Intense Pulsed Light-ion Beam Research Articles

Preparation of silicon nanoparticles for device of photoluminescence

We experimentally demonstrated the synthesis of silicon nanoparticles by using high-density ablation plasma prepared by the interaction of an intense pulsed light-ion beam with a target, known as the intense pulsed ion beam evaporation method. Blue light emission was obtained from the silicon nanoparticles. It was determined that the ambient gas reaction is very important and useful method to obtain the photoluminescence from the silicon nanoparticles.

Diagnostics of ablation process induced by pulsed ion beam

An intense pulsed light ion beam is well known as one of the hopeful candidates for energy drivers of inertial confinement fusion. Recently the ion beam technique has been applied to new material processing for use in generating ablation plasma. This paper reports the principle study of the ablation plasma generated by the intense pulsed ion beams.

Preparation of thin films of dielectric materials using high-density ablation plasma produced by intense pulsed ion beam

By use of a high-density ablation plasma produced by the interaction of an intense pulsed light-ion beam with a solid target, the preparation of thin films has been successfully demonstrated, and is called ion beam evaporation (IBE). In addition to a standard front-side deposition of thin films (FS/IBE), significant improvement of the films has been achieved with much better morphology as well as electrical properties by back-side deposition (BS/IBE), In the BS/IBE configuration, the substrate is placed on the reverse side of the target holder, being free from droplets sometimes observed by the FS/IBE. Using BaTiO 3, (Ba 0.5, Sr 0.5)TiO 3 and SrTiO 3 targets, experimental results are presented in detail on the preparation of these thin films by the BS/IBE.

Synthesis of nanosize powders of alumina by ablation plasma produced by intense pulsed light-ion beam

Nanosize powders of alumina have been synthesized by high-density ablation plasma produced by the irradiation of an intense, pulsed, light-ion beam on an aluminum target in oxygen. Diameters of the powders, which are observed to be spherical, are typically 5–25 nm. At 1 Torr of oxygen, nanosize powders of aluminum are synthesized with those of a small amount of γ-alumina. At 10 Torr of oxygen, on the other hand, γ-alumina powders are produced with a small amount of aluminum powders. Annealing characteristics in nitrogen have also been studied on the transition from γ- to α-alumina.

Three-dimensional, tight focusing of intense pulsed light-ion beam by spherical plasma focus diode

A new type of ion-beam diode, self-magnetically insulated, spherical plasma focus diode (SPFD), was developed. With the SPFD, three-dimensional focusing of an intense pulsed light-ion beam was obtained. Experiments and simulations were carried out to study the behavior of the SPFD. In the experiments, diagnostic results of the Rutherford scattering pinhole camera and the shadow-box showed that the ion beam was focused into a small cylindrical area with ∽0.5 mm in diameter and ∽2.5 mm in length. The average ion-beam current density at the anode surface was found to be ∽2 kA/cm2. In the simulations, it was observed that most of the diode gap is well insulated by the self-magnetic field induced by the diode current. The electron sheath in the diode gap significantly enhances the ion flow from the anode. As a result, the ion current density is several times higher than the single-species space-charge limited value.

Damage structures in Si3N4–Sic films and stainless steel irradiated by intense pulsed light-ion beam

As the input power and energy content of Tokamaks are increased, the erosion rate of the first wall becomes larger, and a thick coating or cladding of low atomic number (Z) materials will be needed. Recently, the present authors prepared Si3N4–SiC films at alow temperature of 400°C by a plasma CVD method for the application to coating materials having high strength and wear resistance on metals and glasses. In this study, irradiation damage of the Si3N4–SiC films and 316 stainless steel (SUS-316) was investigated for the application to the first wall materials in a fusion reactor. The damage studies employed an intense pulsed light-ion beam (LIB) from the “ETIGO-I” device.

Light Ion-Beam Irradiation Damages in the Amorphous Films of Si<sub>3</sub>N<sub>4</sub>-SiC System Prepared by Plasma CVD

