I. V. Smirnov,a,b,c@ E. S. Stepanova,a,b M. Yu. Tyupina,a N. M. Ivenskaya,b S. R. Zaripov,d S. R. Kleshnina,b,d S. E. Solovieva,e and I. S. Antipind,e
aKhlopin Radium Institute, 194021 St. Petersburg, Russian Federation
bOzersk Institute of Technology, 456783 Ozersk, Russian Federation
cSaint Petersburg State University, 199034 St. Petersburg, Russian Federation