Search results for "Nuclear fusion"
showing 10 items of 437 documents
The relativistic mean-field model at large densities
1988
The extrapolation properties of the relativistic mean-field model are investigated in nuclear matter. The results of a recent relativistic Bethe-Brueckner-Gatdstone calculation are taken as ‘data”. Fits in a window of normal nuclear densities are extrapolated to large densities and compared with the ‘data’. We find large discrepancies which hint at an insufficiency of the model in its present parametrisation.
Subshell closure effects on the collectivity of 36 88 Kr52 and the beta decay of88Br to levels in88Kr
1986
The level structure of88Kr has been investigated by measurements on chemically separated bromine samples. A total of 146γ-rays have been assigned to the decay of88Br, and a level scheme with 58 levels is proposed. The collectivity of88Kr has been investigated within the framework of the Interacting Boson Approximation (IBA-2 model). Comparison of our detailedγ-ray data and calculations have led to the establishment of a protonhole boson desciption rather than protonparticle nature. This supports recent works establishingZ=40 as a major subshell closure.
Levels in104Ru populated by the ??-decay of104Tc
1978
Theβ− — andγ-activities of 18.4 min104Tc have been studied with singles and coincidence measurements. Sources were prepared by chemical separation of technetium from the fission products of thermal-neutron-induced fission of235U. A revised level scheme of104Ru up to an excitation energy of 4.26 MeV is proposed. Fromβ-γ coincidence measurements, aQβ-value of 5.62±0.07 MeV has been obtained.
What can be learnt about nuclear polarization from a consistency analysis ofe ? cross sections and muonic X-rays for208Pb and the isotone pair209Bi/2…
1977
A joint analysis of recent electron scattering cross sections and muonic atom X-ray energies is performed for208Pb and the isotone pair209Bi/208Pb. From the compatibility of the experimental data one can learn about the nuclear polarisation correction. However, we find this information not to be as accurate as other authors claimed when we take into consideration the ambiguities in the treatment of the corrections of the higher levels.
Nuclear structure of97Y in the interacting boson-fermion model
1988
Unique-parity states of97Y are studied in the framework of the interacting boson-fermion model (IBFM). Spin assignments for the levels of the unique-parity yrast band are proposed on the basis of nuclear systematics and the IBFM band pattern associated with coupling of a particle-type quasiparticle (g9/2) to the SU(5) core3896Sr58. The good fit of the experimental data with the IBFM calculations confirms the single particle character of this immediate neighbour of the doubly sub-magic nucleus96Zr.
Cross section systematics for the lightest Bi and Po nuclei produced in complete fusion reactions with heavy ions
2005
The production of the very neutron-deficient nuclides $^{184\ensuremath{-}192}\mathrm{Bi}$ and $^{186\ensuremath{-}192}\mathrm{Po}$ in the vicinity of the neutron midshell at N = 104 has been studied by using heavy-ion-induced complete fusion reactions in a series of experiments at the velocity filter SHIP. The cross sections for the xn and pxn evaporation channels of the $^{46}\mathrm{Ti}$+$^{144}\mathrm{Sm}$$\ensuremath{\rightarrow}^{190}\mathrm{Po}{}^{*},$$^{98}\mathrm{Mo}$+$^{92}\mathrm{Mo}$$\ensuremath{\rightarrow}^{190}\mathrm{Po}{}^{*},$$^{50,52}\mathrm{Cr}$+$^{142}\mathrm{Nd}$$\ensuremath{\rightarrow}^{192,194}\mathrm{Po}{}^{*}$, and $^{94,95}\mathrm{Mo}$+$^{93}\mathrm{Nb}$$\ensurem…
Search for long-lived superheavy elements in the reaction of136Xe with238U
1978
A search with radiochemical methods for long-lived superheavy elements in 238U targets bombarded with intense beams of136Xe ions produced negative results. A formation cross section of ≤1×10−35 cm2 is deduced at 95% confidence level for nuclides with half-lives between 1 and 200 d.
Directional correlations of some γ-ray cascades in200Hg
1971
Directional correlation functions of 10 γ-ray cascades in200Hg have been measured using a200Tl source and a Ge(Li)-NaI(Tl) coincidence spectrometer arrangement. Values of the mixing parameter δ for several transitions are determined, and the spin assignments for the following levels in200Hg are established (level energies are given in keV): 1029.4 (0+), 1254.2 (2+), 1573.7 (2+), 1593.4 (2+), 1641.5 (2+), 1730.9 (2+) and 1775.6 (3+).
Decay of 14.6 h90Nb
1975
The disintegration of 14.6 h90Nb produced by bombarding natural Zr with 13 MeV protons was investigated by methods of γ-ray spectrometry. Results from singles, coincidence and anti-Compton spectrometer measurements are reported. A decay scheme is proposed including excited states in90Zr at 1761, 2186.4, 2319.1, 2739.4, 2747.9, 3077.0, 3448.2, 3589.5, 3977.1, 4232.4, 4319.5, 4375.4, 4541.6, 5060.0, 5164.6 and 5432.9 keV. Over 10 γ-ray transitions and several levels proposed in an earlier investigation are shown to be in error.
Exchange currents in electric transitions and the r�le of siegert's theorem: A case study in deuteron photodisintegration
1981
The size of exchange corrections to electric transitions is investigated for deuteron photodisintegration. Large contributions are found in El transitions, which become dominant above 40 MeV. Most of them are already included by using Siegert's theorem together with classical one-body operators. Higher multipoles are only little affected except for rather high energies. The Born approximation for the final states gives in general a poor description.