Decay schemes of /sup 189/Pt (T/sub 1/2/ = 11 hrs) and its daughter product, /sup 189/Ir, produced by 660-Mev proton spallation of gold were studied by e- gamma coincidence. A double-lens spectrometer with 3% resolving power was used for measuning platinum conversion electrons to 170 kev. The e- gamma coincidences with conversion electrons (K113, L71, K140, L81, and L94) of /sup 189/Pt were measured. Coincidence spectra for K113 and L94 are included. The e- gamma coincidence measurements were made with iridium sources in order to confirm gamma cascades belonging to platinum. A decay scheme for /sup 189/OS was constructed on the basis of gamma transitions for /sup 189/Ir (T/sub 1/2/ = 11 days). (R.V.J.)

The conversion electron spectrum of neutron-deficient Pt isotopes formed upon the bombardment of Au by 660Mev protons was investigated with the help of a magnetic beta -spectrometer; the decay processes of the l0-day halflife Pt/sup 188/ were studied by using a beta -spectrometer and a lumdnescence gamma - spectrometer, employing the gamma gamma and the e gamma coincidence method. The lines obtained may be divided in groups with half-lives of l0 to 11 days, 3to 4 days, l0 to l5 hours and 2 to 3 hours. The half-lives of certain conversion lines in a fifth group could not be definitely established; 3 of them belong to the known 28l-kev transition of Pt/sup 188/ and to the 323.4- and 632.4- kev transition of Ir/sup 18 while 5 lines remain unidentified. Pt/sup 188/ decays under formation of the odd-odd Ir/sup 188/ nucleus. By estimating the multipolarity of the gamma -transitions, the values of the Ir/sup 188/ excited level spins could be determined. The 54.6-kev level is assumed to be a rotational one. The moment of inertia of the Ir/sup 188/ nucleus was thereby calculated to be 2.5 times larger than the corresponding value of the neighboring even-even Os/sup 186/. (TTT)

BS>It was reported previously (V. I. Baranov et al., Izvestia Akad. Nauk SSSR 24, 1079 (1960)) that Os daughter samples separated from Ir have an activity with the short half-life of about 20 minutes; this is due to the Os/sup 184*/ formed by the decay of the 3-hour Ir/sup 184/. By studying carefully the total activity of Os daughters, the exact value of this half-life was found to be l0 plus or minus 0.5 minutes. Investigation of the spectrum of the Os daughter with a 100-channel pulse analyzer revealed the 185, 355, and 620 kev gamma - lines, belonging to the Os/sup 190*/ isomer. The intensity of these lines decreases with a l0-minute half-life; accordingly, if any other even, neutron- deficient Os isotopes exist, they must have a T/sub 1/2// of less than 2 minutes. (TTT)

A radioactively pure iridium fraction was sepsrated from the spallation products of a sample of gold (0.5 g) taat had been irradiated with 660-Mev protons for 0.5 to 1 hours in a cyclotron. Then, at various intervals of time (the time of accumulation of the daughter osmium activities was varied from 1.5 to 4.0 hrs), the osmium daughter activity was separated systematically from the iridium activity by distilling OsO/sub 4/ from a perchloric acid solution. The decay of the osmium activity was followed on an end-window counter. A half-life of 1 plus or minus 0.1 hr was assigned to Os/sup 1//sup 8//sup 3/ because of the variation in the amount of Os/sup 1//sup 8//sup 3/ observed as a function of the time of separation of the osmium fraction. (TTT)

Conversion electron spectra and gentic bonds were studied for neutron- deficient platinum isotopes produced by 660-Mev proton spallation of gold. High specific activity platinum and iridium were separated from irradiated metallic gold. The separation of platinum and iridium was accomplished by the chloride complex anion exchange. The curve of Ir(III) wash-out with 8N HCl is shown. The data on platinum fraction conversion electron spectra are tabulated. The half- life periods of platinum isotopes were found by separating the daughter iridium from the platinum fraction at equal time intervals from 1 to 4 hr. The half life for Pt/sup 186/ and Pt/sup 187/ with activity of Ir/sup 186/ (T=15 hr) and Ir/sup 187/ (T=13 hr) was 2.2 plus or minus 0.5 hr, which is in good agreement with published data. The half life of platinum determined with the activity of daughter iridium (T=3 hr) was 2.6 plus or minus 0.6 hr. According to the previously reported data the new isotope Pt/sup 184/ has a half life of 2.6 plus or minus 0.6 hr. (R.J.V.)

A radiochemical method has been used to study (p,π±) and (p,pπ+) reactions with medium weight target nuclei. A marked rise in the cross-sections of these reactions was observed for incident protons having energies between 110 and 480 MeV and the cross-sections reached values of about 10−30 cm2/nucleon in the proton energy interval 480–660 MeV. Similar reactions with heavy elements could not be detected and attempts to identify the products of the reaction Cu(p,2π-±) also failed. The possible occurrence of (p,π±) reactions with nucleon complexes is discussed.