05aD17P
イオンビームその場分析によるW中の同位体交換研究
Deuterium-Hydrogen isotope exchange in self-damaged W studied by in-situ
nuclear reaction analysis
H. T. Lee1), T. Schwarz-selinger2), 大塚裕介1), 上田良夫1),
H. T. Lee1), T. Schwarz-selinger2), OHTSUKA Yusuke1), UEDA Yoshio1)
1)大阪大学大学院工学研究科	  2) マックス・プランクプラズマ物理研究所	 
1) Graduate School of Engineering, Osaka Univ. 2) IPP, Garching

2. Experiment
A single W sample manufactured by Plansee waspolished to a mirror finish, and outgassed at 1223 Kin vacuum. The sample was implanted by 20 MeV
W ions up to 1.4×1014 cm-2 fluence at 300 K andthen recrystallized at 2000 K for 10 minutes invacuum. A dual-beam system [1] connected to atandem accelerator for in-situ ion beam analysis
was used to implant 9 keV D3+ with fluxes of1018–1019 D+/m2s up to a fluence of ~1024 D/m2 at
300 and 450 K. The implanted D concentration wasmeasured using nuclear reaction analysis (NRA)
using the D(3He,p)4He nuclear reaction at 0.69 to
4.0 MeV. D depth profiles were determined bySIMNRA [2] fitting of the spectra. Following D
implantation, H was implanted in smaller fluence
steps using the same source conditions. Between
each H implantation step, NRA was performed tomeasure the change in trapped D concentration
profile.
3. Results and Discussion
D depth profiles measured by NRA are shown inFig. 1 at 300 K and 450 K. At 300 K, the D trapped
within 100 nm is released or replaced following 310
s H implant corresponding to an implanted fluenceof 8×1021 H/m2 (not shown). However, as seen from
Fig. 1, the absolute amount of D trapped at greater
depths is hardly affected but there is a redistributionof the trapped profile even at 300 K. At 450 K, theisotope exchange process is enhanced but theprocess is still inefficient. In this presentation, we300
K experiments
discuss the removal
efficiency
based on the data(bulk D)
D concentrationa function
Depthfor varying
below
as well as as
futureplan offor
improving
theH fluence
Proton Data (144.47 detector – 1.8, 2.4, 3.2, 4.5 MeV)
experiments.
Depth (nm)00.1

D (D/W)

1. Introduction
Neutron damage results in increased T inventoryin tungsten (W), which must be strictly controlled
for safety reasons. Isotope exchange is proposed as
one method for such control. However, the detailed
kinetics of such process is not yet well understood
but is important to clarify to estimate the efficiencyof removal. Therefore, we have performed
preliminarily in-situ experiments examining
Deuterium-Hydrogenisotopeexchangeinself-damaged W to demonstrate the feasibility ofstudying the kinetics of isotope exchange.

2000

40006000

After D implant
After H implant (310 sec)

0.01

• The trapped Dappears to redis
diffuse inwards(• Significant D loobserved.
1E-3• Further experim
450 K experiments (bulkmore robustD
fitti

1E-4
D concentration
as a function of Depth for varying H fluence
010000
20000
30000
40000
Proton Data (150 detector – 1.8, 2.4, 3.2,4.5 MeV)
2Depth (1e15 at/cm )2×1024 D/m2
450 K ; 2×1024 D/m2

2After
23 D/m222×10224 H/m2
(0.4-4)×10300
K2H/m; 2×10
After 8×10H/m22

Figure.1 D depth profiles following H implantationsteps at 300 K (upper) and 450 K (lower).
Reference[1] I. Bizyukov, K. Krieger, Rev. Sci. Instrum. 77(2006) 043501.
[2] M. MAYER, SIMNRA User’s Guide, Report
IPP
9/113,
Max-Planck-Institut
fuer
Plasmaphysik, Garching, Germany (1997).

• Comparisclearly show
not saturate• Significanobserved uµm in the H
covered.

• Deeper dealmost unto