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Abstract: Mesoporous nanocrystalline CaF2powder was produced by pulsed electron beam evaporation (PEBE) in vacuum. The specific surface area (SSA) of CaF2nanopowder (NP) reached 88.7 m2/g. The effect of in-air thermal annealing in the temperature range of 200–900°C on the particle size, morphology, textural, thermal, magnetic, and luminescence properties of NPs is studied. A strong deviation from stoichiometry is observed in produced nanoparticles and a significant increase in the SSA after annealing at 200°C. The obtained CaF2NP shows ferromagnetic (FM) behavior. The FM response appearance can be explained by the formation of structural and radiation defects. An analysis of pulsed cathodoluminescence (PCL) and magnetization curves of CaF2NPs allows conclusions about their interrelation.

An YPT-0.5 repetive-pulse nanosecond electron accelerator designed according to the thyratron-pulse transformer-semiconductor opening switch scheme is described. Its accelerating voltage reaches 0.5 MV, the FWHM pulse duration is 50 ns, and the pulse repetition rate is 200 Hz. A metal-dielectric cathode allows for obtaining an electron beam with a diameter of 30–100 mm at a maximum pulse current density of 40 A/cm2. Operating in the bremsstrahlung generator mode, the accelerator provides an absorbed dose rate of 30.4 Gy/min at a distance of 5 cm from the target.