sachiko suzuki 1, akira yoshikawa 1, hirotada ishikawa 1, yohei kikuchi 1, yuji inagaki 1, naoko...
TRANSCRIPT
Sachiko Suzuki1, Akira Yoshikawa1, Hirotada Ishikawa1, Yohei Kikuchi1,
Yuji Inagaki1, Naoko Ashikawa2, Akio Sagara2, Naoaki Yoshida3,
Yasuhisa Oya1 and Kenji Okuno1
1 Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Japan2 National Institute for Fusion Science, Japan
3 Institute of Applied Mechanics, Kyushu University, Japan
Hydrogen isotope behavior in C+ and D2
+ simultaneous implanted tungsten
Combination usage of tungsten (W) and carbon fiber composite (CFC)
Sputtering by direct contact of plasma
Forming of re-deposition layer (WxCy)
Elucidation of chemical behavior of hydrogen isotopes implanted into C/W mixed materialsElucidation of chemical behavior of hydrogen isotopes implanted into C/W mixed materials
BackgroundBackground
Fig. 1 D2 TDS spectrum in WC
Previous studyPrevious study[1][1]
Peak 1 at 400 K400 K Peak 2 at 490 K 490 K Peak 3 at 600 K600 K Carbon vacancy Peak 4 at 930 K 930 K C-D bond
Trapping sites of deuterium
Interstitial sites
300 500 700 900 11000.0
0.5
1.0
1.5
Des
orpt
ion
rate
/ 10
18 D
2 m-2
s-1
Temperature / K
Peak 1 Peak 2 Peak 3 Peak 4
[1] H. Kimura, et al., Fusion Eng. Des. 81 (2006) 295-299.
Objective Objective
Elucidation of hydrogen isotope behavior in C+ and D2
+ simultaneous implanted tungstenElucidation of hydrogen isotope behavior in C+ and D2
+ simultaneous implanted tungsten
D2+ gun
Ion implantation chamber
Sample insert port
Fig. 2 The simultaneous C+ and D2+ implantation system
C+ gun
ApparatusApparatus
TDS chamber
Ion source gas: CO2E×B mass separation filter
0 100 200 300 400 500 600 7000.0
1.0
2.0
3.0
Ions
D (3 keV D2
+)
C (10 keV C+)
Depth / Ang.
Fig. 3 SRIM calculation results for implantation depth
Energy: 0.5 - 10 keV C+
Flux: 2.0×1017 - 2.0×1018 C+ m-2 s-1
Energy: 0.5 - 3 keV D2
+
Flux: 2.0×1017
– 2.0×1018
D2+ m-2 s-1
SamplesSamples
W (under stress-relieved conditions )
purchased from A.L.M.T. Corp.
Density: 19.3 g/cm3
Size: 10 mmФ0.5 mm
Prepared and polished
Implantation conditions Energy: 3.0 keV D2
+, 10 keV C+
Flux: 1.0 × 1018 ions m-2 s-1
Fluence: 1.0 × 1022 ions m-2
Imp. temp.: R.T.
Heating rate: 0.5 K s-1
Heating temp.: R.T. – 1173 K
C+, D2+
implantations
TDS
XPS
X-ray source: Al K
Implantation procedures Only D2
+ imp. C+ and D2
+ simultaneous imp. D2
+ imp. after C+ imp.
XPS
Experimental procedure 1Experimental procedure 1
Heating temp.: 1173 K Time: 10 min
Preheating
C+ imp.D2
+ imp. and C+ imp.D2+ imp.
Implantation proceduresImplantation procedures
Only D2+ imp. C+ and D2
+ simultaneous imp. C+ and D2+ sequential imp.
D2+ imp.
D2+ gun C+ gun
Implantation conditions Energy: 3.0 keV D2
+, 10 keV C+
Flux: 1.0 × 1018 ions m-2 s-1
Fluence: 1.0 × 1022 ions m-2
Imp. temp.: R.T.
Heating rate: 0.5 K s-1
Heating temp.: R.T. – 1173 K
C+, D2+
implantations
TDS
XPS
X-ray source: Al K
Implantation procedures Only D2
+ imp. C+ and D2
+ simultaneous imp. D2
+ imp. after C+ imp.
XPS
Experimental procedure 1Experimental procedure 1
Heating temp.: 1173 K Time: 10 min
Preheating
Implantation conditions Energy: 3.0 keV D2
+, 10 keV C+
Flux: 1.0 × 1018 D2+ m-2 s-1
Flux: 2.0 × 1017 - 2.0 × 1018 C+ m-2 s-1
Flux ratio of C+/D+: 0.2 -2.00.2 -2.0Fluence: 1.0 × 1022 D2
+ m-2
Fluence: 2.0 × 1021 - 2.0 × 1022 C+ m-2
Imp. temp.: R.T.
