Patin et al. at the LBNL reported in 2002 the synthesis of 255–251No in the 1-4n exit channels and measured further decay data for these isotopes.
The reaction has recently been used at Jyväskylän Yliopisto Fysiikan Laitos (JYFL) using the RITU set-up to study K-isomerism in 254No.
The measurement of the 2n excitation function for this reaction was reported in 2001 by Yuri Oganessian and co-workers at the FLNR.
The measurement of the 1-4n excitation functions for this reaction were reported in 2001 by Yuri Oganessian and co-workers at the FLNR.
[14] The reaction was reported in 2006 by Peterson et al. at the Argonne National Laboratory (ANL) in a study of SF in 250No.
[15] In 2020, a team at FLNR repeated this reaction and found a new 9.1-MeV alpha particle activity correlated to 245Fm and 241Cf, which they assigned to the new isotope 249No.
Further work in 1966 on the reaction examined the detection of 250Fm decay using chemical separation and a parent activity with a half-life of ~50 s was reported and correctly assigned to 254102.
In their experiments they observed a 250 s SF activity, which they tentatively assigned to 250No in the 5n exit channel.
A repeat in 1960 produced 8.9 MeV alpha particles with a half-life of 2–40 s and assigned to 253102 from the 4n channel.
The team were able to detect 250Fm using chemical techniques and determined an associated half-life significantly higher than the reported 3 s by Berkeley for the supposed parent 254No.
Further work later the same year measured 8.1 MeV alpha particles with a half-life of 30–40 s. This reaction was studied in 1966 at the FLNR.
Later work in 1959 produced 8.3 MeV alpha particles with a half-life of 3 s and a 30% SF branch.
The reaction was repeated by scientists at the LBNL in 1958 but they were unable to confirm the 8.5 MeV alpha particles.
Later work in 1959 produced 8.3 MeV alpha particles with a half-life of 3 s and a 30% SF branch.
Later work suggests an assignment to 257No, resulting most likely from the α3n channel with the 252Cf component of the californium target.
Later work suggests an assignment to 257No, resulting most likely from the p5n channel with the 252Cf component of the californium target.
Observations to date are summarised in the table below: Twelve radioisotopes of nobelium have been characterized, with the most stable being 259No with a half-life of 58 minutes.
Further support in the same year from the FLNR appeared with a slightly higher half-life of 43.5 s, decaying by M2 gamma emission to the ground state.
In a recent study by the GSI into K-isomerism in even-even isotopes, a K-isomer with a half-life of 110 ms was detected for 252No.
In 2003, scientists at the FLNR reported that they had been able to synthesise 249No, which decayed by SF with a half-life of 54 μs.
The table below provides cross-sections and excitation energies for cold fusion reactions producing nobelium isotopes directly.
Data in bold represents maxima derived from excitation function measurements.
The table below provides cross-sections and excitation energies for hot fusion reactions producing nobelium isotopes directly.
Data in bold represents maxima derived from excitation function measurements.
However, subsequent work showed that the 54 μs fission activity instead originated from an excited state of 250No.