1. Kickoff meeting - HTS Tl-based coatings for FCC beam screens
M. Eisterer, Atominstitut, TU Wien
CERN, November 13th 2015

2. Outline Introduction of TU Wien
Atominstitut
Department of Low Temperature Physics and Superconductivity
Main facilities
Recent project and results

3. TU Wien (formerly: Vienna University of Technology)
29000 students, 4600 employees
8 faculties
Faculty of Physics:
1893 students (~200 graduates/year)
5 Institutes

4. Atominstitut 8 groups (focus on quantum physics) 32 scientific staff
29 technical staff
75 project staff

5. TRIGA MARK-II reactor Neutron flux density (1985): 2.1 × 1017 m-2s-1
Thermal (<0.55 eV) neutron flux density: 6.1 × 1016 m-2s-1
Fast (>0.1 MeV) neutron flux density: 7.6 × 1016 m-2s-1
About 60 % after core renewal in 2012

6. Low Temperature Physics and Superconductivity (LTP)
Head of group:
Prof. Em.:
Permanent staff:
Franz Sauerzopf
Harald Weber
Michael Eisterer
Postdocs:
Thomas
Baumgartner
Rainer
Prokopec
Martin
Zehetmayer
PhD students:
David
Fischer
Johannes
Hecher
Wofgang
Seeböck
Mayraluna
Lao

7. Equipment LTP: resistive measurements
17 T superconducting magnet
VTI: ~ K
Currents up to 1000 A in liquid helium, and up to 300 A in helium gas
AC-susceptibility insert available
6T superconducting magnet
4-300 K
Up to 150 A
Two-axes goniometer
Assessment of the critical current anisotropy
Variable Lorentz force

8. Equipment LTP: magnetization
Two commercial SQUID (MPMS, Quantum Design)
2-320 K, max. 7 T
DC and AC-susceptibility
Vector VSM (Oxford Instruments)
Split pair magnet: horizontal field
Rotation stage
Parallel and orthogonal magnetic moment
2-350 K
Max. 5 T

9. Equipment LTP: scanning probe measurements
Scanning Hall probe device
Liquid nitrogen
Self-field, AC/DC fields up to 100 mT
Scan range: 10×25 cm2
Spatial resolution: 30 µm

10. Equipment LTP: scanning probe measurements
Scanning Hall probe microscope
3-150 K
8 T superconducting magnet
Scan range: 3×3 mm2
Spatial resolution: 2 µm
Commercial AFM/MFM/STM (attocube)
4-70 K
7 T superconducting magnet
Scan range: 30×30 µm2
Spatial resolution: < 1 nm

11. Recent and Running Projects
Results
Recent and Running Projects

12. FP-7 SuperIron / Austrian Science Fund FWF
Angle-resolved magnetization measurements on Ba-122 single crystals
Angular scaling
Jc(q) in Co-doped
pristine crystal
Small defects (r<x)
Large defects (r>x)
Demonstration of the scaling factor of Jc for large spherical defects

13. FP-7 SuperIron / Austrian Science Fund FWF
Angle-resolved transport measurements on Ba-122 films
cos = cos cos
Jc depends on a only, irrespective of the Lorentz force.
“One-dimensional pinning behavior”

14. FP-7 SuperIron / Austrian Science Fund FWF
Micro-Hall scanning on polycrystalline bulk Ba-122
Gap between Hall probe and surface
2 µm
15 µm
Inter- and intra-granular Jc can be assessed.

15. Fp7-EuroTapes Micro-Hall scanning on RaBiTS tapes
Inversion of the field profile → local currents
Comparison with the local grain structure (EBSD)

16. Fp7-EuroTapes Micro-Hall scanning on RaBiTS tapes
In-field behavior of grain boundary
Pinning within grains

17. Austrian Science Fund (FWF)
Correlation between Jc, fishtail-effect, and vortex arrangement in NbSe2

18. EuroFusion
Influence of neutron radiation on coated conductor performance

19. Collaboration with CERN (LHC upgrade)
Influence of particle irradiation on Nb3Sn wires,
e.g. Ti alloyed RRR Nb3Sn wire (OST)
Nb3Sn wires are still not optimized yet!