Speaker
Description
The discovery of new elements proceeded at a breakneck pace between 1935 and 2010. Twenty-two elements were discovered during that time, with an average discovery rate of every 3 years. Although many exciting developments have occurred in the field of superheavy elements since then, a new element continues to elude the community. The most recently discovered elements used 48Ca beams on actinide (U through Cf) targets with great success. The 48Ca nucleus is special and referred to as doubly magic because it has filled nuclear shells. This unique nuclear structure has been found to greatly increase the likelihood that a compound nucleus reaction will yield an intermediate nucleus that prefers to eject a few neutrons and form a heavier nucleus rather than spontaneously fission. To continue using this successful approach and push beyond Og, the heaviest known element, the actinide target would need to be made of Es or Fm. This requirement creates a currently impassable roadblock. The typical quantity of actinide material needed for a target is tens of milligrams, but both Es and Fm are produced at only microgram and picogram quantities, respectively. Approaches to producing larger quantities of both, especially Es, can be envisioned but would require extraordinary irradiation campaigns in a nuclear reactor with a high neutron flux to produce. An alternative approach is to increase the mass of the ion beam beyond 48Ca, which the community has undertaken. Experiments in recent years have shown that this approach is viable. Currently, Lawrence Berkeley National Laboratory is on a path to explore the possible formation of element 120 using a 50Ti beam with a 249Cf target. Oak Ridge National Laboratory is fabricating the 249Cf target for the experiment using the lab’s unique radiochemical processing facilities. This paper will focus on the process being used to fabricate the 249Cf targets.