Preparation for a neutronics experiment using a discharge fusion device and an imaging plate neutron detector

Abstract

Tritium breeding ratio (TBR) is one of the most important parameters determining the tritium self-sufficiency of a deuterium-tritium fusion reactor. A neutronics experiment is planned to measure the spectral neutron fluences two-dimensionally (2D) using a discharge-type compact fusion neutron source and a neutron imaging plate (NIP), respectively. We report a calibration method for the NIP and optimization of the discharge condition to enhance the neutron production rate. A linear relationship between the neutron fluence in the NIP and photostimulated luminescence (PSL) per area was obtained in the range of the neutron fluence from 10 3 to 10 7 n/cm 2 . A neutron production rate higher than 10 7 n/s was successfully achieved by the optimized discharge condition. It is shown that a quantitative 2D measurement by the NIP is feasible using the linear relationship and a correlation coefficient on the energy spectrum.

2-D Evaluation of Bred Tritium Using Neutron Imaging Plate

“…However, it was later found that neutron counting was influenced by X-rays generated from the neutron source during the operation, especially in a high-voltage condition of >40 kV. This could be a reason for the exponential increase of neutron production rate with applied voltage observed in our previous study [10], in contradiction to the non-exponential increase of D(d,n) 3 He reaction cross-section with the energy (Fig. 3b).…”

“…The results of the present study indicate the feasibility of 2D measurement of the bred tritium with a modest accuracy by counting the captured thermal neutrons using the NIP. Sources of errors in the experiments are Li/B content in the target materials (<±2%), neutron generation (<±5%), PSL density in the read-out image (<±5%) [10], and the calibration (<±4.2%).…”

“…An evaluation is carried out through a read-out process which takes a few decades of minutes. NIP has a high spatial resolution (<200 m) and a wide dynamic range (1:10 5 ) [9], which is sensitive enough to detect neutrons from a compact DD fusion neutron source, with a linearity between neutron fluence and photo-stimulated luminescence (PSL) [10], [11]. Li2O and Li2TiO3, ceramic breeder materials for solid blanket system [12], were irradiated on the NIP to evaluate the amount of the bred tritium in this study.…”

“…Li2O and Li2TiO3, ceramic breeder materials for solid blanket system [12], were irradiated on the NIP to evaluate the amount of the bred tritium in this study. The amounts of bred tritium in the breeders were evaluated using the previous calibration result of the NIP [10].…”

Calibration of imaging plates sensitivity to high energy photons and ions for laser-plasma interaction sources

“…As of today, the employment of radiation diagnostics is one of the biggest challenges faced during the experimental campaigns, which are used to measure plasma characteristics by recording the outgoing emissions. Passive instruments such as radiochromic film (RCF), CR39 and LR-115, while serving an specific purpose, are among the popular tools capable of measuring energy spectra and spatial distribution of emitted ions [9][10][11][12][13], high energy neutron [14,15], epithermal and thermal neutrons [16,17], high energy electrons [18,19], x-rays and gamma radiation [20][21][22]. Yet, apart from the above diagnostics, imaging plates (IP) are remaining between the most commonly used, because of their sensitivity to all types of radiations with a high dynamic range (>10 5 ), while being insensitive to strong electromagnetic pulses created by laser-plasma interactions [23].…”