V.E. Avvakumov - Dr. PhD., associate professor, Experimental physics chair of the Volgograd State Technical University (VSTU). E-mail: xcpvlad@front.ru A.G. Shein - Dr. Sci., professor, Physics chair of the Volgograd State Technical University (VSTU). E-mail: alexandershein39@gmail.com M.C. Martinova - Electronics and computer techniques faculty student of the Volgograd State Technical University. E-mail: marina.111992@gmail.com