22P109-P
Present status of the Nd:YAG Thomson scattering system development
for time evolution measurement of plasma profile on Heliotron J (1)Heliotron J プラズマの分布時間発展計測のための
Nd:YAG トムソン散乱計測装置開発の現状 (1)MINAMI Takashi1 ARAI Shohei2 , KENMOCHI Naoki2 , YASHIRO Hiroaki2 , TAKAHASHI Chihiro1 ,KOBAYASHI Shinji1 , MIZUUCHI Tohru1 , OHSHIMA Shinsuke3 , YAMAMOTO Satoshi1 ,OKADA Hiroyuki1 , NAGASAKI Kazunobu1 , NAKAMURA Yuji1 , HANATANI Kiyoshi1 ,KONOSHIMA Shigeru1 , SANO Fumimichi1
南 貴司1 、荒井翔平 2 、釼持尚輝 2 、八代浩彰 2 、高橋千尋 1 、小林進二 1 、水内 亨 1 、 岡田浩之 1 、
長崎百伸 1 、中村祐司 1 、 花谷 清 1 、 山本 聡 1 、 木島 滋 1 、 大島慎介 3 、佐野史道 1
1

Institute of Advancaed Energy, Kyoto University, Gokasho, Uji 611-0011, Japan
Graduate School of Energy Science, Kyoto University, Gokasho, Uji 611-0011, Japan
3
Pioneering Research Unit for Next Generation, Kyoto University, Gokasho, Uji 611-0011, Japan2

1

京都大学エネルギー理工学研究所, 〒 611-0011 京都府宇治市五ヶ庄
京都大学エネルギー科学研究科, 〒 611-0011 京都府宇治市五ヶ庄
3
京都大学次世代開拓研究ユニット, 〒 611-0011 京都府宇治市五ヶ庄
2A new high repetition rate Nd:YAG Thomson Scattering system is developed for the Heliotron J device. Two high repetition Nd:YAG lasers (>550mJ@50Hz) realize the measurement of the time evolution of the plasma
proﬁle with ∼ 10ms time intervals. The system can measure at 25 spatial pints
with ∼ 10ms resolution . Scattered light is collected with a large concave mirror (D = 800mm, f /2.25) with a solid angle of ∼ 100mstr. The interferenceﬁlter polychromators are used as a spectrometer for the scattered light. The
signal detected by an APD is ampliﬁed by a fast OP ampliﬁer with a DC andAC output. The signals are digitized with Multi-event QDCs, fast gated integrators. The data acquisition is performed by the VME based system which
is operated by the CINOS.

1• Spatial channels: 25Introduction

A time evolution measurement of a plasma proﬁle is essential for an investigation of a transport physics of a magnetic conﬁnement fusion
device. Therefore, we are developing a newNd:YAG Thomson scattering system for theHeliotron J device[1]. Because of the investigation for the internal transport barrier orthe edge transport barrier physics[2], we determine the goal of the new Nd:YAG Thomson
scattering system for the time evolution proﬁle measurement on Heliotron J plasma (major radius: Rax = 1.2m, averaged minor radius:
hai = 0.17m, plasma volume: V = 0.7m3 ) asfollows :• Spatial resolution: ∼ 1cm• Time interval of measurement: ∼ 10ms
• Range of Te : 10eV − 10keV• Range of ne : > 0.5 × 1019 m−3
In this paper, we report the overview of thenew Thomson scattering system design and thepresent status of the development and construction of the Thomson scattering system.
2Design overview

As shown in Fig.1, the laser beam is injected
obliquely from bottom to top and obliquely
backscattered light (scattering angle is 160◦ )is observed to avoid interference with a coiland support structure of the Heliotron J device.
The laser beams are combined closely together
along a common beam path by the mirror andoverlapped in the plasma center where they arefocussed to a common point.
The design of an observation port is optimized for achieving high transmission eﬃciency. The scattered light is collected with alarge concave mirror (D=800mm, f/2.25) witha solid angle of ∼ 80 − 100mstr. The optical system is optimized for high transmission
and low noise in order to maximize the signal
to noise ratio. The collected scattered light istransferred to the 25 polychromators by 25 optical ﬁber bundles.

one is a direct coupled signal and the second
is the scattered light signal which is reducedby the low frequency background light using a
RC ﬁlter. The DC signal is used for a calibration and background light measurement whichused for estimation of a statistical error of thedetected signal. The signals are digitized withCAEN V792 32 Channel Multi-event QDC, fast
gated integrators. A real-time VME computer
system is used for a data acquisition system.
The system is operated by a CINOS(CHS Integrated No Operation System)[3]. The CINOS
is not a multi-task operating system, but a system software that performs a time invariant
data acquisition without OS.
4Summary

We have described the design and present status of the new Nd:YAG Thomson scatteringsystem which is developed in the Heliotron
J for the study of the improved conﬁnement
physics. Two high repetition Nd:YAG lasers
realize the measurement of the time evolutionof the plasma proﬁle with ∼ 10ms time intervals. The system has 25 spatial points with
∼ 10mm resolution using the large concave
mirror (D=800mm) and the interference ﬁlFig. 1: Schematic diagram of Nd:YAG Thom- ter polychromatos. The goal of the measurson scattering system of Heliotron J
able temperature range is from 10eV to 10keV
and the minimum detectable density is approximately 5 × 1018 m−3 .
Acknowledgments
Overview of Polychromator and Data
This work is strongly supported by the CollabAcquisition Systemoration Program of the Laboratory for Complex Energy Processes, IAE, Kyoto UniverThe Nd:YAG Thomson polychromator has 5 sity and the NIFS Collaborative Research Prowavelength channels for the scattering light gram (NIFS10KUHL030, NIFS09KUHL028,
measurement, and one channel for density cal- NIFS10KUHL033).
ibration by the Rayleigh scattering method.
The band-path combination of the interferenceﬁlters is optimized by a performance simulation References
code. The error of the temperature measurement which is caused by the bremsstrahlung [1] T.Minami, S.Kobayashi, T.Mizuuchi,
et.al. Rev.Sci.Inst. 81, 10D532 (2010)is below ∼ 2% from 10eV to 10keV. Though
the error of the density measurement (∼ 3%)is larger than the temperature, the value is low [2] T.Minami, A. Fujisawa, H. Iguchi, Y.
Liang, K. Ida, et.al. Nuclear Fusion, volenough for achieving our experimental objecume 44, issue 2, (2004) p342-349
tive.
The ADA4817 (Analog Devices) is chosen as [3] C. Takahashi, et. al. About timing criticala preampliﬁer of the detected signal. The cirsignal processing. Kyoto University techcuit simulation by the SPICE shows the decaynique collegium (2009)
time is less than 80ns, which reduces the error
from the background light due to the short gate
width available. The ampliﬁer has two outputs:3