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A recoil-mass selector has been used to detect evaporation residues formed by neutron emission from the compound nucleus /sup 176/Pt produced by bombarding /sup 144/Sm with 139.5- to 201-MeV /sup 32/S. The neutron-deficient platinum isotopes /sup 172/Pt (4n emission) and /sup 171/Pt (5n emission) were identified, among others, as well as their alpha daughters, /sup 168/Os and /sup 167/Os. The alpha-decay energies and half-lives are /sup 172/Pt: 6.09 MeV, 0.09 sec; /sup 171/Pt: 6.450 MeV, 0.02 sec, /sup 168/Os: 5.670 MeV, 2.2 sec; and /sup 167/Os: 5.843 MeV, 0.8 sec. Alpha branching ratios of these and other daughters were also measured. An alpha line at 6.547, observed at beam energies above 190 MeV, was tentatively assigned to /sup 170/Pt (6n emission) and at energies around 140 MeV indications of 1n emission were observed. The optimum cross sections for 1n, 2n, 3n, 4n, 5n, and 6n emissions in that order are approximately 0.003, 0.09, 1.5, 0.15, 0.02, and 0.002 millibarns. Formation of iridium isotopes by 2n1p evaporation, etc., was also observed, but is not discussed in detail in this paper.

Evaporation residues from the fusion reactions of 110 MeV /sup 32/S with /sup 58/Ni and 132 MeV /sup 32/S with /sup 70/Ge were observed with the aid of an energy-mass spectrograph. The residues were resolved by mass number, and the masses observed in the /sup 32/S + /sup 58/Ni reaction were A = 84 (23% +- 5%), A = 86 (27% +- 5%), and A = 87 (50% +- 10%). The /sup 32/S + /sup 70/Ge reaction yielded A = 94 (14% +- 1%), A = 95 (23% +- 1%), A = 96 (14% +- 1%), A = 97 (24% +- 1%), A = 98 (21% +- 1%), and A = 99 (5% +- 1%). Angular distributions and velocity spectra were obtained for each mass, allowing partial reconstruction of the residues' kinematic history, and consequently of the particle evaporation modes leading to each residue. Average particle energies and anisotropies for each residue mass may be inferred from comparison with a Monte Carlo simulation of the evaporation process. The results are discussed and compared with calculations made with the aid of a statistical model evaporation code.