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Suzuki, Takahiro; Fujita, Takaaki; Oyama, Naoyuki; Isayama, Akihiko; Matsunaga, Go; Oikawa, Toshihiro; Asakura, Nobuyuki; Takechi, Manabu
Review of Scientific Instruments, 77(10), p.10E914_1 - 10E914_4, 2006/10
Times Cited Count：7 Percentile：36.53(Instruments & Instrumentation)In JT-60U, we measure temporal evolution (100Hz) of the pitch angles of the magnetic field, using a 30 channel motional Stark effect (MSE) diagnostic with photo-elastic modulators (PEMs). This year, we started acquiring the signal intensity of photo-multipliers (PMs) at 0.5-1MHz sampling for fluctuation profile measurement. Response of the PM (180kHz/-3dB) limits the temporal resolution. The system works as the MSE and the beam emission spectroscopy (BES) diagnostic. Coupling between the MSE and BES signals can provide magnetic fluctuation. Here we report on results in spatially resolved electron density (ne) fluctuation profile measurement in various operation regimes. In the core plasma, ne fluctuation induced by rotating tearing mode islands was observed. Phase of the fluctuations are inverted between higher and lower magnetic field sides, which is consistent with an electron cyclotron emission (ECE) measurement. In the scrape-off layer of an ELMy 
-mode plasma, outward propagation of strong emission coincides with ELM crash was also observed. The propagation velocity is about 6km/s along the MSE measurement points, where distance between adjacent channels is 6-7cm in the major radius direction. Detailed description of the optics and the system will be presented.
Hirata, Mafumi*; Miyake, Yasuhiro*; Chujo, T.*; Kohagura, Junko*; Numakura, Tomoharu*; Shimizu, Kiyoaki*; Ito, Marie*; Kiminami, Serina*; Morimoto, Naomichi*; Hirai, Katsuaki*; et al.
Review of Scientific Instruments, 77(10), p.10E719_1 - 10E719_3, 2006/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)no abstracts in English
Asai, Keisuke*; Naoi, Norihiro*; Iguchi, Tetsuo*; Watanabe, Kenichi*; Kawarabayashi, Jun*; Nishitani, Takeo
Review of Scientific Instruments, 77(10), p.10E721_1 - 10E721_3, 2006/10
Times Cited Count：3 Percentile：19.43(Instruments & Instrumentation)A time-of-flight (TOF) neutron spectrometer is one of the candidates of the measurement of the D/T burning ratio in ITER. In the ITER high power experiments, the TOF system would suffer from high event rate or accidental counts due to high radiation intensities, which can be one of background sources for DD neutron measurement. We propose a new neutron spectrometer to apply to the measurement of the D/T burning ratio in the ITER high power operation region. This system is based on the conventional double crystal TOF method and consists of a water cell and several pairs of scintillators. A water cell is inserted before the first scintillator of the TOF system and acts as a radiator or neutron scattering material. Because DD neutrons have a larger cross section of elastic scattering with hydrogen than DT neutrons, the elastic scattering in the radiator enhances the relative ratio of DD/DT intensity by about 3 times before entering the TOF system. The enhancement of the relative intensity of DD neutrons makes the detection of DD neutrons easier. The feasibility of this method as a neutron spectrometer and the basic performances of this system have been verified through a preliminary experiment using a DT neutron beam (20 mm
) at the Fusion Neutronics Source, Japan Atomic Energy Agency.
Naoi, Norihiro*; Asai, Keisuke*; Iguchi, Tetsuo*; Watanabe, Kenichi*; Kawarabayashi, Jun*; Nishitani, Takeo
Review of Scientific Instruments, 77(10), p.10E704_1 - 10E704_3, 2006/10
Times Cited Count：5 Percentile：28.77(Instruments & Instrumentation)The high-energy-resolution neutron spectrometry is a useful method to obtain the ion temperature and velocity distribution in nuclear fusion and/or burn plasmas. For ion temperature measurement in the ITER, we propose a promising neutron spectrometer with high-energy-resolution based on the associated particle detection using a proton recoil telescope (PRT) and a time-of-flight spectrometer (TOF). In a general PRT or TOF spectrometer, uncertainty of incident angles of recoiled protons or scattered neutrons incoming to rear detector, respectively, is a cause of deterioration of their energy resolution. In this system, no angular information is required to obtain the incident neutron energy. It is possible to enlarge the solid angles of the rear detectors subtended by the radiator to increase the detection efficiency without deterioration of the energy resolution. To verify the operational principle and the basic performance of this system, we have constructed a prototype system through Monte Carlo simulations and carried out a preliminary experiment with a deuterium-tritium neutron beam at the Fusion Neutronics Source (FNS), JAEA to obtain the energy resolution around 3.3% (in FWHM) for DT neutrons. As a result of the study for the experiment, it is expected that this system can be applied to ITER at the power within 1 order of magnitude of the maximum with measurement accuracy better than 10%.
