Interactions between ultrashort laser pulses with intensities larger than 1013 W/cm2 and solids during material processing can lead to the emission of X-rays with photon energies above 5 keV, causing radiation hazards to operators. A framework for inspecting X-ray emission hazards during laser material processing has yet to be developed. One requirement for conducting radiation protection inspections is using a reference scenario, i.e., laser settings and process parameters that will lead to an almost constant and high level of X-ray emissions. To study the feasibility of setting up a reference scenario in practice, ambient dose rates and photon energies were measured using traceable measurement equipment in an industrial setting at SCHOTT AG. Ultrashort pulsed (USP) lasers with a maximum average power of 220 W provided the opportunity to measure X-ray emissions at laser peak intensities of up to 3.3 × 1015 W/cm2 at pulse durations of ~1 ps. The results indicate that increasing the laser peak intensity is insufficient to generate high dose rates. The investigations were affected by various constraints which prevented measuring high ambient dose rates. In this work, a list of issues which may be encountered when performing measurements at USP-laser machines in industrial settings is identified.

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Obtaining a glass ceramic via devitrification of a fully amorphous glass phase leads to a pore-free material, in which crystallites with their ferroelectric phase are embedded in a residual glass matrix. This matrix in tum forms a close-to-ideal dielectric. Such a structure offers, in principle, several advantages over conventional sintered ceramics, particularly with respect to ageing and fatigue. We show examples of ferroelectric glass ceramics in which the composition of the ferroelectric phase as well as the size of the crystallites are varied in a systematic way. The dielectric and structural properties are discussed in detail.

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