  We discuss recent experiments performed with an upgraded version of the main
magnetic focus ion source (MaMFIS) at the Joint Institute for Nuclear Research
(JINR) in Dubna. The device operates in the range of electron beam energies
extended up to $40$ keV. The achieved electron current densities are of the
order of $10$ kA/cm$^{2}$. This assessment is consistent both with the very
short ionization time and with the utmost ionization degree of the produced
highly charged ions. Due to its high efficiency, the MaMFIS technology is
especially promising for ionization of short-lived radionuclides. A new scheme
for charge breeding is proposed.
