Since the past 10 years, the recoil separator VASSILISSA has been used for
the investigations of evaporation residues produced in heavy-ion-induced co
mplete fusion reactions. Tn the course of experimental work in the region o
f the elements with 92 less than or equal to Z less than or equal to 94, 14
new isotopes have been identified by the parent-daughter correlations. For
further experiments aimed at the synthesis of the superheavy element isoto
pes (Z greater than or equal to 110) with intensive Ca-48 extracted beams,
improvements in the focal plane detector system have been made. As a result
, energy and position resolutions of the detectors have been significantly
improved, the detection efficiency for the alpha-particles, emitted from th
e implanted into the focal plane detector recoil nuclei, has been increased
to 85%. The decay properties of the now isotope of element 112 and the iso
tope of the new element 114 with mass 287 have been measured in two-nuclei
decays. (C) 2000 Elsevier Science B.V. All rights reserved.