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General remarks UT participation provided all expenses are fully covered. UT/EU-FP7 RTD/JRA funding scheme: - Personnel: 0.75 x (real costs + hourly overhead) - Material/travel: 0.75 x eligible costs
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General remarks • UT participation provided all expenses are fully covered. • UT/EU-FP7 RTD/JRA funding scheme: • - Personnel: 0.75 x (real costs + hourly overhead) - Material/travel: 0.75 x eligible costs • WPs mostly technological, no scientific issues defined (looks like LARP magnet program)
UT role for conductor R&D (Nb3Sn, BSCCO, YBCO) (WP(2), 3, 4 and 5): - 5 vacuum ovens for wire HT +1.5 meter long straight cable samples (FRESCA) - impregnation facilities (small coils, 1.5 meter FRESCA samples) - wire characteristics + Ic(B,T,e) (2000 A, 15 T, 4-30 K, +/- 1%) + (s,e) curves 300,77,4.2 K (virgin, HT strands) + M (meters long wire samples, +/- 6T, 10-240 mT/s) + NZP and MQE measurements (1200 A, 15 T, 4-30 K)) - cable characteristics + calorimetric AC loss (Ra/Rc) measurements (+/- 300 mT, up to 250 mHz, 60 MPa) + direct measurement of Ra/Rc + involved in stability measurements at FRESCA
Nb3Sn MgB2 YBaCuO BSrCaCuO Jc,eJc,0 eii (%) Typical Jc,n- strain (eii) response for various superconductorsinduced by changes in Hc2 and Tc(and finally irreversible crack formation)
(deviatoric) strain sensitivity of Ic(Bc2(e), Tc(e)) of superconductor Fundamental level • + why and why so differently for different kind of conductors+ what happens to the BCS energy gap+ why does the phonon spectrum changes like it does • Wire level • + how does dev. e depend on wire geometry/composite constituents+ how and why affects filament geometry dev. eCable/coil level • + how do strands respond to cabling (proceed with Stefania’s work) • + dev. strain in 3D cable model (cool-down, transverse pressure) (IS RESIN IMPREGNATION MANDATORY, (cooling issues) ?????)+ include non-linear (s,e) behavior in mechanical analysis (not only stress (basic operational limits) but also cable location is very important (accelerator field quality))+ what is the 3D dev. strain state during coil manuf.+ operation (stability !!!!!)
Infinite bronze matrix Z a1/a2=1
Infinite bronze matrix Z a1/a2=1
B Devices for Jc(H,T,e) studies ‘Pacman’ U-spring • Fully reversible -1% < ε < 1 % • Accurate at 1 mV/m level
Devices strand characterisation (ITER) Crossing strands for various wavelengths. Strand tensile stress-strain tests at various T (participation in VAMAS). Bending between contact points for various wavelengths. Ic vs stress for crossing strands at 11 T and 12 T. Stress-strain curve for LMI BM3 (TFMC) strand Reduced Ic vs force for SMI strand with release of load.
Devices strand characterisation 2 Wide T, e-rangeU-spring Point Contact Spectroscopy on U-spring Physical Properties Measuring System • (H,T,eii) Jc (H,T,eii) D (H,eii) Mh (H,T) Cv (H,T)
reversible reduction irreversible degradation stress sensitivity
cooling at 1 minor edge only @ 1.9K wcab = 0.02 m diso = 0.0001 m l = 0.01* T Wm-1K-1 Magnet cooling
3 Magnet cooling (2) • Investigate (part of EU-NED): • perforated insulation at minor edges • radial transport in coils of He II • heat transfer at such surfaces He II channels