IDENTIFICATION OF HO-148 AND HO-149

The new nuclides, Ho148 and Ho149, were identified in B10 bombardments of Sm144. A gas-jet system was used to transport product nuclei to a shielded area suitable for γ-ray measurements. The 21-s isotope, Ho149, was found to decay primarily to a Dy149 level at 1091 keV and less intensely to the i1321073-keV state observed in a previous in-beam γ-ray study. This radioactivity, in analogy to neighboring odd-A terbium and holmium isotopes, probably represents the h112 proton orbital in Ho149 which decays via an allowed β transition to the 1091-keV level. The latter, is therefore, proposed to be the h92 neutron state in Dy149. The 9-s isotope, Ho148, was identified mainly through a 1688-keV γ-ray which: (1)was in coincidence with dysprosium K x rays, (2)increased dramatically in intensity when the B10 bombarding energy was raised from 85 to 96 MeV, and (3)remained constant (over the same range) in intensity relative to that of the 620-keV γ ray known to belong to Dy148 decay. On the basis of systematics for low-lying levels in even-even N=82 nuclei, the 1688-keV transition is though to deexcite the first-excited state in Dy148. RADIOACTIVITY Ho148, Ho149, measured T12, Eγ, Iγ, γγ coin; Dy148, Dy149 deduced levels. © 1979 The American Physical Society.