massimo giovannozzichamonix xv, january 23-27 20061 electrical circuits required for the minimum...

Massimo GioMassimo Giovannozzivannozzi

Chamonix XV, January 23-27 Chamonix XV, January 23-27 2006 2006

11

Electrical circuits required for Electrical circuits required for the minimum workable LHC the minimum workable LHC

during commissioning and first during commissioning and first two years of operationtwo years of operation

M. GiovannozziM. Giovannozzi

SummarySummary::

IntroductionIntroduction

Magnetic circuits: commissioningMagnetic circuits: commissioning

Magnetic circuits: first two Magnetic circuits: first two years of operationyears of operation

RF circuitsRF circuits

Conclusions and outlookConclusions and outlook

Acknowledgements: H. Burkardt, S. Fartoukh, E. Acknowledgements: H. Burkardt, S. Fartoukh, E. Métral, F. Ruggiero, R. Saban,Métral, F. Ruggiero, R. Saban, E. Shaposhnikova, E. E. Shaposhnikova, E. Todesco,Todesco, J. TuckmantelJ. Tuckmantel



22

AimAim: identify circuits (: identify circuits (magnetic and RFmagnetic and RF) that ) that are critical for the commissioning. are critical for the commissioning.

In general it can be stated that low-order In general it can be stated that low-order correctors are mandatory from day 1, while correctors are mandatory from day 1, while higher-order correctors can be delayed to a higher-order correctors can be delayed to a later stage.later stage.

Of course, Of course, the relevance of a circuit is also a the relevance of a circuit is also a function of the beam conditions.function of the beam conditions.

Inspiring presentation made by O. Brüning at Inspiring presentation made by O. Brüning at the 17the 17thth LHCOP meeting. LHCOP meeting.

IntroductionIntroduction



33

Staged commissioning plan for protonsStaged commissioning plan for protons

?25ns ops I

Install Phase II and MKB

25ns ops II

75ns ops

43 bunch operation

Beam commissioning

Machine checkout

Hardware commissioning

?25ns ops I

Install Phase II and MKB

25ns ops II

75ns ops

43 bunch operation

Beam commissioning

Machine checkout

Hardware commissioning

Stage I II III

No beam Beam

IV

I.I. 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 performance (156 bunches, partial squeeze in 1 and 5, push Push performance (156 bunches, partial squeeze in 1 and 5, push intensity)intensity)

II.II. 75ns operation75ns operation Establish multiEstablish multi--bunch operation, moderate intensitiesbunch 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

III.III. 25ns operation I25ns operation I Nominal crossing angleNominal crossing angle Push squeezePush squeeze Increase intensity to 50% nominalIncrease intensity to 50% nominal

