Plasma and Fusion Research

Volume 14, 3405162 (2019)

Regular Articles

Measurement of Thermal and Epithermal Neutron Flux Distribution in the Torus Hall of LHD using Activation Method in the First Deuterium Experiment Campaign
Tomoyo TANAKA, Makoto KOBAYASHI1,2), Sachiko YOSHIHASHI, Akira URITANI, Kenichi WATANABE, Atsushi YAMAZAKI, Takeo NISHITANI1), Kunihiro OGAWA1,2) and Mitsutaka ISOBE1,2)
Nagoya University, Nagoya 464-8603, Japan
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
SOKENDAI (The Graduate University for Advanced Studies), Toki 509-5292, Japan
(Received 10 January 2019 / Accepted 19 September 2019 / Published 8 November 2019)


In the Large Helical Device (LHD) of the National Institute for Fusion Science, a deuterium plasma experiment was performed in March 2017. Neutrons with an energy of 2.45 MeV are generated by d (d, n) 3He reactions. The evaluation of this neutron flux in the torus hall, as well as within the LHD vessel, is very important for the decommissioning of the LHD in the future and the radiation shielding for workers and components around the LHD. In this study, we evaluate the spatial distribution of thermal and epithermal neutron flux on the floor level of the LHD torus hall by measuring the neutron activation of gold foils. The flux information obtained in the experiment can be used for the evaluation of radio-activation and the shielding design.


LHD, neutronics, activation foil, IP, HPGe

DOI: 10.1585/pfr.14.3405162


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