1. The HiLumi LHC Design Study is included in the High Luminosity LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. Follow up of powering schemes for IT, Q4 and D1/D2 M. Fitterer, R. De Maria, M. Giovannozzi Acknowledgments: G. Arduini, A. Ballarino, R. Bruce, J.-P. Burnet, E. McIntosh, F. Schmidt, H. Thiesen, E. Todesco and the LHC@Home volunteers

2. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 2 Outline 1.IT powering schemes: a. trim on Q1 b. scaling with β* 2.Update on tolerances from beam dynamics for D1/D2

3. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 3 Trim on Q1 Baseline powering scheme: proposed by WP3 (HL-LHC preliminary Design report) and presented by A. Ballarino, 4 th LHC Parameter and Layout Committee Q1-Q2a Q2b-Q3: proposed by S. Fartoukh -smallest tune shift for current control regime Q1 Q2a Q2b Q3 PC2 17.4 kA PC1 17.4 kA PC3 ±0.2 kA PC4 ±2.0 kA Q1 Q2a Q2b Q3 PC1 17.4 kA PC2 17.4 kA PC3 ±2.0 kA PC4 ±2.0 kA Q1 Q2a Q2b Q3 PC1 17.4 kA PC2 ±2.0 kAPC3 ±0.2 kAPC4 ±2.0 kA Q1-Q2-Q3: -slightly smaller tune shift than Q1-Q2a Q2b-Q3 for current control regime -best compensation voltage control regime => best scheme (for beam dynamics) Ok! PC4 ±2.0 kA move trim at Q3 to Q1 – better for β* measurement with k-modulation

4. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 current control – Baseline powering scheme: closed orbit distortion induced by uniformly distributed random error on current (±1ppm): Using 4 IT powering schemes – dependence on β* Baseline (1ppm) * β* [m]rms((Q z -Q z0 )) [10 -4 ]rms((Q z -Q z0 ))xβ* opt /β* round round0.15/0.151.37 flat0.075/0.301.981.71 sround0.10/0.102.05 sflat0.05/0.202.972.57 * 1 ppm of I max in table on slide 3 and for HLLHCV1.0 optics, β*=0.15/0.15 m

5. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 current control – comparison of powering schemes: closed orbit distortion induced by uniformly distributed random error on current (±1ppm): 5 IT powering schemes – dependence on β* * 1 ppm of I max in table on slide 3 and for HLLHCV1.0 optics, β*=0.15/0.15 m HL-LHC rms((Q z -Q z0 )) [10 -4 ] roundflatsroundsflat IT Baseline 1.371.982.052.97 IT Q1-Q2-Q3 0.670.981.031.46 IT Q1-Q2a Q2b-Q3 0.550.790.831.19 HL-LHC ΔQ z,rms /ΔQ z,rms (IT Baseline) roundflatsroundsflat IT Baselinex1.0 IT Q1-Q2-Q3x0.5 IT Q1-Q2a Q2b-Q3x0.4

6. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 voltage control – comparison of powering schemes: closed orbit distortion induced by uniformly distributed random error on current (±1ppm): 6 IT powering schemes – dependence on β* * 1 ppm of I max in table on slide 3 and for HLLHCV1.0 optics, β*=0.15/0.15 m HL-LHC max((Q z -Q z0 )) [10 -6 ], f=50 Hz roundflatsroundsflat IT Baseline 1.151.431.722.14 IT Q1-Q2-Q3 0.550.680.821.02 IT Q1-Q2a Q2b-Q3 1.101.371.652.05 HL-LHC ΔQ z,max /ΔQ z,max (IT Baseline) roundflatsroundsflat IT Baselinex1.00 IT Q1-Q2-Q3x0.48 IT Q1-Q2a Q2b-Q3x0.96

7. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 current control: closed orbit distortion induced by uniformly distributed random error on current (±1ppm) – trims not taken into account but expected to be negligible: 7 D1/D2 powering schemes class 1 (1ppm) *rms((z-z 0 )) at IP [μm]rms((Q z -Q z0 )) [10 -4 ] D1L-D2L-D1R-D2R 0.0400.027 D1LD2L-D1RD2R 0.0150.010 D1LD2LD1RD2R 0.0110.013 * 1 ppm of I max in table on slide 3 and for HLLHCV1.0 optics, β*=0.15/0.15 m D2L D1L D1R D2R D2L D1L D1R D2R D1L-D2L-D1R-D2R D2L D1L D1R D2R D1LD2L-D1RD2RD1LD2LD1RD2R - better in terms of orbit deviation and tune shift - D1LD2L-D1RD2R and D1LD2LD1RD2R are equivalent worse in terms of orbit deviation and tune shift main PCtrim PC

8. The HiLumi LHC Design Study is included in the High Luminosity LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. Thank you for your attention!

9. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 9 Tolerances Voltage Control Regime (2) current control “determination of the dangerous frequencies” (orange bar) “frequency spectrum” (orange line) Voltage control Q1Q2a Q2bQ3 line superimposed over Baseline ** for SixTrack slhcv31b x1 the IT magnet parameters from 17.02.2014 (e.g. L Q1/Q2/Q3 =10.8 mH/m), the baseline powering scheme and L tot,circuit =L Q1 =L Q3 =L Q2a =L Q2b tune shift: layout HLLHCV1.1, β*=0.15/0.15 m, magnet parameters see slide 5 ** tolerance: minimum limit over all beam constellations with only IT ripple

10. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 10 Tolerances Voltage Control Regime Q1Q2a Q2bQ3 line superimposed over Baseline Baseline + Q4 superimposed over SixTrack slhcv31b x1 due to its small inductance Q4 contributes as much as the IT in the voltage control regime PS, f=50 HzΔQ(Q4)/ΔQ(PS) Baseline0.68 Q1-Q2-Q31.41 Q1-Q2a Q2b-Q30.71 SixTrack slhcv31b x10.49 tune shift: layout HLLHCV1.1, β*=0.15/0.15 m, magnet parameters see slide 5 tolerance: minimum limit over all beam constellations with only IT ripple

11. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 Option to use a trim for one of the Q4 apertures instead of powering each aperture individually: assume: k=const * I with const = k max /(15.65 kA) with k max =(115 T/m)/Brho(7 TeV) and assume trim for Beam 2 aperture: I B2 =I B1 +I trim -> minimum 2 kA trim necessary for the present optics (which is not the final one) 11 Imbalance Q4 apertures Promising idea, but: -The whole squeeze sequence from the pre-squeeze β* to the VDM to has to be re-evaluated for new layout -imbalance between apertures has to be evaluated for alignment optics (to be developed)

12. 21 st HL-LHC TC, Powering schemes for inner triplet, Q4 and D1/D2, 16.04.2015 from WP3 page 31/03/2015 * values scaled from 132.6 T/m gradient to 140 T/m gradient for HLLHCV1.1 optics version (16.47x140/132.6 kA =17.4 kA) 12 Magnet parameters Q1/Q3Q2a/Q2bQ4D1D2 length [m] 2x4.06.83.836.277.78 I max [kA] 17.4 *15.56 12 I [kA] (T itok ) 11.812.0 B (T ItoB ) 140 T/m115 T/m6.6 T5.1 T L [mH/m] 8.210.774.013.51 R [mΩ] 1.144