1. Future Magnets Report from WP10
Philippe Fazilleau (CEA)
Lucio Rossi (CERN)
With large contribution by Maria Durante (CEA), UniGe, KIT, UTwente, INFN-Mi

2. WP10 structure Task 10.1: Coordination & communication
(L. Rossi – CERN / P. Fazilleau – CEA Saclay)
Task 10.2: Conductors
(L. Bottura – CERN / C. Senatore– UniGeneva)
Task 10.3: Magnet prototype
(M. Durante– CEA Saclay / G. Kirby– CERN)
Task 10.4: Tests (stand-alone configuration)
(G. Volpini – INFN LASA / M. Bajko– CERN)
(Task 10.5: test as insert of background field has been removed from Eucard2 program but is still active for after Eucard2)

3. WP10 main scopes
Develop a 10 kA-class cable in HTS (High Temperature Superconductor) suitable for accelerator (collider) magnets,
Large current to reduce magnet protection issues,
Cable properties suitable for accelerator (AC losses, coupling/persistent currents, mechanical behavior…)
Uniformity of properties over long lengths
Design, Manufacture and test a first accelerator quality, small prototype, dipole
Bore diameter 40 mm
Outside diameter, 99 mm to be inserted in Fresca2
Length > 400 mm
Field 5 T, good homogeneity (< 10-4) stand-alone
Field > 15 T in a HF magnet (Fresca2) – Outside EuCARD2

4. WAMHTS series Workshop on Accelerator Magnets in HTS
Hamburg May 2014: 57 participants 2 EU Industries (1 beneficiary , 1 associate) 5 Industries from outside EU
Targeted to Superconductor and Cable (review of many designs)
Confirming choice of Roebel cable

5. WAMHTS-2 55 participants (21 Asia-Pacific +20 Europe +14 US)
Dedicated to Magnet technology
Synergy with other high Field communities: Lab magnets for matter physics HF NMR

6. Task 2 progress Conductors
Review of HTS material performance and issues:
state-of-the-art,
definition of appropriate performance targets for the R&D work
# T
# T

7. Task 2 progress Conductors
2. HTS materials
YBCO
Main focus of the EU program
Produced by Bruker EST (beneficiary of EuCARD²)
Available from others suppliers (Superpower, Fujikura, Sunam, SuperOx); TCS-UH may enter as « supplier » for EuCARD2.
Anisotropic : Jc (B) # 0,1-0,3 Jc (B//)
Tape: 4, 12 mm (10 mm) width => dedicated cable needed
Very robust: hastelloy layer
React and wind technique
Bi-2212
Backup option for WP10
R&D supported by DOE (US)
Isotropic properties
Round wire -> Rutherford cable
Very sensitive to mechanical strain
Wind and React technique
Reaction # homogeneous 900 ° C under 100 bar with 1 bar of O2
Lucio EuCARD² 2nd annual meeting - 23/042014

8. Conductor: Jeng and Jlayer
Carmine Senatore
Univ. of Geneva
Lucio EuCARD² 2nd annual meeting - 23/042014

9. How far we can go (in reasonable future?)
Data from the 144 SuperPower spools measured at NHMFL for the 32 T project
Recent result (2014)
A factor two is at hand!
Carmine Senatore
Univ. of Geneva
Data extracted from D. Abraimov et al. WAMHTS-1
Lucio EuCARD² 2nd annual meeting - 23/042014

10. Homogeneity along length
Our tape!
Lucio EuCARD² 2nd annual meeting - 23/042014

11. Pre-production at Bruker
240 m tape 4 mm wide produced, by Bruker, for characterisation and optmisation
Production of the 12 mm wide (necessary for our cable), started in 2014
Lucio EuCARD² 2nd annual meeting - 23/042014

12. Roebel cables Roebel cable characteristics SC Roebel cable for Eucard2
Number of tapes (- 15
Cable width
(mm) 12
Cable thickness
1.1
Transposition pitch
226
Minimum critical current (15 T, 4.2 K)
(kA) 5
Expected critical current (15 T, 4.2 K)
7.5
Roebel cable characteristics
SC Roebel cable for Eucard2
Roebel cabel produced (KIT)
Tape ID
Length
(m)
Pitch
(m)
Width
(mm)
Thickness
Tapes
(-)
Tape
E2D-15/ 3
226 12
0.8 15
dummy SS
E2D-15/
1.5
15(SS)+15(Cu)
E2D-15/ 20
E2D-15/ 6
E2S-15/
1.6
SP-KIT
E2S-15/
1.8
SP-KIT
E2D-15/ 13
426 10
Lucio EuCARD² 2nd annual meeting - 23/042014

