Focussing Protons from a Kilojoule Laser for Intense Beam Heating using Proximal Target Structures

The structure of Ta2O5 has been described in the literature in several different crystallographic forms with varying unit cell lattice parameters. Earlier studies on films of Ta2O5 produced by anodization of tantalum have revealed structural features which are not consistent with the parameters of “bulk” Ta2O5 crystalsFilms of Ta2O5 were prepared by anodizing a well-polished surface of pure tantalum sheet. The anodic films were floated off in distilled water, collected on grids, dried and directly examined in the electron microscope. In all cases the films were found to exhibit diffraction patterns representative of an amorphous structure. Using beam heating in the electron microscope, recrystallization of the amorphous films can be accomplished as shown in Fig. 1. As suggested by earlier work, the recrystallized regions exhibit diffraction patterns which consist of hexagonal arrays of main spots together with subsidiary rows of super lattice spots which develop as recrystallization progresses (Figs. 2a and b).

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Fission Gas Bubbles in Fractured UO2

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101177 ◽

1968 ◽

Vol 26 ◽

pp. 286-287

Author(s):

O. M. Katz

Keyword(s):

Electron Microscopy ◽

Thermal Gradient ◽

Gas Bubbles ◽

Inert Gas ◽

Thermal Gradients ◽

Fission Gas ◽

Beam Heating ◽

Limited Application ◽

Bubble Characteristics ◽

Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

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TEM study of buried cobalt disilicide layers formed by ion implantation: Identification of cobalt monosilicide inclusions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176010 ◽

1990 ◽

Vol 48 (4) ◽

pp. 576-577

Author(s):

A. De Veirman ◽

J. Van Landuyt ◽

K.J. Reeson ◽

R. Gwilliam ◽

C. Jeynes ◽

...

Keyword(s):

Ion Implantation ◽

Annealing Treatment ◽

Silicon On Insulator ◽

High Dose ◽

Nitrogen Flow ◽

Cobalt Disilicide ◽

Transmission Electron ◽

Beam Heating ◽

Co Concentration ◽

Silicon On Insulator Technology

In analogy to the formation of SIMOX (Separation by IMplanted OXygen) material which is presently the most promising silicon-on-insulator technology, high-dose ion implantation of cobalt in silicon is used to synthesise buried CoSi2 layers. So far, for high-dose ion implantation of Co in Si, only formation of CoSi2 is reported. In this paper it will be shown that CoSi inclusions occur when the stoichiometric Co concentration is exceeded at the peak of the Co distribution. 350 keV Co+ ions are implanted into (001) Si wafers to doses of 2, 4 and 7×l017 per cm2. During the implantation the wafer is kept at ≈ 550°C, using beam heating. The subsequent annealing treatment was performed in a conventional nitrogen flow furnace at 1000°C for 5 to 30 minutes (FA) or in a dual graphite strip annealer where isochronal 5s anneals at temperatures between 800°C and 1200°C (RTA) were performed. The implanted samples have been studied by means of Rutherford Backscattering Spectroscopy (RBS) and cross-section Transmission Electron Microscopy (XTEM).

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