Scattering Of Fast Neutrons Research Articles

Simplified Simulation of Fast Neutron Scattering for an Explosives Detection Application

In developing applications for fast neutron scattering in explosives detection, Monte Carlo simulations were completed that characterized the scattering behavior of fast neutrons in a simplified geometry. Targets included C, N, O, and Fe, as well as air, water, oil, and the explosive RDX (C3H6N6O6). Work included a study of energy binning, particle histories, and statistical uncertainty. Results of the simulations closely matched expected scatter behavior. Energy bins of 0.2 MeV and 1 × 108 particle histories provided ample statistical certainty.

Fast Neutron Scattering Cross Sections of Sn-118 at 14.9 and 18.0 MeV

Fast Neutron Scattering Cross Sections of Sn-118 at 14.9 and 18.0 MeV

Measurements of Fast Neutron Scattering Cross Sections of Li-7 at 11.0 and 13.0 MeV

Click to increase image sizeClick to decrease image sizeKEYWORDS: experimental dataneutronsscattering cross sectionslithium 74.63-MeV level11.0 and 13.0 MeV rangegas-outtime-of-flight method

Measurements of Fast Neutron Scattering Cross Sections of Li-7 at 11.0 and 13.0 MeV

Measurements of Fast Neutron Scattering Cross Sections of Li-7 at 11.0 and 13.0 MeV

Attenuation and Scattering of Fast Neutrons Ranged from 0. 5 to 14 MeV by Various Shielding Materials

Attenuation and Scattering of Fast Neutrons Ranged from 0. 5 to 14 MeV by Various Shielding Materials

Calibration of a Fast Neutron Scattering Technique for Measurement of Void Fraction in Rod Bundles

A technique based on scattering and transmission of fast neutron beams has been developed for measuring void fraction in two-phase flow through rod bundles. Experiments indicate that the scattered neutron flux varies linearly with void fraction and is largely independent of phase distribution. Measurements of the transmitted neutron flux have been used to determine phase distribution (or flow regime). The technique gives good sensitivity and count rates and appears suitable for void fraction and phase distribution measurements in transient flow boiling.

Scattering of fast neutrons from 103Rh

The scattering of fast neutrons from 103Rh was studied by means of (n, n), (n, n′) and (n, n′γ) measurements at neutron energies up to 2 MeV. More than fifty unknown γ-transitions were identified and a level scheme established which includes fifteen unreported excited states. Branching ratios, spins and parities for these levels were deduced, as well as the effective activation cross sections for the 103Rh(n, n′) 103mRh reaction. The results are compared with existing data and with calculations based on the optical and statistical models.

Fast Neutron Scattering at 180° from Pb and Sn

A measurement of the differential scattering of 3.65 MeV neutrons from the D(d,n)3He reaction at the angles 10° and 180° by Pb and Sn was made. The results at 180° were anomalously high compared with optical model predictions. An experimental arrangement using the associated particle technique and large thin film (CD2)x targets is described which has made measurements of the differential scattering of neutrons at the extreme backward angles (~180°) possible.

Scattering of fast neutrons by 12C, 54Fe, 56Fe, 58Ni and 60Ni

Differential elastic and inelastic neutron scattering cross sections have been measured for 12C, 54Fe, 56Fe, 58Ni and 60Ni between 4,0 and 5.6 MeV.The 54Fe, 56Fe, 58Ni and 60Ni elastic cross sections are compared with predictions of the optical model using standard sets of parameters for the potential. Inelastic angular distributions are calculated assuming the statistical model and, in addition, for each first excited state a direct reaction contribution was calculated using the DWBA. The agreement between theory and experiment is satisfactory.

Fast-Neutron Scattering from Germanium

Elastic and inelastic neutron scattering cross sections of natural germanium were measured in the incident neutron energy range 0.3-1.5 MeV with incident energy resolutions of \ensuremath{\sim}20 keV. Neutron-velocity and $\ensuremath{\gamma}$-ray spectroscopic methods were employed to resolve the scattering to individual low-lying states. The results were interpreted in terms of the optical model and the statistical compound-nucleus model including effects due to fluctuations and correlations of resonance widths. Measured cross sections for inelastic scattering to a number of excited states in even Ge isotopes were reasonably well described by the statistical model of Hauser and Feshbach without corrections for width fluctuations and correlations.

