E. Todesco

STATUS OF FIDEL

E. Todesco for the FiDeL teamMagnets, Superconductors and Cryostats Group

Technology Department, CERN

LHC commissioning working group, CERN 25th August 2009

The team:B. Auchmann, L. Bottura, M. Buzio, L. Deniau, P. Hagen, W.

Venturini Delsolaro, M. Giovannozzi, M. Lamont, S. Redaelli, V. Remondino, F. Schmidt, M. Strzelczyk, L. Walckiers, R. Wolf

I wish to acknowledge L. Bottura who bravely started the project long time ago, and R. Wolf who

steered it in 2008

E. Todesco 25th August 2009 – FiDeL status - 2

CONTENTS

Reminder of the structure

What has been done since 2008 runEvaluation of FiDeL parameters for harmonics (MB already done)Model update:

Penetration componentHysteresis implementation

DatabaseDocumentation

Critical issues and future activitiesCyclesTracking testValidation

E. Todesco 25th August 2009 – FiDeL status - 3

REMINDER OF THE STRUCTURE

The new structure implemented in 2009 allowed toReduce the total number of people involved in the project and increase their percentage

More effective, less time wasted for meetings

Most of the staff dedicated to magnet analysis is within one group, one section

Before it was split between three groups

To have only staff members in charge of the dataI wished to avoid having fellows or student in charge of data, to ensure continuity in an extremely critical phase of the commissioning(Ex. N. Sammut, in charge of the MB data, left in March 2009)

Bi-monthly meetings 12 meetings in January-July 2009Minutes on www.cern.ch/fidel

E. Todesco 25th August 2009 – FiDeL status - 4

REMINDER OF THE STRUCTURE

Each magnet family has a custodian (staff member)Evaluate the parameters from the measurementsFollow-up specific issuesWrite the documentationAble to go back to data and perform analysis in case of need

Estimate of used resources in January-July 2009About 5-6 FTE over 6 months (excluding FTE involved in measurements)

Main dipoles MB L. DeniauMain quadrupoles MQ L. DeniauInner triplet MQXA,MQXB E. TodescoSeparation dipoles MBX,MBRS,MBRB,MBRC B. AuchmannIR quads MQM, MQY W. Venturini Delsolaro

Correctors

MSCB, MCBC, MCBY, MCS,MCDO, MCBX(A), MCSTX, MQTL, MQT/S, MQSX, MCSOX V. Remondino

Resistive

MBAW, MBLW, MBW, MBXW, MBXWH, MBXWS, MBXWT, MCBWH/V, MQWA/B P. Hagen

E. Todesco 25th August 2009 – FiDeL status - 5

CONTENTS

Reminder of the structure

What has been done since 2008 runEvaluation of FiDeL parameters for harmonics (MB already done)Penetration componentHysteresis implementationDatabaseDocumentation

Critical issuesCyclesTracking testValidation

E. Todesco 25th August 2009 – FiDeL status - 6

WHAT HAS BEEN DONE IN 2009:EVALUATION OF FIDEL PARAMETERS

2008: TF of all magnets plus field harmonics of MB2009: FiDeL parameters of all field harmonics

Penetration component added (needed for MQM)

Complete review of correctors has been carried out – one minor mistake foundMB to review, and to update 3-4

2008 2009 2008 2009Main dipoles MB Ready in Sept. 08 Review and 3-4 update - Sept. 09 Ready for Sept. 08 To be reviewed in Sept. 09Main quadrupoles MQ Ready in Sept. 08 Review and 3-4 update - June 09 No model Ready in July 2009

Inner triplet MQXA,MQXB Ready in Sept. 08 Updated - June 09 No model Ready in July 2009

Separation dipoles MBX,MBRS,MBRB,MBRC Ready in Sept. 08 Same as 08 No model Ready in July 2009

IR quads MQM, MQY Ready in Sept. 08 Penetration added - June 09 No model Ready in July 2009

Correctors

MSCB, MCBC, MCBY, MCS,MCDO, MCBX(A), MCSTX, MQTL, MQT/S, MQSX, MCSOX Ready in Sept. 08

Reviewed - one mistake corrected - June 09

Resistive

MBAW, MBLW, MBW, MBXW, MBXWH, MBXWS, MBXWT, MCBWH/V, MQWA/B Ready in Sept. 08

In progress - additional measurements - low currents

missing - cross-check with Roxie model No model

In progress - additional measurements - low

currents missing - cross-check with Roxie model

Transfer function Field harmonics

E. Todesco 25th August 2009 – FiDeL status - 7

WHAT HAS BEEN DONE IN 2009:HYSTERESIS

In some MQM during squeeze the current decreases and one should follow the other branch of the hysteresis

