Differential Neutron Emission Cross Sections Research Articles

A measuring complex for time-of-flight spectrometry of fast neutrons

A measuring complex for solving problems of fast neutron spectrometry using the time-of-flight method has been developed on the basis of an ЗГП-15 electrostatic tandem accelerator operating in a pulsed mode. The pulse repetition rate of the accelerator is 2.5 MHz, and the pulse duration is τ ≤ 1 ns. The accelerator components, some features of their performance, and their main parameters are described. The complex has been used to investigate the differential neutron emission cross sections for different constructional materials. A method providing the stable performance of its measuring channels has been proposed and tested.

Evaluation and validation of d–Li cross section data for the IFMIF neutron source term simulation

A completely new evaluation of the d + 6,7Li interaction cross sections up to 50 MeV has been performed applying a new methodology which takes into account compound nucleus reactions, pre-equilibrium processes, stripping and direct interactions. The evaluated d + 6,7Li cross section data were prepared in the laboratory frame, stored in standard ENDF-6 data format and processed by the NJOY code system. A series of benchmark calculations was performed with the McDeLicious code to test the new data evaluations against experimental thick and thin lithium target neutron yield data up to 40 MeV deuteron energy. It was shown that the new d + 6,7Li cross section data can well reproduce both the thick target neutron yields and differential neutron emission cross sections. Thus there is a clear improvement of the prediction accuracy for the IFMIF neutron source term simulation with the new d + 6,7Li cross section data evaluations.

Double differential neutron emission cross sections for n + 230,231,232,233,234Th reactions

Consistent calculation and analysis of neutron-induced reaction cross sections of 232Th with optical model, the unified Hauser–Feshbach and exciton model, the linear angular momentum dependent exciton density model, the coupled channel theory and the distorted wave Born approximation is carried out in the E n ⩽ 20 MeV energy range based on the experimental data of total, nonelastic, fission, and other reaction cross section and elastic scattering angular distributions. Especially, the analysis includes the elastic and inelastic scattering angular distribution, the inelastic scattering cross sections of discrete levels, the prompt fission neutron spectra, the double differential cross section and the angle-integrated spectra for neutron emission. Theoretical calculations are compared with recent experimental data, other theoretical calculations and evaluated data from ENDF/B6 and JENDL-3. Theoretical models predict the results for n + 230,231,233,234Th reactions.

Measurement of double differential neutron emission cross sections of Fe induced by 14.1 MeV neutrons

We measured the energy spectra and yields of neutrons above 2 MeV emitted from collisions of 14.1 MeV neutrons with an iron target. The measurements we

Modelling double differential neutron emission cross sections for 7LI

Sequential modelling, phase space and two-body scattering models are used to produce a unified model for the double differential neutron cross sections for neutron emission in 7Li for the range of incident neutron energies 5–18 MeV. While satisfactory agreement is obtained with a range of measurements of both double differential and angular distributions, some anomalies are revealed in the competing roles of three-body breakup and sequential reactions in the (n,2n) channel, particularly at the higher incident energies.

Measurements of Double Differential Cross Sections at OKTAVIAN

This is a brief review of the measurements of double differential neutron emission cross sections, which have been done at the OKTAVIAN facility of Osaka University since 1981, for many elements of fusion reactor materials. In the phase-1 experiments, double differential cross sections with high energy resolution and good counting satisfies were accumulated for D, Li, Be, B, C, N, O, F, Na, Al, Si, CI, Ti, Cr, Mn, Fe, Ni, Cu, Zr, Nb, Mo, W and Pb. The ring geometry TOF spectrometer was used in the phase-1, a drawback of which was due to the considerable variation of incident energy. In the phase-2 experiments, a new TOF spectrometer was installed for fixing the incident neutron energy to be 14.1 MeV and keeping the energy resolution and counting statistics. We can then obtain angle-integrated emission spectra and partial differential cross sections from measured double differential neutron emission cross sections. In the phase-2, measurements have been done for Be, C, 10B, 11B, F, Mg, Al, Si, V, Cr, Fe, Ni, Cu, Pb and Bi. All the data in the two phases have been efficiently utilized to improve evaluated neutron cross sections in JENDL-3, EFF-l and ENDF/B-VI.

