10 research outputs found
\b{eta}-delayed three-proton decay of 31Ar
The beta decay of 31Ar, produced by fragmentation of a 36Ar beam at 880
MeV/nucleon, was investigated. Identified ions of 31Ar were stopped in a
gaseous time projection chamber with optical readout allowing to record decay
events with emission of protons. In addition to \b{eta}-delayed emission of one
and two protons we have clearly observed the beta-delayed three-proton branch.
The branching ratio for this channel in 31Ar is found to be 0.07(2)%.Comment: 5 pages, 3 figures, submitted to Physical Rev.
Genetic variability of Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) populations from Latin America is associated with variations in susceptibility to Bacillus thuringiensis cry toxins.
Validación de la producción masiva de las micorrizas como alternativa agroambiental para los pequeños productores del municipio de Restrepo :informe final
Los problemas generados por el uso de la agricultura intensiva en el Piedemonte
Llanero, zona de mayor desarrollo agrícola de los Llanos Orientales, ha propiciado la
degradación progresiva del ambiente y la reducción de la productividad de los cultivos,
por lo cual surge la necesidad de establecer estrategias viables que aportan beneficios
económicos y ambientales como el uso de biofertilizantes donde las micorrizas se
convierten en una importante alternativa para los sistemas de producción integrados,
acompañados de prácticas sostenibles de manejo agrícola que permitan mejorar la
calidad de los agroecosistemas y contribuir al logro de un desarrollo socioeconómico
equitativo de los pequeños productores agrícolas del municipio de Restrepo, mediante
la validación y apropiación de la tecnología de uso y producción de las micorrizas
Spectroscopy of excited states of unbound nuclei 30Ar and 29Cl
Several states of proton-unbound isotopes 30Ar and 29Cl were investigated by measuring their in-flight decay products, 28S + proton + proton and 28S + proton, respectively. A refined analysis of 28S-proton angular correlations indicates that the ground state of 30Ar is located at 2.45+0.05-0.10 MeV above the two-proton emission threshold. The investigation of the decay mechanism of the 30Ar ground state demonstrates that it has the transition dynamics. In the “transitional” region, the correlation patterns of the decay products present a surprisingly strong sensitivity to the two-proton decay energy of the 30Ar ground state and the one-proton decay energy as well as the one-proton decay width of the 29Cl ground state. The comparison of the experimental 28S-proton angular correlations with those resulting from Monte Carlo simulations of the detector response illustrates that other observed 30Ar excited states decay by sequential emission of protons via intermediate resonances in 29Cl. Based on the findings, the decay schemes of the observed states in 30Ar and 29Cl were constructed. For calibration purposes and for checking the performance of the experimental setup, decays of the previously known states of a two-proton emitter 19Mg were remeasured. Evidences for one new excited state in 19Mg and two unknown states in 18Na were found.This work was supported in part by the Helmholtz
International Center for FAIR (HIC for FAIR), the
Helmholtz Association (grant IK-RU-002), the Russian
Ministry of Education and Science (grant No. NSh-
932.2014.2), the Russian Science Foundation (grant
No. 17-12-01367), the Polish National Science Center
(Contract No. UMO-2011/01/B/ST2/01943), the Polish
Ministry of Science and Higher Education (Grant No.
0079/DIA/2014/43,Grant Diamentowy), the Helmholtz-
CAS Joint Research Group (grant HCJRG-108), the
FPA2009-08848 contract (MICINN, Spain), the Justus-
Liebig-Universit¨at Gießen (JLU) and GSI under the JLUGSI
strategic Helmholtz partnership agreement. This
article is a part of PhD thesis of X.-D. Xu. The authors
acknowledge the help of D. Kostyleva in the preparation
of the manuscript.This work was supported in part by the Helmholtz International Center for FAIR (HIC for FAIR), the Helmholtz Association (Grant No. IK-RU-002), the Russian Ministry of Education and Science (Grant No. NSh-932.2014.2), the Russian Science Foundation (Grant No. 17-12-01367), the Polish National Science Center (Contract No. UMO-2011/01/B/ST2/01943), the Polish Ministry of Science and Higher Education (Grant No. 0079/DIA/2014/43, Grant Diamentowy), the Helmholtz-CAS Joint Research Group (Grant No. HCJRG-108), the FPA2009-08848 contract (MICINN, Spain), and the Justus-Liebig-Universitat Giessen (JLU) and GSI under the JLU-GSI strategic Helmholtz partnership agreement. This article is a part of the Ph.D. thesis of X.-D. Xu. The authors acknowledge the help of D. Kostyleva in the preparation of the manuscript
Spectroscopy of excited states of unbound nuclei Ar and Cl
Several states of proton-unbound isotopes Ar and Cl were investigated by measuring their in-flight decay products, S+proton+proton and S+proton, respectively. A refined analysis of S-proton angular correlations indicates that the ground state of Ar is located at MeV above the two-proton emission threshold. The theoretical investigation of the Ar ground state decay demonstrates that its mechanism has the transition dynamics with a surprisingly strong sensitivity of the correlation patterns of the decay products to the two-proton decay energy of the Ar ground state and the one-proton decay energy as well as the one-proton decay width of the Cl ground state. The comparison of the experimental S-proton angular correlations with those resulting from Monte Carlo simulations of the detector response illustrates that other observed Ar excited states decay by sequential emission of protons via intermediate resonances in Cl. Based on the findings, the decay schemes of the observed states in Ar and Cl were constructed. For calibration purposes and for checking the performance of the experimental setup, decays of the previously-known states of a two-proton emitter Mg were remeasured. Evidences for one new excited state in Mg and two unknown states in Na were found
Deep excursion beyond the proton dripline. II. Toward the limits of existence of nuclear structure
Prospects of experimental studies of argon and chlorine isotopes located far
beyond the proton dripline are studied by using systematics and cluster models.
The deviations from the widespread systematics observed in Cl and
Ar have been theoretically substantiated, and analogous deviations
predicted for the lighter chlorine and argon isotopes. The limits of nuclear
structure existence are predicted for Ar and Cl isotopic chains, with Ar
and Cl found to be the lightest sufficiently long-living nuclear
systems. By simultaneous measurements of protons and -rays following
decays of such systems as well as their -delayed emission, an
interesting synergy effect may be achieved, which is demonstrated by the
example of Cl and Ar ground state studies. Such synergy effect
may be provided by the new EXPERT setup (EXotic Particle Emission and
Radioactivity by Tracking), being operated inside the fragment separator and
spectrometer facility at GSI, Darmstadt.Comment: 10 pages, 9 figures. Chapter added, language and some figures
correcte