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Processes sensitive to Operating temperature

Processes sensitive to Operating temperature

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Processes sensitive to Operating temperature

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  1. Processes sensitive to Operating temperature He3 transport by diffusion He3 evaporation Geometrc Phase He3 T2

  2. Constraints Temperature of cells (and 1200l) remains fixed during cycle Pressure on cell ditto Cell tempperature fixed by requirements of vxE-∂B/∂r systematic

  3. Injection of Polarized 3He Mike Hayden – Simon Fraser University → 3He (from ABS) film vapour dry surface? liquid Operating Temperature ? - Sets stage for transport to measurement cell Mike Hayden • n-EDM Operating Temperature Summit • October 2007

  4. Summary Optimal Acceptable Marginal Acceptable Marginal Mike Hayden • n-EDM Operating Temperature Summit • October 2007

  5. Analysis based on data from: Europhys. Lett. 58, 718 (2002) & Physica 18, 433 (1952). Time Constant for Evacuation 8 litres of liquid to pump 15 cm dia. bath (~45 cm deep) vapour 30 cm dia. bath (~11 cm deep) X liquid 50 cm dia. bath (~4 cm deep) 1-D model Mike Hayden • n-EDM Collaboration Meeting • June 2005

  6. Reentrant Geometry external pumps cold surfaces Cs ring or knife-edge in recessed cavity … ? 4.2 K sorb material liquid: 0.3 – 0.5 K to experiment (at ~ 0.3 K) Mike Hayden • n-EDM Collaboration Meeting • June 2005

  7. System Overview

  8. Nominal Operating Temperatures 380 350 – 400 370 – 420 400 380 – 430

  9. Minimal Operating Temperatures 340 350 – 400 310 – 350 320 300 – 400

  10. HEAT FLUSH He3 d cm v_{n} cm/sec Q mw ΔT mK T₈ secs 4 20 6.4 17 32 4 30 9.6 25 21 5 30 15 16 13.6 5 20 10 11 20. 3

  11. Evaporation on

  12. Evaporation on R=1.5cm, L=300cm, R=15cm, h=6cm

  13. Sequestration Possibility of removal to external purifier

  14. Sequestration, Uave=20 cm/sec (parabolic) R=1.5cm, L=300cm, R=15cm, h=6cm

  15. Sequestration R=1.5cm, L=300cm, R=15cm, h=6cm

  16. R=1.5 cm, L=300 cm, 100cm in helium at Tin=0.4K, Lmped element model for cells 8 liter volume

  17. R=1.5 cm, L=300 cm, 100cm in helium at Tin=0.4K

  18. Same pipe insulated

  19. Insulated So heat leakage from walls has small effect..c=0.27 without, vs c=0.3 with leakage Need large tube..

  20. SUMMARY R h r L U evap? F_300 F_200 15 6 1.5 300 20 yes 8E-3 3E-2 “ “ “ “ “ no 9E-3 .035 4 5 “ “ “ yes 8E-3 .05 “ “ “ “ “ no 2E-2 .035 R=1.5cm L=300cm, 100 cm in Helium at Tcell 3 mw, delta T=.02 => U=15 F_300=.03 =.02 insulated

  21. Uave=20 r=2cm, L=300cm, R=20cm, h=5

  22. Uave=20 r=2cm, L=300cm, R=20cm, h=5 Evap

  23. Sequestration R=4cm, h=5, r=1.5, L=300, Uave=20cm/sec

  24. Sequestration R=4cm, h=5, r=1.5, L=300, Uave=20cm/sec

  25. Evaporation R=4cm, h=5, r=1.5, L=300, Uave=20cm/sec

  26. Uave=20 r=2cm, L=300cm, R=20cm, h=5 No Evap

  27. Uave=10 r=2cm, L=300cm, R=20cm, h=5 Evap