« la polarisation au secours de la fusion » ipn orsay, 7 novembre 2011 dt polarization and fusion...
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« La Polarisation au secours de la Fusion »IPN Orsay, 7 novembre 2011
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
DT polarization and Fusion Process
(Kulsrud, 1982)(More, 1983)D + T → 4He (3.5 Mev) + n (14.1 MeV) + 17.6 MeV
S = ½S = 1
S = 3/2S = ½
95% – 99%D + T → He5 (3/2+) → He4 + n
1% – 4%
S = 3/23/2
1/2
-1/2
-3/2
S = 1/21/2
-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 Sin2(θ)- n from DD fusion are suppressed QSF (Jülich – Gatchina)
50 % Increasein 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
(3.37 1011 J/g)
Plasma Density n = 1014 (cm-3) ; Confinement Time τ = 10 (sec) Lawson Criterion (n τ > 1015 (sec/cm3)
Fusion by Magnetic Confinement – (ITER)
ITER
Plasma Volume = 873 m3
τ = 300 (sec)
Power = 500 MW
Fusion by Inertial Confinement – (MEGAJOULE)
Plasma Density n = 1026 (cm-3) ; Confinement Time τ = 10-10 (sec) Lawson Criterion (n τ > 1015 (sec/cm3)
ICF
Target 3mm radiusCarbone &
4 mg cryogenic DT
2000 times compressed300 g/cm3
5 keV
825 MJ within 100 ps
J. MEYER-TER-VEHN, Nucl. Phys. News, Vol 2 N° 3 (1992) 15
Inertial Fusion induced by Laser, Gain = Efus / Ein
DTCS
G = 0.05
For polarized DT DTCS = DTCS × 1.5
G = 4
Mauro TEMPORALUniversidad Politécnicade Madrid, Spain
Code: MULTI – 1D
DTCS × 2G = 76
× 4
α 3.5 Mev
Ein = 185 kJ
DDD2T2
DTD2 T2
?
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 + γ + 5.5 MeV
Expected: Angular distribution of the γ ray Change in the cross section
D + D → 3He + n + 3.267 MeV
Expected: Change in the total cross section Sin2θ angular distribution of the neutrons
Powerful Laser (Terawatt)creates a local plasmaof p and d ions (5 KeV)
5.5 MeV γ ray fromp + d → 3He + γ
2.45 MeV n fromd + d → 3He + n
Tentative Set-Up
Polarized HD Target25 cm3
H (p) polarization > 60%D (d) vect. polar. > 14%
200 mJ, 160 fs 4.5 µm FWHM
970 nm, ~ 1018 W/cm2
The “Few-Body” Problem
d
1/2 1
p d
3He
γ
dσ4/dωγ ~ (1+ cos2 θ) * (S = 3/2)
σ0 (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 γ (EM background).
dσ5/dωn ~ sin2 θ *** (S = 2)
σ n5 / σ0 < 0.5 ; σ0 (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), E. Kuraev, BFKL Dubna
HD Plasma5 keV
3He
d d
n
POLAF proposal (RCNP, ILE and IPN) with themulti-detector “MANDALA” at ILE - Osaka .
An energy resolution of 28 keV for 2.45-MeV DD neutrons is achieved with MANDALA.
13.42 m
Target Chamber
MANDALADD neutron energy [MeV]
Co
un
t ΔE
2
5.82
)()(
keVkeV
ETi
D ~ 2.2 m
neutron detector
t10 cm PMT
10 fcm
BC-408 scintillat
or×422 ch
An energy resolution of 28 keV for 2.45-MeV DD neutrons is achieved with MANDALA.
13.42 m
Target Chamber
MANDALADD neutron energy [MeV]
Co
un
t ΔE
2
5.82
)()(
keVkeV
ETi
D ~ 2.2 m
neutron detector
Static Polarization of HD
B/T > 1500
Dilution Refrigerator 10 mK and 17 T (B/T = 1700)
1220
mm
170mm
70m
m
Mixing Chamber
Nb3Sn joints&Protection Circuit
NbTi joints&Switch
Main CoilCorrection Coil
Null Coil
Rough dimensions of the magnet
400mm
600m
m
550m
m
1K Pot
538m
m
16.990
16.992
16.994
16.996
16.998
17.000
17.002
17.004
17.006
17.008
17.010
- 100 - 80 - 60 - 40 - 20 0 20 40 60 80 100
0
5
10
15
z (mm)
B (T)R(mm)
150mm
500ppm
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
400 500 600 700 800 900 1000 1100 1200
0
10
20
30
40
50
60
70
80
z (mm)
B (T)R(mm)
Static Polarization of HD : DR 10 mK, 17 T solenoid
H D
Lattice of the HD crystal
Polarized HD Molecule
H Hortho-H2
6.4 days
H H para-H2decay
(Honig, 1967)
Polarization of protons in HD targets
L = 1L = 0
L = 0
Polarization of HD targets
H D
Lattice of the HD crystal
Polarized HD Molecule
H H para-H2
(Honig, 1967)
18.2 days
decaypara-D2
D D D D ortho-D2
High relaxation time at ~1K temperature
Polarization of deuterons in HD targets
E
Adding free electrons. For B=2.5 T and T = 1 K, e- polarization = 92%
Proton relaxation time >> electron
92%
~50%
~50%
Initial concentration Needed
o-H2: < 0.02 %p-D2: < 0.1%
e-
e- Proton or Triton
Dynamic Polarization of HD or DT
Solem et al. in 1974 reach 4% H polarizationwith HD containing 4 - 5 % H2 D2
Transitions made possiblethrough microwave excitation: ~70GHz
~50%
~50%
Mass Spectrometer
Sampler Tanks
Distillator
Extraction Valves
Conclusions
Fusion is a MUST for future power plants.We have in Europe (and in France): ITER to study the magnetic confinementand MEGAJOULE for the inertial confinement.
The full polarization of DT fuel increases the reactivity by 50% and control the reaction products direction of emission. Dynamic effects huge gain.The cost of a polarization station (5 106 €) is negligible compared to the cost of a reactor (5 109 € for ITER).
A question remains: D and T relaxation time during fusion process ?
We propose “simple” experiments to answer this fundamental question, at least for the inertial confinement.Feasibility of the experiment confirmed for D + D → 3He + n Ongoing POLAF Project at ILE (OSAKA)
DNP of HD and DT must be revisited seriously somewhere!!!
POLARIZATION: A MUST FOR FUSION J.-P. Didelez1 and C. Deutsch2
1IPN, CNRS/IN2P3 & Université Paris-Sud (UMR-CNRS 8608) Bât. 100, F-91406 ORSAY, France 2LPGP Université Paris-Sud (UMR-CNRS 8578) Bât. 210, F-91405 ORSAY, France
J.-P. Didelez and C. Deutsch, « Persistence of the Polarization in a Fusion Process », LPB 29 (2011) 169
HD Target: NMR Measurements0.85 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 point3 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??)