Diapositive 1

1
DT Polarization for ICF

• DT polarization and Fusion Process
• Magnetic Confinement
• Inertial Confinement
• Persistence of the Polarization
• - Polarized D and 3He 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

J.- P. Didelez
2
DT polarization and Fusion Process
(Kulsrud, 1982) (More, 1983)
D T ? 4He (3.5 Mev) n (14.1 MeV) 17.6
MeV
(3.37 1011 J/g)
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

3
(No Transcript)
4
Fusion by Magnetic Confinement (ITER)
Plasma Density n 1014 (cm-3) Confinement
Time t 10 (sec) Lawson
Criterion (n t gt 1015 (sec/cm3)
ITER Plasma Volume 873 m3 t 300
(sec) Power 500 MW
5
Fusion by Inertial Confinement (MEGAJOULE)
Plasma Density n 1026 (cm-3) Confinement
Time t 10-10 (sec) Lawson
Criterion (n t gt 1015 (sec/cm3)
ICF Target 3mm radius Carbone 4 mg cryogenic
DT 2000 times compressed 300 g/cm3 5 keV 825
MJ within 100 ps
J. MEYER-TER-VEHN, Nucl. Phys. News, Vol 2 N 3
(1992) 15
6
At fixed G EB / EA lt 0.7 for G100 EA 880 kJ
EB 510 kJ EAmin 450
kJ EBmin 290 kJ for E 1 MJ GA
140 GB 307

Aunpolarized DT Bpolarized DT
7
DD
D2T2
?
DT
D2 T2
8
Fusion by Magnetic Confinement (ITER)
Persistence of the Polarization
- Injection of Polarized D and 3He in a Tokamak
(A. Honig and A. Sandorfi)
D 3He ? 4He p 18.35 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 ? 3He ? 5.5 MeV
• Expected Angular distribution of
  the ? ray
• Change in the
  cross section
• D D ? 3He n 3.267 MeV
• Expected Change in the total cross
  section
• Sin2? angular
  distribution of the neutrons

9
Tentative Set-Up
Polarized HD Target 25 cm3 H (p) polarization gt
60 D (d) vect. polar. gt 14
5.5 MeV ? ray from p d ? 3He ? 2.45 MeV
n from d d ? 3He n
Powerful Laser (Terawatt) creates a local
plasma of p and d ions (5 KeV)
200 mJ, 160 fs 4.5 µm FWHM 970 nm, 1018 W/cm2
10
(No Transcript)
11
The Few-Body Problem
ds4/d?? (1 cos2 ?) (S 3/2)
s0 (10 keV) 18 µbarn
1 - 10 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
? (EM background). ds5/d?n sin2 ?
(S 2) s n5 / s0 lt 0.5 s0 (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.
?
d
d
p
3He
1
1/2
HD Plasma 5 keV
3He
n
d d
M. Viviani G. J. Schmid PR C52, R1732
(1995) A. Deltuva , FB Bonn (2009)
12
POLAF proposal (RCNP, ILE and ORSAY) with
themulti-detector MANDALA at ILE - Osaka .
Target Chamber
Target Chamber
13.42 m
13.42 m
D2.2 m
D2.2 m
neutron detector
neutron detector
MANDALA
MANDALA
An energy resolution of 28 keV for 2.45-MeV DD
neutrons is achieved with MANDALA.
An energy resolution of 28 keV for 2.45-MeV DD
neutrons is achieved with MANDALA.
13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
Static Polarization of HD
B/T gt 1500
Dilution Refrigerator 10 mK and 17 T (B/T 1700)
17
Static Polarization of HD DR 10 mK, 17 T
solenoid
18
Dynamic Polarization of HD or DT
Adding free electrons. For B2.5 T and T 1 K,
e- polarization 92
B
50
92
Solem et al. in 1974 reach 4 H
polarization with HD containing 4 - 5 H2 D2
e-
50

e-
Proton or Triton
Initial concentration Needed
o-H2 lt 0.02 p-D2 lt 0.1
Proton relaxation time gtgt electron
19
Extraction Valves
Mass Spectrometer
Distillator
Sampler Tanks
20
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 (107 ) is negligible compared to the
cost of a reactor (1010 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 ? 3He 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 D2 and T2 molecular
jets.
21
J.-P. Didelez and C. Deutsch,  Persistence
of the Polarization in a Fusion Process , LPB
29 (2011) 169
22
TNSA on  thick  Targets
23
HD Target NMR Measurements
0.85 T 1.8 K
Back conversion at room temp. for 5 hours is 30
24
HD Target Production
Over 3 month of ageing necessary
25
Distillation apparatus in Orsay
26
Persistence of the Polarization in a Fusion
Process
What to do ?

• 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??)

27
Mais que diable font les chercheurs émérites
dans ce laboratoire ?