Total Amount Of Deuterium Research Articles

Considerations on hydrogen isotopes release from thin films by laser induced ablation and laser induced desorption techniques

In this paper, we studied the release of deuterium atoms from 1 μm aluminum layers by Laser Induced Ablation and Laser Induced Desorption methods, using a 1053 nm laser source operating with 10 ns pulse duration and 1 kHz pulse repetition rate. The software control of the laser pulse energy successfully accomplished the transition from layer ablation to layer desorption. The layers have been produced by High Power Impulse Magnetron Sputtering technique on substrates with different surface properties.The amount of deuterium released from aluminum layers was evaluated by Quadrupole Mass Spectrometry after ablation respectively desorption of a small area of the sample exposed to the focused laser beam. The results were compared with the one obtained by Thermal Desorption Spectroscopy, which indicated a total amount of deuterium in the analyzed sample of about 2.6 × 1021 D at/m2. The mass spectra data revealed that 85% (2.2 × 1021 D at/m2) and 9% (0.2 × 1021 D at/m2) of total deuterium atoms released from the aluminum layer by Laser Induced Ablation and Laser Induced Desorption, respectively, were detected. The mathematical fitting of the experimental data indicated different laser fluences that boundary the desorption from ablation processes. Through analyses of the morphology of aluminum layer surfaces in connection with the substrate surface quality, the release of deuterium atoms by Laser Induced Ablation or Laser Induced Desorption processes can be identified.

Microstructural Evolution and Behavior of Deuterium in a Ferritic ODS 12 Cr Steel Annealed at Different Temperatures

In the present work, an ODS 12 Cr steel was characterized using Electron Microscopy techniques, in an as-received condition and after annealing treatments between 773 K and 1573 K. Results show a complex microstructure, with the presence of fine Y–Ti–O nanoparticles dispersed in the matrix. After annealing at 1573 K, the average diameter of Y–Ti–O nanoparticles increases from ~ 4 to ~ 7 nm and partial recrystallization occurs. The trapping behavior of deuterium in the steel in its as-received state and annealed at 1573 K was investigated. Samples were exposed to low-energy deuterium plasma and analyzed with thermal desorption spectroscopy, after waiting times of 1 day and 25 days. The samples measured 1 day after exposure released a higher total amount of deuterium than the ones measured after 25 days. The effect of waiting time is explained by the release of deuterium, at 300 K, from sites with low activation energy for detrapping, Ed. In the as-received condition, part of the deuterium detrapped at 300 K was re-trapped by high-Ed sites. For the samples in the annealed condition, the redistribution of deuterium from low-Ed to high-Ed sites was not observed, but the total amount of deuterium released was higher.

Influence of ball milling processing on the microstructure and characteristic of W–Nb alloy

Mechanical alloying was performed in a planetary ball mill by using a rotational speed of 400 r/min and a ball to powder ratio of 20:1 at room temperature. Milling was performed for 5, 15, 25, 36, and 45 h. The effect of milling time on the microstructure and properties of alloy powders, microstructure of W–Nb alloys, and second-phase distribution were studied through field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction analyses. Results showed that crystalline size, lattice strain, and dislocation density significantly changed when the milling time was increased from 5 h to 25 h. Further increase in the milling time slightly influenced the parameters. W–Nb alloy powders exhibited the lowest lattice parameters after 25 h of milling. Among the formed W–Nb solid solutions, W–Nb alloy milled for 25 h exhibited the lowest porosity and contained homogenously and finely distributed Nb-rich phases in the tungsten grains and boundaries. Thermal desorption spectroscopy analysis was also performed to assess deuterium retention after irradiation. Based on the total amount of deuterium in the W–Nb alloys, those milled for 25 h exhibited the optimal irradiation resistance. In conclusion, 25 h is the optimal milling time for mechanical manufacture of W–Nb alloys.

Carbon effect on retention and release of deuterium implanted in Mo

Retention and release behavior of deuterium in carbon deposited Mo single crystals were studied during and after 10 keV D + 2 implantation. Concentration profile of implanted D atoms and chemical composition in the near surface layer of Mo were measured by ion beam analysis techniques. The amount of retained deuterium in Mo at room temperature increased with carbon content in the surface layer of Mo. For the layer containing high concentration of carbon as 0.5 C/Mo, the saturation concentration of the implanted deuterium was found to be about 0.3 D/host atoms, and the total amount of deuterium in the surface layer reached 2 × 10 21 D/m 2 which was 20 times larger than that in a clean surface of Mo. In comparison with the clean surface of Mo, thermal release of deuterium from the carbon contained Mo surface occurred mainly at lower temperature, and no significant release was observed above 450 K.

Plowshare: A program for the peaceful uses of nuclear explosives

The development of thermonuclear weapons in recent years has placed within the grasp of mankind a new, cheap, and almost inexhaustible source of energy. The principal ingredient in thermonuclear reactions is deuterium, a heavy isotope of hydrogen. Deuterium occurs naturally wherever hydrogen is found, since about 0.015 percent of all hydrogen is the heavy isotope, H2. Although the percentage seems low, the total amount of deuterium is extraordinarily large, and a relatively inexpensive process for extracting the deuterium from natural hydrogen has been invented. The atmosphere and oceans of the earth contain enough thermonuclear fuel to last mankind for millions of years at a thousand times the present rate of energy consumption. But, since thermonuclear energy has so far been available only in explosive form, it has not yet been harnessed for nondestructive purposes. Several major research programs currently under way in the United States and other countries are aimed at developing methods of containing and controlling fusion reactions to permit adapting their power output to conventional power‐distribution systems. Substantial progress has been made in this field, but it may be many years before a practical controlled‐fusion machine will be a reality.