DT polarization and Fusion Process Magnetic Confinement Inertial Confinement Persistence of the Polarization - Polarized D and 3 He in a Tokamak - DD Fusion induced by Laser on polarized HD The “Few-Body” Problems Static Polarization of HD Dynamic Polarization of HD and DT POLAF Project at ILE (Osaka) Conclusion DT Polarization for ICF

DT polarization and Fusion Process (Kulsrud, 1982) (More, 1983) D + T → 4 He (3.5 Mev) + n (14.1 MeV) MeV S = ½ S = 1 S = 3/2 S = ½ 95% – 99% D + T → 5 He (3/2 + ) → 4 He + n 1% – 4% S = 3/2 3/2 1/2 -1/2 -3/2 S = 1/2 1/2 -1/2 4 states 2 states 2/3 of the interactions contribute to the reaction rate If D and T are polarized then - all interactions contribute - n and α have preferential directions Sin 2 (θ) - n from DD fusion are suppressed QSF (Jülich – Gatchina) 50 % Increase in released energy The question is to know if the polarization will persist in a fusion process ? Depolarization mechanisms are small: 1) Inhomogeneous static magnetic fields, 2) Binary collisions, 3) Magnetic fluctuations, 4) Atomic effects ( J/g)

Plasma Density n = (cm -3 ) ; Confinement Time τ = 10 (sec) Lawson Criterion (n τ > (sec/cm 3 ) Fusion by Magnetic Confinement – (ITER) ITER Plasma Volume = 873 m 3 τ = 300 (sec) Power = 500 MW

Fusion by Inertial Confinement – (MEGAJOULE) Plasma Density n = (cm -3 ) ; Confinement Time τ = (sec) Lawson Criterion (n τ > (sec/cm 3 ) ICF Target 3mm radius Carbone & 4 mg cryogenic DT 2000 times compressed 300 g/cm 3 5 keV 825 MJ within 100 ps J. MEYER-TER-VEHN, Nucl. Phys. News, Vol 2 N° 3 (1992) 15

A:unpolarized DT B:polarized DT At fixed G: E B / E A < 0.7 for G=100 E A = 880 kJ E B = 510 kJ E A min = 450 kJ E B min = 290 kJ for E = 1 MJ G A = 140 G B = 307

DD D2T2D2T2 DT D 2 T 2 ?

Fusion by Magnetic Confinement – (ITER) Persistence of the Polarization - Injection of Polarized D and 3 He in a Tokamak (A. Honig and A. Sandorfi) D + 3 He → 4 He + p MeV (DIII-D Tokamak of San Diego, USA) Expected: 15% increase in the fusion rate - Powerful Laser on a polarized HD target → P and D Plasma P + D → 3 He + γ MeV Expected: Angular distribution of the γ ray Change in the cross section D + D → 3 He + n MeV Expected: Change in the total cross section Sin 2 θ angular distribution of the neutrons

Powerful Laser (Terawatt) creates a local plasma of p and d ions (5 KeV) 5.5 MeV γ ray from p + d → 3 He + γ 2.45 MeV n from d + d → 3 He + n Tentative Set-Up Polarized HD Target 25 cm 3 H (p) polarization > 60% D (d) vect. polar. > 14% 200 mJ, 160 fs 4.5 µm FWHM 970 nm, ~ W/cm 2

The “Few-Body” Problem d 1/2 1 p d 3 He γ dσ 4 /dω γ ~ (1+ cos 2 θ) * (S = 3/2) σ 0 (10 keV) = 18 µbarn ** radiative captures/laser shot ? For polarized plasma, angular dependence relative to the polarization axis, but forward peaked, small cross section and almost impossible to detect the γ (EM background). dσ 5 /dω n ~ sin 2 θ *** (S = 2) σ n 5 / σ 0 < 0.5 ; σ 0 (1.5 MeV) = 100 mbarn *** For polarized plasma, angular dependence perpendicular to the polarization axis, large cross section and “easy” detection of the very slow neutrons. Possibility to rotate the polarization of the RCNP HD target without any other change. High “D” polarization possible by AFP. * M. Viviani ** G. J. Schmid PR C52, R1732 (1995) *** A. Deltuva, FB Bonn (2009) HD Plasma 5 keV 3 He d n

POLAF proposal (RCNP, ILE and ORSAY) with the multi-detector “MANDALA” at ILE - Osaka. An energy resolution of 28 keV for 2.45-MeV DD neutrons is achieved with MANDALA m Target Chamber MANDALA DD neutron energy [MeV] Count ΔE D ～ 2.2 m neutron detector t10 cm PMT  10 cm BC-408 scintillat or ×422 ch An energy resolution of 28 keV for 2.45-MeV DD neutrons is achieved with MANDALA m Target Chamber MANDALA DD neutron energy [MeV] Count ΔE D ～ 2.2 m neutron detector

Static Polarization of HD B/T > 1500 Dilution Refrigerator 10 mK and 17 T (B/T = 1700)

1220mm 170mm 70m m Mixing Chamber Nb3Sn joints & Protection Circuit NbTi joints & Switch Main Coil Correction Coil Null Coil Rough dimensions of the magnet 400mm 600mm 550mm 1K Pot 538mm Static Polarization of HD : DR 10 mK, 17 T solenoid

B Adding free electrons. For B=2.5 T and T = 1 K, e - polarization = 92% Proton relaxation time >> electron 92% ~50% Initial concentration Needed o-H2: < 0.02 % p-D2: < 0.1% e-e- e-e- Proton or Triton Dynamic Polarization of HD or DT Solem et al. in 1974 reach 4% H polarization with HD containing % H 2 D 2 Transitions made possible through microwave excitation: ~70GHz ~50%

Mass Spectrometer Sampler Tanks Distillator Extraction Valves

Conclusions Polarization looks like a MUST for future power plants. We have in Europe (and in France): ITER to study the magnetic confinement and MEGAJOULE for the inertial confinement. The full polarization of DT fuel increases the reactivity by at least 50% and controls the reaction products direction of emission. Simulations of ICF 100%. The cost of a polarization station (10 7 €) is negligible compared to the cost of a reactor (10 10 € for ITER). A first question remain: D and T relaxation times during fusion process ? We have proposed a “simple” experiment to approach this question, at least for the inertial confinement: POLAF Project accepted at ILE (OSAKA) Feasibility of the experiment confirmed for D + D → 3 He + n reaction which can also test the RPA features Polarization of the fuel? DNP of HD and DT must be revisited seriously somewhere, as well as high intensity polarized D 2 and T 2 molecular jets.

J.-P. Didelez and C. Deutsch, « Persistence of the Polarization in a Fusion Process », LPB 29 (2011) 169

TNSA on « thick » Targets

HD Target: NMR Measurements 0.85 T – 1.8 K Back conversion at room temp. for 5 hours is 30%

HD Target: Production Step I: HD purity monitoring – Quadrupole Mass Spectrometer HD quality on the market ? Step II: HD production – Distillation apparatus in Orsay Over 3 month of ageing necessary

Distillation apparatus in Orsay 3 extraction point 3 temperature probe To mass spectrometer Stainless Steel column filled with Stedman Packing: Heater 1 Heater 2

- Demontrate the persistence with an ultrashort laser and a polarized HD target (HIIF2010, GSI Darmstadt, August 2010) - Develop the Dynamic Nuclear Polarization of HD (SPIN2010, KFA Jülich, September 2010) - DNP of DT molecules (HIIF2012, ? ) - Fusion of polarized DT at Mégajoule (20??)