An analysis has been performed on the observed chains to date previously assigned to 288
115 and 289
115 parents. Preprint is available here: http://xxx.lanl.gov/pdf/1502.03030.pdf
Previously Dubna had assigned all chains ending in SF of Rg to 289
115 as they were all the same length. The above analysis includes the new GSI chains and suggests many of the chains assigned to 289
115 should be assigned to 288
115. If correct, the SF observed is very likely decay of the Even-Even EC daughters as the straight SF lifetimes of the odd-odd nuclei 280
Rg and 284
113 should be hindering significantly relative to adjacent nuclei with only one odd nucleon.
Couple things to think about:
1. If 280
Rg has a ~10% EC branch, its partial EC half-life is ~45 seconds. This means 282
Rg would likely have a significant EC branch (partial EC lifetime prob. ~2 to 10 minutes based on stepping of EC lifetimes seen elsewhere in the nuclear chart).
2. This means a separate reanalysis is probably going to be needed to the chains assigned to 294
117 and 293
117. Some of the chains currently assigned to 293
117 have multiple members with rather long lifetimes compared to the rest. Would appear just on visual inspection of those chain 4-5 of those may actually be 294
117 chains resulting in a ~33% EC branching for 294
117 and a partial EC lifetime of ~4-5 minutes for this nuclide. Probably need additional data here for this, unfortunately availability/short lifetime of 249
Bk makes producing element 117 more challenging.
3. Chain D3 mentioned in the paper. Resembles the longer chains I mentioned in #2. However I think the 1n channel leading to 290
115 is hardly a practical explanation (1n channel has yet to be observed in "hot fusion" reactions). Isomeric state?