Eu 3þ -doped ZnO nanoneedles were fabricated by thermal evaporation. In order to include Eu in ZnO nanostructures, europium nitrate was used to produce starting droplets from which ZnO nanoneedles were grown. Photoluminescence spectra included a sharp blue peak corresponding to the ZnO band gap and a broad red band due to defect states. In addition, sharp intra-4f transitions of Eu 3þ ions were observed. Energy transfer from the ZnO matrix to Eu 3þ was also observed. Study of the photoluminescence excitation revealed absorption tail states below the ZnO band gap induced by the inclusion of Eu ions in the ZnO nanoneedles. The location of Eu ions was assumed to be near the surfaces of the ZnO nanoneedles.

We fabricated Eu 2þ -doped ZnO microstructures by thermal evaporation. Their structures were micrometer-size grains with smooth surfaces or nanometer-size needles. Morphology depended on the temperature region where structures were grown. A strong green luminescence at room temperature is demonstrated. This is attributed to the efficient energy transfer from the ZnO matrix to Eu 2þ ions and their 5d-4f transitions.

No abstract

A comprehensive set of diagnostics is planned for ITER-FEAT. The design of the systems is a substantial technical challenge because of the combination of the harsh environment with the demanding measurement requirements. Through a combination of careful choice of technique, materials, and design, supported by dedicated research and development, an extensive diagnostic set has been developed. The designs are based on existing techniques as much as possible but in some cases novel approaches have to be adopted. In the article the requirements for measurements are outlined and representative diagnostic designs are presented. Key issues in the design are identified and areas requiring further development are highlighted.

The divertor impurity monitoring system of the International Thermonuclear Experimental Reactor has been designed. The main functions of this system are to identify impurity species and to measure the two-dimensional distributions of the particle influxes in the divertor plasmas. The wavelength range is 200-1000 nm. The viewing fans are realized by molybdenum mirrors located in the divertor cassette. With additional viewing fans seeing through the gap between the divertor cassettes, the region approximately from the divertor leg to the x point will be observed. The light from the divertor region passes through the quartz windows on the divertor port plug and the cryostat, and goes through the dog-leg optics in the biological shield. Three different type of spectrometers: ͑i͒ survey spectrometers for impurity species monitoring, ͑ii͒ filter spectrometers for the particle influx measurement with the spatial resolution of 10 mm and the time resolution of 1 ms, and ͑iii͒ high dispersion spectrometers for high resolution wavelength measurements are designed. These spectrometers are installed just behind the biological shield ͑for Ͻ450 nm) to prevent the transmission loss in fiber and in the diagnostic room ͑for у450 nm) from the point of view of accessibility and flexibility. The optics have been optimized by a ray trace analysis. As a result, 10-15 mm spatial resolution will be achieved in all regions of the divertor.