Caspi and Lucas Brouwer Lawrence Berkeley National Laboratory Berkeley CA USA December 11 th 2012 The CantedCosineTheta Dipole CCT For LBNL High Field Magnet Program PhD student UC Berkeley ID: 233608
Download Presentation The PPT/PDF document "Shlomo" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Shlomo Caspi and Lucas Brouwer*Lawrence Berkeley National Laboratory, Berkeley, CAUSADecember 11th 2012
The Canted-Cosine-Theta Dipole (CCT)For LBNL High Field Magnet Program
*
PhD student UC Berkeley
EDMS 1259004Slide2
Superconducting Magnet Program (SMP)LBNL Superconducting base program R&D on high field magnets is exploring a new dipole magnet (CCT) that specifically promises to reduce high stress on coils while maintaining field quality and efficiency. Diego Arbelaez, Lucas Brouwer, Daniel Dietderich
, Helene Felice, Ray Hafalia, Etienne Rochepault
, Soren PrestemonArno
Godeke, Dan Cheng, Xiaorong Wang, Abdi
Salehi
, Charles Swenson, Tiina Salmi
2
Superconducting Magnet Group - S.Caspi
12/11/2012Slide3
OutlineIntroductionShort historical perspective of high field accelerator magnetsThe Canted-Cosine-Theta (CCT) – A new approachThe CCT and the present LHC dipoleA conceptual 18T CCT dipole magnet
Other CCT applicationsConclusions
3Superconducting Magnet Group - S.Caspi
12/11/2012Slide4
33 years of progress in Nb3Sn technologyAn historical perspective:1979-2012
4Superconducting Magnet Group - S.Caspi
12/11/2012
TargetSlide5
Introduction -Types of superconducting dipoles
5
Superconducting Magnet Group - S.Caspi12/11/2012
D20
RD series
HD series
2D viewSlide6
Introduction -Types of superconducting dipoles
Block with stress managementManaged coil blocks, plates
and laminar spring
Direction of
current
New
Canted-Cosine-Theta (CCT)
With stress interception
6
Superconducting Magnet Group - S.Caspi
12/11/2012
TAMU
3D viewSlide7
The CCT - History of the conceptPublished paper by D.I. Meyer and R. Flasck in 1970(D.I. Meyer, and R. Flasck “A new configuration for a dipole magnet for use in high energy physics application”,
Nucl. Instr.and Methods 80, pp. 339-341, 1970.)
Renewed interest during the past decade
7
Superconducting Magnet Group - S.Caspi
12/11/2012Slide8
CCT MotivationSubstantial reduction in coil stressNo accumulation of Lorentz forces in the windingsSmall and large apertures
A high field quality over 85% of the bore.
Intrinsic to the geometryA
Modular concept with nesting different conductor typesOne style fits all
Natural for grading
Combined function
8
Superconducting Magnet Group - S.Caspi
12/11/2012Slide9
The CCT dipole cross-section
9
Superconducting Magnet Group - S.Caspi
12/11/2012
Areas of current are proportional to
cos
-theta
approaching a perfect dipole current density distributionSlide10
The CCT coil termination
Lambertson-Coupland Termination
Harmonic components over such “ends” integrate to zero
10
Superconducting Magnet Group - S.Caspi
12/11/2012Slide11
“Ends” - Termination HarmonicsDipole field Sextupole integrates to zero
Decapole integrates to zero
11Superconducting Magnet Group - S.Caspi
12/11/2012Slide12
CCT – Stress InterceptionStress interceptors (Ribs), thin on the mid-plane thick at the poles
Single conductor turn
Ribs are part of the stress
collector (Spar)
12
Superconducting Magnet Group - S.Caspi
12/11/2012Slide13
Structural Interception – airplane wing The lift force to the skin is transfer to ribs that are tied to a spar connected to the fuselage
MAIN SPAR
Ties all theRIBS together
RIBS
Transfers the skin loads to the SPAR
13
Superconducting Magnet Group - S.Caspi
12/11/2012Slide14
Splitting the force and intercepting StressThe Lorentz force is split into two orthogonal components:The Lorentz forces along the coil’s surface (
