1. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 1 Experience at CEA Experience at CEA Jaroslaw Polinski, Bertrand Baudouy CEA/Saclay CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets

2. Paris, November 190th 2007 2 NED cryostat Stack experiment –Saclay sample with conventional insulation (Kapton) –KEK sample with ceramic insulation Drum experiment –fiberglass-epoxy material as new conventional insulation Contest

3. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 3 Stack experiment Saclay sample construction

4. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 4 Stack experiment Saclay sample construction Dummy conductors Material: Stainless Steel Dimensions: 2.5mm x 17mm x 150mm (Tx W x L) Central surface part machined to real cable geometry Allan Bradley temp. sensors placed in the quarter and half of the conductor length

5. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 5 Stack experiment Saclay sample construction Conventional Kapton insulation 1st layer: Kapton 200 HN (50 μm x 11 mm) in 2 wrappings (no overlap) 2nd layer: Kapton 270 LCI (71 μ m x 11 mm) with a 2 mm gap Thermally treatment at 170 o C for polymerisation

6. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 6 Stack experiment Conventional Kapton insulation Tests conditions 17 Tons on the samples as specified Temperature of the bath Tb= 1.8K, 1.9K and 2.0K Only central conductor heated Supplied current range: 0 – 10 Amps Dissipated heat range: 0 – ≈30 mW/cm 3

7. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 7 Conventional Kapton insulation test results –Temperature of the heated conductor Stack experiment

8. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 8 Conventional Kapton insulation test results –Temperature of the neighbour conductors Stack experiment T III =T T III <T T III >T

9. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 9 Technical solution investigation Stack experiment

10. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 10 Technical solution investigation Stack experiment 20 kN ≈10 MPa Vacuum grease – thermal blockade G10 interlayer spacer 0.9 mm Spacer

11. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 11 Technical solution investigation T Stack experiment

12. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 12 Stack experiment KEK sample construction

13. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 13 Stack experiment KEK sample construction Dummy conductors Material: CuNi Dimensions: 1.9mm x 11mm x 150mm (Tx W x L) Conductor fabricated in real cable technology CERNOX temp. sensors placed in the quarter of the conductor length

14. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 14 Stack experiment KEK sample construction Ceramic (innovative) insulation One layer of Treated for 50 hours at 666 o C at 10 MPa

15. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 15 Stack experiment KEK sample construction Ceramic (innovative) insulation 10 MPa on the samples as specified

16. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 16 Heat Transfer Experiments DRUM SETUP

17. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 17 Heat Transfer Experiments Drum setup –Theoretical Background of the Method (1/2) A – Active area of the heat transfer h k – Kapitza heat transfer coefficient λ – Thermal conductivity of the material l – material thickness R s – overall thermal resistance of the sample T i – temperature of the inner volume T 1 – temperature of the sample surfaces from the inner volume T 2 – temperature of the sample surfaces from the cryostat bath T b – temperature of the cryostat bath TiTi T2T2 T1T1 TbTb QsQs A l Inner volume Cryostat bath

18. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 18 Heat Transfer Experiments Drum setup –Theoretical Background of the Method (2/2) Since  T>>T b it can be assumed that: And finally overall thermal resistance of the sample:

19. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 19 Heat Transfer Experiments Drum setup – Construction of the 1D support for thermal resistance in HeII Tests Sample holder flange Support flange

20. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 20 Heat Transfer Experiments RAL insulation - fiberglass tape and epoxy resin Tested sheets Sheet surface photo

21. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 21 Heat Transfer Experiments RAL insulation –Study of sheets surface area and thickness l h H Thickness determination Surface mathematical description H W Surface roughness tester result Surface Roughness Tester

22. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 22 Heat Transfer Experiments RAL insulation –Computation process, Example for l =0.055 mm Evolution of the temperature difference across the sample with heat flux as a function of the bath temperature. where y = 0.5673x - 0.0013

23. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 23 Heat Transfer Experiments RAL insulation –Computation process

24. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 24 Heat Transfer Experiments RAL insulation –Thermal conductivity, comparison with other materials

25. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 25 Heat Transfer Experiments RAL insulation –Kapitza Resistance

26. CARE-HHH-AMT Workshop on Heat Generation & Transfer in Superconducting Magnets Paris, November 190th 2007 26 September 2006 - October 2007 –Test of Saclay sample (17 tons compressed) –Test of Saclay sample with one flank side thermally insulated with APIEZON greases –Test of first ceramic insulation stack sample (10 MPa load) –1D: Tests of RAL insulation In HeII –Test of Saclay sample with one flank side thermally insulated with G10 interlayer spacer From November 2007 –Ceramic insulation with different loads –Thickness of the RAL insulation materials Tests Summary