The new isotope¹⁷⁹Pb and α-decay properties of¹⁷⁹Tl^<i>m</i>

Abstract

The new isotope 179 Pb has been produced in the complete fusion reaction 40 Ca+ 144 Sm 179 Pb+5n at the velocity filter SHIP (GSI). Its -decay energy of 7350(20) keV and half-life value of 3.5 +1.4 -0.8 ms were deduced based on the recoil-- correlation technique. A spin parity of I = (9/2 -) was tentatively assigned to the ground state of 179 Pb; thus, it is based on the 1h 9/2 orbital. Improved measurements of the -decay properties of 179 Tl m and 175 Au m are also presented.