First measurement of neutron emission profile on JT-60U using Stilbene neutron detector with neutron-gamma discrimination

Abstract

This article describes a diagnostic for measuring neutron emission profile in JT-60U. The Stilbene neutron detector, developed by TRINITI laboratory in Russia, has been installed on the JT-60U Tokamak to measure the neutron emission profile for the first time. The Stilbene neutron detector is a detector which combines a Stilbene crystal scintillator with a neutron-gamma pulse shape discrimination circuit, with a very compact size. Performance tests were carried out using neutron and gamma-ray source prior to installation on JT-60U. Good gamma suppression of the Stilbene neutron detector was verified. Though the neutron emission profile obtained by Stilbene neutron detectors has error of 30% in innermost channel with a calculation using measured plasma parameters, there is an agreement within 10% error in the other channels.

Instability in the Frequency Range of Alfvén Eigenmodes Driven by Negative-Ion-Based Neutral Beams in JT-60U

“…A clear bump in velocity space in the fl ux was observed, which enabled a clear identifi cation of the resonant interaction [24]. We also estimated the change in the energetic ion population spatial profi le by using a neutron emission profi le monitor [25]. The estimated change of the energetic ion spatial profi le induced by a large ALE is shown in Fig.…”

Research and Development of Neutron Detection System using Scintillator and Digital-Signal Processing

“…However, such a measurement has not been realized yet by one diagnostics. The several diagnostics, such as line-integrated neutron emission neutron diagnostics [1][2][3][4], fast ion Dalpha (FIDA) diagnostics [5], fast ion loss detector (FILD) diagnostics [6,7], and fast neutral flux diagnostics [8][9][10], have been used to pick up the aspects of the phase space distribution.…”

“…It is considered that neutron camera will be installed on ITER, too. In JT-60U, d-D author's e-mail: shinohara.koji@jaea.go.jp neutron detectors equipped with analog neutron-gamma (n-γ) pulse shape discrimination circuits [4] was installed in 2000. Here, d-D neutrons are emitted with the energy of 2.5 MeV by deuterium-deuterium reaction.…”

High repetition rate neutron flux array using digital-signal processing and scintillators for study of high performance plasma at JT-60U

“…[1][2][3][4] In JT-60U, this system has contributed to the research on the energetic ion distribution and transport during magnetohydrodynamic activities such as Alfvén eigenmodes [5][6][7] and in beam-driven current drive studies. Therefore, it is important to evaluate the population of energetic ion in developing high performance plasmas.…”