1986Sc10: Attempted in a study to investigate transfer reactions using ²⁵⁴Es as a target with the 88 inch LBL cyclotron and the UNILAC at GSI, this nuclide was not observed. Extrapolated cross-sections are provided for two reactions: 100 nb with ¹⁸O+²⁵⁴Es at 98 MeV and 380 nb with ²²Ne+²⁵⁴Es at 127 MeV. An α-decay half life of 6 hours is suggested but not observed (Table 1).

1987LoZR: report the discovery of two new isotopes ²⁶¹Lr and ²⁶²Lr at LBL with the reaction ²²Ne+²⁵⁴Es. Projectiles were delivered at a BEAM energy of 127 MeV by the 88 inch cyclotron. Lr was separated from other actinides using chemical techniques. α SF halflife of 39 min was attributed to ²⁶¹Lr. No α decay was observed and a preliminary UPPER limit of 20% was suggested. Cross-sections are not reported.

1991HeZT: studied the SF properties of ²⁶¹Lr and ²⁶²Lr at LBL with the 88 inch cyclotron. Using the reaction ²⁴⁸Cm(¹⁸O,5n)²⁶¹Rf(ε), ²⁶¹Lr was produced as the ε daughter. 62 SF events were recorded AND a preliminary SF half-life was determined to be 44 min +17-11. It was not clear whether the SF activity was from ²⁶¹Lr or ²⁶¹No following FURTHER ε decay. The production cross-section was 700 pb 70. The beam energy and other experimental details are not provided in this lab report.

Other: 1989HuZU

Theory: See Nuclear Science References.

Assignment: ²⁴⁸Cm(¹⁸O,5n)²⁶¹Rf(ε), SF (1991HeZT).