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11 T Dipole for DS. B . Auchmann , L. Bottura , B . Holzer , L . Oberli , L . Rossi, D. Smekens ( CERN) N, Andreev, G. Apollinari , E. Bartzi , R. Bossert , F . Nobrega , I. Novitski , A. Zlobin ( FNAL). M. Karppinen TE-MSC-ML On behalf of CERN-FNAL collaboration.
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11 T Dipole for DS B. Auchmann, L. Bottura , B. Holzer, L. Oberli, L. Rossi, D. Smekens (CERN) N, Andreev, G. Apollinari, E. Bartzi, R. Bossert, F. Nobrega, I. Novitski, A. Zlobin(FNAL) M. Karppinen TE-MSC-ML On behalf ofCERN-FNAL collaboration
Collimation Phase II Upgrade in DS • 2013: IR3 (Decision in June) • 2017: IR7 & IR2 (IR3?) • 2020: IR1,5 as part of HL-LHC • Base-line is re-location of magnets to create space for 4.5 m long warm collimator • Cryo-collimator is an R&D project M. Karppinen TE-MSC-ML
DS Upgrade Scenarios halo Shift 12 Cryo-magnets, DFB, and connection cryostat in each DS transversely shifted by 4.5 cm halo New ~3..3.5 m shorter Nb3Sn Dipoles (2 per DS) -4.5m shifted in s +4.5 m shifted in s M. Karppinen TE-MSC-ML
Cryo-collimator 3061 1541 Courtesy of D. Ramos M. Karppinen TE-MSC-ML
Strong DS-Dipole • Plan A (Cryo-collimator, L ≈ 3 m): • 1 x (11.2 T x 10.6 m) magnet, Lcoldmass ≈ 11 m, (MB -4.2 m) => 8 coldmass + 2 spares = 10 CM by 2017 • 2 x (11.2 T x 5.3 m) magnets, Lcoldmass ≈ 11.5 m, (MB -3.7 m) => 16 coldmass + 4 spares = 20 CM by 2017 • Plan B (Warm collimator, L = 4.5 m): • 4 x (11 T x 5.3 m) dipoles, Lcoldmass ≈ 23.0 m • Approx. 7.3 m for collimator and local orbit / higher order correctors (and ICs, bus-bar lyras etc..) => 32 coldmass + 8 spares = 40 CM by 20?? M. Karppinen TE-MSC-ML
Magnet Design Constraints • ∫BdL = 119.2 Tm @ Inom = 11.85 kA • 2-in-1 design, intra-beam distance 194 m • Aperture: Sagitta: 11 m – 5.0 mm, 5.5 m – 1.3 mm => Ø60 mm aperture and straight cold mass • Cold mass outer contour from MB • Heat exchanger location as in MB • 20 % operation margin on the load-line • Field harmonics at 10-4 level (TBC by AP) • Maximum use of existing tooling and infrastructure in both labs M. Karppinen TE-MSC-ML
Nb3Sn Superconductor • Nb3Sn critical parameters (Jc, Bc2 and Tc) very attractive for accelerator magnets • Requires (long) heat treatment @ 680 °C => Only inorganic insulation materials • Brittle, strain sensitive after reaction • Requires vacuum impregnation with resin => less efficient heat extraction by He • Magneto-thermal instabilities => small filaments, small strands, high RRR • Filaments ~50 µm (NbTi 6 µm) • Persistent current effects • Cost ~5 x NbTi • Limited supply and only few suppliers (compared to NbTi) M. Karppinen TE-MSC-ML
Nb3Sn Accelerator Magnet R&D Progress Both the performance and the technological aspects of the Nb3Sn strands and accelerator magnets have significantly advanced. A. Zlobin, PAC-2011 M. Karppinen TE-MSC-ML
Nb3Sn Magnet R&D at Fermilab • Nb3Sn accelerator magnet R&D at Fermilab since 1999 focusing first on small aperture 10 T dipoles for VLHC • Since 2005 focus on large aperture 200 T/m quads for the LHC upgrade. A. Zlobin, PAC-2011 M. Karppinen TE-MSC-ML
11 T Model Program M. Karppinen TE-MSC-ML
End-2011 1-in-1 Demo End-2012 2-in-1 #1 FNAL Coils Mid-2013 2-in-1 #2 CERN Coils End-2013 5.5 m Model M. Karppinen TE-MSC-ML
Production Phase 2014-17 • Coil production (CERN & FNAL) • Collaring (CERN & FNAL) • Cold mass assembly (CERN) • Cryostat integration (CERN) • Testing (CERN) • Installation in the tunnel • Material cost for 20 off 5.5 m CM ~25 MCHF 3..4 years M. Karppinen TE-MSC-ML
Cable & Insulation 250 m Nb3Sn cable produced Jc measurements underway First CERN cabling run expected Beg-May M. Karppinen TE-MSC-ML
Measured Jc (rectangular cable) Courtesy of E. Barzi, FNAL M. Karppinen TE-MSC-ML
