Plasma and Fusion Research

Volume 16, 2405064 (2021)

Regular Articles

Estimation of Anisotropic Neutron Emission Spectrum Using Spatial Neutron Flux Profile Outside Vacuum Vessel
Tomoki URAKAWA and Hideaki MATSUURA
Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
(Received 13 November 2020 / Accepted 9 March 2021 / Published 21 April 2021)

Abstract

It is known that emission spectrum of fusion products is anisotropically distorted from Gaussian distribution when fuel ion velocity distribution function is anisotropic non-Maxwellian distribution. Previously, anisotropic neutron emission has been measured in experiments with the Large Helical Device (LHD). In this study, as an application, a method for evaluating anisotropic neutron emission spectra by measuring the spatial profiles of the neutron flux is presented. Assuming beam-heated deuterium plasma in a JT-60SA class tokamak device, it was confirmed that the effect of neutron flux emission appears in the neutron flux spatial profile outside the vacuum vessel when the energy region to be measured is set to the high energy side. In addition, it was shown that the characteristic change of the anisotropic emission spectrum is reflected in the spatial profile of the neutron flux. Estimating the neutron anisotropic emission spectrum by this measurement method can lead to new proposals for fast ion diagnosis such as analysis of velocity distribution functions.

Keywords

anisotropic neutron emission spectrum, neutron measurement, spatial neutron flux profile

DOI: 10.1585/pfr.16.2405064

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