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Silicon has been recently proposed as a very promising phase change material for applications in latent heat thermal energy storage (LHTES) and conversion systems working at ultra-high temperatures. However, in order to successfully develop such kind of devices, suitable refractories showing low reactivity and non-wetting behavior upon the melting and storing of molten silicon at temperatures much higher than its melting point have to be selected. In our previous work, we have documented that the non-wetting behavior in Si/h-BN system is preserved at temperatures up to 1650 C, with the absence of new reaction products formed at the interface. These findings make hexagonal boron nitride (h-BN) a reasonable first candidate for Si-based LHTES applications. Nevertheless, the rather poor mechanical strength of ''pure'' h-BN ought to be improved in order to enhance the reliability under thermocycling operational conditions and to increase the life period of the device. Therefore, in the present paper, we examine for the first time the interactions at ultra-high temperatures between a high strength commercial h-BN-based composite and molten Si. At temperatures up to 1750 C, the wettability of the h-BN-based composite (h-BN+SiC+ZrO2) with molten Si is much lower if compared to the pure h-BN counterpart. Additionally, the role of reinforcements (SiC+ZrO2) and occured microstructural evolution is discussed based on the results obtained by SEM and XRD analyses.

Oral Presentation of the AMADEUS Project at the SolarPaces 2017 Conference

Single-crystal Diamond Detectors (SDD) are good candidates as high-energy neutron detectors in the extreme conditions of the next generation thermonuclear fusion facilities like the ITER experiment, due to their high radiation hardness, fast response time and small size. Neutron detection in SDDs is based on the collection of electron-hole pairs produced by charged particles generated by neutron interaction on 12 C. In this work the SDD response to neutrons with energies between 2.8 and 3.8 MeV was determined at the Legnaro CN accelerator at the INFN Laboratories in Legnaro (PD, Italy). This work is relevant for the characterization of SDDs response functions, which are key points for Deuterium-Deuterium and Deuterium-Tritium plasma diagnostic.

New solid-state detectors, based on chemical vapour deposited (CVD) polycrystalline diamonds produced by hot-filament (HF) or microwave plasma (MW) assisted deposition methods, were constructed for radiation therapy dosimetry. Properties of diamond crystals, such as high radiation sensitivity, resistance to radiation damage and tissue-equivalence giving a low-energy dependence are very advantageous for clinical dosimetry. Therefore the encapsulation was specially designed for these detectors to have as little influence as possible on the radiation response. The prototypes were irradiated with use of a wide range of photon beam qualities (60Co ?-rays, 6 and 18 MV X-rays). The radiation sensitivity varied considerably between samples deposited with HF (9 nC Gy-1 mm-3) and MW (66 and 144 nC Gy-1 mm-3) methods. For all detectors the leakage current was of the order of 10% of the radiation-induced current (bias voltage 100 V, dose rate 0.3 Gy/min). When irradiated with 60Co ?-rays, the detectors showed a dose-rate linearity with an exponential ? parameter close to unity. However, a difference of 8% was found between ? values for the different beam qualities. A small energy dependence was observed, for which the most probable sources are interface effects due to the silver electrodes and partly the geometry of the encapsulation which needs to be further optimized. Despite some limitations in the performance of present prototype detectors, with an improved CVD technique producing crystals of better electrical and dosimetric properties, and with a well-designed tissue-equivalent encapsulation, CVD-diamonds could serve as very good dosimeters for radiotherapy.