164Ta, identification of a new isotope

Abstract

The new isotope 164Ta (T1/2 = 13.6(2)s) was produced in the ~27I(4~ 3n) reaction and transported to a measuring station by helium jet. Decay properties were observed with e, 7, and 7-7 spectroscopy. The Z assignment of the new isotope was based on v-Xray coincidence measurements. The mass assignment was deduced from measured excitation functions. The two 7 rays assigned to the new activity most likely originate from the 4 +--* 2+--* 0 § decay sequence in ~64Hf. A small e branch, <0.016(5)%, with an e decay energy of E~=4,625(15)keV was found and assigned to the decay of 164Ta. The deduced upper limit of the e width for this branch, W~0.6(2), is in accordance with those known for neighbouring nuclei.