نتایج جستجو برای: neutron flux
تعداد نتایج: 130682 فیلتر نتایج به سال:
@ Neutron and gamma radiation levels around a Cockcroft-Walton neutron generator producing 14-Mev neutrons at an approximate rate of 1010 neutrons per second were measured under conditions typical of those required for activation analysis. Neutron flux reduction to acceptable levels for limited operation was accomplished by 12 feet of distance that included shielding consisting of 27 inches of ...
Traditional neutron tomography allows to reconstruct the attenuation cross section, a measure for the material distribution, at high spatial resolution and non-destructively. However, it does not state anything about the ordering structure of the atoms inside this material. Extending the setup with a second neutron imaging detector, diffracted neutrons from the ordered crystal lattice could be ...
At present work, under initial inventory with Th and U, the evolution of nuclides in subcritical devices under given thermal, fast, hardening fast and fission neutron field are studied without the detail structure of sub-critical device and the burn-up being considered. It is supposed that the subcritical reactor consists of uniform in which the flux of neutron is homogeneous. The fissile nucli...
The optimization of the ballistic guide design for the SNS Fundamental Neutron Physics Beamline 8.9 Å line is described. With a careful tuning of the shape of the curve for the tapered section and the width of the straight section, this optimization resulted in more than 75% increase in the neutron flux exiting the 33 m long guide over a straight m = 3.5 guide with the same length.
The construction of the new German high flux neutron source FRM-II is finished and FRM-II is waiting for its licence to start nuclear operation. With the beginning of the routine operation 22 instruments will be in action, including 5 irradiation facilities and 17 beam tube instruments, most of them use neutron scattering techniques. Additional instruments are under construction. Some of these ...
This work presents the preliminary design of a PGNAA (Prompt Gamma Neutron Activation Analysis) facility at the TRIGA IPR-R1 research reactor of the CDTN. The results of experimental and calculated neutron flux in a vertical tube are presented and discussed. The results confirm the technical feasibility of the installation of PGNAA at the TRIGA reactor and the possibility of enhancing the appli...
We investigate the viability of the Galactic halo model of γ-ray bursts by calculating the spatial distribution of neutron stars born with high velocities in the Galactic disk, and comparing the resulting brightness and angular distribution with the BATSE data. We find that the Galactic halo model can reproduce the BATSE peak flux and angular distribution data for neutron star kick velocities >...
where kD=1.602 10 Gy⋅g/MeV — energy conversion factor from MeV to Gy×g, (obtained from the known ratio: 1 MeV=1.602 10 J); Е – neutron energy, MeV; Ф(r,Е) dE – neutron flux in the point r on the energy interval dE, neutron/cm/s: ni – atomic density of the i-th nuclide of the medium, atom/cm; σij(E) –microscopic cross-section of reaction j at interaction of a neutron with energy Е on the i-th nu...
Protons of 35 and 65 MeV and deuterons of 35 MeV were used to bombard beryllium and lithium targets of various thicknesses. Four types of experiments were conducted in order to characterize the neutron fields. They were (1) central axis depth-dose measurements in a water phantom, (2) dose buildup at small depths in tissue-equivalent plastic, (3) microdosimetric measurements and LET distribution...
We calculate the flux of neutrinos generated by the propagation of ultra-high energy iron over cosmological distances and show that even if ultra-high energy cosmic rays are composed of heavy nuclei, a significant flux of high-energy neutrinos should be present throughout the universe. The resulting neutrino flux has a new peak at ∼ 10 14 eV generated by neutron decay and reproduces the double ...
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