6,460 research outputs found
Time of flight mass spectrometer with feedback means from the detector to the low source and a specific counter Patent
Design and characteristics of time of flight mass spectrometer to measure or analyze gases at low pressures and time of flight of single gas molecul
RPA calculations with Gaussian expansion method
The Gaussian expansion method (GEM) is extensively applied to the
calculations in the random-phase approximation (RPA). We adopt the
mass-independent basis-set that has been tested in the mean-field calculations.
By comparing the RPA results with those obtained by several other available
methods for Ca isotopes, using a density-dependent contact interaction and the
Woods-Saxon single-particle states, we confirm that energies, transition
strengths and widths of their distribution are described by the GEM bases to
good precision, for the , and collective states. The GEM is
then applied to the self-consistent RPA calculations with the finite-range
Gogny D1S interaction. The spurious center-of-mass motion is well separated
from the physical states in the response, and the energy-weighted sum
rules for the isoscalar transitions are fulfilled reasonably well. Properties
of low-energy transitions in Ca are argued in some detail.Comment: 30 pages including 12 figure
Effects of heavy ions on electron temperatures in the solar corona and solar wind
The effects of the reduction in the thermal conductivity due to heavy ions on electron temperatures in the solar corona and solar wind are examined. Large enhancements of heavy ions in the corona appear to be necessary to give appreciable changes in the thermal gradient of the electrons
Interplanetary magnetic fields as a cause of comet tails
Interplanetary magnetic fields as cause of comet tail
Recent Advances in the Application of the Shell Model Monte Carlo Approach to Nuclei
The shell model Monte Carlo (SMMC) method is a powerful technique for
calculating the statistical and collective properties of nuclei in the presence
of correlations in model spaces that are many orders of magnitude larger than
those that can be treated by conventional diagonalization methods. We review
recent advances in the development and application of SMMC to mid-mass and
heavy nuclei.Comment: 6 pages, 5 figures, Proceedings of the Eleventh International Spring
Seminar on Nuclear Physic
Isospin-projected nuclear level densities by the shell model Monte Carlo method
We have developed an efficient isospin projection method in the shell model
Monte Carlo approach for isospin-conserving Hamiltonians. For isoscalar
observables this projection method has the advantage of being exact sample by
sample. The isospin projection method allows us to take into account the proper
isospin dependence of the nuclear interaction, thus avoiding a sign problem
that such an interaction introduces in unprojected calculations. We apply our
method in the calculation of the isospin dependence of level densities in the
complete shell. We find that isospin-dependent corrections to the
total level density are particularly important for nuclei.Comment: 5 pages including 4 figure
Particle-Number Reprojection in the Shell Model Monte Carlo Method: Application to Nuclear Level Densities
We introduce a particle-number reprojection method in the shell model Monte
Carlo that enables the calculation of observables for a series of nuclei using
a Monte Carlo sampling for a single nucleus. The method is used to calculate
nuclear level densities in the complete -shell using a good-sign
Hamiltonian. Level densities of odd-A and odd-odd nuclei are reliably extracted
despite an additional sign problem. Both the mass and the dependence of
the experimental level densities are well described without any adjustable
parameters. The single-particle level density parameter is found to vary
smoothly with mass. The odd-even staggering observed in the calculated
backshift parameter follows the experimental data more closely than do
empirical formulae.Comment: 14 pages, 4 eps figures included, RevTe
Microscopic description of Gamow-Teller transitions in middle pf--shell nuclei by a realistic shell model calculation
GT transitions in nuclei are studied in terms of a large-scale
realistic shell-model calculation, by using Towner's microscopic parameters.
values to low-lying final states are reproduced with a reasonable
accuracy. Several gross properties with respect to the GT transitions are
investigated with this set of the wavefunctions and the operator. While the
calculated total GT strengths show no apparent disagreement with the
measured ones, the calculated total GT strengths are somewhat larger than
those obtained from charge-exchange experiments. Concerning the Ikeda sum-rule,
the proportionality of to persists to an excellent
approximation, with a quenching factor of 0.68. For the relative GT
strengths among possible isospin components, the lowest isospin component
gathers greater fraction than expected by the squared CG coefficients of the
isospin coupling. It turns out that these relative strengths are insensitive to
the size of model space. Systematics of the summed values are
discussed for each isospin component.Comment: IOP-LaTeX 23 pages, to appear in J. Phys. G., 5 Postscript figures
available upon reques
A method of implementing Hartree-Fock calculations with zero- and finite-range interactions
We develop a new method of implementing the Hartree-Fock calculations. A
class of Gaussian bases is assumed, which includes the Kamimura-Gauss basis-set
as well as the set equivalent to the harmonic-oscillator basis-set. By using
the Fourier transformation to calculate the interaction matrix elements, we can
treat various interactions in a unified manner, including finite-range ones.
The present method is numerically applied to the spherically-symmetric
Hartree-Fock calculations for the oxygen isotopes with the Skyrme and the Gogny
interactions, by adopting the harmonic-oscillator, the Kamimura-Gauss and a
hybrid basis-sets. The characters of the basis-sets are discussed. Adaptable to
slowly decreasing density distribution, the Kamimura-Gauss set is suitable to
describe unstable nuclei. A hybrid basis-set of the harmonic-oscillator and the
Kamimura-Gauss ones is useful to accelerate the convergence, both for stable
and unstable nuclei.Comment: LaTex 32 pages with 6 Postscript figure
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