1. Mitglied der Helmholtz-Gemeinschaft on the LEAP conference Polarized Deuterium/Hydrogen Molecules Possible Fuel for Nuclear Fusion Reactors? by Ralf Engels JCHP / Institut für Kernphysik, FZ Jülich 14.11.2013

2. 2 Important Questions for Polarized Fusion -Can the total cross sections of the fusion reactions be increased by use of polarized particles? (See talks by Paetz gen. Schieck, Deltuva, Kravchenko, Kravtsov) -Will polarization survive in a plasma? (See talks by Holler and Didelez) -What will happen in the different types of fusion reactors? (See talks by Temporal and Sandorfi) -How to get and how to handle polarized fuel?

3. 3 PIT@ANKE internal experiments – with the circulating beam external experiments – with the extracted beam p, p, d, d with momenta up to 3.7 GeV/c

4. 4 PIT @ ANKE/COSY Main parts of a PIT: Atomic Beam Source Target gas hydrogen or deuterium H beam intensity (2 hyperfine states) 8.2. 10 16 atoms / s Beam size at the interaction point σ = 2.85 ± 0.42 mm Polarization for hydrogen atom P Z = 0.89 ± 0.01 (HFS 1) P Z = -0.96 ± 0.01 (HFS 3) Polarization for deuterium atoms atom P Z = 0.88 / P ZZ = 0.88 (HFS 1/6) P Z = 0.005 / P ZZ = -1.71 (HFS 2/5) Lamb-Shift Polarimeter Storage Cell M. Mikirtychyants et al.; NIM A 721 (0) 83 (2013)

5. 5 ABS and Lamb-shift polarimeter 6-pole magnet 6-pole magnet rf-transition

6. 6 Polarized H 2 Molecules Is there a way to increase P m P (surface material, T, B etc)? P m = 0.5 P a Eley-Rideal Mechanism

7. 7 Polarized H 2 Molecules T= 300 K:3:1 T 0 K:0:4 J = 1, 3, 5 J = 0, 2, 4 o-H 2 ↔ p-H 2 : ΔE = - 0.08 kJ/mol

8. 8 Polarized H 2 Molecules - para-Deuterium orto-Deuterium

9. 9 Measurements from NIKHEF, IUCF, HERMES show that recombined molecules retain a fraction of initial nuclear polarization of atoms! Polarized H 2 Molecules The HERMES Collaboration; Eur. Phys. J. D 29, 21–26 (2004) DOI: 10.1140/epjd/e2004-00023-5

10. 10 Theory A.Abragam: The Principles of Nuclear Magnetism Hamiltonian to describe the nuclear spin relaxation of H 2 molecules H = ω I ( I 1 z + I 2 z ) + ω J J z + ω‘ (I 1 + I 2 )·J + ω‘‘ { I 1 · I 2 – 3(I 1 · n)(I 2 · n)} I 1 and I 2 are the spins of the two protons I 1 + I 2 = I J is the rotational angular momentum of the molecule ω I = - γ I H 0 is the proton Lamor frequency in the applied field H 0 ω J = - γ J H 0 is the Lamor frequency of the rotational magnetic moment of the H 2 ω‘ = - γ I H‘ is the strength of the coupling between the magnetic moment of the protons and the magnetic field produced at their positions by the rotation of the molecule ( H‘ = 2.7 mT) ω‘‘ = 2 γ I H‘‘ = γ I 2 ħ/ b 3 is the strength of the dipolar coupling between the protons, b is their distance, and n is the unit vector b/b (H‘‘ = 3.4 mT). B c (H z ) ≠ B c (D z ) ≠ B c (D zz )

11. 11 Nuclear Polarization of Hydrogen Molecules from Recombination of Polarized Atoms T.Wise et al., Phys. Rev. Lett. 87, 042701 (2001). Polarized H 2 Molecules Spin Relaxation of H 2 /D 2 Molecules A. Abragam: The Principles of Nuclear Magnetism (1961) The polarization losses during a single wall collision depend on: -Nuclear Spin I -Polarization P m -Temperature -Magnetic field in the cell P (B,n) = P m · e - n ( ) 2 BcBc B n ≈ 1000 Polarization losses of the molecules B c = 6.1 mT

12. 12  Recombination of polarized atoms into molecules  Conversion of polarized atoms and molecules into ions  Separation of protons and H 2 by energy with the Wienfilter  Measurement of proton and H 2 polarization in LSP polarized cell wall B ~ 1T The idea + +

13. 13 The Setup ISTC Project # 1861 PNPI, FZJ, Uni. Cologne DFG Project: 436 RUS 113/977/0-1

14. 14 + H 2 + e → H + 2e + … H 2 + e → H 2 + 2e The Ionization Processes + (E e = 150 eV: σ = 0.46 · 10 -16 cm 2 ) (E e = 150 eV: σ = 0.88 · 10 -16 cm 2 ) (E e = 150 eV: σ = 0.082 · 10 -16 cm 2 ) (www.nist.gov) H + e → H + 2e +

15. 15 Experimental results Mass separation with the Wienfilter F el = F B E q = - q v B

