Search for superheavy elements in damped collisions betweenU238andCm248

Negative results for the production of superheavy elements in damped collisions between ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ projectiles and ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$ targets are reported. This reaction was believed to permit a closer and more widespread approach to the predicted island of stability near Z=114 and N=184 than any practical fusion reaction. Aqueous and gas phase chemistry techniques were used to isolate superheavy element fractions. The fractions were counted for spontaneous fission activity, fragment kinetic energies, and neutron multiplicities. Cross-section limits for half-lives from hours to several years are >4×${10}^{\mathrm{-}35}$ ${\mathrm{cm}}^2$.