Working point & EM Forces Measured Jc OST 108/127 Ø0.70 mm 10% degr. 80.4% M. Karppinen TE-MSC-ML
Coil Ends & Practice Coil First practice coil wound with SLS end spacers Yoke cut-back determined such that the Bp is in the straight section M. Karppinen TE-MSC-ML 17
2-in-1 & 1-in-1 Models B0(11.85 kA) = 11.21 T B0(11.85 kA) = 10.86 T M. Karppinen TE-MSC-ML
1-in-1 Demonstrator Mechanical Structure • The 25-mm thick slightly elliptical stainless steel collar. • The vertically split iron yoke clamped with Al clamps. • The 12-mm stainless steel skin. • Two 50-mm thick end plates. • The coil pre-stress at room temperature is 100 MPa to keep coil under compression up to 12 T. • The mechanical structure is optimized to maintain the coil stress below 160 MPa - safe level for brittle Nb3Sn coils. A. Zlobin, PAC-2011 The structure and assembly tooling design is in progress. M. Karppinen TE-MSC-ML
Design Parameters Note: Cryostat, beam-screen, beam-pipe, (slight) permeability of collars not included M. Karppinen TE-MSC-ML
Courtesy of B. Holzer • AP: Effects to be expected • magnets are shorter than MB Standards change of geometry • distortion of design orbit by ~7 mm • non-linear transfer function (3.5 TeV) distortion of closed orbit • ~15..20 mm • R-Bends S-Bends edge focusing • feed down effects from sagitta ? • multipole effect on dynamic aperture ? • Analytical approach / Mad-X / Sixtrack Simulations beta beat: tune shift: M. Karppinen TE-MSC-ML
Courtesy of B. Holzer difference in radial coordinate standard LHC – Nb3Sn LHC local result Δx ≈7 mm M. Karppinen TE-MSC-ML
Transfer Function Correction Below Inom 11 T Dipole is stronger than MB MCBM 1.9 Tm @55 A MCBCM 2.8 Tm @100 A MCBYM 2.6 Tm @ 88 A M. Karppinen TE-MSC-ML
Courtesy of B. Holzer The Story of the Transfer Function ... a closed orbit problem effect of nb3sn field error (1.5 Tm) two dipoles distorted orbit, but partially compensated in a closed 180 degree bump ΔΦ = 4.545 ≈ modulo180 degree one Nb3Sn magnet Δx ≈ ± 15 mm M. Karppinen TE-MSC-ML
The Story of the Transfer Function ... a closed orbit problem Courtesy of B. Holzer effect of nb3sn field error (1.5 Tm) two dipoles distorted orbit, and corrected by the “usual methods” x(m) x(m) Δx ≈ -0.5 ... + 1.5 mm ≈ 5 σ at 3.5 TeV corrected by 20 orbcor dipoles two Nb3Sn magnets M. Karppinen TE-MSC-ML
The Story of the Transfer Function ... a closed orbit problem Courtesy of B. Holzer field error corrected by 3 (20) most eff. correctors zooming the orbit distortion ... local distortion due to Δϕ ≈ 4.545 phase relation, closed by MCBH correctors ! MCBH corrector strength: available: 1.900 Tm needed: 0.805 Tm = 42 % M. Karppinen TE-MSC-ML
New RB Circuit (Type 1) Trim2 C8 C9 C10 C11 C8 0.15H RB.A23 0.1H Trim1 Main Power Converter TRIM Power Converters Total inductance:15.5 H (152x0.1H + 2x0.15H) Total resistance: 1mW Output current: 13 kA Output voltage: 190 V Total inductance: 0.15 H Total resistance: 1mW RB output current: ±0.6 kA RB output voltage: ±10 V • (+) • Low current CL for the trim circuits • Size of Trim power converters • (-) • Protection of the magnets • Floating Trim PCs (>2 kV) • coupled circuits Courtesy of H. Thiessen M. Karppinen TE-MSC-ML
Nested Trim Circuit 11 T Dipole current needs to be reduced M. Karppinen TE-MSC-ML
Coil Magnetization >10 X MB (NbTi) 11 T Dipole Nb3Sn Mid-Plane Inner Layer Mid-plane Outer layer Inner Layer Pole Outer Layer Pole M. Karppinen TE-MSC-ML
Persistent Current Effects M. Karppinen TE-MSC-ML
Persistent Current Effects M. Karppinen TE-MSC-ML
Additional Correctors? MCS B3 = 0.0518 Tm MCD B5 = 0.000266 Tm M. Karppinen TE-MSC-ML
Higher Multipoles Main Dipole 11 T Dipole b9 b9 M. Karppinen TE-MSC-ML