16. 16 Recombination

17. 17 Experimental results Wienfilter function of the protons in the LSP E kin (p) = 1 keV

18. 18 Experimental results Wienfilter function of the H 2 ions in the LSP +

19. 19 Experimental results How are the polarized H 2S produced from H 2 ? + 2-step process (Stripping at the Cs + H 2S production) 1-step process: Direct production: H 2 + Cs → H 2S + Cs + … + Cross section: σ(p→H 2S ) ≈ 35·σ(H 2 →H 2S ) +

20. 20 Theory P m = 0.5 B c = 6.1 mT H2H2 +

21. 21 Theory

22. 22 Theory

23. 23 See Talk by A. Nass on Friday Experimental results Protons:

24. 24 0.6 0.5 0.4 0.3 0.2 0.1 0 Experimental results Polarization of the Protons (HFS 1, E p = 4 keV, Gold Surface, B=0.28 T)

25. 25 Experimental results Measurements on Fused Quartz Glass in the first hours P m = 66 % of the original atomic Polarization T Cell = 100 K

26. 26 Experimental results Measurements on Fused Quartz Glass after several days T Cell = 100 K P m = 0.328 ± 0.007 n = 368 ± 23 P a = 0.85 ± 0.01 n = 363 ± 29 c = 0.986 ± 0.002

27. 27 Experimental results Measurements on Fused Quartz Glass after several days T Cell = 50 K P m = 0.307 ± 0.007 n = 321 ± 23 P a = 0.46 ± 0.21 n = 351 ± 104 c = 0.98 ± 0.02 No real changes between 50 and 100 K

28. 28 Experimental results Measurements on Fomblin (Perfluorpolyether PFPE) HFS 3 T Cell = 100 K H 2 : P m = - 0.84 ± 0.02 n = 217 ± 24 Protons: P m = - 0.81 ± 0.02 n = 136 ± 15 c = 0.993 ± 0.005 +

29. 29 Experimental results J.S. Price and W. Haeberli, “Measurement of cell wall depolarization of polarized hydrogen gas targets in a weak magnetic field” Nuclear Instruments and Methods in Physics Research A 349 (1994) 321-333

30. 30 Experimental results Measurements on Fomblin Oil (Perfluorpolyether PFPE) HFS 3: Next day T Cell = 100 K H 2 : P m = - 0.80 ± 0.02 n = 110 ± 47 Protons: P m = - 0.80 ± 0.02 n = 336 ± 104 c = 0.526 ± 0.015 P a = - 0.80 ± 0.02 +

31. 31 Experimental results Measurements on Fomblin (Perfluorpolyether PFPE) HFS 2+3: Next day T Cell = 100 K H 2 : P m = - 0.68 ± 0.02 n = 184 ± 29 Protons: P m = - 0.68 ± 0.02 n = 409 ± 87 c = 0.88 ± 0.02 P a = -0.68 ± 0.02 +

32. 32 Experimental results Measurements on Fomblin (Perfluorpolyether PFPE) Measurement on the 3. day Measurement on the 4. day T=100 K (only H 2 ) +

33. 33 Experimental results Measurements on Fomblin (Perfluorpolyether PFPE) HFS 3 HFS 2+3 B cell = 0.4 T, H 2 only +

34. 34 Experimental results Very first results on water (Fomblin): (3. day) p H2H2 + Very Preliminary HFS3

35. 35 Experimental results Very first results on water (Gold): T cell = 100 K -0,44 P m = 0.28 ±0.01 n = 317 ± 16 P m = - 0.25 ±0.01 n = 330 ± 26 P m = - 0.27 ±0.01 n = 605 ± 27

36. 36 Experimental results Measurements on Fused Quartz Glass after several days Deuterium: HFS 3+4 (Vector and Tensorpolarized) P m,z = - 0.40 ±0.01 n = 686 ± 75 P m,zz = 0.24 ± 0.03 n = 950 ± 246 (P a,z = - 0.91 ± 0.01 / P a,zz = + 0.85 ± 0.02) P m,zz = 0.24 ± 0.03 n = 1590 ± 590 c = 0.980 ± 0.006 P m,z = - 0.40 ±0.01 n = 701 ± 180 c = 0.984 ± 0.008 T Cell = 100 K

37. 37 Conclusion We can measure: -the recombination of hydrogen/deuterium atoms on different surfaces and for different HFS. -the polarization of atoms and molecules in a storage cell. -the number of wall collisions of the molecules in the cell. At least, we can see the difference between „hard“ and „soft“ materials (elastic scattering or cos x -distribution). -the B c for vector- and tensor-polarized Deuterium. -We can increase the target density with recombined molecules. => B c (D z ) = 7 ±1 mT / B c (D zz ) = 10 ±1 mT

38. 38 To-do List -Calculation of B c for vector- and tensor-polarized Deuterium - Additional cryo-catcher between ABS and ISTC-chamber -Measurements on different surfaces: - Aluminium - Teflon - … -More measurements on a water surface (Maybe the surface below has some influence …) -Development of a new openable storage cell for ANKE -Polarized Deuterium Fuel for polarized fusion reactors

39. 39 Polarized H 2 Molecules - para-Deuterium orto-Deuterium