The Super-FRS project at GSI Geissel, H.; Weick, H.; Winkler, M. ...
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms,
05/2003, Letnik:
204
Journal Article, Conference Proceeding
Recenzirano
The GSI projectile fragment separator FRS has demonstrated with many pioneering experiments the research potential of in-flight separators at relativistic energies. Although the present facility has ...contributed much to the progress in the field of nuclear structure physics, major improvements are desirable in the future. The characteristics of the proposed next-generation facility at GSI, the Super-FRS, will be presented and compared to other projects. The Super-FRS is a large-acceptance superconducting fragment separator followed by different experimental branches including a combination with a new storage-cooler ring system. This system consists of a collector ring (CR) and a new experimental storage ring (NESR) which allow precision mass and lifetime measurements as well as in-ring reaction studies. The NESR can be operated in combination with an electron ring to measure electron scattering with exotic nuclei. This electron heavy-ion collider will open up new fields for nuclear structure research.
Decay heat studies for nuclear energy Algora, A.; Jordan, D.; Taín, J. L. ...
Hyperfine interactions,
2014/1, Letnik:
223, Številka:
1-3
Journal Article
Recenzirano
The energy associated with the decay of fission products plays an important role in the estimation of the amount of heat released by nuclear fuel in reactors. In this article we present results of ...the study of the beta decay of some refractory isotopes that were considered important contributors to the decay heat in reactors. The measurements were performed at the IGISOL facility of the University of Jyväskylä, Finland. In these studies we have combined for the first time a Penning trap (JYFLTRAP), which was used as a high resolution isobaric separator, with a total absorption spectrometer. The results of the measurements as well as their consequences for decay heat summation calculations are discussed.
A total absorption spectrometer, constructed and briefly operated at the on-line isotope separator OASIS at Lawrence Berkeley Laboratory, has been moved and installed at the on-line mass separator of ...GSI Darmstadt. At GSI, the spectrometer has been used for β-decay strength function measurements of nuclei in the vicinity of
100Sn and
146Gd.
The eukaryotic 25 S, 18 S, and 5.8 S rRNAs are synthesized as a single transcript with two internal transcribed spacers (ITS1 and ITS2), which are removed by endo- and exoribonucleolytic steps to ...produce mature rRNA. Genetic selection for suppressors of a polyadenylation defect yielded two cold-sensitive alleles of a gene that we named RRP6 (ribosomalRNA processing). Molecular cloning ofRRP6 revealed its homology to a 100-kDa human, nucleolar PM-Scl autoantigen and to Escherichia coli RNase D, a 3′–5′ exoribonuclease. Recessive mutations in rrp6 result in the accumulation of a novel 5.8 S rRNA processing intermediate, called 5.8 S*, which has normal 5′ ends, but retains ~30 nucleotides of ITS2. Pulse-chase analysis of 5.8 S rRNA processing in anrrp6- strain revealed a precursor-product relationship between 5.8 S* and 5.8 S rRNAs, suggesting that Rrp6p plays a role in the removal of the last 30 nucleotides of ITS2 from 5.8 S precursors. A portion of 5.8 S* rRNA assembles into 60 S ribosomes which form polyribosomes, suggesting that they function in protein synthesis. These findings indicate that Rrp6p plays a role in 5.8 S rRNA 3′ end formation, and they identify a functional intermediate in the rRNA processing pathway.
Recent developments at the ISOL facility of GSI Darmstadt Roeckl, E.; Blazhev, A.; Burkard, K. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
05/2003, Letnik:
204
Journal Article
Recenzirano
The research programme pursued at the ISOL facility of GSI Darmstadt focuses on the study of decay properties of nuclei along the
N≅
Z line between the double shell closures at
56Ni and
100Sn. In ...this report, the major scientific achievements obtained in the past two years are reviewed, with particular emphasis being put on the detection techniques.
