K. Iwasaki

K. Takahara

K. Takiyama

K." Sato

S. Kusakabe

S. Namba

T. "Oda

T. Katsuta

National Institute for Fusion Science (NIFS-Repository)

§15. YAG Thomson Scattering System and VUV Monochromator for TPD-11 Oda, T., Takiyama, K., Katsuta, T. (Dept. Applied Phys. & Chern. Fac. Eng., Hiroshima Univ.) Takahara, K., Kusakabe, S., Namba, S. (Dept. Energy Eng. & Sci., Nagoya Univ.) Iwasaki, K., Sato, K. For quantitative study of the contact phenomena of a plasma with a neutral gas, Y AG Thomson scattering system and VUV monochro-mator have been installed in the TPD-II device (see Fig. 1 ). Q- switching Y AG laser( 10 Hz rep. rate, 80 mJ/s, pulse width 12 ns ) and poly-chromator for analyzing the scattered light ( f = 250 mm, F = 4.3 ) equipped with 1024 channel photo-diode array have been fabricated. In order to use a detection system in visible wavelength region, 2nd harmonics of 532 nmlight is inject-ed into the plasma. Because of a small output power of the laser, typically 1000 laser shots Plasma Region To 75cm visible Target (Mo) He plasma • SOcc/min • 60cc/min ~~~~~~~~ • ?Occ/min l 1 1 .... ~~- . ~~~~~-~~-~ ... ::r:~::::r::::::::r:::t 10 9 8 l l 1 l • 1 • l • • ••••• ••••••~•••• •• ••••••••••.,• • •••••••••••••••:•••••••••••••-••-:--•••••••••••• ••• •('o•••••••••o•u•••+••.a•••••••u > 7 ~ j 1 j 1 • j j ~ 6 ............. ~ ................ .;. ............ ) ................. ~ ............... ~ ................ ~ ........... .. j 1 .1• j j j ............. ~ ................ ~ ............... ) ................................... ~ .............. ) ............ .. ~ 5 ~ • ~ ~ l l ~ ~ ~ ; ~ ; ............................. T ............... T ................ 1' ............... T ................ T .......... .. 4 : : : : : : 3 30 40 50 60 70 80 90 100 discharge current Fig. 2. Dependence of electron temperature on discharge current as a function of He gas flow rate into a discharge region. are necessary to get a good SIN ratio. Figure 2 shows the measured electron temperature in helium plasma at TPD-II. In addition to the Thomson scattering system, calibrated VUV monochromator was used for the electron temperature measurement. The electron temperature deduced from the intensity ratio of CIV 2p - 2s, and 3p - 2s agrees fairly well with the results of Thomson scattering. Discharge Region Orifice Gas inlet I Cathode Floating electrodes Pump Pump monochromator Pump Anode (grounded) Fig. 1. Schematic of TPD-II device. 175 

YAG Thomson Scattering System and VUV Monochromator for TPD-II

YAG Thomson Scattering System and VUV Monochromator for TPD-II

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