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Kondoh, Takashi; Miura, Yukitoshi; Lee, S.*; Richards, R. K.*; Hutchinson, D. P.*; Bennett, C. A.*
Review of Scientific Instruments, 74(3), p.1642 - 1645, 2003/03
Times Cited Count:20 Percentile:68.13(Instruments & Instrumentation)Measurements of energy spectrum and density profile of confined alpha-particles are required for ITER. Several methods have been proposed, however, a measurement technique hasn't been established yet. A collective Thomson scattering (CTS) system based on a pulsed CO laser is being developed to demonstrate feasibility of alpha-particle diagnostics for ITER. The pulse laser (15J, 1m, 0.6 m) and a wide band (~ 8GHz) heterodyne receiver with a quantum-well infrared photodetector (QWIP) have been developed and installed in the JT-60U tokamak. Stray light is reduced by a notch filter with hot CO gas. Heterodyne receiver is absolutely calibrated using large area blackbody radiation source. Scattered signal from JT-60U plasma has not detected because of electrical noise originated from discharge of the pulsed laser and stray signal caused by impurity of the spectrum of the pulsed laser.
Kondoh, Takashi; Lee, S.; Miura, Yukitoshi
Proceedings of 10th International Symposium on Laser-Aided Plasma Diagnostics, p.109 - 114, 2001/00
A collective Thomson scattering (CTS) diagnostic system based on a CO laser has come into operation to establish measurement technique of ion temperature and fast alpha particle in fusion plasmas. A pulsed CO2 laser (wavelength 10.6m, beam energy 15 J, pulse width 1s) and a heterodyne receiver were developed by Oak Ridge National Laboratory (ORNL) and were installed in the JT-60U tokamak. Commissioning of the CTS system by injecting the CO laser into the plasmas has been proceeded.
Yamauchi, Toshihiko; Ito, Shinichi*; Minehara, Eisuke
Technical Digest on 4th Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim 2001), p.I_148 - I_149, 2001/00
The decomposition of dioxin analogues by infrared (IR) laser irradiation includes thermal destruction and multiple-photon dissociation. It is important for the decomposition to choose the laser wavelength which is highly absorbed. The thermal decomposition takes place by the irradiation of the low IR laser power. Considering the model of thermal decomposition, it is discussed that the adjacent water vapor assists the decomposition (dechlorination) of dioxin analogues in addition to the thermal decomposition by the direct laser absorption.