13. Test on axial strain (tape) at UniGeneva
Manufacturer
Irreversible strain limit
BHTS
0.74 < εirr < 0.75 %
FUJIKURA
0.55 < εirr < 0.57 %
SUNAM
0.69 < εirr < 0.71 %
SUPEROX
0.47 < εirr < 0.49 %
SUPERPOWER
0.67 < εirr < 0.70 %
Fujikura & SuperOx: delamination  steps  lower εirr
SuperOx
Fujikura
Lucio EuCARD² 2nd annual meeting - 23/042014

14. Special compressive test at University of Twente (NL)
Do HTS Roebel cables withstand the pressure levels expected in the winding pack of an accelerator insert magnet?
KIT cable on hairpin holder
Sample + pressure anvil
Cryogenic press + hairpin sample
Cross-section (Araldite + filler) - impregnated cable
Lucio EuCARD² 2nd annual meeting - 23/042014

15. The coils must be impregnated
150MPa
T = 4.2K;
Bapplied = 10.5T
Talk Jerome Fleiter at h15.20 on Roeble cable
Suitably impregnated cables meet magnet design requirement (150 MPa)
S. Otten et al. “Transverse stress tolerance of epoxy impregnated REBCO Roebel cables”, accepted for publication SUST 2015
Lucio EuCARD² 2nd annual meeting - 23/042014

16. Roebel cables made by KIT
Dummy‘s for magnet winding (to CERN
and CEA Sacley)
Short cables for transverse pressure
Short samples for AC losses
Single tapes with filaments
Talk Jerome Fleiter at h15.20 on Roeble cable
Lucio EuCARD² 2nd annual meeting - 23/042014

17. Punching tape for Roebel cabling
Width mm compared to specification < 12.1 mm
Solutions in work:
Modification of the punching machine for wider tapes
Copper plating after punching
Punching defect
Lucio EuCARD² 2nd annual meeting - 23/042014

18. Baseline Lay-out 1. Magnet design studies – Aligned block design
Electromagnetic design of EuCARD2 magnet Feather-M2 and subscale model Feather-M0 completed
Mechanical models : Finite element models Feather-M2 and Feather-M0 ongoing
Glyn Kirby
Jeroen van Nugteren
Jaakko Murtomaki
CERN
Lucio EuCARD² 2nd annual meeting - 23/042014

19. From conceptual to engineerign design
1. Magnet design studies – Aligned block design
Feather-M2 detailed mechanical design ongoing
Glyn Kirby
Jeroen van Nugteren
Jaakko Murtomaki
CERN
Lucio EuCARD² 2nd annual meeting - 23/042014

20. Alternative: new life for the classical cos layout?
1. Magnet design studies – cos design
Electromagnetic and mechanical model completed
Effort led by CEA
(C.Lorrin, M. Durante, Ph.Fazilleau)
Talk h16.50 by Clement Lorin, CEA
radial
20 MPa
azi.
60 MPa
Lucio EuCARD² 2nd annual meeting - 23/042014

21. Alternative lay-out: stacked tape cable
1. Magnetic design studies – Stack design
23 turn block-coil magnet design ongoing
Parameter
Value
Central field B0
5 T
Current density Jop
650 A/mm²
Field quality B3
1.55 unit B5
0.78 unit
Block-coil size
4 x 4 mm
Conductor area
1472 mm²
Bmax = 6.4 T
Min(Je) = 870 A/mm²
John Himbele
Arnaud Badel
Pascal Tixador
INPG
Field distribution

22. Stacked cable - 2 1. Magnet design studies – Stack design
Detailed 3D design completed
Mechanical structure design ongoing
Twist and bend return end
John Himbele
Arnaud Badel
INPG
No twist on lead end

23. A real issue: Protection quench does not propagate
1. Magnet design studies – Quench analysis
Feather-M0 Quench Behaviour
Current Sharing Temperature studies
Heat Generation in FM0 Hotspot
Iop: 6 kA
Quench voltage and Hot spot temperature as a function of time and Iop
Current sharing in FM0
Erkki Härö
Tiina Salmi
Antti Stenvall
TUT

24. A key feature: early detection
1. Magnet design studies – Quench detection
Voltage taps (low current)
Temperature sensors (high current)
Pickup coils high current (Feather zero trial)
Acoustics sensors
WAMHTS-3
10-11 September, Lyon (connected to EUCAS2015) Topic: Quench Protetion

