Lawrencium-261

Main isotopes of lawrencium

iso NA half-life DM DE (MeV) DP 266Lr syn 10 h SF 262Lr syn 3.6 h ε 262No 261Lr syn 44 min SF/ε? 260Lr syn 2.7 min α 8.04 256Md 259Lr syn 6.2 s 78% α 8.44 255Md 22% SF 256Lr syn 27 s α 8.62, 8.52, 8.32, ... 252Md 255Lr syn 21.5 s α 8.43, 8.37 251Md 254Lr syn 13 s 78% α 8.46, 8.41 250Md 22% ε 254No

Lawrencium (₁₀₃Lr) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was ²⁵⁸Lr in 1961. There are twelve known radioisotopes from ²⁵²Lr to ²⁶⁶Lr, and 1 isomer (^253mLr). The longest-lived isotope is ²⁶⁶Lr with a half-life of 11 hours. Heavier isotopes are expected to have longer half-lives.

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR. Evidence was provided for the formation of ²⁵³Lr in the 2n exit channel.

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR.

This reaction was reported in 1984 by Yuri Oganessian at the FLNR. The team was able to detect decays of ²⁴⁶Cf, a descendant of ²⁵⁴Lr.

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR. Results are not readily available.

This reaction has been used to study the spectroscopic properties of ²⁵⁵Lr. The team at GANIL used the reaction in 2003 and the team at the FLNR used it between 2004-2006 to provide further information for the decay scheme of ²⁵⁵Lr. The work provided evidence for an isomeric level in ²⁵⁵Lr.

This reaction was first studied in 1965 by the team at the FLNR. They were able to detect activity with a characteristic decay of 45 seconds, which was assigned to²⁵⁶Lr or ²⁵⁷Lr. Later work suggests an assignment to ²⁵⁶Lr. Further studies in 1968 produced an 8.35–8.60 MeV alpha activity with a half-life of 35 seconds. This activity was also initially assigned to ²⁵⁶Lr or ²⁵⁷Lr and later to solely ²⁵⁶Lr.

This reaction was studied in 1970 by the team at the FLNR. They were able to detect an 8.38 MeV alpha activity with a half-life of 20s. This was assigned to²⁵⁵Lr.

This reaction was studied in 1971 by the team at the LBNL in their large study of lawrencium isotopes. They were able to assign alpha activities to²⁶⁰Lr,²⁵⁹Lr and ²⁵⁸Lr from the 3-5n exit channels.

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