1. Mitglied der Helmholtz-Gemeinschaft on the LEAP conference Polarized Fusion by Ralf Engels JCHP / Institut für Kernphysik, FZ Jülich 26.06.201

2. 2 Can the total cross section of the fusion reactions be increased by using polarized particles ? Polarized Fusion Total cross section

3. 3 Can the trajectories of the ejectiles be controlled by use of polarized particles ? Polarized Fusion Total cross section Differential cross section

4. 4 Can the total cross section of the fusion reactions be increased by using polarized particles ? 3 He + d 4 He + p Factor: ~1.5 at 430 keV [Ch. Leemann et al., Helv. Phys. Acta 44, 141 (1971)] t + d 4 He + n Factor: ~1.5 at 107 keV J = 3/2 + / s-wave dominated H. Paetz gen. Schieck, Eur. Phys. J. A 44, 321-354 (2010) Polarized Fusion

5. 5 Measurements in Basel 1971 An increased total cross section is possible !!! Polarized fuel will increase the diff. cross section for ϑ = 0°/180° and decrease for ϑ = 90° !!!

6. 6 What is the advantage for fusion reactors ? Polarized Fusion Laser Pellet target (DT pellets) (Berkeley, Orsay, Darmstadt, …)

7. 7 What is the advantage for fusion reactors ? 1.) Calculation by M. Temporal et al. for the „Megajoule“ Project Polarized Fusion Accepted for publication by „Nuclear Fusion“.

8. 8 What is the advantage for fusion reactors ? Polarized Fusion Laser Pellet target (DT pellets) Magnetic field -More gain by use of (more) elliptic targets ? -Trajectories of ejectiles aligned with magnetic holding field => simplified cooling of the reactor

9. 9 What is the advantage for fusion reactors ? 1.) Calculation by M. Temporal et al. for the „Megajoule“ Project Polarized Fusion No optimization of the laser power: Gain increased by factor 4 with use of polarized fuel

10. 10 Which questions must be solved ? 1.) Dependence of the total cross section from the polarization for all fusion reactions. Polarized Fusion d + d t + p 3 He + n Can cross sections be increased ? Can neutrons be suppressed ? Can the trajectories of the neutrons be controlled?

11. 11 Spins of both deuterons are aligned: Only p z (q z ) and p zz (q zz ) ≠ 0 Only beam is polarized: (p i,j ≠ 0, q i,j = 0) σ(,Φ) = σ 0 () · {1 + 3/2 A y () p y + 1/2 A xz () p xz + 1/6 A xx-yy () p xx-zz + 2/3 A zz () p zz } Polarized Fusion

12. 12 Deltuva and Fonseca, Phys. Rev. C 81 (2010) Polarized Fusion

13. 13 The Experimental Setup in St. Petersburg ABS from the SAPIS project: (after upgrade) ~ 4 ∙ 10 16 a/s → ~ 2 ∙ 10 11 a/cm 2 POLIS (KVI, Groningen) Ion beam: I ≤ 20 μA → 1.5 ∙ 10 14 d/s ( E beam ≤ 32 keV ) dd-fusion polarimeter LSP from POLIS LSP from the SAPIS project Luminosity: 3 ∙ 10 25 /cm 2 s → count rate: ~ 40 /h → 2 month of beam time Detector Setup: 4π covered by - large pos. sens. Detectors - (~300 single PIN diodes ?) See next talk by Peter Kravtsov

14. 14 The Electron Screening Effect Distance Coulomb Potential Astrophysical S-Factor: F. Raiola et al.; Eur. Phys. J. A 13, 377 (2002) Nuclear Potential

15. 15 The Electron Screening Effect Distance Coulomb Potential ?

16. 16 Which questions must be solved ? 1.) Dependence of the total cross section from the polarization for all fusion reactions. 2.) Polarization conservation in the different plasmas ? a.) Magnetic confinement: - R.M. Kulsrud et al.; Phys. Rev. Lett. 49, 1248 (1982) b.) Inertial Fusion: - J.P. Didelez and C. Deutsch; 2011 Laser and Particle Beams 29 169. - M. Büscher (IKP) / Prof. O. Willi (Uni. Düsseldorf) „Laser Acceleration“ Polarized Fusion

17. 17 Laser Acceleration ~ 100 GV/m Proton rich dot 20x20x0.5 μm 10 8 protons at 1.5 MeV 10 11 protons up to 10 MeV Laser Acceleration of pol. 3 He 2+ ions from pol. 3 He gas targets

18. 18 Which questions must be solved ? 1.) Dependence of the total cross section from the polarization for all fusion reactions. 2.) Polarization conservation in the different plasmas ? 3.) How to produce polarized fuel ? - inertial fusion: - HD targets are available (10 mK, ~1 T) (relatively small polarization ~ 40%) - frozen spin DT targets possible - magnetic confinement: a.) pol. 3 He is available („Laser-pumping“) b.) pol. T will be possible with a similar method c.) pol. D ??? Polarized Fusion

19. 19 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 atoms P Z = 0.89 ± 0.01 P Z = -0.96 ± 0.01 Lamb-Shift Polarimeter Storage Cell

20. 20 Polarized H 2 /D 2 Molecules Nuclear Polarization of Hydrogen Molecules from Recombination of Polarized Atoms T.Wise et al., Phys. Rev. Lett. 87, 042701 (2001). Measurements from NIKHEF, IUCF, HERMES show that recombined molecules retain fraction of initial nuclear polarization of atoms! polarized unpolarized P m = 0.5 Naïve model Is there a way to increase P m (surface material, T, B etc)?

21. 21 Polarized H 2 /D 2 Molecules  Recombination of polarized atoms into molecules  Conversion of polarized atoms and molecules into ions  Conversion of H 2 + and H + ions into protons with different energy (suggested by W.Haeberli)  Separation of protons by energy  Measurement of proton polarization in LSP polarized cell wall B ~ 1T

22. 22 Polarized H 2 Molecules 0.5 0.4 0.3 0.2 0.1 0 Polarization of Hydrogen Molecules as a Function of the Magnetic Field (Surface: Gold, T= 47 K, HFS 1, Q = 3 keV)

23. 23 Polarized H 2 Molecules Ratio of the ion beams intensity: ~ 1 : 2 (H 2 + ions ?) 0.6 0.5 0.4 0.3 0.2 0.1 0 Polarization of Hydrogen Molecules as a Function of the Cell Temperature (Surface: Gold, HFS 1, B = 0.28 T, Q = 4 keV

24. 24 Which questions must be solved ? 1.) Dependence of the total cross section from the polarization for all fusion reactions. 2.) Polarization conservation in the different plasmas ? 3.) How to produce polarized fuel ? - inertial fusion: - frozen spin DT targets possible (relatively small polarization ~ 40%) - HD targets are available - magnetic confinement: a.) pol. 3 He is available („Laser-pumping“) b.) pol. T will be possible with a similar method c.) pol. D ??? => see talk by D. Toporkov Polarized Fusion

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