The method of synthesis of transfermium elements in the irradiation of lead isotopes with ions with mass A_I40 atomic units, investigated earlier [12] for the example of the reaction Pb(⁴⁰Ar, xn)Fm, is also extremely effective using⁵⁰Ti ions. The reactions Pb(⁴⁰Ar, 2n)Fm and Pb(⁵⁰Ti, 2n)Ku have approximately equal cross sections, which might have been expected on the basis of theoretical estimates. This permits us to hope that this method can be used successfully for the synthesis of heavier elements in the reactions induced by⁵⁴Cr,⁵⁵Mn, and⁵⁸Fe ions.

In all probability, the substantial changes in the systematics of the half-lives for even-even isotopes of kurchatovium are associated with the structure of the barriers to fission of these nuclei. From this standpoint, it seems important to investigate the properties of more neutron-deficient isotopes of kurchatovium, using, in particular, the reactions with²⁰⁴Pb, and to attempt to advance into the region of elements with Z 106. On the other hand, a detailed theoretical analysis must be made of the data obtained on the basis of the modern theory of nuclear fission, which, in our opinion, will aid in a more reliable prediction of the properties of heavy and ultraheavy elements.