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

Beam

From Roger’s From Roger’s talktalk



44

Trajectory-Trajectory-orbitorbit

Beam commissioning for Stage IBeam commissioning for Stage I

Physics partially squeezedPhysics partially squeezed

Commission squeezeCommission squeeze

PhysicsPhysics

Two beams to physics energyTwo beams to physics energy

Single beam to physics energySingle beam to physics energy

Ramp Ramp –– single beamsingle beam

Snapback Snapback –– single beamsingle beam

Nominal cycleNominal cycle

450 GeV: 2 beams450 GeV: 2 beams

450 GeV: detailed measurements450 GeV: detailed measurements

450 GeV: initial commissioning450 GeV: initial commissioning

Circulating beamCirculating beam

First turnFirst turn

InjectionInjection

43 on 4343 on 43

Pilot ++Pilot ++

1 on 1 1 on 1 …… 43 on 4343 on 43

Pilot ++Pilot ++

Pilot ++Pilot ++

Pilot ++Pilot ++

Pilot ++Pilot ++

PilotPilot

Single IntermediateSingle Intermediate



PilotPilot

PilotPilot

PilotPilot

1 to 4 101 to 4 10101014

13

1 to 4 101 to 4 10101012

11

10

9

1 to 2 101 to 2 1010108

7

6

5

3 to 4 103 to 4 1010104

3

2

5 to 10 105 to 10 10991

Physics partially squeezedPhysics partially squeezed

Commission squeezeCommission squeeze

PhysicsPhysics

Two beams to physics energyTwo beams to physics energy

Single beam to physics energySingle beam to physics energy

Ramp Ramp –– single beamsingle beam

Snapback Snapback –– single beamsingle beam

Nominal cycleNominal cycle

450 GeV: 2 beams450 GeV: 2 beams

450 GeV: detailed measurements450 GeV: detailed measurements

450 GeV: initial commissioning450 GeV: initial commissioning

Circulating beamCirculating beam

First turnFirst turn

InjectionInjection

43 on 4343 on 43

Pilot ++Pilot ++

1 on 1 1 on 1 …… 43 on 4343 on 43

Pilot ++Pilot ++

Pilot ++Pilot ++

Pilot ++Pilot ++

Pilot ++Pilot ++

PilotPilot




PilotPilot

PilotPilot

PilotPilot

1 to 4 101 to 4 10101014

13

1 to 4 101 to 4 10101012

11

10

9

1 to 2 101 to 2 1010108

7

6

5

3 to 4 103 to 4 1010104

3

2

5 to 10 105 to 10 10991 - From Chamonix XIV -

From Roger’s From Roger’s talktalk

Optics: tune, Optics: tune, chromaticitychromaticityRF onRF on



55

Stage 1: initial commissioning Stage 1: initial commissioning - I- I

Orbit correctors:Orbit correctors:Arc correctors (in SSS) Arc correctors (in SSS)

Insertion correctors (in Insertion correctors (in special SSSspecial SSS, used also , used also for crossing scheme, and near for crossing scheme, and near warm warm quadrupolesquadrupoles))

All orbit correctors are needed from day 1All orbit correctors are needed from day 1



66

Stage 1: initial commissioning Stage 1: initial commissioning - II- II

Optics correctors: Optics correctors: Tune correctionTune correction

Coupling correctionCoupling correction

Optics in the insertionsOptics in the insertions

MQTMQT: trim quadrupoles in SSS (: trim quadrupoles in SSS (Q14-Q21 L/RQ14-Q21 L/R))

MQTLMQTL: long trim quadrupoles used in special SSS (: long trim quadrupoles used in special SSS (Q11Q11) to ) to trim the insertion optics and in trim the insertion optics and in Q6Q6 in in IR3IR3 and and IR7IR7

MQSMQS: skew quadrupoles in SSS for coupling correction : skew quadrupoles in SSS for coupling correction ((Q23, Q27 L/RQ23, Q27 L/R))

All MQT and MQTL correctors are needed from day All MQT and MQTL correctors are needed from day 11



77

Stage 1: initial commissioning Stage 1: initial commissioning - III- III

Coupling correction Coupling correction Pre-requisite for tune settingPre-requisite for tune setting

Estimate of CEstimate of C- - without correction (without correction (S. Fartoukh S. Fartoukh 31. LCC,31. LCC, O. Brüning – Chamonix 2003O. Brüning – Chamonix 2003) -> 0.193 ) -> 0.193 using 9901 error table for MBs using 9901 error table for MBs

The estimate did not change drastically using The estimate did not change drastically using data from MB production.data from MB production.

Therefore, all MQS correctors are needed from day Therefore, all MQS correctors are needed from day 11

yx

i

kyx

QQcack

kykx

kk

2

154

1

e



88

Stage 1: initial commissioning Stage 1: initial commissioning - IV- IV

Sextupolar correctorsSextupolar correctorsSpool pieces: all MBs are Spool pieces: all MBs are equipped with sextupolar equipped with sextupolar correctors (correctors (MCSMCS))

Contribution to Contribution to chromaticity from chromaticity from bb33 error error in MBsin MBsCorrection of dynamic Correction of dynamic effects: decay and snap effects: decay and snap backbackRemark: Remark: 1 unit of b3 -> 45 1 unit of b3 -> 45 units of Q’units of Q’Remark: specifications are Remark: specifications are ((S. Fartoukh O. Brüning S. Fartoukh O. Brüning LHC PR 501LHC PR 501))

