[gippgig]

2 atoms of a new isotope (assigned to 282) of element 113 have been made by bombarding Np-237 with Ca-48 (Physical Review C 76 011601(R)). The decay chains are:
113: 88.9 ms  a 10.6 MeV              122.7 ms  a 10.6 MeV
Rg:   6.2 ms  a 10.7 MeV                5.8 ms  a 11 MeV
Mt: 472.6 ms  a 10 MeV                810.1 ms  a 9.8 MeV
Bh:  87.98 s  a 8.9 MeV                97.02 s  a 8.5 MeV (identification tentative)
Db:  31.74 min SF, EC-SF, or a-EC-SF  Not detected in 2nd decay chain
I think it's time to try for 117 with a Bk-249 target.

[pantone159]

I'd like to see a picture of this Bk-249 target.  Photos of berkelium are hard to come by.

[shelanachium]

Might we not have the same problems with elements 116 onwards that we meet with Po to Fr - namely that they will be very short-lived. If 114 is 'magic' like Pb (Z=82) then we would expect most isotopes of 116 to rapidly alpha-decay to 114 as most Po isotopes do to Pb. And At, Rn and Fr which correspond to elements 117, 118 and 119 are even shorter-lived. Claims for 118 had to be withdrawn, I suspect that like Rn it is unstable indeed! Whether there is yet a further 'island of stabilty' beyond these, like Th, U and Pu beyond Fr I very much doubt, and we will have an even greater problem with neutron deficiency than we have with earlier post-fermium elements, all post-fermium nuclei so far made being highly neutron-deficient.

[gippgig]

Element 118 has been rediscovered (Physical Review C 74 044602). Its half-life of 1 ms is less than 116 & much less than 114 but at least part of the reason is that a Cf-249 target was used (I strongly recommend trying Cf-252) resulting in a particularly neutron-deficient isotope (assigned to 294).
Incidentally, Md-259, Md-260, & No-262 aren't neutron deficient.

[Dan1195]

This chain helps to fill the "chain gap" that exists between SHE generated by "cold fusion" like 112-277 and "hot fusion" for as all elements 114 and above.

Figuring out how the decay chain ends is a lot more tricky since they do not decay into know nuclides. Electron capture decay is impossible to observe directly via the observation methods used and alpha decays can always be missed. Having already observed chains such as the two heavier isotopes of element 113 helps.  Most likely the Db-266 decays by EC to Rf-266 which fissions. Reasoning is follows: Db-267 has a half life longer then Db-266. Since odd-odd nuclei have additional fission hinderance that removes direct SF as a decay mode. Assuming no missed alpha thats leaves EC.  Also, the heaviest odd-odd nuclei in the region (incl. Lr-262) also EC decay.

Verified Odd-odd nuclei SF decays are very rare. Md-258 and Md-258 w/half-lives of days are the only confirmed examples.

[gippgig]

It's Md-260, not 258, that decays by SF (32 day half-life). Some odd-odd dubnium isotopes (i.e. Db-262) have significant SF branches.

[Dan1195]

Re: Db-262.  According to the ENSDF data set, it is unclear whether the SF is from Db-262 or the EC daughter. The SF half-life of Db-263 is 47 seconds. Odd N isotopes generally have SF hindrance factors of a 500-1000 compared to adjacent even N nuclides.  Systematics say no significant SF branch. Also All other Odd-odd Db isotopes have significant EC branches.

[ik3]

Currently, the odd-Z nuclei with N-Z=56 to 60 have been synthesized by 48Ca-based hot fusion as follows.
N-Z=56: 237Np(48Ca, 3n) 282Uut
N-Z=57, 58: 243Am(48Ca, 3-4n) 287Uup, 288Uup
N-Z=59, 60: 249Bk(48Ca, 3-4n) 293Uus, 294Uus
The unknown the odd-Z transactinide decay chain with N-Z=54 and 55 would be synthesized by these ways with a cross-section of about 1pb. These decay chains will fill the “chain gap” between cold and hot fusions. If the α-decays of 264Db and 265Db are detected, the decay chains will be connected to the known nuclei 260Lr and 261Lr.
N-Z=54: 231Pa(48Ca, 3n) 276Rg
N-Z=55: 237Np(48Ca, 4n) 281Uut

Furthermore, the unknown neutron-rich odd-Z nuclei with N-Z=61 to 63 would be synthesized by the p4n to p2n channel as follows. The cross-sections of these reactions are expected to be about 100fb based on the cross-section ratio between the pxn and the xn channel of the 248Cm + 18O reactions. These neutron-rich decay chains will be terminated by the spontaneous fission of Bh and Mt nuclei around N=170, and these neutron-rich nuclei are located at near the β-stability line. It is noted no β-stable nuclei are known above Z=105 (Db).
N-Z=61, 62, 63: 248Cm(48Ca, pxn) 291-293Uup (x=2~4)

[Dan1195]

Based on systematics in the region, Db-264 should decay mostly by EC->Rf-264 which certainly decays by SF. Db-265 Probably decays mostly by SF. Both of these nuclides likely have lifetimes of 5-20 mins with detectable alpha branches (i.e. more than a few percent). Have not read of any plans to attempt either of those two reactions you  mentioned.

I do know that LBL has plans to attempt to Synthesize 275-277Ds to fill the even Z "chain gap" been 271Hs and 273Hs (273Hs was recently observed in the 285-114 chain) and connect the "hot" fusion isotopes with the main body of the isotope chart providing further confirmation to isotope assignments.

Re: pxn channels. Those are generally much less favorable than the xn channels. 100fb is approaching the levels seen with RIKEN and 278-113, requiring many months of time to get one atom.