No abstract available

No abstract available

[en] Data from in-beam γ spectroscopy and from detection of charged particles in p-nucleus and π-nucleus interaction at intermediate energies are reviewed. Preliminary data from coincidence experiments are presented showing the apparent weak component of fragmentation in p-nucleus interaction and the primary role of absorption in π-nucleus interaction. In these experiments the energy spectra of emitted particles were found strongly dependent on exit channels giving a powerful tool to test reaction mechanism models

[en] The spectra of alpha particles emitted in (n,α) reactions induced by 14 and 18 MeV neutrons on adjacent target nuclei, one with the magic neutron shell (82 neutrons) and the other near magic (83 neutrons) with one neutron outside the shell, are measured and compared. The nuclei investigated are Nd-142 and Nd-143. The weak population of low energy levels in the residual nucleus from the near magic target nucleus (Nd-143) and the strong excitation of low energy levels in the residual nucleus from neighbour magic target (Nd-142) convincingly prove that the unpaired neutron outside the magic shell acts as a spectator in the process

[en] The decay of ²⁸Si energy levels at 4.98, 6.28, 6.69, 7.42, 7.80, and 7.93 MeV excited in the ²⁷Al(p,γ)²⁸Si reaction has been investigated. Lifetime and branching ratio studies on 0⁺ and 2⁺ levels leads to the conclusion that the existence of an excited prolate rotational band cannot be definitely ruled out, so that both prolate and oblate intrinsic states may be present as predicted by Hartree-Fock calculations. From these calculations, two low-lying (Jsup(π),K) = (3⁺,3) levels due to particle-hole type excitations of the oblate and prolate intrinsic states should be present: emphasis was given to measurements on levels at 6.28 and 7.80 MeV as possible candidates. The mixing ratio for the 3⁺→3⁺ gamma ray transition has been studied from angular distribution measurements. An E2 strength of 17 +- 6 Wu (Wu = Weiskopf unit) is proposed, which is in agreement with a strong deformation of both states, but in disagreement with an important shape difference like prolate versus oblate. (author)

[en] The results of a photoemission study of icosahedral single-grain ZnMg(Y, Ho) quasicrystals and their crystalline approximant Zn₂Mg are presented. Synchrotron radiation photoemission measurements have been performed on in situ cleaved samples at low temperature of ∼90 K and 10^-10 mbar pressure. The spectra obtained indicate simple metal-type valence bands (VB) with distinct Fermi edge cutoff. Analysis of the Fermi edge spectra reveals the presence of a pseudogap in i-ZnMg(Y, Ho) quasicrystals. The pseudogap corresponds to a rather sharp DOS dip at the Fermi level with the ∼50% (of the normal DOS) depth and the ∼0.8 eV width. The values of i-ZnMg(Y, Ho) pseudogap parameters are comparable with those of other quasicrystals

[en] Measurements of α-particle spectra in (n,α) reactions induced on /sup 142,143,144/Nd by neutrons with energy between ≅12 and 20 MeV are presented. The spectra are greatly affected by the shell structure of the target nucleus. A semi-microscopic calculation made in the framework of the pickup model, assuming dominance of transitions to neutron-hole states of the residual nucleus, provides a satisfactory reproduction of the data. Transitions to single neutron states through a knockout process have also been considered, but it is found that they may only slightly contribute to the measured α-particle yield

[en] The energy distribution and forward-backward asymmetry of α-particles emitted in the ¹⁴⁷Sm(n,α)¹⁴⁴Nd reaction has been measured at the neutron energy 19.5 MeV. The results have been analyzed in in terms of statistical, pre-equilibrium, and knock-on models

[en] The enero.y distribution of α particles emitted in the ¹⁴⁷Sm(n,α)¹⁴⁴Nd reaction was measured at a neutron energy of 19.5 MeV. The results were analysed in terms of statistical, pre-equilibrium and knock-on models. (author)

[en] A method for recovery of the damaged Si(SB) detectors is described. (orig.)