y. kawano, 12th meeting of the itpa topical group on diagnostics pppl, 26 – 30 march 2007 1 status...
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Status of Diagnostic Development in JAEA
Y. Kawanofor
T. Kondoh, T. Hatae, M. Ishikawa, N. Asakura, K. Fujimoto
Japan Atomic Energy Agency
12th Meeting of the ITPA Topical Group on DiagnosticsPPPL, 26 – 30 March 2007
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Contents1 Development of CO2 laser for collective Thomson scatteri
ng diagnostic (T. Kondoh et al.)
2 Thomson scattering diagnostics with Fourier transform spectroscopy (T. Hatae et al.)
3 Fast measurement of neutron emission profile in JT-60U (M. Ishikawa et al.)
4 Dust measurement with fast TV camera (N. Asakura et al.)
5 Computer tomography for divertor plasma spectroscopy (K. Fujimoto et al.)
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
1 Development of CO2 laser for collective Thomson scattering diagnostic
T. Kondoh, T. Hayashi, Y. Kawano, Y. Kusama, T. Sugie, Collective Thomson scattering for alpha-particle diagnostic in burning plasmas, submitted to J. Plasma and Fusion Research
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
T. Kondoh, T. Hayashi, Y. Kawano, Y. Kusama, T. Sugie, Y. Miura, High-repetition CO2 laser for Collective Thomson scattering diagnostic of a particles in burning plasmas,16th HTPD (2006)
ITER collective Thomson scattering using CO2 laser
CO2 laser: (20 J, 40 Hz), (30 J, 20 Hz), (50 J, 10 Hz)
Laser
Scattered light
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
High power, high repetition rate single mode pulsed TEA CO2 laser has been developed
Main electrodes
Pre-ionization electrodes
Heat exchanger
Fans
Output energy of 17J at a repetition rate of 15Hz has been achieved.
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Prospect for -particle diagnostic on ITER
• Output energy of 17J at 15Hz has been achieved so far.• CO2 laser for -particle diagnostic will be obtained by adding high voltage power source and discharge units.
FY200617J, 15Hz
2
5
10
20
30
50
0.1 1 10 100
Output energy (J)
Repetition rate (Hz)
Commercially available laser
FY199815J, 0.5Hz(JAERI-ORNL)
Add voltage power source
36J, 20Hz24J, 30Hz
-particle diagnostic
Add twodischarge units(6 --> 8 units)
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
2 Thomson scattering diagnostics with Fourier transform spectroscopy
T. Hatae, J. Howard, Y. Hirano, H. Koguchi, O. Naito, S. Kitamura, Development of Polarization Interferometer Based on Fourier Transform Spectroscopy for Thomson Scattering Diagnostics, IEA RFP Workshop (2007)
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Development of a polarization interferometer for Thomson scattering
• A method based on measurement of the optical coherence of scattered radiation at a fixed optical delay has been proposed for incoherent Thomson scattering.
• However, this method has not been demonstrated. • We are developing a prototype polarization interferometer for Thomson
scattering. Proof-of-principle tests will be carried out in TPE-RX reversed-field pinch (RFP) machine.
JT-60U (JAEA)TPE-RX (AIST)Te < ~1 keV Te < ~30 keV
Proof-of-principle tests Feasibility check
Apply to burning plasma or future program(ITER, JT-60SA)
J. Howard, Plasma Phys. Control. Fusion 48, 777 (2006)
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Polarization interferometer for Thomson scattering diagnostics
• The collected light is transmitted by a wideband filter to a polarization interferometer that generates an image of the optical coherence at a fixed delay.
• The delay plate fast axis is at 45° to the first polarizer axis.• Depending on the orientation of the final polarizer, it is possible to measure either
a ‘bright’ or ‘dark’ interference fringe.• The final Wollaston polarizer produces separate images of the bright and dark frin
ges onto two APD detectors.J. Howard, Plasma Phys. Control. Fusion 48, 777 (2006)
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
The magnitude of the change in fringe visibility agrees with the
numerical calculation• To compare between the numerical simulation
and the experiment, initial test using a blackbody radiation source was carried out.
• When the temperature of the blackbody radiation source (LAND R1500T) was changed, fringe visibility was measured.
• T=1000,1100,1200,1300,1400,1500°C
Polarization interferometerAPD
Numerical simulation
Experimental data
Next: PoP tests at TPE-RX
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
3 Fast measurement of neutron emission profile in JT-60U
M. Ishikawa, T. Itoga, T. Okuji, M. Nakhostin, K. Shinohara, T. Hayashi, A. Sukegawa, M. Baba, T. Nishitani, Fast collimated neutron flux measurement using stilbene scintillator and flashy analog-to-digital converter in JT-60U, Rev. Sci. Instrum. 77 (2006) 10E706
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
・ horizontal : 6 channelsJT-60U tokamak
・ detector : Stilbene neutron detectorStilbene scintillator + analog n- pulse shape discrimination (PSD)
Advantage : high n- discrimination high energy resolution
・ vertical : 8 channels
Profile measurements usingmulti-channel collimator array
Disadvantage : Max. count rate ~ 105 cps. -> large statistical error
Shield room
PIG room
Flash-ADC
StilbenePC
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Development and Installation of a digital signal processing (DSP) system for fast measurements
Stilbene scintillator + Flash ADC (8GHz, 10bit) & PC- Optimization of sampling time, integration time- Correction of gain fluctuation of PMT.