LSA in 2009 had only one branch (the lower one), giving for Q6.ip5 an error of 35 units at b*=0.55 m

Q6 in IP5 during squeeze decreasing to low currents – error of 30 units if hysteresis is neglected

0

2

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12

-20

-15

-10

-5

0

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10

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0 1000 2000 3000 4000 5000

b*(m

)

TF

(Uni

ts)

Current (A)

Ramp up

Ramp down

q6.ip5 current vs beta

MQM in Q6 IP5

Injection

Ramp

SqueezeSqueeze

Squeeze

SqueezeIn 2008 at the end of the squeeze LSA would have been there instead Than on the corresponding valueof the upper branch

In 2009 at the end of the squeeze LSA will be there (right place)

E. Todesco 25th August 2009 – FiDeL status - 8

WHAT HAS BEEN DONE IN 2009:HYSTERESIS – MQM and MQY

In some MQM during squeeze the current decreases and one should follow the other branch of the hysteresis

Neglecting this effect is not dramatic, but has some impact on the beam (estimates from Massimo)

This is already modelled in the FiDeL equationsIt is enough to change the sign of the DC magnetization

Decision: LSA should be able to switch from one branch to the other one according to dI/dt

Implemented in July 2009 (Marek S.)To be checked soonIt will be possible to switch off this option

E. Todesco 25th August 2009 – FiDeL status - 9

WHAT HAS BEEN DONE IN 2009:HYSTERESIS – SPOOL PIECES

Other types of hysteresis:Spool pieces (MCS, MCDO) have decreasing currents during injection plateau, due to decay, and then they cross zero current during ramp

Neglecting the hysteresis, has a negligible impact on the beamMarginal for the sextupole spool pieces

TF versus current in MCS showing some hysteresis at low current (note that one square is 1% variation in TF)

9.50E-05

9.60E-05

9.70E-05

9.80E-05

9.90E-05

1.00E-04

1.01E-04

1.02E-04

1.03E-04

1.04E-04

1.05E-04

-1000 -800 -600 -400 -200 0 200 400 600 800 1000

TF

[T m

/ A

]

Current [A]

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-0.04

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rgy

(TeV

)

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ted

b3 (u

nits

)

Time (s)

Uncorrected b3

Energy

b3 to be corrected in the dipoles in one of the octants, with zero crossing at 0.8 TeV

Uncorrected b3 if hysteresis is neglected

E. Todesco 25th August 2009 – FiDeL status - 10

WHAT HAS BEEN DONE IN 2009:HYSTERESIS – other cases

Lattice sextupoles MSWork at very low current (6 and 10 A)At 6 A hysteresis gives 7% difference in TFSince one corrects 90 units …Neglecting this gives 6 units of uncorrected chromaticity

Proper pre-cycle is needed, and DCmagnetization has to be included in the FiDeL parameters (Walter remark)

Some correctors (orbit correctors, MQT, MQS, …) have no nominal settings and can work around zero current

Here, we do not even know on which branch we areOrbit correctors proved to be ok !This effect is deemed to be not important and is neglected for the first phases of commissioningCase of MQT was discussed widely, additional measurements in progress

8.60E-04

8.70E-04

8.80E-04

8.90E-04

9.00E-04

9.10E-04

9.20E-04

9.30E-04

9.40E-04

-800 -600 -400 -200 0 200 400 600 800

Assemblies

Modules

TF of the lattice sextupole MS

E. Todesco 25th August 2009 – FiDeL status - 11

WHAT HAS BEEN DONE IN 2009:PENETRATION COMPONENT

Some MQM and MQY operate below the penetration field

A penetration component with two parameters has been added to the FiDeL equations has been proposed by W. Venturini Delsolaro

)()( IExpAITFp

MQM transfer function: measurements versus FiDeL fit with penetration component

-20

-15

-10

-5

0

5

10

15

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0 1000 2000 3000 4000 5000

TF

(Uni

ts)

Current (A)

Ramp up

Ramp down

Ramp up with penetration

MQM in Q6 IP5

E. Todesco 25th August 2009 – FiDeL status - 12

WHAT HAS BEEN DONE IN 2009:PENETRATION COMPONENT

Some MQM and MQY operate below the penetration field

We now have a model that fits also this behaviourNeglecting this component would have given non-negligible beta-beating (estimates of M. Giovannozzi)

