[en] Abstract only

[en] Light charged particle emission from ²⁵²Cf has been investigated with silicon detector telescopes with the purpose to observe possible spontaneous emission of mesons. Upper limits for the branching of this process are obtained in the range 10^-8, for meson energy interval from 1.6 to 9.5 MeV. (authors)

[en] The precise measurement of the standard neutron spectrum from spontaneous fission of ²⁵²Cf requires the optimum experimental arrangement corresponding to the energy range to be measured. The most important requirements to be met in a ²⁵²Cf(sf) neutron spectrum measurement, are summarized briefly. Theoretical models for the calculation of fission neutron spectra are based on the predominant emission mechanism, i.e., the evaporation from fully accelerated fragments. Some approaches which were studied in the framework of both the Weisskopf formalism and the Hauser-Feshbach theory are discussed. The results of new Cf spectrum calculations are compared with recent experimental data which confirm a Maxwellian spectrum at energies below ∼ 1 MeV for T=1.42 MeV. Between 1.5 and 4 MeV, measured data tend to exceed this Maxwellian by about 3%. Significant deviations from a Maxwellian with T=1.42 MeV appear between 6 and 20 MeV where a fit of experimental data yields a value of T close to 1.37 MeV. Recent theoretical calculations of the Cf neutron spectrum agree very good with measured data. Especially, the complex cascade evaporation model permits a conformable description of recent experimental data in the whole energy range (1 keV-20 MeV) if introducing the centre-of-mass system anisotropy of emission. (author). 7 figs., 46 refs

[en] Published in summary form only

[en] Abstract only. 1 ref

[en] The unusual background observed experimentally in the (ΔE,E) energy region below that characteristic of the LRA's emission from ²⁵⁷F is interpreted as being produced by the negative pions emitted in the spontaneous fission of ²⁵⁷Fm. If this interpretation is correct then the inferred yield for the negative pionic nuclear radioactivity is: Γ_π/Γ_SF = (1.2±0.1) 10^-3.(authors)

[en] Nuclear emulsions were irradiated in the presence of ²⁵²Cf source at a total spontaneous fission number of 9.66* 10⁶. Upper limits for pion emission in the range 10^-7, depending on the pion energy, were derived. (authors)

[en] Nuclear emulsions were irradiated in the presence of a ²⁵²Cf source at a total spontaneous fission number of 9.66 10⁶. Upper limits for pion emission in the range 10^-7, depending on the pion energy were derived. (authors)

No abstract available

No abstract available