Analysis Of Neutron Energy Spectra Research Articles

Monte Carlo particle collision model for qualitative analysis of neutron energy spectra from anisotropic inertial confinement fusion

A Monte Carlo (MC) code simulating the kinetics of two-particle collisions has shown to have certain advantages in the spectral analysis of neutrons from fast-ignition inertial confinement fusion (ICF). The MC code quickly displays neutron spectra produced in the expected fusion plasma kinetics (incl. ion energy spectrum, anisotropy, and collision geometry). This allows to explore various potential mechanisms of neutron production without using time-consuming hydrodynamic or particle simulations and makes it possible to give a feedback to ongoing experiments. The validity of this model was demonstrated in the ”cone-free-shell” fast ignition experiment at the GEKKO-XII - LFEX laser facility, where the model provided a clear explanation for the significant spectral modulation of D(d, n)3He neutrons generated through the interaction between a high-power laser and a long-scale plasma.

MCNP simulation of neutron energy spectra for a TN-32 dry shielded container

This paper presents a numerical analysis of neutron energy spectra for a TN-32 spent fuel dry storage cask using Monte Carlo simulation. The analysis results were compared with experimental measurements to determine the suitability of using such codes for neutron flux calculations in soft-spectrum neutron environments. Complete spent fuel compositions were generated using Scale 4.4a. Variations in source definition and geometry determined that geometric and source simplifications in the computational model have negligible effect on final neutron energy distribution. Variations between experimental and computed spectra at energies above 1 MeV and below 100 keV demonstrated the shortfalls of various detection instruments used to collect the experimental neutron energy spectra data principally because these instruments were calibrated based on high neutron energy spectra. The MCNP calculations were generally in agree with the experimental data, but predicted that the detectors would over-respond to the neutron spectra around a spent fuel dry shielded container. Computed neutron energy spectra were always conservative when compared to experimental spectra.

Simulation and analysis of neutron energy spectra from irradiation channels of the IBR-2 reactor

With the purpose of perfecting neutron activation analysis calculation methods, neutron energy spectra for three irradiation channels were modeled and analyzed. On the basis of the results obtained, the renormalization factors were obtained for resonance integrals of the real resonance neutron spectrum from one of the irradiation channels.

Analysis of neutron energy spectra from neutral beam heated plasmas in the JET tokamak

Neutron energy spectra from deuterium neutral beam heated plasmas at the Joint European Torus (JET) have been measured with a time-of-flight spectrometer. The different source fractions, resulting from thermal-thermal (TT), beam-thermal (BT) and beam-beam (BB) interactions have been extracted. The measured TT fraction and associated ion temperature is checked for consistency with diagnostic data for electron density ne, effective charge Zeff, ion temperature Ti and total neutron emission. Two different ways of comparing the data are represented. Firstly, the measured TT fraction, total neutron emission, ne, Zeff and Te profile shape are used to deduce a consistent Ti, which is compared with Ti values obtained independently by other diagnostics. Secondly, the measured TT fraction, total neutron emission, ne profile shape and Ti are used to determine a consistent thermal deuterium density nD, which is compared with nD obtained from Zeff measurements.

Neutron production from thick targets bombarded by alpha particles: Experiment and theoretical analysis of neutron energy spectra.

The neutron energy spectra and angular distributions have been measured for thick targets of $^{9}\mathrm{Be}$, $^{181}\mathrm{Ta}$, and $^{197}\mathrm{Au}$ bombarded by 40--60 MeV alpha particles. These data as well as those of other authors have been analyzed in terms of the extended exciton model formalism of nuclear reactions. The model takes into account the emission of neutrons through the single-step direct, multistep direct, multistep compound, and compound-nuclear evaporation processes.