نتایج جستجو برای: neutron effect

تعداد نتایج: 1684090  

2003
Ashok Goyal

Recently there have been important developments in the determination of neutron star masses which put severe constraints on the composition and equation of state (EOS) of the neutron star matter. Here we study the effect of quark and nuclear matter mixed phase on mass radius relationship of neutron stars employing recent models from two classes of EOS’s and discuss their implications.

1998
SUJAN SENGUPTA

The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating both the effect of neutron star cooling and the effect of space-time curvature produced by the intense gravitational field of the star. For this purpose a stationary and static gravitational field has been considered with the standard as well as the accelerated cooling models of neutron ...

2008
V. V. Fedorov

Recently strong electric fields (up to 10 V/cm) have been discovered, which affect the neutrons moving in noncentrosymmetric crystals. Such fields allow new polarization phenomena in neutron diffraction and optics and provide, for instance, a new feasibility of a search for the neutron electric dipole moment (EDM). A strong interplanar electric field of the crystal and a sufficiently long time ...

Background: One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment.Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. Methods: Simulations were performed using MCNPX Monte...

2013
Trenton E. Franz M. Zreda T. P. A. Ferre R. Rosolem

[1] The cosmic-ray neutron probe measures soil moisture over tens of hectares, thus averaging spatially variable soil moisture fields. A previous paper described how variable soil moisture profiles affect the integrated cosmic-ray neutron signal from which depthaverage soil moisture is computed. Here, we investigate the effect of horizontal heterogeneity on the relationship between neutron coun...

ژورنال: سنجش و ایمنی پرتو 2019

The 252Cf brachytherapy source is a spontaneous fission decay source, which is used as a neutron-emitting source. In addition to neutrons emitted from this source, gamma rays are also emitted with the average energy of 1 MeV. In this study, using the Monte Carlo N-Particle code (MCNPX), the absorbed dose rates of the neutrons, the primary gamma and the secondary gamma that generated by thermal ...

Journal: :iranian journal of astronomy and astrophysic 0
mohsen bigdeli department of physics, university of zanjan, p.o. box 45195-313, zanjan, iran nariman roohi department of physics, university of zanjan, p.o. box 45195-313, zanjan, iran mina zamani department of physics, university of zanjan, p.o. box 45195-313, zanjan, iran

in the present work, we have obtained the equation of state for neutron star matter considering the in uence of the ferromagnetic and antiferromagnetic spin state. we have also investigated the structure of neutron stars. according to our results, the spin asymmetry sti ens the equation of state and leads to high mass for the neutron star.

1996
H. Oberhummer

The halo effect in the final states of astrophysically relevant direct neutron–capture reactions by neutron–rich nuclei is discussed. As an example, we calculate the cross sections for O(n,γ)O at thermonuclear and thermal energies.

2011
J. G. Fantidis G. E. Nicolaou C. Potolias N. Vordos D. V. Bandekas

A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studi...

A. Vejdani-Noghreiyan, H. Miri-Hakimabad, H. Panjeh,

Background: Prompt gamma neutron activation analysis (PGNAA) is known as a non-invasive technique capable of measuring elemental concentration in voluminous samples in a short period of time. Also it is a valuable diagnostic tool for total body elemental measurements. 252Cf and 241Am-Be sources which are usually used in this method, generate not only neutrons, but also emit high-energy and unwa...

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