azimuthal and axial, not only in theta) are intercepted by ribs (no accumulation)Intercepted forces are carried by the spar to which the ribs are connected
The radial Lorentz force are partially restrained by the spars and an outer structure
Ribs and Spars = “Cable-in-Conduit”
14
Superconducting Magnet Group - S.Caspi
12/11/2012Slide15
Example: a CCT type LHC dipole
15Superconducting Magnet Group - S.Caspi
12/11/2012
Same bore size and cable as LHC dipole
! bore [mm]
15.35 ! Layer 1 width [mm]
2.15 ! Layer 1 thick [mm]
1.25 ! Layer 1 keystone angle [deg]
15 ! Layer 1 tilted angle [deg]
0.45 ! Layer 1 mid-plane rib thickness) [mm]
0.2857 ! Layer 1
Asc
/
Acable
15.35 ! Layer 2 width [mm]
1.73 ! Layer 2 thick [mm]
0.9 ! Layer 2 keystone angle [deg]
12.54 ! Layer 2 tilted angle [deg]
0.45 ! Layer 2 mid-plane rib thickness) [mm]
0.2462 ! Layer 2
Asc
/
Acable
Same straight section of 0.7m using 41m of cableSlide16
Example: a CCT LHC dipole16Superconducting Magnet Group - S.Caspi12/11/2012
Field
Field quality Stored Energy
Stress Conductor length
Comparison of a canonical LHC dipole with an equivalent CCT
56mm
137
137
693
Coil
Ribs and SparSlide17
Short-sample comparison at 1.9 KShort-Sample
LHC
With-Iron
CCT
With-Iron
56 mm bore, 2 layers, same cables
B
0
(T)
9.7
9.2
B
max
(T)
10.0
9.6
I
max
(kA)
13.8
15.67
J
e
(A/mm^2)
419
475
E
(kJ/m)
334
294
Inductance (mH/m)
3.48
2.39*
S
theta
(MPa)
88
~ 8
*
Courtesy of
Jeoren
Van
Nugteren
17
Superconducting Magnet Group - S.Caspi
12/11/2012
Lower field, proportional to slanted angle
cos
(15)=0.966
Low stress
Similar stored energy and inductance
Similar conductor length
For this comparison we chose to keep the same bore, number of layers, strand sizes and cable sizes.
Choosing other parameters would have raise the field.Slide18
CCT 18Superconducting Magnet Group - S.Caspi
12/11/2012Field (Bmod
) around inner boreField (
Bmod) between layersSlide19
CCT – Harmonics (no-iron)19Superconducting Magnet Group - S.Caspi
12/11/2012CCT - less than 2 units at 85% of the bore
LHC b3 ~ 3 units
b5 ~ -1 unitSlide20
Field profiles along the z axis20Superconducting Magnet Group - S.Caspi
12/11/2012No ironSlide21
Stress on Ribs and Spar
Turn
Ribs
Radial Stress ~ Cos(theta)
Normal Stress
~ Sin(theta)
21
Superconducting Magnet Group - S.Caspi
12/11/2012
Radial forces are intercepted
by spars and structureSlide22
Modeling and Minimum symmetryCoil
Spar with Ribs
Coil Minimum
Symmetry
22
Superconducting Magnet Group - S.Caspi
12/11/2012Slide23
LaminationRibs
Conductor
23Superconducting Magnet Group - S.Caspi
12/11/2012
Lamination can simplify analysis
Reduce cost
Reduce lossesSlide24
Lamination - 10.05 mm thick
24Superconducting Magnet Group - S.Caspi
12/11/2012
Ribs and SparCoil
Coil Ribs and Spar
The lamination hold exactly one turn of coil, rib and sparSlide25
Lamination
25
Superconducting Magnet Group - S.Caspi
12/11/2012Slide26
Laminated Model in TOSCA Bmod (14.85 kA)
26Superconducting Magnet Group - S.Caspi
12/11/2012Slide27
Mechanical Analysis27Superconducting Magnet Group - S.Caspi
12/11/2012We have just started stress analysis on the coil ribs and spar.Need to demonstrate that stress interception works, the force carried by the spar and the ribs should withstand the force
Three mechanical models in progress
ANSYS Workbench
one lamination at 10T and 20T
ANSYS Classical - one lamination
CASTEM– one turn at 10T and 20TSlide28
Workbench - Ribs and Spar10T - Axial deformation spar and ribs
28Superconducting Magnet Group - S.Caspi
12/11/2012
20T
–
Azimuthal
stress spar and ribsSlide29
CASTEM Model – 20T
front
behind
Rib + ring +
coil Axial displacement
29
Superconducting Magnet Group - S.Caspi
12/11/2012
Coil
Rib
Spar (3mm)
Von-
Mises
Stress (
MPa
)
0-55
