Toshiyuki Iida

Multibody fusion model to explain experimental results

AbstractWorldwide cold fusion experiments have given anomalous results with regard to levels of kilo-electronvolts per atom excess heat, 4He generation, level of emission of neutrons and tritons with a 10−4 to 10−7 neutron-to-triton yield ratio, and emission of high-energy charged particles, which cannot be explained by the known d + d fusion process. A previously proposed multibody deuteron fusion model in solids is elaborated further to explain these anomalous results. A transient dynamics in metal deutendes is proposed to generate close pairs and clusters of deuterons with time-dependent deep atomic potential inducing a strong screening effect on Coulomb barrier penetration. Very approximate numerical estimations of reaction rates for the competing 2D, 3D, and 4D fusion processes in PdDx and TiDx are obtained with high-level reaction rates enough to explain observed heat levels. Decay channels of virtual compound states, i.e., 4He*, 5Li*, 6Li*, 7Be*, and 8Be* by 2D, H + 2D, 3D, H + 3D, and 4D fusions, ...

Improvement of microwave feeding on a large bore ECRIS with permanent magnets by using coaxial semi-dipole antenna

We are constructing a tandem type electron cyclotron resonance (ECR) ion source (ECRIS). The first stage of this ECRIS has a large-bore with cylindrically comb-shaped permanent magnets. 2.45GHz and 11-13GHz microwaves can be supplied individually and simultaneously to the plasma chamber. For 2.45GHz, a coaxial semi-dipole antenna is used to feed the microwaves. In previous experiments, there were two problems encountered when running the 2.45GHz microwaves. High incident power was necessary to keep ECR discharge at low operating pressure because of high reflected microwave power. The surface of a support insulator between the inner and the outer electrodes of coaxial semi-dipole antenna was easily metalized by sputtering of the metal wall inside the chamber. The purpose of this study was to solve these problems. Performing several simulation experiments supports the hypothesis that the position of the support insulator is significant for microwave power efficiency. The end result was the ability to sustain ECR discharges at extremely low incident microwave power, several tens of watts, by optimized matching of the position and shape of the insulator.

Ion beams extraction and measurements of plasma parameters on a multi-frequencies microwaves large bore ECRIS with permanent magnets

We have developed an all-permanent magnet large bore electron cyclotron resonance ion source (ECRIS) for broad ion beam processing. The cylindrically comb-shaped magnetic field configuration is adopted for efficient plasma production and good magnetic confinement. To compensate for disadvantages of fixed magnetic configuration, a traveling wave tube amplifier (TWTA) is used. In the comb-shaped ECRIS, it is difficult to achieve controlling ion beam profiles in the whole inside the chamber by using even single frequency-controllable TWTA (11-13GHz), because of large bore size with all-magnets. We have tried controlling profiles of plasma parameters and then those of extracted ion beams by launching two largely different frequencies simultaneously, i.e., multi-frequencies microwaves. Here we report ion beam profiles and corresponding plasma parameters under various experimental conditions, dependence of ion beams against extraction voltages, and influence of different electrode positions on the electron density profile.

Enhanced production of ECR plasma by using pulse mode microwaves on a large bore ECRIS with permanent magnets

In order to enhance the efficiency of an electron cyclotron resonance (ECR) plasma for a broad and dense ion beam source at low pressure, the magnetic field configuration is constructed by all permanent magnets. By using the pulse mode, we aim at the generation of plasma with parameters that cannot be achieved in the CW mode at microwave frequencies of 11-13GHz, under the constraint of the same average incident microwave powers. It is found that the total beam currents are increased by the pulse mode operation compared with the case of the CW mode. According to probe measurements of the ECR plasma, it is found that the electron density in the pulse mode is larger than that in the CW mode, while the electron temperatures in the pulse mode are lower than that in the CW mode. These results are discussed from the viewpoint of relaxation times obtained on plasma parameters and ECR efficiency. The cause of the beam current increment and operational windows spread due to the pulse mode are also discussed on these parameters suitable to production of molecular/cluster ions.