Q’=2Q’=2±1, Q’±1, Q’xx=Q’=Q’y y

New specs given by O. New specs given by O. Brüning (see MAC Brüning (see MAC presentation December presentation December 2004), but not 2004), but not substantially differentsubstantially different

Spool pieces are needed Spool pieces are needed from day 1from day 1

SectorSector

Average bAverage b33 in in MB at MB at

injection [10injection [10--

44]]

Rms bRms b33 in MB in MB at injection [10at injection [10--

44]]

V1V1 V2V2 V1V1 V2V2

7-87-8 -2.12-2.12 -2.13-2.13 1.611.61 1.611.61

8-18-1 -4.49-4.49 -4.39-4.39 1.191.19 1.171.17

4-54-5 -4.22-4.22 -4.29-4.29 1.051.05 1.011.01

3-43-4 -5.51-5.51 -5.42-5.42 1.401.40 1.341.34Courtesy S. Fartoukh, MEB-107 Courtesy S. Fartoukh, MEB-107 presentationpresentation

Cou

rtesy L

. C

ou

rtesy L

. B

ott

ura

Bott

ura



99

Stage 1: initial commissioning Stage 1: initial commissioning - V- V

Sextupolar correctorsSextupolar correctors

All SSS are equipped with chromaticity sextupoles (All SSS are equipped with chromaticity sextupoles (MSMS))Natural chromaticity is Natural chromaticity is Q’Q’xx=-93, Q’=-93, Q’y y =-87=-87

Correction of natural chromaticity is essential for tune Correction of natural chromaticity is essential for tune measurement (decoherence)! measurement (decoherence)!

Chromaticity sextupoles are needed from day 1Chromaticity sextupoles are needed from day 1Four skew sextupoles are installed in each arc (Four skew sextupoles are installed in each arc (MSSMSS))Specification (Specification (S. Fartoukh O. S. Fartoukh O. BrüningBrüning LHC PR 501LHC PR 501) based on ) based on bound on Q’’ (bound on Q’’ (aa33 has no has no impact on dynamic apertureimpact on dynamic aperture))

aa33(sys)=0(sys)=0

aa33(ran)=0.7(ran)=0.7

aa33(unc)=1.5(unc)=1.5

a3(sys)=a3(sys)= -0.088 – -0.088 – injinj

a3(ran)=a3(ran)= 0.42 - inj 0.42 - inj

a3(sys)=a3(sys)= -0.115 - -0.115 - collcoll

a3(ran)=a3(ran)= 0.42 - coll 0.42 - coll

Courtesy E. Courtesy E. TodescoTodesco

Skew sextupoles might not be needed from Skew sextupoles might not be needed from day 1day 1



1010

Stage 1: initial commissioning Stage 1: initial commissioning - VI- VI

Octupolar correctorsOctupolar correctors

Spool pieces: MBs type A are equipped Spool pieces: MBs type A are equipped with octupolar correctors (with octupolar correctors (MCDOMCDO))

Specification (Specification (S. Fartoukh O. Brüning S. Fartoukh O. Brüning LHC PR 501LHC PR 501) based on bound on Q’’ and ) based on bound on Q’’ and anharmonicity (anharmonicity (b4 has an impact on b4 has an impact on dynamic aperturedynamic aperture))

b4(sys)=b4(sys)=±±0.20.2

b4(ran)=0.5b4(ran)=0.5

b4(unc)=0.4b4(unc)=0.4

MB-intrinsic b4 is fine. The main source MB-intrinsic b4 is fine. The main source of b4 comes from feed-down from MCD.of b4 comes from feed-down from MCD.

Feed-down effects are nearly on Feed-down effects are nearly on specification.specification.

