Two Proton Emission in the Hyperspheric Harmonics Approach

Nuclear decays into three-particle channels are considered in a few-body approach of hyperspherical harmonics with emphasis on simultaneous, or direct, emission of two protons. General conditions of direct decays are described and their main features, being experimentally established in decays of light nuclei, are reported. The analysis method based on an expansion of decay amplitude into a series of hyperspherical harmonics is reviewed. The basis of hyperspherical harmonics functions is a generalisation of the spherical function basis in three-body systems. The method is tested on analysis of the direct 2p-decay of Be^6 where the three-body components in the nuclear structure of Be^6 have been studied. In particular, the observed strong proton-proton correlations are treated as a manifestation of a specific three-body quantum effect: the kinematic focusing of fragments over momenta and in space. The hyperspherical harmonics method is applied for the predictions of proton-proton correlations and life-time estimates of the nuclei Mg^19, Ca^34 and Ni^48 - candidates for two-proton radioactivity. Each direct 2p-decay should result in a set of peaks in the E_(p-p) spectrum whose number and positions depend on the structure of initial nucleus, opposite to the diproton model, predicting the He^2 emission with one peak at E_(p-p)~0 in all cases.Comment: invited talk at Int. Symposium on Proton-Emitting Nuclei, October 7-9, 1999, Oak Ridge, Te, USA, 10 pages, Latex, 4 eps-figure

Two-proton emission and related phenomena

One of characteristic phenomena for nuclei beyond the proton dripline is the simultaneous emission of two protons (2\emph{p}). The current status of our knowledge of this most recently observed and the least known decay mode is presented. First, different approaches to theoretical description of this process, ranging from effective approximations to advanced three-body models are overviewed. Then, after a brief survey of main experimental methods to produce 2\emph{p}-emitting nuclei and techniques to study their decays, experimental findings in this research field are presented and discussed. This review covers decays of short-lived resonances and excited states of unbound nuclei as well as longer-lived, ground-state radioactive decays. In addition, more exotic decays like three- and four-proton emission are addressed. Finally, related few-body topics, like two-neutron and four-neutron radioactivity, and the problem of the tetraneutron are shortly discussed.Comment: 109 pages, 62 figures, accepted by Progress in Particle and Nuclear Physic

Two-Proton Emission in the Hyperharmonics Approach

Abstract. Nuclear decays into three-particle channels are considered in a few-body approach of hyperspherical harmonics with emphasis on simultaneous, or direct, emission of two protons. General conditions of direct decays are described and their main features, being experimentally established in decays of light nuclei, are reported. The analysis method based on an expansion of decay amplitude into a series of hyperspherical harmonics is reviewed. The basis of hyperspherical harmonics functions is a generalisation of the spherical function basis in three-body systems. The method is tested on analysis of the direct decay 6 Be → α+p+p where the three-body components in the nuclear structure of 6 Be have been studied. In particular, the observed strong protonproton correlations are treated as a manifestation of a specific three-body quantum effect: the kinematic focusing of fragments over momenta and in space. The hyperspherical harmonics method is applied for the predictions of proton-proton correlations and life-time estimates of the nuclei 19 Mg, 34 Ca and 48 Ni- candidates for two-proton radioactivity. Each direct 2p-decay should result in a set of peaks in the Ep−p spectrum whose number and positions depend on the structure of initial nucleus, opposit

Facilities and problems of processing organic wastes by family-type biogas plants in Ukraine

The potential of organic wastes in Ukraine for biogas production and the prospects of using the family-type biogas plants for this purpose are shown. In the biogas laboratory of the Ukrainian National Forestry University the efficiency of the anaerobic mesophilic digestion of chicken manure of Poltava poultry farm, Kamianets-Podilsky poultry farm and sewage sludge from Lviv wastewater treatment plant (WWTP) was investigated. Different integral indicators of the biogas production and significantly different dynamics of its formation over time were obtained for three investigated substrates. The value of average specific biogas production from the sewage sludge of Lviv WWTP is 0.494 dm3∙(day∙kg FM)–1, which is 5.1 times more comparing the chicken manure of Kamianets-Podilsky poultry farm and 8.0 times more than for the chicken manure of Poltava poultry farm. Strong negative effect of antibiotic treatment of chickens on methane content in the obtained biogas was established experimentally