2.1390

2.1440

2.1490

2.1540

2.1590

2.1640

0 1000 2000 3000 4000 5000 6000

Current (A)

TF

(T

m/k

A)

Model all components

data

)()( IExpAITFp

MQM transfer function: measurements versus FiDeL fit with penetration component

E. Todesco 18th August 2009 – FiDeL status - 13

WHAT HAS BEEN DONE IN 2009:DATABASE

FiDeL parameters are stored in Oracle database

Five tables:REFPARM – all parameters, with loading date to track changesREFPARM_2008 and REFPARM_2009 – with 2008 and 2009 values – these tables contain generics

The generics allows avoid repeating several times the same data – easier for input

REFPARM_200X_EXPANDED – with all parameters, expanded – easier for having a global view

Database active in the final form since May 2009 (L. Deniau, P. Hagen, based on the work of R. Wolf)

Easy access to check all parameters

E. Todesco 25th August 2009 – FiDeL status - 14

WHAT HAS BEEN DONE IN 2009:DOCUMENTATION

The information relative to each magnet family is given in a report

To be published as LHC Project NoteInformation about:

Magnet parametersOperational currentsAvailable measurementsEstimate of the transfer function parametersEstimate of the field harmonics parametersOpen issues

250 pages of documentation are already available on the FiDeL web site: http://www.cern.ch/fidel

DocumentationMain dipoles MB End of SeptemberMain quadrupoles MQ DoneInner triplet MQXA,MQXB DoneSeparation dipoles MBX,MBRS,MBRB,MBRC DoneIR quads MQM, MQY End of AugustCorrectors DoneResistive In progress

E. Todesco 25th August 2009 – FiDeL status - 15

FUTURE ACTIVITIES AND CRITICAL POINTS

Complete the documentation

Validation LSA vs FiDeL

Correction of decay and snapback: tracking test

Pre-cycle prescriptions

E. Todesco 25th August 2009 – FiDeL status - 16

FUTURE ACTIVITIES: TRACKING TEST B3

Tracking test campaigns have been carried out in 2007-2008

B1/B2 tracking test: one dipole and one quadrupole powered together – during the ramp one checks the stability of the tune, the ratio between B1 and B2 - success !

B3 tracking test: a dipole ramped with b3 spool pieces – one integral b3 measured to checks the validity of the local correction

Point of view of the beam: needed correction is 0.05 units – obtained correction: 0.3 units

b3 Tracking test, dipole 2624, aperture 1 (left) and aperture 2 (right)

E. Todesco 25th August 2009 – FiDeL status - 17

FUTURE ACTIVITIES: TRACKING TEST B3

Point of view of the magnet:Injection current (geometric+persistent) about -8 units, 0.2 units left (correction works at 98% - good)Decay: about 0.6-1 unit, 0.2 units left (correction works at 65-80%)Snapback and after: about 0.6-1 unit, 0.4 units left (correction works at about 50% - bad) – much longer than snapback … During the ramp: variation of about 7 units reduced to 0.3 units, (correction works at 95% - not bad)Still a lot to understand

New tracking test in SM18Results in SeptemberEmpirical way of correctingAlso important cross-check ofnew measuring system b3 Tracking test, dipole 2598, aperture 1

E. Todesco 25th August 2009 – FiDeL status - 18

FUTURE ACTIVITIES: TRACKING TEST B3

Another relevant point: ramp rateAll SM18 measurements on MB and MQ have been done at 50 A/s ramp rate, different from nominal (10 A/s) – there is a strong impact on decay and snapbackWith 50 A/s the decay and associated snapback is much larger (fatctor two)Rescaling of all measurements to operational conditions is delicate

E. Todesco 25th August 2009 – FiDeL status - 19

FUTURE ACTIVITIES: PRE-CYCLES

Database of pre-cyclesR. Wolf created an Oracle DB in 2007-2008 with optimized pre-cycles based on FiDeL activities and LEP experienceLSA has an Oracle DB of pre-cycles used in the LHC sequencer: this was used during the successful 2008 runA synchronization between the two is needed asap

For the 3.5 TeV runAll efforts should be done to reduce as much as possible the pre-cycle time (nearly 2 h for the MB in the DB of Rob) taking advantage of the reduced energy MB ramp will last 550 s instead of 1000 sDecay proportional to flatop energy at 3.5 TeV we will have half of the decay