In reply to mix...@bigpond.com's message of Sat, 11 Oct 2014 15:02:00 +1100: Hi, [snip] >Hi, > >17O & 18O are also potential neutron donors, interesting both because there is >so much Oxygen, and the central charge on Oxygen is only 8. (The lower the >central charge, the closer the nuclei can get, which strongly affects the >chances of a tunneling reaction occurring.)
Note also that there wasn't sufficient Lithium in the reactor to account for the neutrons required to convert the Nickel, however there was ample Oxygen present in the form of the alumina tube in which the reaction took place. Each of the fast particles produces by the reactions could easily have freed thousands of O atoms from the walls of the tube. If Oxygen is 0.2% O18 (i.e. about 1 in 500 atoms is O18), then each O18 consumed could easily have freed enough from the walls to supply follow up reactions with the Ni. E.g.The following double neutron transfer reactions. 18O+58Ni => 60Ni + 16O + 8.200 MeV 18O+59Ni => 61Ni + 16O + 7.021 MeV 18O+60Ni => 62Ni + 16O + 6.230 MeV 18O+62Ni => 64Ni + 16O + 4.309 MeV <=== Since this doesn't happen, we can probably conclude that double neutron transfer reactions are rare to non existent. Single neutron transfer reactions:- 18O+58Ni => 59Ni + 17O + 0.955 MeV 18O+59Ni => 60Ni + 17O + 3.344 MeV 18O+61Ni => 62Ni + 17O + 2.552 MeV This series stops at 60Ni. (I.e. 61Ni is not formed). However the Li reaction could get over that hurdle, as could 17O+60Ni => 61Ni + 16O + 3.677 MeV. Unfortunately the reaction:- 17O + 62Ni => 63Ni + 16O + 2.695 MeV is quite happy to occur, and throw a spanner in the works, but the scarcity of O17 might make this reaction unlikely? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
