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W. Venturini Delsolaro, AT MTM

Status of Block 4 measurement programs and draft proposal of special measurements on MS and DS quadrupoles. W. Venturini Delsolaro, AT MTM. FQWG meeting, 19 September 2006. Outline. Correctors Status of the measurement program Updates on corrector measurements

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W. Venturini Delsolaro, AT MTM

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  1. Status of Block 4 measurement programs and draft proposal of special measurements on MS and DS quadrupoles W. Venturini Delsolaro, AT MTM FQWG meeting, 19 September 2006

  2. Outline • Correctors • Status of the measurement program • Updates on corrector measurements • MS and DS quadrupoles • Results of TF and harmonics measurements • Special measurements: preliminary results • Proposal of special measurements program

  3. Correctors in SM18

  4. Correctors in B4 The program was delayed by MQTL acceptance tests (finished at the end of June 2006) Done in 2006 The rest can still be achieved at the end of 2006 and beginning of 2007, on spare magnets

  5. MCBC TF, 2 apertures, (1.9 K)

  6. MCBY TF, 4 apertures (4.4 K)

  7. MQTL (SSW and B4, completing the puzzle)

  8. Lattice Sextupoles

  9. MQM results • 18 magnets measured: ΔB2 and harmonics on load lines Good W-C correlations (complete data published in 2 memos) b3 warm-cold a3 warm-cold

  10. MQM TF (relative)

  11. MQY results • 12 magnets measured: ΔB2 and harmonics on load lines Good W-C correlations as for MQM, (save for b6: permeability?) b6 warm-cold (cold on horizontal axis) b3 warm-cold

  12. MQY TF (relative)

  13. Special measurements proposed (I)Cycles for operation at 450 GeV • Aim: assess the influence of a modified pre-cycle (i.e. with a lower flat top current due to “missing commissioning”) on the transfer function and on the field harmonics • Procedures: Measure on load lines up to the equivalent of 450 GeV, varying the flat top current in the pre cycles (current levels to be specified), including a standard cycle. • Number of measurements: 2 MQM and 2 MQY (approx 3 weeks cold tests)

  14. (II) Decay as a function of the injection current • Aim: determine the variation of the decay amplitude (of the main field and of the harmonics) as a function of the injection current (which is different from magnet to magnet) • Procedures: Measure on LHC cycles, varying the injection current (current levels to be specified) • Number of measurements: 2 MQM and 2 MQY (approx 3 weeks cold tests)

  15. (III) Decay as a function of the pre-injection and injection time • Aim: investigate the variation of the decay amplitude with pre injection and injection times • Procedures: Measure on LHC cycles, varying the injection time • Number of measurements: 2 MQM and 2 MQY (approx 3 weeks cold tests)

  16. (IV) Squeeze Cycles • Aim: investigate the variation of the main field and of the harmonics during the squeeze, with respect to what can be expected from the results of standard measurements • Procedures: Measure on LHC cycles including squeezing; measure decay on stopping the ramp during squeeze • Number of measurements: 2 MQM and 2 MQY (approx 1.5 months cold tests)

  17. (V) Influence of other pre cycle parameters: flat top duration, ramp rate • Aim: Verify the possibility of gaining time by shortening the operational cycles ( increase integrated luminosity) • Procedures: Measure on LHC cycles, varying one parameter at a time • Number of measurements: 2 MQM and 2 MQY (approx 1 month cold tests)

  18. (VI) Influence of the acceleration parameter at the start of the rampVerify following conjecture: the snapback path in the field-current plane is (practically) independent of ramp rate • Aim: In case beam is lost during snapback, the possibility to slow down, “stretching” the snapback phase would ease operation, allowing measurement and correction of the beam parameters, to recover then the standard cycle • Procedures: LHC cycles, varying the parabola coefficient at the start of the ramp • Number of measurements: 1 MQM and 1 MQY (approx 2 weeks cold tests)

  19. Influence of acceleration parameter: preliminary results • Ramp rate (non)-dependence of b6 snapback in MQY • Acceleration parameter I(t)=γ I2

  20. (VII) Current unbalances between apertures • Aim: measure the cross talk between apertures (up to 20% unbalance) • Procedures: to be defined • Number of measurements: 1 MQM and 1 MQY (2 weeks cold tests) • Tests to be carefully prepared with the people in charge of the PC (risk of damaging PC)

  21. (VIII) Ramp rate effects (Field advance) • Aim: Tracking between different circuits • Procedures: Measurement with fixed coils and integrators (fast acquisition) • Number of measurements: to be defined

  22. Conclusions • Still a lot of work to finish cold magnetic measurements of correctors (and MQTL) • Standard measurements on MS and DS quads almost done • A detailed extended program is proposed (6-7 months cold, excluding preparations) • Requires focus and resources in 2007

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