1. 1 IL 3 He Relaxation Jacob Yoder UIUC Feb. 15 2007

2. 2 Outline Status as of Oct. 2006 meeting Progress To Do

3. 3 As of October 2006 The “final” cryogenic test cell was made The magnet was in place RT NMR test results in overall T 1 < 1 min, small polarization in “cold” cell Background gradients most likely problem Large gradients induced by testing with magnet

4. 4 Background Field Several magnetic parts were removed, but… Many things could not be removed easily Converted transformer into degaussing magnet and passed over all parts of cryostat in situ

5. 5 Results of Degaussing 1 K pot / 3 He condenser Bellows weld joints Room temp T 1 ~ 2 min after degaussing

6. 6 Gas System Built 4 He supply 3 He supply Pump out Cold trap Cell 4 He storage 3 He storage

7. 7 State of Manifold Appears to be leak tight, but contaminated Able to achieve MEOP, but polarization roughly ¼ of previous system Will be baking components under vacuum

8. 8 Future Work Simplify and clean manifold/cell Cryo test with pyrex cell at ~ 0.3 K Begin materials testing

9. 9 Future Cryo Cell 20 cm 3 cell, 50 cm 2 surface area EDM cell will be 4000 cm 3, with 2000 cm 2 surface area S/V for test cell will be 2.5 cm -1, S/V for dTPB EDM cell will be 0.5 cm -1 Test Material

10. 10 Comparison of test cell and EDM cell 1/T 1 ~ S/V 10,000 s T 1 in EDM cell equivalent to 2000 s T 1 in test cell T 1 from gradient proportional to diffusion constant D ~ T 1/2, so 100 s T 1 at room temp implies 3000 s T 1 at 0.3 K Gradient induced T 1 can be improved by increasing amount of 3 He in test cell or adding correction coils