Chemical compound targets for SHIP on heated carbon backings

The application of metallic lead and metallic bismuth targets is limited at high beam currents due to their low melting temperature. To permit using increased beam intensity, we have investigated chemical compounds with higher melting temperatures as targets. Their substitution for metallic targets is crucial for increasing the sensitivity of superheavy element experiments. Heating the carbon backing during evaporation proved to be essential for a successful application of PbS targets in a production run for superheavy elements. It turned out that this procedure quite generally leads to an enhancement of the durability of the carbon backings during evaporation of additional material. Such improved 208PbS targets were irradiated with 54Cr and the cross-section for the production of 261Sg was directly compared with the one obtained from metallic 208Pb. The performance of Bi2O3 and BiF3 targets was also tested using the same projectile to determine which compound would be the more promising substitute for metallic bismuth.