The present study examined the effects of Dizocilpine (MK-801; a noncompetitive
N-methyl-
d-aspartate receptor antagonist) on flash-evoked potentials recorded from both the visual cortex (VC) and ...superior colliculus (SC) of chronically implanted hooded rats. The potentials were recorded at 5, 20, and 35 min following IP injections of saline, and of 0.1, 0.3, and 1.0 mg/kg MK-801 on separate days. The amplitude of VC component P1 was unaltered following drug treatment. N1 was increased in amplitude by the 0.1-, 0.3-, and 1.0-mg/kg doses, while two other negative peaks in the VC emerged, beginning with the 0.1-mg/kg dose, to complicate the waveform. One negative peak developed between N1 and P2, while the other effectively split peak P2 (forming P2A and P2B). P2A was depressed at all doses, while P2B was depressed at 0.1 mg/kg but augmented at the 1.0-mg/kg dose. N2 was elevated by the 0.3- and 1.0-mg/kg doses, while P3 was increased in amplitude by all doses. N3 was transiently enhanced by the 0.3-mg/kg dose. SC amplitudes were less affected, with P3 and N4 reduced in amplitude by the 0.3- and 1.0-mg/kg doses. The latencies of most components in both structures were decreased, often with all doses, but generally at the later recording times. A second experiment demonstrated significant MK-801-induced hyperthermia at all of the above doses, although a higher dose of 3.0 mg/kg MK-801 caused hypothermia. The reduction in component latencies may, therefore, result at least in part from a drug-induced hyperthermia. A third experiment demonstrated MK-801–induced changes in locomotor activity in rats in an open field. The effects were both dose and time dependent. The 0.3-mg/kg dose of MK-801 produced significant increases in the number of line crossings from 20–60 min in comparison to the saline condition. Increases in the number of line crossings with the 1.0-mg/kg dose peaked at 15 min, and then gradually declined. It is unlikely, however, that these changes in movement can account for the effects of MK-801 on evoked potentials. In conclusion, the results show that blockade of the ion channel associated with the NMDA receptor produces profound changes in the activity of the neural pathways that are reflected in the middle components of the flash-evoked potential recorded from the VC.
Beta-decay studies near 100Sn Karny, M.; Batist, L.; Banu, A. ...
The European physical journal. A, Hadrons and nuclei,
09/2005, Letnik:
25, Številka:
S1
Journal Article
Recenzirano
The {beta}-decay of {sup 102}Sn was studied by using high-resolution germanium detectors as well as a Total Absorption Spectrometer (TAS). A decay scheme has been constructed based on the ...{gamma}-{gamma} coincidence data. The total experimental Gamow-Teller strength B{sub GT}{sup exp} of {sup 102}Sn was deduced from the TAS data to be 4.2(9). A search for {beta}-delayed {gamma}-rays of {sup 100}Sn decay remained unsuccessful. However, a Gamow-Teller hindrance factor h = 2.2(3), and a cross-section of about 3nb for the production of {sup 100}Sn in fusion-evaporation reaction between {sup 58}Ni beam and {sup 50}Cr target have been estimated from the data on heavier tin isotopes. The estimated hindrance factor is similar to the values derived for lower shell nuclei.
The Rare ISotopes INvestigation at GSI project combines the former EUROBALL Ge-Cluster detectors, the MINIBALL Ge detectors, BaF
2-HECTOR detectors, and the fragment separator at GSI for ...high-resolution in-beam
γ
-ray spectroscopy measurements with radioactive beams. These secondary beams produced at relativistic energies are used for Coulomb excitation or secondary fragmentation experiments in order to explore the nuclear structure of the projectiles or projectile like nuclei by measuring de-excitation photons. The newly designed detector array is described and the performance characteristics are given. Moreover, particularities of the experimental technique are discussed.
The research programme at the GSI Online Mass Separator focuses on the study of exotic nuclei far from the valley of stability. Special emphasis is placed on the investigation of decay properties of ...isotopes along the
N=
Z line between the double shell closures at
56Ni and
100Sn. In this contribution, the major recent achievements along with the corresponding experimental methods are reviewed.
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