Friday, 5 February 2016

New isotopes from 2015

The announcement came through today from the Discovery of Nuclides Project that they have compiled their list of discoveries of new isotopes as announced in papers published in 2015.  It's not quite as exciting as the discovery of new elements, which seems a rum deal for the poor old neutron, with a never-before seen number of neutrons combining with an already-observed number of protons not making such a splash as a new number of protons, but such is the tyranny of our social constructs upon the way science is done and presented.

The list of new isotopes is given in a table in this pdf file, along with the papers in which their discovery was announced.  Slightly more than half the new discoveries were made in one experiment, at RIKEN in Japan.  The coauthors and codiscoverers of those isotopes includes a one of my colleagues from Surrey (Zsolt Podoly├ík) along with his erstwhile PhD student Zena Patel.

The newly-minted isotopes are: 118 Mo, 121Tc, 127Rh, 129Pd, 132Ag, 134Cd, 136 In, 137In, 139Sn, 141Sb, 144Te, 216U, 59Ge, 223Am, 229Am, 233Bk, 284Fl, 29Cl, 30Ar, and 221U.

Included in the list are two isotopes of uranium (216U and 221U).  Perhaps surprisingly these two light isotopes of uranium do not sit right next to each other.  U–216 is the lightest isotope of uranium yet made, while U–221 was in a little gap in the table, with some lighter ones made and measured in the past:  U–217 in 2000, U–218 in 1992, U–219 in 1993, with U–220 still awaiting observation. 

The picture shows a uranium glass cake plate, though lacking any of the very short-lived isotopes discovered last year.