[en] Full text: SIMS has been utilised as a tool for biological research since the early 1970's. SIMS' abilities in isotopic detection with high sensitivity, imaging capabilities at a subcellular level, and the possibility of molecular imaging have been the main areas of interest for biological development. However, whilst hundreds of instruments are available in industrial and university laboratories for semiconductor and materials analysis, only a handful successfully perform biological research. For this reason there is generally a lack of awareness of SIMS by the biological community. Biological SIMS analysis requires a working knowledge of both biology and SIMS. Sample preparation is a critical and time consuming prerequisite for any successful biological SIMS study. In addition, for quantification to be possible a homogeneous, matrix matched standard must be available. Once these difficulties are more widely understood and overcome there will be a greater motivation for the biological community to embrace SIMS as a unique tool in their research. This paper provides an overview of some of the more successful biological SIMS application areas internationally, and summarises the types of biological SIMS requests received by ANSTO

[en] Thin nanometre films of SiO₂ on Si have been measured using a variety of IBA techniques. High-energy non-Rutherford backscattering and NRA were found to be the most suitable methods for relative thickness determinations, giving precisions to ∼1 nm, comparable to that obtained using ellipsometry. The information obtained is used to determine the oxygen areal density and bulk density of sol-gel films

[en] In the 1950s and early 1960s, the United Kingdom conducted nuclear tests at Maralinga in the north-west of South Australia. Apart from a series of fully nuclear explosions, many smaller trials were made to investigate various developmental aspects of nuclear components. Some of these 'minor trials' resulted in the atmospheric dispersion of plutonium oxide particles from non-nuclear explosions. Several, superficial, wind dispersed plumes of Pu extended 20 km or more from the experimental sites, well beyond the area currently being considered for further rehabilitation. 2 refs

[en] Soil structural and soil organic matter decline is a worldwide problem and the return of plant residues is being used in many areas to attempt to increase soil C, which can lead to an improvement in structure. Studying the impact of residue incorporation on soil C can be difficult because of the large background of residual C. The use of isotope-labelled plant material allows the investigation of the effects of newly incorporated residue on C dynamics. An experiment was conducted to evaluate the effect of plant residues - with differing breakdown rates, incubated at different temperatures and for various time periods - on the incorporation of C and the stability of the soil aggregates to wetting. No increase in total C within the soil aggregates was found, however, there were large increases in soil aggregate stability. The rate of incorporation of the C from the added residues differed between plant materials

[en] Soil structural and soil organic matter decline is a worldwide problem and the return of plant residues is being used in many areas to attempt to increase soil C, which can lead to an improvement in structure. Studying the impact of residue incorporation on soil C can be difficult because of the large background of residual C. The use of isotope-labelled plant material allows the investigation of the effects of newly incorporated residue on C dynamics. An experiment was conducted to evaluate the effect of plant residues - with differing breakdown rates, incubated at different temperatures and for various time periods - on the incorporation of C and the stability of the soil aggregates to wetting. No increase in total C within the soil aggregates was found, however, there were large increases in soil aggregate stability. The rate of incorporation of the C from the added residues differed between plant materials

[en] Cement is often used to condition and encapsulate low level radioactive waste before it is disposed of in a repository. Ground water can attack these waste-forms by transporting aggressive ions into the cement paste and by removing radioactive ions from the paste. The extent of the attack will be governed by the diffusion of the ions in the cement paste. In this study we examine the migration of aggressive carbonate ions and inactive Cs and Sr through cement pastes. The use of SIMS for establishing the penetration depths and diffusion profiles for Cs and Sr in cement will be explored. The penetration profiles of Cs and Sr in a non-zeolite cement paste were examined and compared to those of a paste made with zeolite. The effects of the non-homogeneous nature of the cement was most pronounced in the study of the zeolite rich cement; Cs being preferentially accumulated in the zeolite material. (authors)

[en] Full text: TiO_xN_y thin films have useful properties as selective solar absorbers when used in tandem with a collector substrate. Such films are transparent across a reasonable window of the solar spectrum, but have low thermal emissivity. They are however limited by their thermal stability under the typical operating conditions they experience. In this study, TiO_xN_y films have been deposited on Si and Cu substrates using ion beam assisted deposition. The films are amorphous and x and y were controlled by altering the O₂/N₂ ratio in the gas source. After annealing at temperatures of 200 - 400 deg C, films have been depth profiled using Secondary Ion Mass Spectrometry. Profiles reveal the degradation of the film by migration of the substrate atoms through the films, to the sample surface. In general, films with x<1 and y>1 show improved stability, ultimately at the expense of a reduced transmission window. Thermal stability is also improved by the use of diffusion barriers either at the substrate film interface or at the surface of the film. However contrary to previous suggestions, the degradation mechanism involves the formation not of an oxide at the film surface but a phase which is nitrogen rich. The nature of this phase, formed by diffusion of the substrate atoms, has been investigated by X-ray photoelectron spectroscopy (XPS). These investigations reveal very complex behaviour in the early stages of film failure, with an almost intact TiO_xN_y layer surviving, but being progressively buried by the growth of the reaction layer at the film surface. Copyright (1999) Australian X-ray Analytical Association Inc

[en] Cs⁺ diffusivity through ordinary Portland cement (OPC) samples was investigated using Inductively Coupled Plasma Mass-Spectrometry (ICP-MS) and Secondary Ion Mass-Spectrometry (SIMS). Intrinsic diffusivities were calculated using modified diffusion equations. The intrinsic diffusivities of Cs⁺ through OPC and cemented clinoptilolite samples cured at 25 deg C, 60 deg C and 150 deg C were compared. As expected, Cs⁺ diffusivity was found to increase with increasing cure temperature of OPC. Cs⁺ diffusivity through cemented clinoptilolite also varied with cure temperature. The addition of clinoptilolite to OPC reduced Cs⁺ diffusivity through the sample, and this effect was more pronounced at greater cure temperatures

[en] Increasing the hardness and wear resistance is of practical importance to many different materials, including stainless steel. Human prostheses and products subject to continual abrasive mechanical contact require materials that will last a substantial time with negligible damage. One method of increasing the hardness of stainless steel is through incorporation of nitrogen (nitriding). However, austenitic stainless steels have proved difficult in the past to nitride without degradation of their corrosion resistance. Through the use of the Plasma Immersion Ion Implantation (PI³) technique at ANSTO, it is possible to introduce a nitrided layer to the stainless steel. Secondary Ion Mass Spectrometry (SIMS) was then performed to characterise the nitrogen profile in the stainless steels. The samples used were AISI-316 austenitic stainless steels, implanted by PI³. SIMS was performed using a Cs⁺ primary beam to determine the nitrogen distribution after implantation. The secondary species were monitored either as an MCs⁺ adduct or alternatively as negative species. MCs⁺ was found to be the most appropriate SIMS technique for these samples, giving better depth resolution and a reduction in matrix effects

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