[en] Short communication

No abstract available

[en] A neutron activation analysis procedure was developed for the determination of osmium in geological materials. The method consists in the measurement of the 129.4 keV γ-rays of ¹⁹¹Os after radiochemical separation of osmium. The sample decomposition, the chemical separation process and the optimal measuring conditions are described and discussed. (author)

[en] Short note. 1 ref.; 1 tab

[en] Short communication. 3 refs

[en] Using the activation technique, 14.7 MeV neutron cross sections of Os-isotopes were measured. Induced γ-activities were counted with a calibrated Ge(Li)-spectrometer. Cross-sections are given relative to sigma²⁷Al(n,α) = 112mb: sigma¹⁸⁴Os(n,2n)¹⁸³gOs = (1449 +- 99)mb; sigma¹⁸⁴Os(n,2n)sup(183m)Os = (488 +- 39)mb; sigma¹⁸⁶Os(n,2n)¹⁸⁵Os = (2004 +- 120)mb; sigma¹⁹⁰Os(n,α)¹⁸⁷W = (0.82 +- 0.06)mb; sigma¹⁹⁰Os(n,n'γ)¹⁹⁰Os = (11 +- 1.1) mb. The total (n,2n)-cross-sections found agree with theoretical estimates, but disagree with smaller values given in the literature. (orig.)

No abstract available

[en] The ¹⁹⁰Os(n, γ)¹⁹¹Os reaction was studied with the average resonance neutron capture technique at a neutron energy centered on 2 keV. Thermal capture data were also recorded. Primary transitions to states up to an excitation energy of approximately 1700 keV were detected. From the average capture data it appears possible to distinguish E1 from M1 multipolarities and thereby to map out the 1/2^-, 3/2^- states in ¹⁹¹Os. By elimination, it is possible to treat the Jsup(π) not = 1/2^-, 3/2^- states as well, albeit with greater uncertainty. Combination of these results with existing data from the (d, p) reaction allows an extension of earlier treatments of the fragmentation of Nilsson strength in this mass region. Although other mechanisms may also suffice it is possible to qualitatively interpret the complex fragmentation systematics in terms of a simple model of large hexadecapole deformations varying in a reasonable manner. (Auth.)

No abstract available

[en] Gamma-ray transitions in ¹⁹²Os have been studied following twofold neutron capture on ¹⁹⁰Os. Precise γ-ray energies have been obtained with the use of bent crystal spectrometers. The thermal capture cross section on the ¹⁹¹Os ground state (Tsub(1/2) = 15d) has been determined to be 383 +- 54 b. A level scheme has been constructed. With the use of branching ratio and population systematics arguments these levels are assigned to various rotational bands whose character is discussed in terms of the transition occurring in the region between the O(6) limit of the interacting boson approximation model and the symmetric rotor. (Auth.)