Elastic and Inelastic Scattering of Fast Neutrons from 10B, 11B, Natural Ge, and 93NB

The differential elastic- and inelastic-scattering cross sections of 10B, 11B, natural Ge, and 93Nb have been measured at incident neutron energies of 7.02 and 7.55 MeV for 10B; 7.55 MeV for 11B; 7.55 MeV for Ge; and 5.95 and 7.47 MeV for 93Nb. The cross sections were measured with a neutron time-of-flight spectrometer relative to the cross section for neutron scattering from hydrogen.

Fast-Neutron Scattering from Ta, Re, and Pt

The scattering of neutrons with energies of \ensuremath{\lesssim}1.5 MeV from the elements Ta, Re, and Pt was experimentally studied. Elastic and inelastic neutron-scattering angular distributions were determined at incident-neutron-energy intervals of \ensuremath{\lesssim}20 keV throughout the range 0.3 to 1.5 MeV. Time-of-flight measurements were made concurrently at eight or more scattering angles between 25\ifmmode^\circ\else\textdegree\fi{} and 155\ifmmode^\circ\else\textdegree\fi{} with sufficient scattered-neutron-energy resolution to separate the elastically scattered component from most inelastically scattered neutron groups. Differential inelastic scattering cross sections corresponding to the excitation of the following states were observed: in Ta at 144\ifmmode\pm\else\textpm\fi{}10 (doublet), 313\ifmmode\pm\else\textpm\fi{}15, 506\ifmmode\pm\else\textpm\fi{}20, 620\ifmmode\pm\else\textpm\fi{}20, 720\ifmmode\pm\else\textpm\fi{}20, and 930\ifmmode\pm\else\textpm\fi{}25 keV; in Re at 132\ifmmode\pm\else\textpm\fi{}10, 219\ifmmode\pm\else\textpm\fi{}15, 313\ifmmode\pm\else\textpm\fi{}15, 387\ifmmode\pm\else\textpm\fi{}18, 518\ifmmode\pm\else\textpm\fi{}20, 637\ifmmode\pm\else\textpm\fi{}20, 767\ifmmode\pm\else\textpm\fi{}25, 865\ifmmode\pm\else\textpm\fi{}25, 963\ifmmode\pm\else\textpm\fi{}25, 1060\ifmmode\pm\else\textpm\fi{}25, and 1135\ifmmode\pm\else\textpm\fi{}25 keV; and in Pt at 130\ifmmode\pm\else\textpm\fi{}20, 214\ifmmode\pm\else\textpm\fi{}20, 348\ifmmode\pm\else\textpm\fi{}15, 420\ifmmode\pm\else\textpm\fi{}15, 620\ifmmode\pm\else\textpm\fi{}20, 719\ifmmode\pm\else\textpm\fi{}15, 838\ifmmode\pm\else\textpm\fi{}25, and 935\ifmmode\pm\else\textpm\fi{}20 keV. The experimental results were compared with calculations based upon the optical model and the Hauser-Feshbach formula including corrections for resonance-width fluctuations. The experimentally observed level structure is discussed in the context of single-particle and rotational states of deformed nuclei.