Heating rate: 0.5 K s-1
Heating temp.: R.T. – 1173 K
C+, D2+
implantations
TDS
XPS
X-ray source: Al KXPS
Experimental procedure 2Experimental procedure 2
Heating temp.: 1173 K Time: 10 min
Preheating
CC++ and D and D22++ simultaneous imp. simultaneous imp.
Implantation proceduresThe flux dependence of CThe flux dependence of C++
Results and Discussion (1)Results and Discussion (1)
Fig. 4 XPS spectra of C-1s with various implantation procedures
C-W bond ・・・ 282.7 eV [1] C-C bond ・・・ 284.6 eV [2]
[1] H. Kimura, et al., Fus. Eng. Des. 81 (2006) 295-299.
[2] C. D. Wagner, et al. Handbook of X-ray photoelectron spectroscopy, Rerking- Elmer Corp., Physical Electronics, Division.
Fig. 5 Peak areas of C-C and C-W bonds with various implantation procedures
The decrease of C-C bond by D2+ imp. on C+-D2
+ sequential imp.
The sputtering of carbon by D2+ imp.
The area of C-C bondSimultaneous imp. Simultaneous imp. > > Sequential imp.Sequential imp.
Aggregation of carbon on surface after C+-D2+ simultaneous imp.
C-W bondC-C bond
295 290 285 280 2752.0
2.5
3.0
3.5 Only C+ imp. Sequential imp. Simultaneous imp.
Inte
nsit
y / a
rb.u
nit
Binding energy / eV1 2 3
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
SimultaneousOnly C+
Peak
are
a / a
rb.u
nit
C-C bond C-W bond
SequentialImplantation procedures
Fig. 6 XPS spectra of W-4f with various implantation procedures
[3] J. Kovac, et al., Vacuum 82 (2008) 150-153.
C+-D2+ simultaneous imp. ・・・ The positive peak shift of about 0.4 eV
Only C+ imp. ・・・ The positive peak shift of about 0.9 eV
C+-D2+ simultaneous implantation→C-W bond
Only C+ implantation → carbon rich tungsten carbide (WCx)
Main chemical states
Results and Discussion (2)Results and Discussion (2)W : 31.5 eV [3]
38 36 34 32 300.0
1.0
2.0
3.0
4.0
Inte
nsit
y / a
rb.u
nit
Binding energy / eV
Simultaneous imp. Sequential imp.
Only C+ imp.
Only D2
+ imp.
After preheating
The higher desorption peak at around 800K800K ・・・ C-D bondC-D bondThe least total deuterium retention in Simultaneous imp.
[4] T. Suda, et al., Fus. Eng. Des. 82 (2007) 1762-1766.
In C+-D2+ simultaneous implantation
deuterium was hardly trapped at higher temperature.
Results and Discussion (3)Results and Discussion (3)
Fig. 7 TDS spectra with various implantation procedures
Fig. 8 Total D retention with various implantation procedures
400 600 800 1000 12000.0
0.5
1.0
1.5
2.0
2.5
3.0
D
esor
ptio
n ra
te /
1017
D2 m
-2 s
-1 Only D2
+ imp.
Sequential imp. Simultaneous imp.
Temperature / K
600-1100 K
400 K
0.0
1.0
2.0
3.0
4.0
Des
orpt
ion
rate
/ 10
18 D
2 m-2 s
-1
HOPG[4]
1 2 34.0
5.0
6.0
7.0
8.0
Simultaneous imp.Sequential imp.
D retention
D r
eten
tion
/ 10
19 D
2 m-2
Implantation proceduresOnly D
2
+ imp
The large desorption peak at around 400 K 400 K → Interstitial of WInterstitial of W
300 400 500 600 700 800 900 1000 11000.0
0.5
1.0
1.5
2.0
2.5
3.0
C+/D+=0.2
C+/D+=1
C+/D+=2
Des
orp
tion
rat
e / 1
017 D
m-2
s-1
Temperature / K
Results and Discussion (4)Results and Discussion (4)The flux dependence of CThe flux dependence of C++
Fig. 9 TDS spectra for the simultaneous implanted W with various C+/D+ flux ratio
Fig. 10 Total peak area of C-1s as a function of C+/D+ flux ratio
C+/D+ = 0.2 : The large desorption peak at around 800 K 800 K → C-D bondC-D bond Carbon concentration was decreased as the C+/D+ ratio increased
The enhancement of carbon re-emission in high C+/D+ ratio The low re-emission of carbon leads high retention of D trapped by carbon.
