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The research and scientific training programme of GLADNET is split in 5 work packages containing 16 different projects. Each project is coordinated by one of the GLADNET partners. In order to help the young researches trained with in this Marie-Curie Research Training Network, projects will not only be hosted by one partner but at-least two. The researchers employed for the projects will therefore get the possibility of working at different places during their employment.
State of the Art
In Analytical Glow Discharge Spectrometry, the sample to be analysed forms the cathode of a discharge in a noble gas at a low pressure; the elements present are sputtered from the cathode, excited and ionised and then detected by either Optical Emission Spectroscopy (OES) or mass spectrometry (MS). The most commonly used source for OES is the Grimm source or developments thereof. Other discharge cells have been used for MS but some new MS instrumentation is also based on Grimm type sources.
GD-OES, originally introduced for the analysis of bulk materials, was then developed for the analysis of layers several µm thick, e.g. zinc layers on steel. However, both the range of applications (e.g. layers ~ 50 nm thick on medical implants) and the capability of the method to analyse very thin layers has steadily increased. The figure below shows the presence of three different layers within 3 nm in a "quantified" depth profile; this is in general agreement with results from other techniques, but the improvements to the quantification are required. Whilst originally the use of a dc discharge limited the applications to conducting materials, the use of RF discharges allows the method to be applied to non-conducting samples and layers. High vacuum techniques are not required so that the analysis is much quicker (and therefore less costly) than competing techniques such as Auger Electron Spectroscopy (AES); e.g. a material with 300 layers, each 3.5 nm thick, was recently analysed by both GD-OES and AES. The results were very similar, but the GD-OES analysis of all 300 layers, with 80 data points per layer, took ~ 4 min, at a commercial cost of <50 Euros, whereas the analysis of the top 70 layers by AES (with only 12 data points per layer) took more than 13 hrs, at a cost of ~3000 Euros.
Whilst GD-OES has detection limits of ~ µg g-1 for solids, limits of ng g-1and better are obtained using HR-GD-MS, and such instruments are used extensively for the analysis of ultrapure materials. However, until recently, the only commercially available equipment required long analysis times, perhaps 1 hour or more per sample, and depth profiling was difficult. Only dc discharges are available in commercial MS instruments, so that non-conducting samples can be analysed only by special techniques (e.g. grinding and mixing with a conducting powder (which of course destroys any structural information).
Situation at Mid-term
In the first two years already outstanding results were achieved, which can be proven by a number of realised prototypes, publications in high impact journals, several training events and events at international conferences. No major changes to the schedule originally proposed in the project research work plan for the projects are foreseen at the moment. In the sections on the work packages and projects, more detailed on the scientific achievements are presented.
Summarising, all milestones (M1.1, M1.2, M2.1, M2.2, M3.1, M4.1, M4.2, M5.1, M5.2) were achieved. The FTS spectrometer was installed (M2.1) at ICSTM and the pulsed GD-TOFMS instrument is operating at CRI-SPSU (M1.1). The selection of H-containing samples was accompanied by fundamental studies based on H-gas introduction (M4.2). The vacuum system for studies of fundamental rate coefficients is running (M5.1). Leco has setup an experimental methodology for high resolution and broadband spectral studies (CCD- and FTS system). An experimental system for the determination of excited and ionised species in the discharge chamber has been setup (M2.2). We are waiting for first experimental results. At IFW mixed gases can be studied now using both dc and rf excitation (M1.2). UA modelled Ar/N2 systems for the Grimm type source (M3.1) – the responsible scientist has done most of the work herself due to an unsuitable ESR candidate. The LA-GDTOFMS system has been setup at EMPA/TOFWERK (M4.1). RISSP presented a model for crater shape calculation (M3.1).