Remark tracking studies showed that Remark tracking studies showed that without MCO the minimum dynamic without MCO the minimum dynamic aperture drops from aperture drops from 11.2 11.2 to 9.6 to 9.6 ( (see see M. Hayes LHC PR 522M. Hayes LHC PR 522).).

b4(sys)=b4(sys)= -0.005 – -0.005 – injinj

b4(ran)=b4(ran)= 0.14 - inj 0.14 - inj

b4(sys)=b4(sys)= -0.008 - -0.008 - collcoll

b4(ran)=b4(ran)= 0.21 - coll 0.21 - coll




1111

Stage 1: initial commissioning - Stage 1: initial commissioning - VIIVII

Octupolar correctorsOctupolar correctors

Lattice octupoles: all SSS not equipped with Lattice octupoles: all SSS not equipped with MQT or MQS are equipped with a Landau MQT or MQS are equipped with a Landau octupole (octupole (MOMO) -> ) -> 168 per ring168 per ring

Not used at injectionNot used at injection

Used to stabilise the beams at top energy (Used to stabilise the beams at top energy (before before starting beam collisionsstarting beam collisions). Under the beam ). Under the beam conditions of the initial commissioning they should conditions of the initial commissioning they should not be usednot be used

However, the beam brightness is the relevant However, the beam brightness is the relevant parameter (parameter (e.g. TOTEM, see E. Métral and A. e.g. TOTEM, see E. Métral and A. Vérdier LHC PN 345Vérdier LHC PN 345))

MCO might not be needed from day 1.MCO might not be needed from day 1.

MO are not needed from day 1, but…MO are not needed from day 1, but…



1212

Stage 1: initial commissioning - Stage 1: initial commissioning - VIIIVIII

Decapolar Decapolar correctorscorrectors

Spool pieces: Spool pieces: MBs type A are MBs type A are equipped with equipped with decapolar decapolar correctors correctors ((MCDOMCDO))

Specification (Specification (S. S. Fartoukh O. Fartoukh O. Brüning Brüning LHC PR LHC PR 501501) based on ) based on bound on Q’’’ and bound on Q’’’ and chromo-geometric chromo-geometric detuning (detuning (b5 has b5 has an impact on an impact on dynamic dynamic apertureaperture))




1313

Stage 1: initial commissioning Stage 1: initial commissioning - IX- IX

A possible solution for MCO and MCD A possible solution for MCO and MCD correctors would be to suppress them only in correctors would be to suppress them only in few arcs (few arcs (see M. Hayes LHC PR 522see M. Hayes LHC PR 522).).

To be checked with the latest version of the To be checked with the latest version of the LHC layoutLHC layout



1414

Stage 1: initial commissioning Stage 1: initial commissioning - X- X

Spectrometer compensator magnets (Spectrometer compensator magnets (IP2IP2 and and IP8IP8))

Since the first physics run, the spectrometers of Since the first physics run, the spectrometers of ALICE and LHC-b will be on. ALICE and LHC-b will be on.

Hence the three warm magnets/IP used to Hence the three warm magnets/IP used to compensate the bump should be available compensate the bump should be available from day 1from day 1



1515

Stage 1: initial commissioning Stage 1: initial commissioning - XI- XI

Nonlinear corrector package in the triplet Nonlinear corrector package in the triplet quadrupolesquadrupoles

No impact on machine performance if beta* > 1 mNo impact on machine performance if beta* > 1 m

Not needed from day 1, but maybe MQSX and Not needed from day 1, but maybe MQSX and MCSX in IP2MCSX in IP2



1616

Stage 1: initial commissioning - Stage 1: initial commissioning - XIIXII

Experimental solenoidsExperimental solenoids

They will not be rampedThey will not be ramped

Effect negligible at top energy (Effect negligible at top energy (see J.-P. Koutchouk et see J.-P. Koutchouk et al. SL-94-33al. SL-94-33))

At injection At injection CC- - ~ 5×10~ 5×10-3-3 for the CMS solenoid (H. for the CMS solenoid (H. Burkhardt, LOC meeting)Burkhardt, LOC meeting)

MQSXMQSX could be used to correct the coupling from could be used to correct the coupling from solenoids -> work in progress (solenoids -> work in progress (H. Burkhardt et al.H. Burkhardt et al.))