SummarySummary
Elucidation of the trapping sites and role of carbon on hydrogen isotope retention in C/W mixed materials
Elucidation of the trapping sites and role of carbon on hydrogen isotope retention in C/W mixed materials
D desorption at higher temperature side in C+-D2+ sequential imp.
→ C-D bond Total D retention Only D2
+ imp. C+-D2
+ sequential imp.
Further studies Further studies
Establishment of the simultaneous CEstablishment of the simultaneous C++ and D and D22
++ implantation system implantation system
<About 25%
C+-D2+ simultaneous imp.
Elucidation of hydrogen isotope behavior in C+ and D2
+ simultaneous implanted tungsten
The flux dependence of CThe flux dependence of C++
The low reemission of carbon leads high retention of D trapped by carbon.
Thank you for your attention
42 40 38 36 34 32 30 280.0
0.5
1.0
1.5
2.0
Inte
nsi
ty /
arb
. un
it
Binding energy / eV
Imp. Temp. 873 K 773 K 673 K 573 K 423 K 323 K Before
295 290 285 280 2750.0
0.5
1.0
1.5
2.0
2.5
Inte
nsit
y / a
rb. u
nit
Binding energy / eV
Imp. Temp. 873 K 773 K 673 K 573 K 423 K 323 K before
284.6 eV C-C + C-D 31.4 eV W-C
Fig. 11 C-1s and W-4f XPS spectra after D2+ implantation at various implantation temperatures.
282.7 eV C-W
Interstitial site I Interstitial site II
W DC
Dependence of implantation temperature on change of Dependence of implantation temperature on change of chemical state of C and W in WCchemical state of C and W in WC
Peak 1Peak 1: Interstitial site IPeak 2Peak 2: Interstitial site II
300 500 700 900 1100 13000.0
0.5
1.0
1.5
Des
orpt
ion
rate
/ 10
18 D
2 m-2
s-1
Temperature / K
Imp. temp. / K 323 423 573 673 873
Energy : 1 keV D2
+
flux : 1.0 x 1018 D+ m-2 s-1
Fluence : 1.0 x 1020 D+ m-2
Analysis methodsAnalysis methods
• TDS (Thermal Desorption Spectroscopy)• XPS (X-ray Photoelectron Spectroscopy)
D2+ implantation
QMS
Heating
Analyzer
X-ray
XPSTDS
Fig. 6 XPS spectra of W-4f with various implantation procedures
[4] J. Kovac, et al., Vacuum 82 (2008) 150-153.
C+-D2+ simultaneous imp. ・・・ The positive peak shift of about 0.4 eV
Only C+ imp. ・・・ The positive peak shift of about 0.9 eV
W : 31.5 eV [4]
38 36 34 32 300.0
1.0
2.0
3.0
4.0
Inte
nsit
y / a
rb.u
nit
Binding energy / eV
C+-D2
+ simultaneous imp.
C+-D2
+ sequential imp.
Only C+ imp.
Only D2
+ imp.
After preheating
C+-D2+ simultaneous implantation→C-W bond
Only C+ implantation → carbon rich tungsten carbide (WCx)
Main Chemical states
Results and Discussion (2)Results and Discussion (2)
400 600 800 1000 12000.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0 W imp. D
2
+
Simultaneous Sequential
WC imp. D2
+
Temperature/K
Fig. TDS spectra with various implantation procedures
0.0 0.5 1.0 1.5 2.0
1.0
1.5
2.0
2.5
3.0
Ret
enti
on /
1017
D m
-2
C+/D+ / -
Fig. Total retention for the simultaneous implanted W with various C+/D+ ratio
0 100 200 300 400 500 600 7000.0
1.0
2.0
3.0
Ions
D (3 keV D2
+)
C (10 keV C+)
Depth / Ang.
Implantation DepthImplantation Depth
Fig. 2 SRIM calculation results for implantation depth
The implantation depth of 10 keV C+ is almost the same as that of 3 keV D2+
Deuterium ion gun
Ion implantation chamber
Sample insert port
Fig. 1 The simultaneous C+ and D2+ implantation system
(a) Photograph (b) Diagrammatic illustration
Carbon ion gun
ApparatusApparatus
TDS chamber
D2+ ion gun
QMS
Manupilator
Differential pumping system
G.V.
C+ ion gun
TDS chamber
Ion implantation chamber
(a) (b)Ion source gas: CO2
E×B mass separation filter