233 research outputs found
The NUBASE evaluation of nuclear and decay properties
This paper presents the first version of the NUBASE evaluation of nuclear and decay properties of nuclides in their ground- and isomeric-states. All nuclides for which some experimental information is known are considered. NUBASE has basically been derived from the âEvaluated Nuclear Structure Data Filesâ and from the âAtomic Mass Evaluationâ of 1995, but it also includes information from recent literature or literature missed in one of these two evaluations and is meant to cover all experimental data along with their references. In case no experimental data is available, whenever possible, trends in the systematics of neighboring nuclides have been used to derive estimated values (labeled in the database as non-experimental). Adopted procedures and policies are presented
HEAVY RESIDUE PRODUCTION IN HEAVY ION INDUCED REACTIONS ON 124 Sn BETWEEN 10 AND 84 MeV/NUCLEON
Heavy residue velocity spectra of 12C, 20Ne, 40Ar + 124Sn reactions induced in the 10-84 MeV/nucleon energy range have been measured between 0° and 10°. Asymmetric incomplete fusion process calculations are in agreement with the data
Strong fragmentation of low-energy electromagnetic excitation strength in Sn
Results of nuclear resonance fluorescence experiments on Sn are
reported. More than 50 transitions with MeV were
detected indicating a strong fragmentation of the electromagnetic excitation
strength. For the first time microscopic calculations making use of a complete
configuration space for low-lying states are performed in heavy odd-mass
spherical nuclei. The theoretical predictions are in good agreement with the
data. It is concluded that although the E1 transitions are the strongest ones
also M1 and E2 decays contribute substantially to the observed spectra. In
contrast to the neighboring even Sn, in Sn the
component of the two-phonon quintuplet built on top of
the 1/2 ground state is proved to be strongly fragmented.Comment: 4 pages, 3 figure
Beta decay of 115-In to the first excited level of 115-Sn: Potential outcome for neutrino mass
Recent observation of beta decay of 115-In to the first excited level of
115-Sn with an extremely low Q_beta value (Q_beta ~ 1 keV) could be used to set
a limit on neutrino mass. To give restriction potentially competitive with
those extracted from experiments with 3-H (~2 eV) and 187-Re (~15 eV), atomic
mass difference between 115-In and 115-Sn and energy of the first 115-Sn level
should be remeasured with higher accuracy (possibly of the order of ~1 eV).Comment: 9 pages, 3 figures; talk at the NANP'05 Conferenc
Remarcs on the shape transition from spherical to deformed gamma unstable nuclei
Energies and transition probabilities for low lying states in Ba and
^{104Ru were calculated within a hybrid model.The ground and the first
states are described alternatively as a harmonic and anharmonic vibrator states
while the remaining states as states with E(5) symmetry. One concludes that a
gradual setting of the 'critical' potential yields a better agreement with the
experimental data. Very good agreement with the data is obtained for
Ru. Comparing the present results with those of E(5) symmetry, it is
conspicuous that the present formalism add corrections to the E(5) formalism by
bringing the predictions closer to the experimental data. Analytical
relationship between the states with U(5) symmetry and those given by the E(5)
description is established.Comment: 21 pages, 3 figures, submitted for publicatio
Search for the electric dipole excitations to the multiplet in Sn
The odd-mass Sn nucleus was investigated in nuclear resonance
fluorescence experiments up to an endpoint energy of the incident photon
spectrum of 4.1 MeV at the bremsstrahlung facility of the Stuttgart University.
More than 50 mainly hitherto unknown levels were found. From the measurement of
the scattering cross sections model independent absolute electric dipole
excitation strengths were extracted. The measured angular distributions
suggested the spins of 11 excited levels. Quasi-particle phonon model
calculations including a complete configuration space were performed for the
first time for a heavy odd-mass spherical nucleus. These calculations give a
clear insight in the fragmentation and distribution of the , , and
excitation strength in the low energy region. It is proven that the
component of the two-phonon quintuplet built on
top of the ground state is strongly fragmented. The theoretical
calculations are consistent with the experimental data.Comment: 10 pages, 5 figure
Description of the two neutrino double beta decay in deformed nuclei with projected spherical single particle states
Using an angular momentum projected single particle basis, a pnQRPA approach
is used to study the properties of ten isotopes, exhibiting
various quadrupole deformations. The mother and daughter nuclei exhibit
different quadrupole deformations. Since the projected basis enables a unified
description of deformed and spherical nuclei, situations where the nuclei
involved in the double beta decay process are both spherical, both deformed or
one spherical and another deformed, can be treated through a sole formalism.
Dependence of single and strength distribution on atomic
mass number and nuclear deformation is analyzed. For the double beta decay
process, the Gamow-Teller transition amplitudes and half lives are calculated.
Results are compared with the experimental data as well as with the predictions
of other theoretical approaches. The agreement between the present results and
experimental data is fairly good.Comment: 39 pages, 5 figure
Mass and half-life measurements of neutron-deficient iodine isotopes
Neutron-deficient iodine isotopes, 116I and 114I, were produced at relativistic energies by in-flight fragmentation at the Fragment Separator (FRS) at GSI. The FRS Ion Catcher was used to thermalize the ions and to perform highly accurate mass measurements with a Multiple-Reflection Time-of-Flight Mass-Spectrometer (MR-TOF-MS). The masses of both isotopes were measured directly for the first time. The half-life of the 114I was measured by storing the ions in an RF quadrupole for different storage times and counting the remaining nuclei with the MR-TOF-MS. The measured half-life was used to assign the ground state to the measured 114I ions. Predictions on the possible α-decay branch for 114I are presented based on the reduced uncertainties obtained for the Qα-value. Systematic studies of the mass surface were performed with the newly obtained masses, showing better agreement with the expected trend in this mass region.peerReviewe
High-resolution study of the 113
The gamma-ray spectrum and the decay scheme of 114Cd obtained from a radiative neutron capture experiment on 113Cd samples are modelled in the framework of extreme statistical model. The unfolding of the experimental spectrum with proper normalization yields a total capture cross section of 21640 b and an average gamma-ray multiplicity of 4.1. Using the extreme statistical model the development of the low energy decay scheme of 114Cd is in progress. In the model the constant-temperature level density is used, where the temperature parameter was very sensitive to the shape of the modelled gamma-ray spectrum. Using this sensitivity T = 0.62âMeV was obtained with the constraint of good description of low energy level density and the level density at the binding energy. This is in full agreement with our earlier publication. For the description of the continuum shape of the unfolded spectrum the inclusion of low energy enhancement for the photon strength function was an important new addition
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