Measurements of double differential cross sections at OKTAVIAN.

This is a brief review of the measurements of double differential neutron emission cross sections, which have been done at the OKTAVIAN facility of Osaka University since 1981, for many elements of fusion reactor materials. In the phase-1 experiments, double differential cross sections with high energy resolution and good counting satisfies were accumulated for D, Li, Be, B, C, N, O, F, Na, Al, Si, CI, Ti, Cr, Mn, Fe, Ni, Cu, Zr, Nb, Mo, W and Pb. The ring geometry TOF spectrometer was used in the phase-1, a drawback of which was due to the considerable variation of incident energy. In the phase-2 experiments, a new TOF spectrometer was installed for fixing the incident neutron energy to be 14.1 MeV and keeping the energy resolution and counting statistics. We can then obtain angle-integrated emission spectra and partial differential cross sections from measured double differential neutron emission cross sections. In the phase-2, measurements have been done for Be, C, 10B, 11B, F, Mg, Al, Si, V, Cr, Fe, N...

Measurement of Double Differential Neutron Emission Cross Sections for Incident Neutrons of 14 MeV

To provide accurate double differential neutron emission cross sections of fusion reactor candidate elements at En = 14 MeV, a fixed 8.3 m TOF facility with an NE213 detector of 25.4 cm diameter was installed in the 85° direction of a pulsed D-T source. Detail of scattering experiment using this facility is described. Energy resolution is ± 0.21 MeV at 14 MeV and good counting statistics is attained by about 1/h run using a cylindrical sample of 3 cm in diameter and 7 cm long. Measurements of double differential neutron emission cross sections are carried out for C, F, Mg, Al, Si, V, Cu and Pb. Results are compared with evaluated neutron emission data. Energy resolution is sufficient enough to deduce partial angular differential cross sections for elastic and discrete inelastic scatterings.

Measurement of double differential neutron emission cross sections for incident neutrons of 14MeV.

Measurement of double differential neutron emission cross sections for incident neutrons of 14MeV.

Neutron emission cross section measurements with a 14 MeV neutron generator

The PINSTECH 14 MeV Neutron Generator Facility has been used for the measurements of double differential neutron emission cross sections of Al, Cu and Pb in the emitted neutron energy range of 3–14 MeV and in the 30°–130° range. Integrated neutron emission cross sections are given and compared with previously reported values.

Double differential neutron emission cross sections of10B AND11B at 6, 10 and 14 MeV and of6Li,7Li and12C at 14 MeV

Abstract Neutron emission spectra of 10B and 11B were measured at 6, 10 and 14.1 MeV and those of 6Li, 7Li. and carbon at 14.1 MeV using time-of-flight techniques. Absolute double differential cross sections were obtained by using scattering from hydrogen as a cross section reference. Integration over energy ranges and solid angle yielded integrated elastic and total neutron emission cross sections. At 6 and 10 MeV excellent agreement with total cross section data is found; at 14.1 MeV the new data tend to be higher than expected. The biggest error source in the continuous spectra stems from uncertainties in the input library (ENDF/B-V) of the Monte Carlo correction for multiple scattering. In particular, the library for 11B appears to be very unrealistic, with a total elastic cross section at 14.1 MeV which should be higher by 50%.

Measurements of Double Differential Neutron Emission Cross Sections for Fusion Reactor Candidate Elements

Measurements of Double Differential Neutron Emission Cross Sections for Fusion Reactor Candidate Elements

Measurements of double differential neutron emission cross sections for fusion reactor candidate elements.

Double differential neutron emission cross sections (DDX) are useful for the fusion neuronics calculations. Using the intense 14 MeV neutron source facility OKTAVIAN, an experimental system has been established to measure DDX of candidate material elements for fusion reactor. Energy spectra of secondary neutrons from ring scattering samples are measured with high accuracy by means of the time-of-flight technique. The DDX data for D, O, Si, F, Ti, Mn and Bi are shown in the energy range of 14–0.3 MeV of secondary neutrons and the data for Li, Be, Pb and Bi are given in the range of 14 MeV–50 keV. Measured data are mainly compared with the calculations based on ENDF/B-IV.