.5m, 2.5m, 2m, …)

7.7. Repeat steps 3 to 6 (target for this phase 2m)Repeat steps 3 to 6 (target for this phase 2m)

4 shifts/beam

4 shifts/beam

4 shifts/beam


Machine protection systemMachine protection system

Beam Interlock SystemBeam

Dumping System

Injection InterlockPowering

Interlockssc magnets

PoweringInterlocks

nc magnets

QPS(several 1000)

Power Converters

~1500

AUG

UPS

Power Converters

Magnets

Magnet Current Monitor

CryoOK

RFSystem

Movable Detectors

LHCExperiments

Beam LossMonitors

BCM

Experimental Magnets

CollimationSystem

CollimatorPositions

Environmentalparameters

Transverse Feedback

Beam ApertureKickers

BeamLifetimeFBCM

Screens / Mirrors

BTV

Access System

Doors EIS

VacuumSystem

Vacuumvalves

AccessSafetyBlocks

RF Stoppers

Beam loss monitors

BLM

SpecialBLMs

Monitorsaperture

limits(some 100)

Monitors in arcs

(several 1000)

Timing System (Post Mortem

Trigger)

Operator Buttons

CCC

SafeLHC

Parameter

SoftwareInterlocks

LHCDevices

Sequencer

LHCDevices

LHCDevices

Safe Beam Parameter

Distribution

SafeBeamFlag

Little beam dependence Core Systems

Protection elements


Machine protection systemMachine protection system

Commissioning of individual systems treated elsewhereCommissioning of individual systems treated elsewhere

Documented by Machine Protection System Commissioning WGDocumented by Machine Protection System Commissioning WG Now need to manage the overall system Now need to manage the overall system

In all circumstances the state of the MPS In all circumstances the state of the MPS should be knownshould be known

Inventory of ‘hardware’ which is not standardInventory of ‘hardware’ which is not standard SettingsSettings Interlock LevelsInterlock Levels MaskingMasking DisablingDisabling

In all circumstances the operational limits and In all circumstances the operational limits and conditions of the machine should be clearconditions of the machine should be clear

For the standard conditionsFor the standard conditions If one is allowed to only run under special If one is allowed to only run under special

conditionsconditions A body is needed to advise the EIC when A body is needed to advise the EIC when

significant changes to MPS systems and their significant changes to MPS systems and their settings need to be made to continue or settings need to be made to continue or optimise operationoptimise operation

Tool(s) required for keeping track of MPS conditions

Tool(s) required for keeping track of allowed machine conditions

LHC Protection Panel


Selected points from the discussions

experiments: initial pile-up ~ 2 events/Xing; turning on experimental experiments: initial pile-up ~ 2 events/Xing; turning on experimental solenoids & dipoles; injection inhibits from experimentsolenoids & dipoles; injection inhibits from experiment

injection: optics study prior to aperture checks; TCDI/TLCIs retracted injection: optics study prior to aperture checks; TCDI/TLCIs retracted during commissioning; stability studies – dump can fire every 20 sduring commissioning; stability studies – dump can fire every 20 s

power converters: excellent performance, but two systematic spikes power converters: excellent performance, but two systematic spikes on the ramp caused by high precision ADCs ; important time saving on the ramp caused by high precision ADCs ; important time saving from “recatching” the magnet current after failure; inner triplet = still from “recatching” the magnet current after failure; inner triplet = still terra incognita; tools for ramping 8 sectors in parallel & dipole-terra incognita; tools for ramping 8 sectors in parallel & dipole-quadrupole synchronism; ; commissioning of energy meterquadrupole synchronism; ; commissioning of energy meter

RF: effect of RF phase noise on the beam; path length difference RF: effect of RF phase noise on the beam; path length difference between the two beams; phase drifts between CCC and IR4; alternative between the two beams; phase drifts between CCC and IR4; alternative techniques to correct injection phase errorstechniques to correct injection phase errors

radiation levels: 1 week CNGS ~ 1 year LHC; move out of UJ with radiation levels: 1 week CNGS ~ 1 year LHC; move out of UJ with sensitive electronics; week-21 calibration experiment on TED for point sensitive electronics; week-21 calibration experiment on TED for point 2 and point 8; sensitivity to single-event failures 100 times worse than 2 and point 8; sensitivity to single-event failures 100 times worse than assumed previously; new AB-AT-TS working group assumed previously; new AB-AT-TS working group


Selected Selected points from the discussions

instrumentation: BPM polarity checks possible only with beam; BPM instrumentation: BPM polarity checks possible only with beam; BPM intensity mode has huge error (50% variation) for single bunch – so it intensity mode has huge error (50% variation) for single bunch – so it may not be useful; two monitors of beam size in store (wire scanner & may not be useful; two monitors of beam size in store (wire scanner & SLM); multi-turn acquisitions on the ramp for optics validation; BLMs SLM); multi-turn acquisitions on the ramp for optics validation; BLMs and common BPMs are only instruments sensitive to both beams; and common BPMs are only instruments sensitive to both beams; matching monitor available only for 1 beam 1 plane study only in 2008 - matching monitor available only for 1 beam 1 plane study only in 2008 - no fallback solution; resolution of screens in the dump lineno fallback solution; resolution of screens in the dump line

damper: abort gap cleaning before ramp; injection kicker rippledamper: abort gap cleaning before ramp; injection kicker ripple

collimation: periodic verification of protection hierarchy; relative cross collimation: periodic verification of protection hierarchy; relative cross calibration; monitoring of beta beating; test of cleaning efficiency with calibration; monitoring of beta beating; test of cleaning efficiency with transverse blow up? ; how to go through the squeeze without making transverse blow up? ; how to go through the squeeze without making circles with quenches and beam loss?circles with quenches and beam loss?

machine protection: “LHC Protection Panel” will make decisions; machine protection: “LHC Protection Panel” will make decisions; interlock on optics? concept of “safe” beam; damage level uncertainty interlock on optics? concept of “safe” beam; damage level uncertainty


Concluding remarksConcluding remarks

Now need to cross check information given with Now need to cross check information given with the existing chronological proceduresthe existing chronological procedures

Time estimates shown are for system Time estimates shown are for system commissioning needs by the relevant specialists commissioning needs by the relevant specialists and have been given in many cases in some detailand have been given in many cases in some detail

Overall time estimates need to include other Overall time estimates need to include other activities (ramp, measurement and correction of activities (ramp, measurement and correction of machine parameters, machine protection)machine parameters, machine protection)

Parallelism of certain activities to be explored, Parallelism of certain activities to be explored, either by working in parallel on one beam or by either by working in parallel on one beam or by working with 2 beams quasi-independentlyworking with 2 beams quasi-independently

Several discussion points also to be followed upSeveral discussion points also to be followed up

75 shifts

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