25. Getting to engineering
3. Cable behavior studies – mechanical model
Finite element model : stresses in the Roebel cable when an actual tension is applied, developed by Jaakko Murtomaki (CERN)
Roebel Max acceptable tension < 15.5 kg
Acceptable winding tension of the order of 5 kg
Von-Mises stress distribution of a portion of the model showing the elbow geometry

26. The second big issue of HTS FQ and current distribution
3. Cable behavior studies – current distribution
Electrical Network Model for REBCO Cables and Coils developed by J. van Nugteren (CERN)
Validation with measurements data ongoing
Current distribution in Roebel cable during quench
Current density distribution in Feather-M2

27. Technology progress 3. Cable behavior studies – bending tests (KIT)
Bending radii from 50 to 10 mm
Bending radii > 10 mm do not degrade the Ic
6.5% degradation

28. Getting ready 3. Cable behavior studies – winding tests
Winding test with Roebel cable
Winding tests with stacked tapes cable
Aligned block configuration (CERN)
Costheta configuration (CEA)
Twist region studies (INPG)

29. Exploring various insulation
4. Cable insulation studies – DTI
Studies of commercially available HTS tape insulation types
Evaluation of new insulation techniques:
Epoxy with a heat-conducting filler
Silica based solution (Sol-Gel approach)
Studies of defects in thermally cycled coils impregnated with epoxy resin
Sol-Gel solution considered as a new insulation for the alternative coil configuration (CEA led effort)
Delamination of HTS layer seen in impregnated coil

30. INFN-LASA test facility
3 x 10 kA P.S.
3000 l LHe storage tank
Current transmission line
breaker, dump resistor
10+ kA gas cooled
CuP current leads
Lucio EuCARD² 2nd annual meeting - 23/042014

31. Modifications for testing Featehr-M2 and other HTS magnets
3000
ID 510
New cryostat
to be fitted within existing
DISCORAP cryostat
(not shown)
top view
10+ kA gas cooled
CuP current leads
Magnet under test
Giovanni Volpini
INFN-Milano

32. CONCLUSIONS The program is going pretty well, interest worldwide
DLVs have been met (for cable just on time)
Next -3rd- year) should be the year of exploring practical magnet technology
Various subsize coils anf test
First Magnet
The progress of YBCO are impressive
Progress in Ic of tapes are a factor two in last two years
Even YBCO round wires are being investigated
YBCO may be come a serious competitor to Nb3Sn for FCC and for other applications (WP3, WP4) if:
We are successful (role of EuCARD2)
Cost of material is reduced

33. WP10 collaboration Associated Several institutes: Industrial:
CERN (L. Rossi, L. Bottura, A. Ballarino, G. Kirby, M. Bajko)
CEA Saclay (M. Durante, P. Fazilleau),
INPG (P. Tixador),
INFN LASA (G. Volpini, M. Sorbi),
KIT (W. Goldacker, A. Kario),
University of Geneva (C. Senatore),
University of Twente (M. Dhallé),
University of SouthHampton (Y. Yang),
Tampere University of Technology (Antti Stenvall)
Danish Technological Institute (N. Zangenberg)
Industrial:
Bruker EST (A. Usoskin)
Associated
LBNL, BNL, FNAL, S.Carolina Univ., KEK, UniKyoto, entering:

34. Spare slides
L Rossi
Lucio EuCARD² 2nd annual meeting - 23/042014

35. MS and Deliverables 2nd year
1 Milestone / 2 Deliverables :
Dipole design (MS64-DL10.1),
Prototype cable (D10.2)
Lucio EuCARD² 2nd annual meeting - 23/042014

36. MS and Deliverable 3rd year
Tests
SC Cable
Reports
Lucio EuCARD² 2nd annual meeting - 23/042014

37. Task 1 progress Coordination & communication
Meetings:
Regular coordination video-meetings with task leaders/deputies
WP10 see :
Visit to industry (BEST)
Video-meetings with the USA labs (NHMFL, LBNL, FNAL, BNL and OST)
Visit to Houston (Texas Center for Superconductivity –TCS– at Univ. of Houston)
A collaboration base on a MoU between UH and CERN for FCC will make a formal link EuCARD2 and TCS-UH
WP10 website
Preparation of first periodic report
Set up of collaboration between EuCARD2 (via CERN) and US labs (via ASC of Nat. High Magnetic Fiels Lab of Florida Stata Univ.) MS62: exchange of letter of intents. Now CERN will engage also with a small contract.

38. Extract from letter
Lucio EuCARD² 2nd annual meeting - 23/042014