The α decay characteristics of 88 decay lines emanating from 74 isotopes are presented, including new α decay lines identified in the neutron deficient nuclides ${}_{}{}^{158}{}_{}{}^{}\mathrm{Ta}$ (${\mathit{E}}_{\mathrm{\alpha }}$=5969±8 keV, ${\mathit{t}}_{1/2}$=46±4 ms), ${}_{}{}^{159}{}_{}{}^{}\mathrm{Ta}$ (${\mathit{E}}_{\mathrm{\alpha }}$=5516±5 keV, ${\mathit{t}}_{1/2}$=1100±100 ms), ${}_{}{}^{160}{}_{}{}^{}\mathrm{Ta}$ (${\mathit{E}}_{\mathrm{\alpha }}$=5313±5 keV, ${\mathit{t}}_{1/2}$=1700±200 ms), ${}_{}{}^{168}{}_{}{}^{}\mathrm{Ir}$ (${\mathit{E}}_{\mathrm{\alpha }}$=6323±8 keV, ${\mathit{t}}_{1/2}$=161±21 ms, ${\mathit{b}}_{\mathrm{\alpha }}$=82±14%), and ${}_{}{}^{170}{}_{}{}^{}\mathrm{Ir}$ (${\mathit{E}}_{\mathrm{\alpha }}$=6083±11 keV, ${\mathit{t}}_{1/2}$=830±300 ms, ${\mathit{b}}_{\mathrm{\alpha }}$=36±10%). Their correlations with other decay lines are discussed. The alpha decay of a high-spin isomer in ${}_{}{}^{157}{}_{}{}^{}\mathrm{Ta}$ has been discovered, with an energy of 7744±8 keV and a half-life of 1.7±0.1 ms, while the half-life of the corresponding isomeric alpha decay line of ${}_{}{}^{158}{}_{}{}^{}\mathrm{W}$ has been measured for the first time as 160±50 μs. First half-life and branching ratio measurements are also reported for the 5454±4 keV ${}_{}{}^{156}{}_{}{}^{}\mathrm{Lu}$ line (${\mathit{t}}_{1/2}$=494±12 ms), ${}_{}{}^{162}{}_{}{}^{}\mathrm{Re}$ (${\mathit{b}}_{\mathrm{\alpha }}$=85±9%), ${}_{}{}^{163}{}_{}{}^{}\mathrm{Os}$ (${\mathit{t}}_{1/2}$=${12}_{\mathrm{-}7}^{+11\mathrm{}}$ ms), ${}_{}{}^{166}{}_{}{}^{}\mathrm{Ir}$ (${\mathit{t}}_{1/2}$=12±1 ms), ${}_{}{}^{167}{}_{}{}^{}\mathrm{Ir}$ (${\mathit{t}}_{1/2}$=34±4 ms), the 6227±15 keV ${}_{}{}^{168}{}_{}{}^{}\mathrm{Ir}$ line (${\mathit{t}}_{1/2}$=125±40 ms), and ${}_{}{}^{171}{}_{}{}^{}\mathrm{Ir}$ (${\mathit{b}}_{\mathrm{\alpha }}$=58±11%). New decay measurements for the proton emitter ${}_{}{}^{156}{}_{}{}^{}\mathrm{Ta}$ (${\mathit{E}}_{\mathit{p}}$=1108±8 keV, ${\mathit{t}}_{1/2}$=375±54 ms, ${\mathit{b}}_{\mathit{p}}$=4.2±0.9%; ${\mathit{E}}_{\mathit{p}}$=1007±5 keV, ${\mathit{t}}_{1/2}$=144±24 ms) are presented. All energies have been measured using a consistent energy calibration procedure for protons and α particles. © 1996 The American Physical Society.

• Received 12 October 1995

DOI:https://doi.org/10.1103/PhysRevC.53.660