0-200
200-400
Coil Von-
Mises
StressSlide30
Example – 6 layers 18T dipole, 56mm bore 3D analysis, no iron 6 layers graded. Coil is 60mm thick (no spars*)
Current 10.5 kA Bore field 18 T at 1.9K Intercepted stress < 30MPa
30
Superconducting Magnet Group - S.Caspi12/11/2012Slide31
Example – 6 layers 18T dipole, 56mm boreLayer 1, 30 strandsLayer 2, 26 strandsLayer 3, 22 strands
Layer 4, 18 strandsLayer 5, 14 strandsLayer 6, 12 strands
56mm
31Superconducting Magnet Group - S.Caspi
12/11/2012
Proof of principle
Spars omitted*
Spars and stress analysis will be next
* Adding spars of any size will not change the field in the boreSlide32
Example – Load lines (no iron)Stored Energy:18T10.5kA
2.22 MJ/m44 mH/m
32
Superconducting Magnet Group - S.Caspi
12/11/2012Slide33
Field along the magnet center33Superconducting Magnet Group - S.Caspi
12/11/2012Slide34
Mid-plane Stress - without interception34Superconducting Magnet Group - S.Caspi
12/11/2012
The mid-plane stress in each of the layers if the Lorentz force is not interceptedSlide35
Normal stress cable-rib - with interceptionTangential Stress (Normal to Rib)
35
Superconducting Magnet Group - S.Caspi
12/11/2012
The Lorentz stress in each of the layers if the Lorentz force
is interceptedSlide36
Other Applications – A curved CCT dipole for a gantry
36
Superconducting Magnet Group - S.Caspi
12/11/2012*D. S. Robin, C. Sun, A. Sessler
, W. Wan, M.
YoonSlide37
A “pure” dipole field
Bd
=5T37
Superconducting Magnet Group - S.Caspi
12/11/2012Slide38
A “pure” quadrupole field
G=-25T/m,
Single layer
Double layers
38
Superconducting Magnet Group - S.Caspi
12/11/2012Slide39
A “pure” sextupole field
S=400 T/m
2
Double layers
Single layer
39
Superconducting Magnet Group - S.Caspi
12/11/2012Slide40
Combined Function - Dipole+Quad+Sextupole
Bd
=5T, G=-2.26T/m, S=1.3 T/m
2
40
Superconducting Magnet Group - S.Caspi
12/11/2012Slide41
Other Applications – ECR
41
Superconducting Magnet Group - S.Caspi
12/11/2012Slide42
SummaryA New Magnet Type – Canted-Cosine-ThetaGeneric design – for all NbTi, Nb3Sn, HTS, simplified toolingStress interception
not accumulation (independent of the # of turns)A linear structure (not dominated by conductor Young’s modulus)High field quality
over an extended range (no optimization, better quality)Magnet “end harmonics
” naturally integrate to zero (no end spacers)Combined function field, (offsets in geometric errors included)
Islands and wedges replaced by ribs
Grading
using a single strand
with different cables, hybrids Nb3sn+HTS
Possible no conductor insulation (to ground only, ceramic coating)
Extended technology to
curved coils
and other type magnets
42
Superconducting Magnet Group - S.Caspi
12/11/2012Slide43
Need to ExploreFabrication: Nb3Sn dimensional changes during heat treatment Electrical integrity (conductor to spar)Mechanics:Structure, pre-stress, cool-down
Shear stress at interfaceProtection:protection scheme protection heaters and other instrumentation
Short-sample and training
43Superconducting Magnet Group - S.Caspi
12/11/2012Slide44
Possible Next StepsSubscale demonstrators – a 3T-4T, 56mm bore NbTi dipoleSubscale demonstrators – a small bore HTS dipole (YBCO)
Subscale demonstrators – a 12T, 56mm bore Nb3Sn dipole
A full scale ~20T design
44
Superconducting Magnet Group - S.Caspi
12/11/2012Slide45
Selected References D. S. Robin, D. Arbelaez, S. Caspi, A. Sessler, C. Sun, W. Wan, and M. Yoon, Nucl. Instrum. Meth. Phys. Res.A 659 (2011) 484-493.S. Caspi, D. Arbelaez, H. Felice, R. Hafalia, D. Robin, C.Sun, W. Wan and M. Yoon, Conceptual Design of a 260 mm Bore 5T Superconducting Curved Dipole Magnet for a Carbon Beam Therapy Gantry, IEEE Trans. Appl. Superconduct., Vol. 22, no. 3, p. 4401204, (2012).
