1. M. Karppinen TE-MSC-ML On behalf of CERN-FNAL collaboration
11 T Dipole for DS
M. Karppinen TE-MSC-ML
On behalf of CERN-FNAL collaboration
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)

2. 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
May 2, 2011
M. Karppinen TE-MSC-ML

3. DS Upgrade Scenarios halo
Shift 12 Cryo-magnets, DFB, and connection cryostat in each DS
-4.5 m shifted in s
halo
+4.5 m shifted in s
transversely shifted by 4.5 cm
New ~ m shorter Nb3Sn Dipoles (2 per DS)
May 2, 2011
M. Karppinen TE-MSC-ML

4. Cryo-collimator Courtesy of D. Ramos 3061 1541 May 2, 2011
M. Karppinen TE-MSC-ML

5. May 2, 2011
M. Karppinen TE-MSC-ML

6. 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??
May 2, 2011
M. Karppinen TE-MSC-ML

7. Magnet Design Constraints
∫BdL = Inom = 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
May 2, 2011
M. Karppinen TE-MSC-ML

8. Nb3Sn Superconductor
Nb3Sn critical parameters (Jc, Bc2 and Tc) very attractive for accelerator magnets
Requires (long) heat 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)
May 2, 2011
M. Karppinen TE-MSC-ML

9. Nb3Sn Accelerator Magnet R&D Progress
Year
Laboratory
Magnet type (name)
Results
1967
BNL
quadrupole
85 T/m (3 T)
1979
dipole
4.8 T
1982
CERN
71 T/m
1983
CEN/Saclay
5.3 T
1985
LBNL
dipole (D10)
8 T
1986
KEK
4.5 T
1988
7.6 T
1991
CERN/ELIN
9.5 T
1995
dipole (hybrid D19H)
8.5 T UT
dipole (MSUT)
11.2 T
1996
dipole (D20)
13.3 T
2003
dipole (RD3c)
10 T
2004-6
Fermilab
dipole (HFDA05-07)
2008
dipole (HD2)
13.4 T
A. Zlobin, PAC-2011
Both the performance and the technological aspects of the Nb3Sn strands and accelerator magnets have significantly advanced.
May 2, 2011
M. Karppinen TE-MSC-ML

10. 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
May 2, 2011
M. Karppinen TE-MSC-ML

11. 11 T Model Program
May 2, 2011
M. Karppinen TE-MSC-ML

12. 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
May 2, 2011
M. Karppinen TE-MSC-ML

13. 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
May 2, 2011
M. Karppinen TE-MSC-ML

14. Cable & Insulation 250 m Nb3Sn cable produced Jc measurements underway
First CERN cabling run expected Beg-May
May 2, 2011
M. Karppinen TE-MSC-ML

15. Measured Jc (rectangular cable)
Courtesy of E. Barzi, FNAL
May 2, 2011
M. Karppinen TE-MSC-ML

16. Working point & EM Forces
Measured Jc
OST 108/127
Ø0.70 mm
10% degr.
80.4%
May 2, 2011
M. Karppinen TE-MSC-ML

17. 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
May 2, 2011
M. Karppinen TE-MSC-ML 17

18. 2-in-1 & 1-in-1 Models B0(11.85 kA) = 11.21 T B0(11.85 kA) = 10.86 T
May 2, 2011
M. Karppinen TE-MSC-ML

19. 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.
May 2, 2011
M. Karppinen TE-MSC-ML

20. Design Parameters
Note: Cryostat, beam-screen, beam-pipe, (slight) permeability of collars not included
May 2, 2011
M. Karppinen TE-MSC-ML

21. AP: Effects to be expected
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
~ 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:
May 2, 2011
M. Karppinen TE-MSC-ML

22. difference in radial coordinate standard LHC – Nb3Sn LHC local result
Courtesy of B. Holzer
difference in radial coordinate
standard LHC – Nb3Sn LHC
local result
Δx ≈7 mm
May 2, 2011
M. Karppinen TE-MSC-ML

