Ryoichi Taniguchi

Detection of Charged Particles Emitted by Electrolytically Induced Cold Nuclear Fusion

We have tried to obtain evidence for electrolytically induced cold nuclear fusion by detecting charged particles associated with the nuclear reaction. Charged particles were detected by a conventional silicon surface barrier detector attached close to the thin foil cathode which formed the bottom of an electrolysis cell. The efficiency and signal-to-noise ratio of this system are higher than those of neutron detection systems, which made it easy to determine whether the fusion occurred or not. The energy spectrum measured with the electrolysis of D2O suggested that the nuclear reaction took place in palladium cathode.

Tritium depth profiling in surface regions of solids by use of the T(d, α)n reaction

Abstract Tritium depth profiling with an incident deuteron beam by use of the T(d, α)n reaction was studied for the case where the energy spectrum of the emitted α-particles is used to evaluate the depth profile. Appropriate probing energies were considered to be from 100 keV to 1 MeV. The characteristics of this method were evaluated for a variety of experimental measurement conditions. The method was demonstrated for thin titanium layers containing tritium at probing energies of about 600 keV. The distribution of tritium obtained were almost uniform with depth, as expected, and the measured tritium content agreed well with that nominally stated.

Depth profiling of tritium in solids with the nuclear reaction induced by deuteron bombardment

A method for the measurement of depth profiles of tritium in solids has been developed in which the 3H(d,n)4He reaction is used. This method is nondestructive with relatively high depth resolution in the surface region of the solids. The validity of the present method has been supported by the examination of the depth profile measured for a tritium target as is used for a neutron source.

MULTIELEMENT PHOTON ACTIVATION ANALYSIS OF A BULK LANTHANUM SAMPLE BY A GE-BGO COMPTON-SUPPRESSION SPECTROMETER

Abstract Photon activation analysis with a Ge-BGO Compton-suppression γ spectrometer has been studied for measuring the concentration of trace elements in a bulk lanthanum sample. Thirteen kinds of trace elements included in a test sample system have been analyzed, and the detection limit ranges from 9 × 10 −2 to 1 × 10 −3 μ g/g, which corresponds to improvement by a factor of from 1.5 to 2.5 over that obtained by a conventional γ-ray spectrometer.

Hydrogen Gas Generation from the Water by Gamma-Ray Radiolysis with Pre-Irradiated Silica Nanoparticles Dispersing

The yield of hydrogen gas generated by radiolysis of water with SiO2 nanoparticles dispersing was found to increase with the dose of gamma rays pre-irradiation of the particles. Pre-irradiation experiments will be carried out also by using electron beams and for nanoparticles of other kind of materials to investigate the mechanism of hydrogen gas generation

Point defects in silicon crystals studied via complexes with hydrogen

We studied the properties of irradiation-induced point defects and thermal equilibrium vacancies in Si by detecting hydrogen interacting with these point defects. First, we show the irradiation temperature dependence of the point defect concentration. We studied the optical absorption spectra of complexes of hydrogen and point defects generated by electron irradiation of hydrogenated Si crystals at low temperatures. The concentrations of complexes of hydrogen with vacancy and Frenkel pairs showed a non-monotonic dependence on irradiation temperature. Hence, a metastable interstitial-vacancy (Frenkel pair) model is not applicable to electronirradiated Si. From the dependences of the intensity ratios of the optical absorption due to complexes of H2 and point defects, we determined the migration energies of self-interstitial and Frenkel pairs relative to that of the vacancy. The energies were similar. Second, we determined the vacancy formation energy in high-purity Si by a new quenching method: specimens were heated in H2 gas at various temperatures followed by quenching in water. The formation energy determined by the above method was 4.0 eV, which agrees well with recent theoretical values.

In situ observation of deuteride formation inpalladium foil cathode by an X-ray diffraction method

Abstract In situ X-ray diffraction observation of a palladium foil cathode (10 μm in thickness)was carried out during electrolysis of alkaline heavy water and light water with high overpotentials. The foil cathode served as a wall of an electrolytic cell. One of the purposes was to evaluate the deuterium concentration in the palladium cathode used by Taniguchi et al. who claimed the possible occurrence of electrochemically induced “cold fusion” in a similar cell. No literature data were found by which we could evaluate the high chemical potential of deuterium in a palladium cathode during the electrolysis of alkaline heavy water with such high overpotentials. The lattice constants of the deuteride and hydride phases (β-PdDx and β-PdHx) were investigated as a function of applied potential by iterative in situ X-ray diffraction measurement during the electrolysis. The highest lattice constants observed were 4.07for both deuteride and hydride.

Effects of neutron and gamma-ray irradiation on the thermal properties of muscovite mica: Implications for the defect structure

Abstract The effect of neutron and gamma-ray irradiation on the resistance to thermal decomposition of muscovite mica has been studied. Samples of mica have been exposed to reactor neutrons and 60 Co gamma rays. The results show that the neutron irradiation alone does not cause any significant change in the resistance up to a fast neutron fluence of 9 × 10 16 n/cm 2 . However, the resistance of samples exposed to a gamma-ray dose of about 1.3 × 10 9 R prior to neutron irradiation increases with increasing fast neutron fluence ranging from 5 × 10 15 to 2× 10 16 n/cm 2 . Numerous shallow pits are observed in chemically etched mica subjected to the gamma-ray or neutron irradiation. The defect structure in heavily irradiated muscovite mica has been deduced by combining its thermal property and etchability.

Statistical Properties of Real-Time Neutron Radiographic Image

Actually statistical quality of raw images produced by neutron radiography is very poor. We analysed the statistical properties of neutron images obtained from the cyclotron-based real-time neutron radiography system of Sumitomo Heavy Industries, Ltd., which uses a set of LiF/ZnS(Ag) screen and high sensitive TV camera.

The effect of high gamma-ray doses on the thermal properties of muscovite mica: Application to dosimetry

Abstract Differential thermal analysis has been made for muscovite mica exposed to 60 Co gamma rays of doses up to 1.2×10 10 R. The thermal curves show a endothermic peak below 950°C. The starting temperature of the endothermic reaction increases from 770 to 855°C with increasing dose. The resistance to the thermal decomposition of muscovite mica is increased by gamma-ray irradiation. The change in thermal properties has been utilized for measuring and recording high gamma-ray and electron doses. A simple mechanism is suggested to understand the radiation-induced effect on the thermal properties of muscovite mica.