A new paper was just released, http://xxx.lanl.gov/PS_cache/arxiv/pdf/0904/0904.1093v1.pdf
, detailing the production of 266,267
Bh. The main purpose was to confirm the daughter decay properties of 278
113. The data seems to confirm the previous studies done. Unfortunately because only data from after the beam was turned off was considered the lifetimes of the Bh atoms themselves were not obtained.
Only interesting thing I noticed the last two chains, 31 & 32, which were unable to be assigned. Both had an 8090 keV alpha follow by a 2-3 minute SF. Obviously that alpha was not from Bh (or Db daughters). The only thing that is a possibility is the alpha is from the EC daughter of 267
Sg and the SF is from the g.s. of 263
Rf. From Phys Rev Lett 100, 132503 (2008), 267
Sg has a small alpha branch, with one 8200 keV alpha observed assigned to 267
Sg which decays to an apparent isomeric state of 263
Rf with an 12 second lifetime. If this is this case then 261,263
Rf both have a longer lived g.s. along with an isomeric state decaying mostly by SF. The 8090 alpha goes to the g.s. and the 8200 goes to the isomer. Would be important to note that since 263,265
Sg have isomers with similar lifetimes, 267
Sg may also!!
Note than the SF of 267
Sg would not appear in this study as they were looking for a-a or a-SF correlations, which EC>SF does not. Also, since the maximum correlation time analyzed was 300 seconds, other 263
Rf decays could have been missed.
Needless to say better data on 267
Sg is needed to confirm this possibility