Vertical crossing angle in IP2Vertical crossing angle in IP2

Change of polarity in spectrometer will change a2 Change of polarity in spectrometer will change a2 generated from feed-down of b3. generated from feed-down of b3.

a2 correction with a2 correction with MQSXMQSX not possible for both beams not possible for both beams and with and with MQSMQS not effective not effective

MCSXMCSX could be used to correct the b3 could be used to correct the b3



1717

Stage 1: initial commissioning - Stage 1: initial commissioning - XIIIXIII

RF system (RF system (see T. Linnecar Chamonix 2005 for RF see T. Linnecar Chamonix 2005 for RF failuresfailures))

Independent for each ringIndependent for each ring

TwoTwo modules of modules of 44 cavities each. Each cavity delivers cavities each. Each cavity delivers 2 MV2 MV

Nominal conditions: Nominal conditions: 8 MV8 MV at injection and at injection and 16 MV16 MV at at top energytop energy



1818

Stage 1: initial commissioning - Stage 1: initial commissioning - XIVXIV

8 MV at injection leaves margin for beam loading 8 MV at injection leaves margin for beam loading from nominal beamfrom nominal beam

For reduced beam intensity one might think of using For reduced beam intensity one might think of using onlyonly 8 MV 8 MV throughout the whole cycle ->throughout the whole cycle -> only one only one module module would be usedwould be used

However:However:

it would be wise to capture with full voltage (16 it would be wise to capture with full voltage (16 MV) during stage 1 to have maximum longitudinal MV) during stage 1 to have maximum longitudinal acceptance (e.g. energy errors between SPS/LHC)acceptance (e.g. energy errors between SPS/LHC)

No spare would be available and commissioned in No spare would be available and commissioned in case of problemscase of problems

Hence, all modules should be available from day Hence, all modules should be available from day 11



1919

Stages 2 and 3Stages 2 and 3

Beam conditions will approach the nominal Beam conditions will approach the nominal ones.ones.

All the corrector circuits will be needed to All the corrector circuits will be needed to ensure the performanceensure the performance

No staging seems possibleNo staging seems possible



2020

Conclusions - IConclusions - IStage 1:Stage 1:

Circuits mandatory for day 1:Circuits mandatory for day 1:Orbit correctorsOrbit correctorsMQTs, MQTLs, MQSMQTs, MQTLs, MQSMCS, MSMCS, MSSpectrometer compensatorsSpectrometer compensatorsAll RF modulesAll RF modules

Circuits required for day 2(!):Circuits required for day 2(!):MCD (decapoles)MCD (decapoles)MCO (octupoles)MCO (octupoles)MQSXMQSXMCSX in IP2MCSX in IP2MOMO

Circuits not required for day 1:Circuits not required for day 1:MSSMSSNonlinear correctors in the triplet Nonlinear correctors in the triplet quadrupolesquadrupoles

Stages 2 and 3:Stages 2 and 3:Put in operation all the circuits still missingPut in operation all the circuits still missing



2121

Conclusions - IIConclusions - II

Some additional details are needed for Some additional details are needed for evaluating the (beneficial) impact of reducing evaluating the (beneficial) impact of reducing the number of circuits required in the various the number of circuits required in the various stages of LHC commissioning, namelystages of LHC commissioning, namely

What is the time required for the hardware What is the time required for the hardware commissioning of the circuits not required for commissioning of the circuits not required for day 1?day 1?

Is it possible to perform the hardware Is it possible to perform the hardware commissioning in case it is found that they are commissioning in case it is found that they are actually needed? actually needed?

In this case what would be the time required to In this case what would be the time required to commission the circuits?commission the circuits?

massimo giovannozzichamonix xv, january 23-27 20061 electrical circuits required for the minimum...

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