Seoul Nat’l Univ. Dept. of Nuclear Eng. Plasma Application Laboratory ICTP School TDS Study of Effect of High Energy Ion induced Cascade Damage on Deuterium Retention in Tungsten Younggil Jin, Jae-Min Song, Ki-Baek Roh, Gon-Ho Kim [email protected]Plasma Application Laboratory Energy Systems Engineering, Seoul National University, Korea July 18 th , 2016 O4
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TDS Study of Effect of High Energy Ion induced Cascade ......TDS Study of Effect of High Energy Ion induced Cascade Damage on Deuterium Retention in Tungsten. Younggil Jin, Jae-Min
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Seoul Nat’l Univ.Dept. of Nuclear Eng.
PlasmaApplicationLaboratoryICTP School
TDS Study of Effect of High Energy Ion induced Cascade Damage on Deuterium
T retention increase with damage (dpa) of Low energy fuel ion (D+, Ei < 100
eV), Energetic ion (W+, Be+, C+, Fe+ for ITER and DEMO, sub keV ~ MeV),
fusion product (He ash and n, E ~ 14.5 MeV).
Common Issue: Non-linearity b/w retention and dpa (damage level)
Scattered retention expectation and transition [1]
[1] J. Roth, PSI-18 Toledo, May 26, 2008[2] N. Fedorczak et al., Journal of Nuclear Materials 463 (2015) 85–90
Energetic ion (W+) eject flux in JET-ILW [2]
Safetylimit
Transition?
3/19
Research Topic and StrategyIntroduction
Retention mechanism
By Low energy fuel
ion
Change by Impurity chemical trapping
Change by Defect induced trapping
By self ion
Ion-induced Cascade damageduring operation
Impurity implantation during operation
Desorption due to thermal effect Decrease of
retention
Comprehensive understanding on
1) Retentionfor safety
2) Recycling for PSI analysis
Present topic
Cause of non-linearityIntrinsic retention
W Transmutation effect due to
neutronNeutron effect
4/19
Energetic Ion Irradiation Facility: HIT
Cs ion
FeO2-
FeO Target
FeO2-
Charge exchange gas
Grid : + 1.4 MV
Fe2+
Ion get max. 2.8 MeV : applied V x 2
Quadruple magnetic
lens
W specimen
[3] F. Hinterberger, et al., “Electrostatic accelerators”, Springer, (2005).
High fluence irradiation facility (HIT)In Tokyo University [3]
5/18
Cascade Ion Damage of Fe2+ and Similarity with W+Experiment
Facility: HIT in Tokyo Univ. Damage profile of Fe2+ and W+ (SRIM-2013)
Property ConditionSelf-ion simulate ion Fe2+ ion
Ion energy 2.8 MeV
Incident angle 75° (15° tilted)
Target temperature 300 K (spec.: ~ 873 K)
Damage range 0-0.7 dpa(spec.: dep. on time)
Comparison of cascade damage for heavy ion (Fe2+) to W ion.Property (Estimated by SRIM) 74 W ion (self ion) 26 Fe ion (HIT) Capability of demonstration
Damage(∝dpa)
(1) Target displacement 70959/W Ion 39948/Fe Ion Adjustable by 1.776 times fluence
(2) Target vacancy 60361/W Ion 34079/Fe Ion Adjustable by 1.776 times fluence
Displacement per vacancy generation ratio (=(1)/(2)) 1.175 1.172 (≒ W)
Unadjustable (Intrinsic): it decide TDS spectrum shape Essential for demonstration
(a) 2.8 MeV W ion, 75° (b) 2.8 MeV Fe ion 75°
This research can show representative effect of cascade damage using energetic ion, and then it gives insight to expect tungsten self ion effect.
TDS Spectrum Variation of Ion Cascade Damaged WResult
Dislocation Vacancy Cluster
0
1x1016
2x1016
3x1016
4x1016
0
1x1016
2x1016
3x1016
4x1016
0
1x1016
2x1016
3x1016
4x1016
0
1x1016
2x1016
3x1016
4x1016
300 400 500 600 700 800 9000
1x1016
2x1016
3x1016
4x1016
Des
orpt
ion
flux
[D2/m
2 -s]
Temperature (K)
0 dpa
0.01 dpa
0.05 dpa
0.2 dpa
0.7 dpa
dpa TDS peak and dominant trapping
400-500 K D-dislocationtrap (Edes=0.75-0.95 eV)
580-680 K D-vacancy trap (Edes1.83 eV)
710-810 K D- cluster trap (Edes=2.34 eV)
0.00 O (461 K) O (638 K): dominant X
0.01 O (490 K) O (581 K, 666 K) O (800 K)
0.05 O (473 K) O (624 K, 730 K) O (810 K)
0.20 O (390 K, 488 K, 527 K): dominant
X O (799 K)
0.70 O (394 K, 482 K, 572 K): dominat
X O (808 K)
Variation: Dominant vacancy Dominant dislocation
The variation defined by peak analysis:Theoretical and Literature value of TDS peak
Edes [eV] Es [eV] TP (Error range) [K]0.75-0.95 0.35-55 (dislocation) 350-550 K, Literature [6]
1.83 1.43 (vacancy) [7, 8] 616 (566-666), Theory
2.34 1.94 (vacancy cluster) [9] 796 (746-846), Theory
[6] H. Fujita et al., Phys. Scr. T167 (2016) 014068[7] D. F. Johnson et al., J. Mater. Res., Vol. 25, No. 2, Feb 2010[8] K. Heinola et al., Physical Review B 82, 094102 2010 [9] Ogorodnikova, Roth, and Mayer, J. Appl. Phys. 103, 034902 2008
Fuel ion only retention
+ Cascade damaged
13/18
Retention Property under Low Ei Fuel Ion Only (~0 dpa) [10]
Result
0.0
2.0x1018
4.0x1018
6.0x1018
8.0x1018
1.0x1019
300 400 500 600 700 800 900 1000 1100 12000.0
2.0x1018
4.0x1018
6.0x1018
8.0x1018
1.0x1019
Des
orpt
ion
flux
(D2/m
2 -s)
Temperature (K)
TDS measurement for 2.0 x 1025 D/m2
Fit Peak 1 at 452 K Fit Peak 2 at 670 K Cumulative Fit Peak
Des
orpt
ion
flux
(D2/m
2 -s)
Temperature (K)
TDS measurement for 4.0 x 1025 D/m2
Fit Peak 1 at 455 K Fit Peak 2 at 680 K Cumulative Fit Peak
1. Mechanism for retention under fuel ion only = vacancy trapping (Eb=1.43 eV)
Fluence dependence of vacancy trapping(Plotted with TDS peak deconvolution)
Change: from solution to vacancy trapping
Vacancy trapping dominates retention after the
fluence over 2.0 x 1025 D/m2 with Eb=1.43 eV.
Es=0.89 eV Es=1.43 eVEdes=0.89 eV Edes=1.83 eV
300 400 500 600 700 800 900 1000 1100 12000.0
2.0x1018
4.0x1018
6.0x1018
8.0x1018
1.0x1019
Des
orpt
ion
flux
(D2/m
2 -s)
Temperature (K)
0.5x1025D/m2 (No peak) 2.0x1025D/m2 Gaussian fit (462 K) 4.0x1025D/m2 Gaussian fit (676 K)
D Solution in W Vacancy trapping
[10] Y. Jin et al., Journal of Korean Physical Society, 2016
Occur of vacancy
Dominant vacancy
14/18
Retention Property under Low Ei Fuel Ion Only (~0 dpa) [10]