Photoemission cells with high sensitivity to photons in the ultraviolet (UV) range of the spectrum have a wide range of practical applications in accelerator technology and generators of ultrashort electromagnetic pulses in the microwave range. The potential benefits of using UV photocathodes in these areas of technology are determined by such a combination of their properties as high electrical strength and high quantum efficiency. The report presents the results of experimental studies of the characteristics of photocathodes based on magnesium-barium (Mg-Ba) alloys and cesium iodide (CsJ). Photocathodes were fabricated by thermal vacuum sputtering on polished stainless steel substrates. It is shown that the dielectric strength of vacuum gaps with UV cathodes is significantly higher than with antimony-cesium cathodes in the visible range of the spectrum (for CsJ cathodes – 2.5 times, for Mg-Ba cathodes – more than three times). The quantum efficiency of Mg-Ba cathodes is ~1% at a wavelength of 247 nm, and that of CsJ cathodes is 7.5% at a wavelength of 196 nm. The results of studies of the dynamics of a decrease in the quantum efficiency of photocathodes under repetitively pulsed irradiation with laser pulses with a fluence 6 μJ/cm2. The characteristics of photocathodes are compared from the point of view of their practical applications.

For experiments on laser interaction with matter, a method has been developed for manufacturing a low-density material from aluminum and copper by the method of resistive sputtering in an inert gas – argon. Deposition was carried out at two gas pressures: 40 Pa and 440 Pa. The densities of the obtained samples were determined by the gravimetric method: the mass of the sprayed layer was measured by weighing the substrate before and after deposition, the volume was calculated based on measurements of the material thickness using an optical profilometer. The thickness of the deposition layer is 74.8 ± 0.9 μm. The minimum density was achieved on a sample of a porous aluminum layer obtained at a pressure of 440 Pa. Its value was (72 ± 4) mg/cm3. According to the images obtained with a scanning electron microscope, it was found that the pore size in the material does not exceed 3 microns. Measurements of the chemical composition with an X-ray fluorescence spectrometer showed the presence of oxygen on the samples, which indicates the oxidation of the surface layer of the prepared samples. targets (2 pcs.) for experiments on laser interaction with matter were made from the samples of porous aluminum obtained in this work.

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