The experiment was originally planned to continue to November 2012, but was stopped early to make use of the Bk target to confirm the synthesis of tennessine (thus changing the projectiles to Ca). This reaction between Bk and Ti was predicted to be the most favorable practical reaction for formation of element 119, as it is rather asymmetrical, though also somewhat cold. (The reaction between Es and Ca would be superior, but preparing milligram quantities of Es for a target is difficult.) Nevertheless, the necessary change from the "silver bullet" Ca to Ti divides the expected yield of element 119 by about twenty, as the yield is strongly dependent on the asymmetry of the fusion reaction.