23. Transfer Function Correction
Below Inom 11 T Dipole is stronger than MB
MCBM A
MCBCM 2.8 A
MCBYM A
May 2, 2011
M. Karppinen TE-MSC-ML

24. 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,
but partially compensated in a closed 180 degree bump
ΔΦ = ≈ modulo180 degree
one Nb3Sn magnet
Δx ≈ ± 15 mm
May 2, 2011
M. Karppinen TE-MSC-ML

25. 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 ≈ mm
 ≈ 5 σ at 3.5 TeV
corrected by 20 orbcor dipoles
two Nb3Sn magnets
May 2, 2011
M. Karppinen TE-MSC-ML

26. ! 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 ≈ phase relation,
closed by MCBH correctors
MCBH corrector strength:
available: Tm
needed: Tm
= 42 % !
May 2, 2011
M. Karppinen TE-MSC-ML

27. New RB Circuit (Type 1) Trim2 Trim1 Main Power Converter
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
May 2, 2011
M. Karppinen TE-MSC-ML

28. Nested Trim Circuit 11 T Dipole current needs to be reduced
May 2, 2011
M. Karppinen TE-MSC-ML

29. Coil Magnetization MB (NbTi) 11 T Dipole Nb3Sn >10 X
Mid-Plane Inner Layer
Mid-plane Outer layer
Inner Layer Pole
Outer Layer Pole
May 2, 2011
M. Karppinen TE-MSC-ML

30. Persistent Current Effects
May 2, 2011
M. Karppinen TE-MSC-ML

31. Persistent Current Effects
May 2, 2011
M. Karppinen TE-MSC-ML

32. Additional Correctors?
MCS B3 = Tm
MCD B5 = Tm
May 2, 2011
M. Karppinen TE-MSC-ML

33. May 2, 2011
M. Karppinen TE-MSC-ML

34. Higher Multipoles 11 T Dipole Main Dipole May 2, 2011b9 b9
May 2, 2011
M. Karppinen TE-MSC-ML

35. Sagitta: Feed Down Effects: Courtesy of B. Holzer l ρ aperture
Δr = s l ρ
aperture
feed down effects φ
Feed Down Effects:
Bdl I b3(syst) b3(pc) Σb Bρ
450 GeV Tm A *103 Tm
3.5 TeV Tm A *104 Tm
7 TeV Tm A *104 Tm
May 2, 2011
M. Karppinen TE-MSC-ML

36. Feed Down Effects: Courtesy of B. Holzer Quadrupole Error: Tuneshift:
Beta Beat
k1l ΔQ
Δβ/β
450 GeV
2.79*10-3
0.031
20%
3.5 TeV
2.35*10-4
1.76%
7 TeV
2.41*10-4
1.80%
Phase 1 D1
b3=3*10-4
0.0059
3.9%
considered as
tolerance limit (DA)
per Magnet
May 2, 2011
M. Karppinen TE-MSC-ML

37. Field Quality: Dynamic Aperture Studies collision optics, 7 TeV
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.
May 2, 2011
M. Karppinen TE-MSC-ML

38. Field Quality: Dynamic Aperture Studies
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.
May 2, 2011
M. Karppinen TE-MSC-ML

39. 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 GeV can be tolerated up to ˜20 units, which seems achievable (passive shimming, B3 corrector..).
May 2, 2011
M. Karppinen TE-MSC-ML

40. 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.
May 2, 2011
M. Karppinen TE-MSC-ML

41. 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
[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
May 2, 2011
M. Karppinen TE-MSC-ML

42. Acknowledgements R. Assmann, R. Denz, G. De Rijk, P. Fessia,
Milanese, R. Ostojic, D.Ramos, H. Thiessen,
E. Todesco
May 2, 2011
M. Karppinen TE-MSC-ML