C. Sun, D. Arbelaez, S. Caspi, D. Robin, A. Sessler, W. Wan and M. Yoon, Compact beam delivery system for ion beam therapy, Proceedings of IPAC2011, San Sebastian, Spain p. 3633-3635 (2011).S. Caspi, D. Arbelaez, L. Brouwer, D. Dietderich, R. Hafalia, D. Robin, A. Sessler, C. Sun, and W. Wan,
Progress in the Design of a Curve Superconducting Dipole for a Therapy Gantry, Proceedings of IPAC2012, New Orleans, Louisiana, p. 4097-4099 (2012).D.I. Meyer, and R. Flasck, A new configuration for a dipole magnet for use in high energy physics applications
, Nucl. Instrum. Meth., pp. 339-341, 1970.C.L. Goodzeit, M.J. Ball, and R.B. Meinke, The Double-Helix dipole-a novel approach to accelerator magnet design
, IEEE Trans. Appl. Superconduct., Vol. 13, no. 2, pp. 1365-1368, June 2003.
A.V. Gavrilin, et al.,
New concepts in transverse field magnet design, IEEE Trans. Appl. Supercond.,Vol.13, no. 2, pp.1213-1216,June 2003.
A. Devred, et al., Overview and status of the next European dipole joint research activity, Supercond. Sci. Technol. 19, pp 67-83, 2006.
C. Goodzeit, R. Meinke, M. Ball, Combined function magnets using double-helix coils, Proceedings of the Particle Accelerator Conference, 2007 PAC IEEE, pp. 560-562, 2007.
S. Caspi, D.R. Dietderich, P. Ferracin, N.R. Finney, M.J. Fuery, S.A. Gourlay, and A.R. Hafalia,
Design, Fabrication, and Test of a Superconducting Dipole Magnet Based on Tilted Solenoids
, IEEE Trans. Appl. Supercond, Vol. 17, part 2, pp. 2266-2269, 2007.
H. Witte, T. Yokoi, S.L. Sheehy, K. Peach, S. Pattalwar, T. Jones, J. Strachan, N. Bliss,
The Advantages and Challenges of Helical Coils for Small Accelerators-A Case Study
, IEEE Transactions on Applied Superconductivity, Vol. 2, p. 4100-4110 (2012)
S. Caspi, S. Gourlay, R. Hafalia,, A. Lietzke, J. O'Neill, C. Taylor and A. Jackson,
The use of pressurized bladders for stress control of superconducting magnets,
IEEE Trans. on Appl. Superconductivity, Vol, 11, no 1, p. 2272-2275 (2001).
S. Caspi, D. Arbelaez, L. Brouwer, D. R. Dietderich, H. Felice, R. Hafalia, D. Robin, C.Sun, W. Wan,
A Canted Cosine-Theta Curved Superconducting Dipole Magnet for a Particle Therapy Gantry,
Nucl. Instrum. Meth. To be published 2012/13
L. J. Laslett, S. Caspi, and M. Helm,
Configuration of coil ends for multipole magnets
, Particle Accelerators, 1987, Vol. 22, pp. 1-14.
45
Superconducting Magnet Group - S.Caspi
12/11/2012