For the application to first wall materials of fusion reactor, irradiation damages of Si3N4-SiC amorphous films that were prepared by plasma CVD method have been investigated experimentally by use of an intense pulsed light-ion beam. The ionbeam irradiation was carried out by using a magnetically insulated diode of flat-type, where an external transverse magnetic field was applied to insulate the motion of electrons. The inductively calibrated diode voltage was being kept constant at 650kV, and the dose rate of the beam was 1013 ions cm-2 shot-1 (H+ ion). The content of the H+ ion found to be more than 80%, and the remainder consisted of C+, C2+, C3+ and H2+ ions. From the changes of surface texture, film thickness, composition, and cross-sectional views, we evaluated these irradiation damages. Blistering for SiN1⋅42(-Si3N4) film, flaking for SiC1⋅04(-SiC) film and the intermediate texture between blistering and flaking for SiN0⋅65C0⋅62 film were observed after the irradiation, A ccording to the observation of cross section of the films, the irradiation damage was limited in the surface layer, and peeling off of the whole film from the substrate (316 stainless steel) did not occur. Erosion rate (the decrease in film thickness per one shot of irradiation) was in the range from 0.46 to 0.73μm shot-1, where the SiN1⋅42 film showed the smallest rate. N and C contents in the films were found to have decreased, and Si content was found to have increased by EPMA measurements.

Geometric focusing of intense pulsed ion beams from racetrack type magnetically insulated diodes

Focusing properties and mechanisms are experimentally investigated of an intense pulsed light-ion beam or a medium-mass ion beam extracted from racetrack type magnetically insulated diodes. Quantitative determinations are made for three factors that affect the focusing ability of the beam, i.e., local divergence angle, deviation angle from ideal trajectory and space-charge effect. Behaviour of electrons in an anodecathode gap as well as neutralizing process of the ion beam by electrons are studied in connection with beam focusing. It is found that there is a close correlation between ion yield and electron irradiation on the anode. By adopting a perforated cathode instead of a vane cathode to ensure good uniformity of electric field in the accelerating gap, we have succeeded in significantly reducing the divergence angle. Several new diagnostic techniques and methods have been developed, yielding information such as the time-resolved trajectory and profile or incident angle of the beam. Electron temperature of the anode plasma is theoretically anticipated from the ions observed experimentally. From an estimate of beam divergence due to a space-charge effect, it is suggested that ‘breakeven’ can be achieved without using conventional z-discharged plasma channels if a bunch of boron beams is utilized.

Planar-type self-magnetically-insulated diode as a new source of intense pulsed light-ion beam

A new type of ion diode named the ‘‘Planar-Type Self-Magnetically-Insulated Diode’’ is developed. Good efficiency of ion production (∼30%) is obtained with good reproducibility. A multiple-shot operation (40 shots or even more) is possible with relatively high power (900 kV, 180 kA). Surface flashover of the anode is affected by an initial irradiation of lower-energy electrons of the incident voltage pulse.

I.2.2. Light ion-beam fusion

The Technological University of Nagaoka and the Institute of Plasma Physics at Nagoya University report on experimental and theoretical studies in inertial confinement fusion by using an intense pulsed light-ion beam (LIB). The main efforts are made in the production, focusing, and transport of the LIB and the development of several diagnostic techniques, while fewer efforts are made to study a LIB-target interaction. New approaches are also tried for research and development of a medium-mass ion beam and a direct power input into pellets. A table summarized the activities and specifications of the pulse-power machines installed in universities in this particular field and a brief review is given.

Transport of an intense pulsed light-ion beam through a plasma channel in the Nagaoka etigo-I

The transport efficiency of an intense pulsed proton beam has been studied experimentally through a z-discharge plasma channel (50 cm long) produced by an exploding wire. At V ch(charging voltage of channel) = 30 kV and I ch(channel current) = 50 kA, a good transport efficiency has been obtained, yielding an efficiency of more than 80%.

Recent Topics on Inertial-Confinement Fusion by Intense Pulsed Light-Ion Beam

Recently, much attention has been paid to inertial-confinement fusion (ICF) by an intense pulsed light-ion beam (LIB). In this paper, the focusing and the transport of the LIB, that are believed to be most important themes in these fields of interests, are to be reviewed, from which particular points of the problems to be solved in the near future will be made clear.

Experiments on Propagation of an Intense Pulsed Light-Ion Beam in the Nagaoka ETIGO-I

Transport characteristics of an intense pulsed light-ion beam (LIB) have been studied experimentally through a z-discharged plasma channel. The channel is produced by an exploding wire of copper (0.16mmφ, 50cm long).Using a caloriemetric technique, we have found an overall efficiency more than 80 % after being passed through the plasma channel. Moreover, we have also measured the transport efficiency by a nuclear activation technique. In the absence of plasma channel, we have found the transport efficiency of the order of 15 % under the same condition of the above experiment. From these studies, it is concluded that the LIB injected into a z-discharged plasma channel yields a relatively good efficiency of propagation.