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Based on the Gravel algorithm and the MLEM algorithm, the neutron energy spectrum unfolding algorithms has been developed by using the SY2001 plastic scintillator detector in its entirety to experimentally measure neutron source characterization of the compact D–D neutron generator. In particular, the degree of optimization of the Mean Relative Error (MRE) is proposed as a determinant of the appropriate termination point for iterations to improve the adaptive nature of the algorithm. The developed neutron energy spectrum unfolding algorithms measure the neutron energy spectra and the neutron angular yields of the compact D–D neutron generator, which are compared with Monte Carlo calculated results. Given the good agreement with the existing results, the developed unfolding algorithms can be used to accurately unfolding neutron energy spectrum, especially, for non-pulsed neutron sources. The measured neutron source characterization results show that the compact D–D neutron generator can produce high yields and quasi-mono-energetic neutrons in the range from 2.2 to 2.8 MeV. The D–D neutron angular yields are anisotropic distributions, particularly, which are relatively higher with neutron emission angles ranging from 40 ∘ to 120 ∘ . This work measure the neutron energy spectra and the neutron angular yields of the compact D–D neutron generator in Lanzhou University, which provide detailed neutron source characterization for using it in neutron physics and neutron application technology.

Worldwide efforts to tackle the nature of exotic nuclei comprise the construction of new-generation Radioactive Ion Beam facilities. The Italian community is deeply involved in the process and the construction of SPES at Legnaro National Laboratories (INFN) is progressing. This contribution describes the layout of SPES in all its flavours, from Nuclear Physics to Applications in Nuclear Medicine and Neutron Physics. In particular, the status of the SPES-β ISOL facility, together with some of the relevant physics cases and the associated equipment are described.

Results of the measurements of neutron spectra at two points at the intense resonance neutron source (IREN) of the JINR’s Laboratory of Neutron Physics are presented. Powerful neutron fluxes are obtained using an electron accelerator and the thick tungsten target, in which neutrons are produced by bremsstrahlung gamma-quanta of electrons hitting the target. The tungsten target is placed in a cylindrical vessel filled with water. Neutron spectra were obtained using a multisphere Bonner spectrometer at two points behind biological shielding. Based on the spectra obtained, the effective neutron dose rates at the measurement points were determined, which is of importance both for assessing the radiation situation at IREN and for comparison with the readings of neutron dosimeters of the automated radiation monitoring system.

As part of an international cooperation the research team from the Slovak University of Technology is involved in the development of new radiation shielding experimental workplaces for code verification and demonstration of radiation shielding principles. One of these activities is the so called “Mini Labyrinth” experiment. It is a simple neutron and gamma shielding benchmark, inspired by the ALARM-CF-AIR-LAB-001 ICSBEP experiment. The STU Mini Labyrinth, as its name implies, is a mini version of the original IHEP Labyrinth, currently with dimensions of 96 × 60 × 25 cm. The experimental setup is placed on a special deck in the neutron physics laboratory of STU and uses remote source handling mechanism and video surveillance. It consists of several NEUTRONSTOP C5 shielding blocks (polyethylene with 5% boron), several detector positions and two channels to insert the neutron source and to generate thermal neutrons. The first one is a plastic tank filled with liquid moderator and a second one is a solid graphite prism, which is ideal to produce thermal neutrons. In the previous works of the research team, efforts were made to find the best setup for measurement inside and outside the Mini Labyrinth. It was found out that the 25 cm height was not appropriate, therefore it was increased to 50 cm by adding an extra level of NEUTRONSTOP blocks. This paper brings the results of first measurements performed on the V3-50-R measurement geometry and their comparisons with simulations using the Monaco code from the SCALE 6 system. In this measurement setup, the neutron source is placed inside the graphite prism and the aim is to measure and simulate the thermal neutron count-rate.

A neutron gate is proposed for the accumulator with nonmagnetic walls. The gate is a part of the accumulator wall to which a magnetic field is applied during the neutron pulse as inflow of neutrons into the accumulator occurs. At this time, the gate operates based on the compensation of the nuclear potential of the neutron interaction by the magnetic potential. In intervals between neutron pulses, the probability of neutron absorption in the gate and in the entire accumulator is defined by the subbarrier reflection of neutrons from the accumulator wall, being as small as 10 –5 −10 –4

A number of fast reactor projects suggest using neptunium nitride (NpN) as a fuel. Given that the neutron-physical characteristics of Np-237 are insufficiently studied, a detailed analysis of the libraries of evaluated nuclear data is necessary for numerical modeling of the reactor operation. The purpose of this study is to compare libraries to reduce the errors in calculating the critical mass of Np-237. The experimental values of K -eff (found in the experiment conducted at Los Alamos National Laboratory in 2002) are compared with the calculated values obtained using various software packages (MCNP, Serpent) and 14 libraries of evaluated nuclear data (JEFF, ENDF, JENDL, TENDEL, ROSFOND).

The Italian theorist Gian-Carlo Wick is well known for his work in mathematical physics. Nevertheless, working with Fermi’s group in Rome in the 1930s, he took on several behind-the-scenes roles that resulted in important papers in neutron physics. He clarified Fermi’s methodology for calculating neutron slowing down probabilities; using transport theory, he provided a comprehensive general method for calculating the neutron scattering albedo; and with an insight into the way, neutron scattering could yield information about lattice dynamics, he formulated the first theory of inelastic thermal neutrons scattering in crystalline materials. This work and his contributions are not well known today. We discuss its physical essence, its relevance to neutron physics, and its subsequent impact in later work.

Several neutron sources are available at Research Centre Řež (CVŘ) that are usable in neutron physics and radioanalytical measurements, namely two experimental nuclear reactors—a ‘zero’ power (maximum 5 kW) LR-0 reactor and a medium power (maximum 10 MW) LVR-15 reactor, a 252 Cf source and a D–T generator of fast neutrons. Their basic parameters and modes of applications in various fields of science and technology are described. The reactors and other neutron sources are equipped with a number of gamma-ray (mostly High Purity Germanium (HPGe)), and neutron spectrometers to allow for assay of studied materials. Most of the above facilities are available in an open-access regime.

The CERN n_TOF facility is a research infrastructure specifically designed for studying neutron-induced nuclear reactions. Pulsed white neutron beams are delivered toward three experimental areas, two of them at different baselines to apply the time-of-flight technique, and another one very close to the neutron source for activation studies. High intensity and high neutron energy resolution make n_TOF a unique facility. A major component of the physics program at n_TOF is dedicated to the measurement of key neutron induced reactions for nuclear astrophysics, relevant to nucleosynthesis in stars, the Big Bang primordial nucleosynthesis as well as Cosmochronology. A review of the relevant results obtained at the n_TOF facility is reported, together with details of challenging new measurements in preparation.

The problem of finding the depolarization losses of neutrons is investigated in connection with the need to determine the systematic error for experiments with magnetic storage of ultracold neutrons in traps. In this paper, we consider three methods to estimate the neutrons depolarization probability: classical, quantum mechanical and approximate one. They are used to estimate the depolarization probability of ultracold neutrons in two magnetic traps: the trap developed in Los Alamos National Laboratory (LANL) and the one designed in the neutron physics laboratory of “NRC Kurchatov Institute”—PNPI. It is shown that all three methods are successfully used to estimate depolarization. This is of particular importance to compare of theoretical predictions with the results of measurement in experiments to determine the neutron lifetime.