The unique properties of neutron interaction with materials have long been applied to the study of geological materials, with Shull and Smart using them in 1949 to determine the antiferromagnetic structure of manganosite (MnO). Neutron diffraction provides an accurate method for crystal structure determination of hydrous phases, particularly ices, and investigations of cation ordering of elemen...

Fuzzy finite element solution of uncertain neutron diffusion equation for imprecisely defined homogeneous triangular bare reactor S. Nayak and S. Chakraverty * Department of Mathematics, National Institute of Technology, Rourkela, Odisha -769008, India Abstract: Scattering of neutron collision inside a reactor depends upon geometry of the reactor, diffusion coefficient and absorption coefficien...

Magnetic field estimates for nearby isolated neutron stars (INS) help to constrain both the characteristics of the population and the nature of their peculiar X-ray spectra. From a series of XMM-Newton observations of RX J2143.0+0654, we measure a spin-down rate of ν̇ = (−4.6 ± 2.0)× 10 Hz s. While this does not allow a definitive measurement of the dipole magnetic field strength, fields of & 10...

The XMM-Newton spectra of the isolated neutron star RX J0720.4−3125 obtained over 4.5 years can be described by sinusoidal variations in the inferred blackbody temperature, the size of the emitting area and the depth of the absorption line with a period of 7.1±0.5 years, which we suggest to be the precession period of the neutron star. Precession of a neutron star with two hot spots of differen...

Polarizability tensor of a strongly magnetized plasma and the polarization vectors and opacities of normal electromagnetic waves are studied for the conditions typical of neutron star atmospheres, taking account of partial ionization effects. Vacuum polarization is also included using a new set of fitting formulae that are accurate for wide range of field strengths. The full account of the coup...

We are developing a high-efficiency neutron detector with 1 cm position resolution and coarse energy resolution for use at high-flux neutron source facilities currently proposed or under construction. The detector concept integrates a segmented (3)He ionization chamber with the position sensitive, charged particle collection methods of a MicroMegas detector. Neutron absorption on the helium pro...

Most isotopes of elements with atomic numbers Z > 30 are synthesized via neutron capture reactions. These “n-capture” elements are the majority of the periodic table. In the so-called s-process, neutron fluxes are small enough to allow β-decays to occur between successive neutron captures, and element buildup proceeds along the valley of β-stability. In the r-process, huge but short-lived neutr...

We have identified three possible ways in which future XMM-Newton observations can provide significant constraints on the equation of state of neutron stars. First, using a long observation of the neutron star X-ray transient Cen X–4 in quiescence one can use the RGS spectrum to constrain the interstellar extinction to the source. This removes this parameter from the X-ray spectral fitting of t...

Thermal neutron emissions from the lunar surface provide a direct measure of bulk elemental composition that can be used to constrain the chemical properties of near-surface (depth <1 m) lunar materials. We present a new calibration of the Lunar Prospector thermal neutron map, providing a direct link between measured count rates and bulk elemental composition. The data are used to examine the c...

Background: Miniature neutron sources with high neutron flux have abundant applications in medicine, industry and researches. The most important general characteristic of miniature neutron sources is their diameter which is 3mm in average. In this research, we have surveyed and designed an Am-Be miniature neutron source fabrication. Materials and Methods: This investigation resulted in creation...