  We have built and operated a cryogenic Penning trap arrangement that allows
for the efficient production, selection, and long-term storage of highly
charged atomic ions. In close similarity to an electron-beam ion trap (EBIT) it
works by electron-impact ionisation of atoms inside a dedicated confinement
region. The electrons are produced by field emission at liquid-helium
temperature and are subsequently accelerated to the keV energy range. The
electron beam is reflected through the trap multiple times to increase the
ionisation efficiency. We show a characterisation of the system and
measurements with argon and tungsten ions up to Ar$^{16+}$ and W$^{27+}$,
respectively.