Fast-Neutron Scattering from Nuclides in the Lead Region

Fast-Neutron Scattering from Nuclides in the Lead Region

Gamma Rays from Fast-Neutron Scattering inFe54

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Fast-Neutron Scattering from the 182, 184, and 186 Isotopes of Tungsten

The differential cross sections for the elastic and the inelastic scattering of fast neutrons from ${\mathrm{W}}^{182}$, ${\mathrm{W}}^{184}$, and ${\mathrm{W}}^{186}$ were experimentally determined at incident neutron energy intervals of $\stackrel{\mathrm{\ensuremath{\sim}}}{l}$ 25 keV from 0.3 to 1.5 MeV. The excitation, by inelastic scattering, of states in ${\mathrm{W}}^{182}$ was observed at 102\ifmmode\pm\else\textpm\fi{}5 and 327\ifmmode\pm\else\textpm\fi{}10 keV; in ${\mathrm{W}}^{184}$ at 110\ifmmode\pm\else\textpm\fi{}5, 360\ifmmode\pm\else\textpm\fi{}10, 901\ifmmode\pm\else\textpm\fi{}10, 1003\ifmmode\pm\else\textpm\fi{}10 and 1120\ifmmode\pm\else\textpm\fi{}10 keV; and in ${\mathrm{W}}^{186}$ at 121\ifmmode\pm\else\textpm\fi{}5, 398\ifmmode\pm\else\textpm\fi{}10, 738\ifmmode\pm\else\textpm\fi{}10, 863\ifmmode\pm\else\textpm\fi{}10, 942\ifmmode\pm\else\textpm\fi{}10 and 1035\ifmmode\pm\else\textpm\fi{}10 keV. The differential elastic- and inelastic-scattering cross sections were measured at 8 or more angles between 27 and 150 deg by means of a multiangle fast time-of-flight system. The resolution was sufficient to resolve most of the scattered neutron groups. The experimental results were interpreted in terms of a deformed optical model, coupled-channel direct interaction, and Hauser-Feshbach theory. Good agreement with measurement was obtained when the effects of resonance-width fluctuations and correlations were included.

Fast-Neutron Scattering from Nuclides in the Lead Region

Fast-Neutron Scattering from Nuclides in the Lead Region

Fast Neutron Scattering from Beryllium, Sodium, and Aluminum

Essentially monoenergetic neutrons are scattered from Be, Na, and Al at incident neutron energy intervals of ≲50 keV throughout the range 0.3 to 1.5 MeV. Fast neutron time-of-flight techniques are ...

Scattering of fast neutrons by 238U

Elastic and inelastic scattering of fast neutrons by 238U have been studied in the energy range 75–1620 keV using time-of-flight techniques. The differential cross sections for inelastic scattering to the 45 and 149 keV levels have been measured with good resolution up to an incident neutron energy of 750 keV. Excitation functions of differential scattering cross sections were obtained at 90° for 13 levels in 238U up to 1190 keV. All these cross sections were determined in an absolute manner. Levels at 939 and 968 keV not previously observed by Coulomb excitation are strongly excited and are most probably intrinsic states of 238U. The differential cross sections at 90° for an incident neutron energy of 1620 keV have also been determined for eight 238U levels between 1210 and 1470 keV. The results have been analysed using the optical model and the theory of Hauser-Feshbach corrected for level with fluctuations within the compound nucleus.

Small-Angle Elastic Scattering of Fast Neutrons and the Electric Polarizability of the Neutron

The differential cross section for elastic scattering of 0.57-MeV neutrons by uranium was measured at seven angles between 3.6\ifmmode^\circ\else\textdegree\fi{} and 18\ifmmode^\circ\else\textdegree\fi{} to a relative accuracy of about 4%. After subtraction of the Schwinger scattering contribution, the data show no evidence of enhanced small-angle scattering such as that previously observed at higher energies by Aleksandrov and by Dukarevich and Dyumin. The present data are consistent with an electric polarizability $\ensuremath{\alpha}$ of the neutron of less than 2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}40}$ ${\mathrm{cm}}^{3}$. As this upper limit to $\ensuremath{\alpha}$ is smaller than the value needed to account for the anomalous small-angle scattering reported by Aleksandrov and by Dukarevich and Dyumin, it is concluded that the enhanced scattering is not produced by an electric polarizability of the neutron.

Elastic and Inelastic Scattering of Fast Neutrons from Co, Cu, and Zn

Elastic and Inelastic Scattering of Fast Neutrons from Co, Cu, and Zn