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Conductor for LHC Upgrades Hi- Lumi -LARP Annual Meeting Frascati , November 2012 A. Ballarino

Conductor for LHC Upgrades Hi- Lumi -LARP Annual Meeting Frascati , November 2012 A. Ballarino. Ballarino, B. Bordini , L. Bottura, L. Oberli and L. Rossi CERN, European Center for Nuclear Research, Geneva Switzerland. LHC Performance . LHC: week 43 E= 4 TeV /beam

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Conductor for LHC Upgrades Hi- Lumi -LARP Annual Meeting Frascati , November 2012 A. Ballarino

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  1. Conductor for LHC Upgrades Hi-Lumi-LARP Annual Meeting Frascati, November 2012 A. Ballarino Ballarino, B. Bordini, L. Bottura, L. Oberli and L. Rossi CERN, European Center for Nuclear Research, Geneva Switzerland

  2. LHC Performance LHC: week 43 E= 4 TeV/beam Peak luminosity = 7.51033 cm-2 s-1 Int. luminosity in 2012 = 18.4 fb-1 Courtesy of S. Myers, June 2012 A. Ballarino

  3. LHC Performance LUMINOSITY  BEAM INTENSITY H-Lumi Meeting, Frascati, Nov. 2012 A. Ballarino

  4. Conductor for HE accelerator magnets • To maintain luminosity, particle losses must be limited. • Multiple field errors lead to particle losses which reduce the • beam lifetime FIELD ERRORS  PARTICLE LOSSES • The field quality specification must meet the criteria for stability • and control of the beam FIELD QUALITY  STABILITY AND CONTROL OF THE BEAM A. Ballarino

  5. Conductor for HE accelerator magnets DA calculations: Courtesy of B. Holzner 11 T Dipole Project • A single IR with 2 modified bending dipoles with a b3 (sextupole) error in the range of few 10-3 would induce a visible degradation • Compensations and corrections are feasible, but result in reduced flexibility(e.g. new ATS optics where local  can be increased by a factor 5) |b3| < 27 units Effect of sextupole components on dynamic aperture of the beam A. Ballarino

  6. Conductor for Hi-Luminosity LHC 11 T Dipole Project Injection current (760 A) • The effect of “large” filaments is twofold: • Larger absolute field error • Larger field swing (penetration) Effect of Nb3Sn magnetization on the sextupole field of a 11 T DS-MB operated at 1.9 K Deff < 30 m A. Ballarino

  7. 1 1.5 2 2.5 3 3.5 4 200 150 100 50 Conductor Specification Performance Peak field Cost JC (kA/mm2) Hi-Luminosity wire target performance: Jc > 2.5 kA/mm2 Dfil < 30 m RRR > 150* Dream wire target performance: Jc > 3 kA/mm2 Dfil < 20 m RRR > 150* * Virgin strand target Magnetization Field Quality Stability 10 20 50 100 RRR (-) Dfil (m) Stability Protection A. Ballarino

  8. Specification of conductor A. Ballarino

  9. Magnetization instability (1/3) Measurement of several virgin strands in the VSM CERN test station - different temperatures (1.9 K to 14.5 K, He gas environment) - different fields (up to 10.5 T) RRP PIT 54/61 108/127 132/169 198/217 114 192 A. Ballarino

  10. Magnetization instability (2/3) Jc, Deff, RRR Measurements by D. Richter A. Ballarino

  11. Magnetization instability (3/3) RRP, 11 T Dipole Project PIT, 11 T Dipole Project Measurements by D. Richter Deff of RRP wires larger (12 %-23 %) than diameter of sub-elem. before reaction Deff of PIT wires  diameter of sub-elem. before reaction A. Ballarino

  12. Self-field instability (1/4) Bordini’s plot A. Ballarino

  13. Self-field instability (2/4) • Ic-station equipped with a 100 um core optical fibre • Fibre connected to Q-Switched UV-Laser 355 nm (or 532 nm green) • Other end of the fibre is on top of the strand • Strand is mounted on a VAMAS barrel • Pulse width ~1 ns! • Single shot • 26 uJ/pulse absorbed energy • Attenuator (2%-100%) • 0.5 uJ – 26 uJ PhD Thesis of E. Takala [2] E. Takala et. al., “An Experimental Setup to Measure the Minimum Trigger Energy for Magneto-Thermal Instability in Nb3Sn Strands”, IEEE Trans. Appl. Supercond. vol. 22 no. 3, pp. 6000704, 2012. A. Ballarino