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
0
1
2
0 5 10 15time (s)
(d) SND
0
1
2 (b) total neutron0
1
2
0
10
20
30
IP
PPNBP
NNB
12345 (c) DSP
E46052
saturation
Ip/Bt =1.6MA/3.8T
Measurement of collimated neutron flux using the DSP system
Time trace of neutron counts of the DSP system is almost agree with that of total neutron emission rate.
Plasma configuration and both sight lines
Neutron counts of the PSD was saturated at ~ 1 105 cps due to pile up effect.
DSPPSD
read out end
Neutron flux has been successfully measured with up to ~ 1 106 cps.n- discrimination is possible in the case of pile-up events.
applicable to ITER as a neutron detector of neutron camera A pipe line technique is needed for long time measurement ?
more detail investigation of energetic ions (-particle) transport due to Alfven Eigenmode
(d) PSD
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Preliminary: Observation of change in pulse height spectrum
E46052
0
10
20
5 6 7 8 9
PNB
(MW)
time (ms)
DD
DD
DT
Pulse height spectrum of neutron counts for 1sPulse height spectrum of neutron counts (higher energy range) changes as the power of NBI changes
As a result of energy calibration, second peak ( ~ 0.7 V) of pulse height spectrum corresponds to energy of a DT neutron
one of candidate for a neutron spectrometerHowever, more detail analysis is needed.
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
4 Dust measurement with fast TV camera
Nobuyuki Asakura, N.Ohno, H.Kawashima, T.Nakano, S.Takamura, Y.Uesugi, First report of dust movement in JT-60U discharges, Joint US-Japan workshops on "Dynamics of dust particles in fusion devices" & "Non-Diffusive Plasma Transport and Its Statistics in Edge Plasmas of Fusion”, Nagoya Univ. January 10-11, 2007
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
neutron shield
Fast TV camera& Optical system
Mechanical shutter Interference-filter
Camera Memory & Controller
Timing control system
Ip start
Ethernet+Optical link
JT-60U machine room
15m
scope
JT-60U
Viewing divertor area with Δ~3mm
-Image guide
Control room:PC
,Camera control ,Data acquisition
Timing pulse control
Dust measurement with fast TV camera
Visible light image was measured with fast TV camera from tangential port: Typical frame rate of 2 kHz (1024x1024 pixs, 3s) - 8 kHz (256x256 pixs, 8s). Narrow (9º) and wide (35º) viewing angles for divertor and main plasma, respectively, can be selected.
Timing control (CAMAC)
Camera&IILens&shutter
Memory& Controller
Neutron shield
Viewing main plasma with Δ~1cm
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
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Dust movement in SOL
• A dust is exhausted from NBI port (P12): V =0.9m/(18frs x0.5ms)~0.1km/s
• A dust moves towards near-toroidal direction (ion drift),
with V =5 m/(32frs x0.5ms)~0.3km/s
outer (LFS) midplane
P14
32 frames (16ms)
Divertor
ELMy H-mode plasma (Ip=1.8MA, Bt=4T,PNBI=17MW): many dusts were observed at start of the first shot after high Ip plasma disruptions and overnight-GDC.
V
NBI port (P12) Main TMP (P14)
18 frames (9ms)
Example 1 (main SOL):
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Dusts are produced at HFS (inner) divertor
moving in toroidal direction (ion drift) with V = 0.8m/(17frsx0.16ms)~0.27km/s.
17 frames (3ms)
ELMy H-mode (Ip=1.4MA, Bt=3.9T,PNBI=12MW): HFS strike-point was moved to upper target (on dense C-deposition layers)=> Deposition layers at HFS divertor are removed by ELMs => Dusts are produced,
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32 frames (5.5ms)ELM ELM
Many dusts from inner divertor
HFS divertor
512x512
Large dusts from HFS divertor Many small dusts from HFS divertor
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
K. Fujimoto, T. Nakano, H. Kubo, K. Shimizu, T. Takizuka, K. Sawada, H. Kawashima, N. Asakura, Two-dimensional Spectroscopic Measurement of Deuterium Balmer-series lines in JT-60U Divertor Plasmas, submitted to J. Plasma and Fusion Research
5 Computer tomography for divertor plasma spectroscopy
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Two-dimensional distribution is obtained properly from two-directional measurement
Square grid(traditional grid)
Grid along to view lines(improved grid)
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Radiation of Balmer-series lines (D and D)in inner detached and detached plasma
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
0.0
0.2
0.4
0.6
0.8
0.1 1 10 100
5E19 m-3
1E20 m-3
5E20 m-3
1E19 m-3
Te (eV)
ne=5E18 m-3
Ionizing
Recombining
0.0
0.2
0.4
0.6
0.8
0.1
Two-dimensional distribution of ionizing and recombining component makes clear
< Inner divertor region > Recombining region distributes above the inner strike point along to separatrix. Partial detached plasma is formed.< Outer divertor region > Ionizing region distributes around the outer strike point. Attached plasma is formed.
Recombining(detachment)
Ionizing(attachment)
I(D
)/I(
D)
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Y. Kawano, 12th Meeting of the ITPA Topical Group on Diagnostics PPPL, 26 – 30 March 2007
Summary
1 Prospect of CO2 laser for CTS in ITER was obtained.
2 Development of Thomson scattering diagnostics with Fourier transform spectroscopy was progressed.
3 Neutron spectra were obtained by SND (preliminary).
4 Dust behavior was measured by fast TV camera.
5 Computer tomography technique for divertor plasma spectroscopy was improved.