laser for collective Thomson scattering diagnostic of 
particles in burning plasmasKondoh, Takashi; Hayashi, Toshimitsu; Kawano, Yasunori; Kusama, Yoshinori; Sugie, Tatsuo; Miura, Yukitoshi; Koseki, Ryoji*; Kawahara, Yoshihiro*
Review of Scientific Instruments, 77(10), p.10E505_1 - 10E505_3, 2006/10
Times Cited Count：6 Percentile：32.92(Instruments & Instrumentation)A collective Thomson scattering (CTS) technique based on a pulsed CO laser is being developed in order to establish a diagnostic method of confined -particles in burning plasmas. In International Thermonuclear Experimental Reactor (ITER), measurement of velocity and spatial distributions of confined -particles requires temporal resolution of 0.1 s and spatial resolution of a/10, where a is plasma minor radius. A new laser system (Energy 
10J, repetition 10Hz) has been developed based on a commercially available laser (Shibuya Kogyo Co., Ltd, SEL4000) to meet the requirement of temporal resolution of ITER and to improve a signal-to-noise ratio. The laser has unstable resonator with a cavity length of 4 m and discharge electrodes with heat exchanger of laser gas for high-repetition operation. Proof-of-principle test of the CTS technique will be performed with the new laser system on JT-60U (JAEA Tokamak 60 - Upgrade). This work was supported by Grant-in-Aid for Scientific Research on Priority Areas "Advanced Diagnostics for Burning Plasmas" from Ministry of Education, Culture, Sports, Science and Technology, No.16082210.
laser calibration of the infrared imaging video bolometer for the JT-60U tokamakParchamy, H.*; Peterson, B. J.*; Konoshima, Shigeru; Hayashi, Hiromi*; Seo, D. C.*; Ashikawa, Naoko*; JT-60U Team
Review of Scientific Instruments, 77(10), p.10E515_1 - 10E515_4, 2006/10
Times Cited Count：15 Percentile：60.96(Instruments & Instrumentation)no abstracts in English
Shinohara, Koji; Isobe, Mitsutaka*; Darrow, D. S.*
Review of Scientific Instruments, 77(10), p.10E521_1 - 10E521_4, 2006/10
Times Cited Count：5 Percentile：32.92(Instruments & Instrumentation)A scintillator probe can measure the temporal evolution of both the gyro-radius and the pitch angle of the escaping ions with relatively large energy. On this system, the time resolution of the 2D measurement is determined by a framing rate of the camera. The framing rate of the old camera was 60Hz, thus the time resolution was about 17 ms. Our interest is to understand the energetic ion transport in fast events such as a bursting Alfv
n eigenmode. The typical time scale of these event interested is less than a few ms. The time resolution of the old camera was not enough for this purpose. The FASTCAM ultima II, which is a product of Photron Co., is an image-intensified high-speed video camera system with the ability to record up to 13,500 frames per second. By replacing the old camera with this ultima II, the temporal resolution was improved from about 17 ms to 0.075 ms. We have successfully installed the fast camera and captured some fast events caused by MHDs, which was not observed by the old camera. Here, we will present the specification of this system and the preliminary results using this fast camera.
Hatae, Takaki; Naito, Osamu; Nakatsuka, Masahiro*; Yoshida, Hidetsugu*
Review of Scientific Instruments, 77(10), p.10E508_1 - 10E508_6, 2006/10
Times Cited Count：31 Percentile：76.40(Instruments & Instrumentation)no abstracts in English
Ishikawa, Masao*; Itoga, Toshio*; Okuji, Toshio*; Nakhostin, M.*; Shinohara, Koji; Hayashi, Takao; Sukegawa, Atsuhiko; Baba, Mamoru*; Nishitani, Takeo
Review of Scientific Instruments, 77(10), p.10E706_1 - 10E706_3, 2006/10
Times Cited Count：25 Percentile：71.34(Instruments & Instrumentation)no abstracts in English
