ISSN: 2641-9165
Authors: Vardanyan J*, Hovhannisyan M, Agajanyan H and Nersisyan M
The UV and VUV spectral range of photons is an important area for experimental studies in the field of life sciences and materials science, especially for studies of large molecules, crystals, surface science, etc. Currently, all synchrotron radiation facilities have a special program of experimental studies in the field of VUV spectrum. Large-format ultraviolet image sensors have been and are being actively developed for various space astronomical missions. The detector plays a crucial role in the overall capabilities of the device. There are many detector systems, none of which are ideal for all applications. The wavelength ranges of interest are 10–200 nm for studies in solar physics, 280 nm for communications and missile warnings, and 200–400 nm for studies of the atmosphere. Compactness, high sensitivity, durability and reliability are critical requirements for space applications. One of the earliest methods used to record a system (detection, visualization) - a system based on a scintillator of ionizing radiation (image scanners) remains one of the most flexible and successful methods. However, conventional scintillators have significant limitations: degradation in vacuum, limited point spread function (PSF) (usually> 100 microns FWHM) due to scattering on the screen of a polycrystalline phosphor. Solid scintillation films are ineffective because typically> 90% of the light is captured on the screen by total internal reflection, i.e. <10% of the light is emitted. The partial solution to improve the spatial resolution of the detecting system is the usage of rigidly structured scintillator, for example, fiber, needle. The fiber-optical systems are widely used in life and material sciences, bio and nanotechnology. We conducted numerous spectral studies with multiple corundum crystals (with various impurities and their concentrations, as well as their ratios Cu, Fe, Ga, Ge, Mg, Mn, Ni, Pb, Se, Si, Ti, V, Zn.Sc. In the course of work, the crystal samples were subjected to technological processing methods that allow changing the optical density of corundum in order to identify the mechanisms of energy transfer and the optimal use of crystals as sensors for VUV, UV, and IR radiation. As a result of the studies, those substances, their concentrations and ratios that have resonance absorption lines not only in the UV, but also in the VUV spectral regions were identified. Such resonant lines have lanthanum and lanthanides, scandium and others. Theoretically, this is understandable: having large atomic radii, they can create new exciton-photon interactions, which lead to new transitions and energy transformations.
Keywords: Detector; Ultraviolet radiation; Impurities; Corundum; Luminescence; Optical fiber