  14. Full characterization with the LQT System of RRP 108/127,   0.7 mm (11 T dipole strand) Self-field instability (3/4) RRR = 129 4.3 K 1.9 K Jc(4.3 K,12 T) = 2670 A/mm2 11.2 T E. Takala A. Ballarino

  15. Self-field instability (4/4) 0.7 mm RRP: RRR 21 vs 129 at 4.3 K E. Takala Review paper of A. Ghosh, ASC 2012, 4MF-01 A. Ballarino

  16. Mechanical properties Icvs transversal stress – Strand Measurements at UNIGE PIT 288,  = 1.25 mm G. Mondonico, UNIGE A. Ballarino

  17. HFM Nb3Sn cables FRESCA 2 cable PIT 192 Rectangular un-cored cable PIT 192 , 40 strands,  = 1 mm (cabled) RRP 132/169, 40 strands,  = 1 mm Width = 20.9 mm Thickness = 1.82 mm Transposition pitch = 120 mm Compaction factor = 87.6 % Measured Ic degradation (extracted strands) ≤ 5 % Up to now, only Fresca cables from PIT strands were made at CERN A. Ballarino

  18. HFM Nb3Sn cables FRESCA 2 cable RRR of extracted strands Performanceof PIT round strands are according to specification Round shaped filaments enable a concentric movement of the Nb3Sn reaction front  high Jc and high RRR A. Ballarino

  19. HFM Nb3Sn cables 11 T cable Keystoned cored cable Core = AISI 316 L, 12 mm width, 25 μm thickness RRP 108/127, 40 strands,  = 0.7 mm (cabled) PIT 102 , 40 strands,  = 0.7 mm (to be cabled in the next weeks) Width = 14.7 mm Transposition pitch = 100 mm Keystone angle = 0.79o Compaction factor = 87.3 % Measured Ic degradation (extracted strands) cored cables ≤ 1 % Cored cable (UL = 230 m) A. Ballarino

  20. Mechanical properties Icvs transversal pressure – Cable 11 T cable: 40 strands, =0.7 mm, RRP 108/127, Ic(4.2 K, 11.T)=17.6 kA Measurements @ Twente University A. Ballarino

  21. Mechanical properties Icvs transversal pressure – Cable CERN sample holder A. Ballarino

  22. Irradiation (1/4) • High Lumi LHC target: integrated luminosity (3000 fb-1). • Triplet quadrupole cables and insulators will undergo the following radiation peak values: • ~ 100 MGy (dose) • ~ 1016 pions/cm2 • ~ 2 x 1017 neutrons/cm2 Neutrons 87.0 % Protons 3.2% Pions (+/-) 9.8% F. Cerutti A. Ballarino

  23. Irradiation (2/4) • 24 GeVproton irradiation at CERN, IRRAD1 (PS beam). Up to 3×1013 p/cm2 per hour. Maximum fluence of 1017 p/cm2 has been accumulated during 2011 and 2012 • 1.4 GeVproton irradiation at CERN on ISOLDE target (booster beam). Catherall. Relatively high fluences >1017 p/cm2 can be achieved within one week • 65 MeV proton irradiation at Cyclotron of Universitécatholique de Louvain (UCL). About 8×1015 p/cm2 per hour. Maximum fluence was 1017 p/cm2 • 30 MeV proton irradiation of Nb3Sn and Ic transport current measurement samples planned at Kurchatov Institute, Moscow. Maximum targeted fluence is 1018 p/cm2 • Fastneutron irradiation at the TRIGA reactor in Vienna A. Ballarino

  24. Irradiation (3/4) Fast neutron irradiation at the TRIGA reactor in Vienna RRP +Ta, =0.8 mm RRP + Ti, =0.8 mm PIT +Ta, =1 mm IT +Ta, =1.25 mm A. Ballarino

  25. Irradiation (4/4) R. Flukiger et al. ASC 2012, Neutron irradiation: Variation of Jc with increasing neutron fluence A. Ballarino

  26. Conclusions • Upgrading the LHC will not be easy • Today’s wires and cables are perfectly adequate for the model and prototyping phase • Nb3Sn needs a final push to demonstrate the quality, uniformity and yield required by the two main magnet phases of HL-LHC (11 T, quads) A. Ballarino

  27. Thanks for your attention ! A. Ballarino

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