Investigation of short-lived PT and PB α emitters near the proton drip line

In a series of experiments at the Argonne ATLAS Accelerator Facility, several α emitters near the proton drip line were produced with fusion evaporation reactions, separated from the beam and dispersed in M/Q with a recoil mass spectrometer, and implanted and studied in a double-sided silicon strip detector. In 78Kr bombardments of 92Mo and 96Ru, the new isotopes 166Pt and 167Pt were identified via their α-decay properties and more accurate half-lives were measured for 169Pt and 170Pt. The light isotopes of lead, 180Pb, 182Pb, and 184Pb were produced in Mo bombardments of Zr target nuclei. The α-decay energies and half-lives of the new isotopes are as follows: (1) 166Pt, Eα = 7110(15) keV, T1/2 = 0.3(1) ms; and (2) 167Pt, Eα = 6988(10) keV, T1/2 = 0. 7(2) ms. Also, the half-life of 168Pt, which was previously unknown, was determined to be 2.0(4) ms and that of 170Pt was observed to be 14.7(5) ms. The tentative α-decay energies and half-lives of the even Pb isotopes are: (1) 184Pb, Eα = 6625(10) keV, T1/2 =500(25) ms; (2) 182Pb, Eα = 6895(10) keV, T1/2 = 62(5) ms; and (3) 180Pb, Eα = 7250(15) keV, T1/2 = 5.8 +2.8-1.4 ms. The a-decay rates for these Pt and Pb nuclides are compared with earlier measurements and systematic trends of the reduced widths with neutron number are discussed