Teruhisa Takamatsu

Inertial electrostatic confinement fusion device with an ion source using a magnetron discharge

An inertial electrostatic confinement (IEC) fusion device is studied for a compact fusion neutron/proton source using a built-in magnetron ion source. The addition of an ion source to the IEC fusion device enhances fusion reactions by allowing a lower operating gas pressure and by providing a beam-like ion energy distribution. Under lower gas pressures, charge exchange collisions are reduced, resulting in longer ion lifetime and thus enhanced ion re-circulation. The performance characteristics of this IEC fusion device found in the experiments were compared with the numerical calculations and found qualitatively in good agreement. An improvement in normalized neutron yield (defined as neutron yield divided by the product of grid current and operating gas pressure), more than a factor of two, has been observed compared with the conventional glow-discharge driven IEC fusion device.

Research and Development of the Humanitarian Landmine Detection System by a Compact Fusion Neutron Source

Results of 5 years task are described on the research and development of the advanced humanitarian landmine detection system by using a compact discharge-type fusion neutron source called IECF(inertial-electrostatic confinement fusion) device and dual sensors made of BGO and Nal. With 107 neutrons/s stably produced in CW mode, 10.8 MeV, gamma rays from (n, gamma) reaction with nitrogen atoms in the explosives (explosive simulant in our study) are measured for two kinds of explosives(TNT, RDX), under the conditions of three different buried depths, and soil moistures. Tentative detection probability for arid soil is found to be in excess of 80%.

Research and Development of Landmine Detection System by a Compact Fusion Neutron Source

Abstract Current results are described on the research and development of an advanced anti-personnel landmine detection system by using a compact discharge-type fusion neutron source called IECF (Inertial-Electrostatic Confinement Fusion). Landmines are to be identified through backscattering of neutrons, and specific-energy capture γ-rays by hydrogen and nitrogen atoms in the landmine explosives. For this purpose, improvements in the IECF were made by various methods to achieve a drastic enhancement of neutron yields of more than 108 n/s in pulsed operation. This required R&D on the power source, as well as analysis of envisaged detection systems with multi-sensors. The results suggest promising and practical features for humanitarian landmine detection, particularly, in Afghanistan.

Research and Development on Humanitarian Landmine Detection System by Use of a Compact D-D Fusion Neutron Source

Abstract Current results are described on the research and development of the advanced humanitarian landmine detection system by using a compact discharge-type fusion neutron source called IECF (Inertial-Electrostatic Confinement fusion) devices. With a 50 mm-thick water-jacketed IEC device (IEC20C) of 200 mm inner diameter can have produced 107 neutrons/s stably in CW mode for 80 kV and 80 mA. Ample 10.8 MeV σ-rays produced through (n,σ) reaction with nitrogen atoms in the melamine (C3H6N6) powder (explosive simulant) are clearly measured by a BGO-NaI-combined scintillation sensor with distinct difference in case of with/without melamine, indicating identification of the buried landmines feasible.

Research and development of the humanitarian landmine detection system by a compact fusion neutron source

A 5 year task is described on the research and development of the advanced humanitarian landmine detection system by using a compact discharge-type fusion neutron source called IECF (Inertial-Electrostatic Confinement fusion) device and 3 dual sensors made of BGO and NaI. With 107 D-D neutrons/s stably produced in steady-state mode, H-2.2 MeV, N-5.3, 10.8 MeV, gamma rays from (n, gamma) reaction with nitrogen atoms in the explosives are measured for two kinds of explosives (TNT, RDX), under the conditions of three different buried depths, and soil moistures. Final detection probabilities for arid soil are found to be 100 % in the present tests, i.e., depths not exceeding 15 cm, moisture content of 18.5 % or less, and 20-minute measurements. The neutron backscattering method is found also excellent.

Magnetron-discharge-based ion source for improvement of an inertial electrostatic confinement fusion device

Abstract A magnetron discharge as a built-in ion source have studied both experimentally and numerically for a compact discharge-type fusion neutron source called IECF (Inertial Electrostatic Confinement Fusion). With this magnetron discharge, ions are produced in the vicinity of the vacuum chamber (anode) at negative electric potential. Therefore, produced ions are expected to have nearly full energy corresponding to the applied voltage to the IECF cathode but slightly smaller energy preventing them from hitting the anode of the opposite end, eventually improving both fusion reaction rate and ion recirculation life. Also, the magnetron ion source was found to produce ample ion current for maintenance of the discharge. With the optimization of the configuration of the magnetron discharge, further improvement of the fusion reaction rate is found feasible.

Magnetron Discharge Characteristics for Improvement of an Inertial Electrostatic Confinement Neutron/Proton Source

Abstract A magnetron discharge was adopted in the inertial-electrostatic confinement (IEC) fusion device for drastic improvement of fusion reaction rate. With this discharge in the vicinity of the vacuum chamber, a substantial number of ions produced there are expected to have almost full energy corresponding to the applied voltage to the transparent IEC cathode under relatively low pressures compared with the conventional glow discharge. The magnetron discharge is found to occur even for the pressure of 0.07 mTorr (H2) in the present configuration of the experiment, compared with 5 mTorr in the glow discharge.

Performance characteristics of an inertial-electrostatic confinement fusion device with magnetron discharge

A magnetron discharge as a built-in ion source for an inertial-electrostatic confinement fusion (IECF) device was experimentally studied aiming at a drastic improvement of fusion reaction rate. With this discharge in the vicinity of the grounded vacuum chamber, produced ions are expected to have almost full energy corresponding to the voltage applied to the central transparent cathode. Also, the magnetron-glow hybrid discharge is found to be effective to make the operation free from glow discharge restriction among the discharge voltage, current and gas pressure. As a consequence, the neutron yield normalized by the gas pressure shows higher value than the conventional glow-discharge-based IECF, although the gas pressure we achieved is found to remain still the region where the fusion reaction between the ion beam and background gas is dominant.

Development of a High-performance Landmine Detection System Through Gamma-ray Detection by Using a Compact Fusion Neutron Source and Dual-sensors

An anti-personnel landmine detection system using an inertial-electrostatic confinement fusion (IECF) neutron source and dual sensors showed excellent performance, particularly, for humanitarian landmine detection. Averaged probability of detection (POD) in this test was found to be 100% for arid soil, and 99% for other conditions including very wet soil moisture of 18.5wt%. Further improvements in reliability by making use of neutron backscattering are found to be efficient.

Research and Development of Compact Neutron Sources based on Inertial Electrostatic Confinement Fusion

Recent progress is described in the research and development of an inertial‐electrostatic confinement fusion (IECF) device. Use of a water‐cooling jacket with non‐uniform thickness shows promising success for landmine detection application, such as effective channeling of neutron flux toward the target and a very stable dc yield in excess of 107 D‐D neutrons/sec. Addition of an ion source to the conventional glow‐discharge‐driven IECF enhances the converging deuterium ion energy distribution by allowing a lower operating gas pressure. Improvement in normalized neutron yield, which corresponds to the fusion cross‐section averaged over the device radius, by a factor often has been observed.