Courtesy of B. Holzer Sagitta: Δr = s l ρ • aperture • feed down effects φ Feed Down Effects: Bdl I b3(syst) b3(pc) Σb3 Bρ 450 GeV 7.7 Tm 758 A 13.96 +95.8 109.8 1.5*103 Tm 3.5 TeV 59.6 Tm 5639 A 13.99 -4.72 9.27 1.2*104 Tm 7 TeV 119.1 Tm 11517 A 13.37 +0.44 13.81 2.3*104 Tm M. Karppinen TE-MSC-ML
Courtesy of B. Holzer Feed Down Effects: Quadrupole Error: Tuneshift: Beta Beat considered as tolerance limit (DA) per Magnet M. Karppinen TE-MSC-ML
Courtesy of B. Holzer Field Quality: Dynamic Aperture Studies collision optics, 7 TeV dyn aperture luminosity optics, 7 TeV, minimum of 60 seeds dynamic aperture for ... ideal Nb3Sn dipoles (red) full error table (green) and for completeness: limits in DA for the phase 1 upgrade study (blue) for the experts: the plot shows the minimum DA for the 60 error distribution seeds used in the tracking calculations. M. Karppinen TE-MSC-ML
Courtesy of B. Holzer Field Quality: Dynamic Aperture Studies injection optics, 450 GeV, no spool piece correctors dyn aperture injection optics, minimum of 60 seeds dynamic aperture for Nb3Sn case: full error table (red) b3 reduced to 50% (green) b3 reduced to 25% (violett) b3 = 0 and to compare with: present LHC injection for the experts: unlike to the collision case: at injection the b3 of the Nb3Sn dipoles is the driving force to the limit in dynamic aperture. A scan in b3 values has been performed and shows that values up to b3 ≈ 20 units are ok. Alternative solution: strong local spool piece corrector ... which is being studied at the very moment. M. Karppinen TE-MSC-ML
Summary (1/2) • The magnet technology exists and can meet the requirements. Base-line is 5.5 m long CM. • Magnet design is based on engineering choices proven by the HFM programs and LHC magnet production. • The 2 m 1-in-1 demonstrator magnet is well underway and the engineering design of the 2-in-1 demonstrator is in progress. • First optics studies: • Orbit can be corrected by using a significant factor of corrector strength outside of DS. Trim PC would solve the problem. • b3 @450 GeVcan be tolerated up to ˜20 units, which seems achievable (passive shimming, B3 corrector..). M. Karppinen TE-MSC-ML
Summary (2/2) • The integration into the LHC is common effort with with the (cryo-) collimator R&D. • The time scale of the planned upgrade is challenging and requires close collaboration and parallel production lines at CERN and at FNAL. M. Karppinen TE-MSC-ML
Refs [1] A.V. Zlobin, G. Apollinari, N. Andreev, E. Barzi, V.V. Kashikhin, F. Nobrega, I. Novitski, B. Auchmann, M. Karppinen, L. Rossi “Development Of Nb3sn 11 T Single Aperture Demonstrator Dipole For Lhc Upgrades”, presented at PAC-2011, New York, March 2011. [2] G. de Rijk, A. Milanese, E. Todesco, “11 Tesla Nb3Sn dipoles for phase II collimation in the Large Hadron Collider”, sLHC Project Note 0019, 2010. [2] A.V. Zlobin et al., “Development of Nb3Sn accelerator magnet technology at Fermilab”, Proc. of PAC2007, Albuquerque, NM, June 2007. [3] J. Ahlbäck et al., “Electromagnetic and Mechanical Design of a 56 mm Aperture Model Dipole for the LHC“, IEEE Trans. on Magnetics, July 1994, vol 30, No. IV, pp. 1746-1749 [4] G. Ambrosio et al., “Magnetic Design of the Fermilab 11 T Nb3Sn Short Dipole Model”, IEEE Trans. on Applied Supercond., v. 10, No. 1, March 2000, p.322. [5] M.B. Field et al., “Internal tin Nb3Sn conductors for particle accelerator and fusion applications,” Adv. Cryo. Engr., vol. 54, pp. 237–243, 2008. [6] G. Chlachidze et al., “The study of single Nb3Sn quadrupole coils using a magnetic mirror structure,” presented at ASC’2010, Washington, DC, 2010. [7] V.V. Kashikhin and A.V. Zlobin, “Correction of the Persistent Current Effect in Nb3Sn Dipole Magnets”, IEEE Trans. on Applied Supercond., v. 11, No. 1, March 2001, p. 2058. M. Karppinen TE-MSC-ML
Acknowledgements R. Assmann, R. Denz, G. De Rijk, P. Fessia, • Milanese, R. Ostojic, D.Ramos, H. Thiessen, E. Todesco M. Karppinen TE-MSC-ML