نتایج جستجو برای: neutron density

تعداد نتایج: 452104  

2009
Isaac Vidaña Constança Providência Arnau Rios

We perform a systematic analysis of the density dependence of the nuclear symmetry energy within the microscopic Brueckner–Hartree–Fock (BHF) approach using the realistic Argonne V18 nucleon-nucleon potential plus a phenomenological three body force of Urbana type. Our results are compared thoroughly to those arising from several Skyrme and relativistic effective models. The values of the param...

2014
Lee Lindblom

The observable macroscopic properties of relativistic stars (whose equations of state are known) can be predicted by solving the stellar structure equations that follow from Einstein’s equation. For neutron stars, however, our knowledge of the equation of state is poor, so the direct stellar structure problem can not be solved without modeling the highest density part of the equation of state i...

Journal: :The Review of scientific instruments 2012
D L Bleuel C B Yeamans L A Bernstein R M Bionta J A Caggiano D T Casey G W Cooper O B Drury J A Frenje C A Hagmann R Hatarik J P Knauer M Gatu Johnson K M Knittel R J Leeper J M McNaney M Moran C L Ruiz D H G Schneider

Neutron yields are measured at the National Ignition Facility (NIF) by an extensive suite of neutron activation diagnostics. Neutrons interact with materials whose reaction cross sections threshold just below the fusion neutron production energy, providing an accurate measure of primary unscattered neutrons without contribution from lower-energy scattered neutrons. Indium samples are mounted on...

1997
Kei Iida Katsuhiko Sato

Transitions of nuclear compositions in the crust of a neutron star induced by stellar spin-down are evaluated at zero temperature. We construct a compressible liquiddrop model for the energy of nuclei immersed in a neutron gas, including pairing and shell correction terms, in reference to the known properties of the ground state of matter above neutron drip density, 4.3 × 10 g cm. Recent experi...

2008
P. Schmidt-Wellenburg P. Geltenbort V. V. Nesvizhevsky C. Plonka T. Soldner F. Vezzu O. Zimmer

We present the status of the development of a dedicated high density ultra-cold neutron (UCN) source dedicated to the gravitational spectrometer GRANIT. The source employs superthermal conversion of cold neutrons to UCN in superfluid helium. Tests have shown that UCN produced inside the liquid can be extracted into vacuum. Furthermore a dedicated neutron selection channel was tested to maintain...

2005
OMAR BENHAR Omar Benhar

The EOS of strongly interacting matter at densities ten to fifteen orders of magnitude larger than the typical density of terrestrial macroscopic objects determines a number of neutron star properties, including the pattern of gravitational waves emitted following the excitation of nonradial oscillation modes. This paper reviews some of the approaches employed to model neutron star matter, as w...

2007
H.-J. Schulze

We provide a microscopic calculation of neutron-proton and neutron-neutron cross sections in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Paris potential. We investigate separately the medium eeects on the eeective mass and on the scattering amplitude. We determine average cross sections suitable for application in the dynamical s...

2008
M. Prakash

The multifaceted role of the density dependent nuclear symmetry energy in the nuclear astrophysics involving neutron stars is highlighted. Efforts toward a model independent determination of the dense matter equation state through a deconstruction of the neutron star structure equation utilizing the masses and radii of several individual neutron stars are described. The need for observational d...

2006
C. J. Horowitz

Heavy ion experiments provide important data to test astrophysical models. The high density equation of state can be probed in HI collisions and applied to the hot protoneutron star formed in core collapse supernovae. The Parity Radius Experiment (PREX) aims to accurately measure the neutron radius of Pb with parity violating electron scattering. This determines the pressure of neutron rich mat...

2008
U. A. Mofiz

We consider electrostatic plasma modes along the open field lines of a rotating neutron star. Goldreich-Julian charge density in general relativity is analyzed for the neutron star with zero inclination. It is found that the charge density is maximum at the polar cap and it remains almost same in certain extended region of the pole. For a steady state Goldreich-Julian charge density we found th...

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