The energy dependence of the light output for secondary charged particles (protons and alpha-particles) was measured in the neutron energy range of 1.5-14.0 MeV for an array of scintillation detectors based on a EJ-200 scintillator. The scattering of a tagged neutron beam with an energy of 14.1 MeV on graphite and polyethylene samples was used to obtain neutrons with known energies at different angles. Based on the obtained data, both the response function and the intrinsic efficiency of the detectors used were simulated in GEANT4. To verify the simulated efficiency a method based on the measurement of elastically scattered neutrons from the 1H(n,n0)1H reaction was implemented.

Data taking has been started at the first stage of the SPASCHARM experiment on systematic study of the spin effects in strong interactions. The current setup configuration is described, and the detector characteristics attained during the beam data taking in the runs of 2018–2022 are listed.

Within the TANGRA project framework, a new experimental setup has been constructed for the measurement of reaction cross sections (n, X, γ) in the interaction of 14.1 MeV neutrons with nuclei. The facility has a special feature: the use of the tagged neutron method. This method enables efficient separation of background and useful events, as well as accurate tracking of neutron flux. Test measurements were performed on 28Si, 12C, and 16O nuclei, and the results showed satisfactory agreement with available experimental data. This paper presents the features of the setup design and the methodology for processing the obtained experimental data

Most gamma-ray scintillation detectors currently in use are made from inorganic materials that have a relatively high electron density. Quite often they are used to build multidetector systems that provide high scintillation light output. The performance of a gamma radiation detector (its detection efficiency) depends on the shape and size of the crystal, as well as on the source-to-detector geometry used. The NaI(Tl) gamma detector exhibits moderate energy resolution but relatively high gamma-ray detection efficiency and fast time response. In this work, the efficiency and resolution of a scintillation hexagonal detector are studied to optimize its response function. This type and size of scintillator were selected to construct a budget-friendly, reconfigurable, easy-to-maintain multidetector system for registering gamma-rays following fission, capture, and inelastic neutron scattering reactions, with reasonably good energy and time resolutions The research results made it possible to establish a geometric solid angle that increases the efficiency of recording gamma-ray radiation of the hexagonal NaI(Tl) scintillation probe under study.

A study of the inelastic scattering of neutrons with an energy of 14.1 MeV on the nuclei of oxygen, phosphorus and sulfur was carried out at the TANGRA facility at JINR (Dubna). The purpose of the experiment was to refine existing and obtain new data on the yields and angular distributions of γ-quanta emitted by the studied nuclei as a result of neutron-induced nuclear reactions using the tagged neutron method. Two types of detector systems were used to register γ-quanta. The γ-ray yields were measured using a high-purity germanium (HPGe) detector. The angular distributions of γ-rays were obtained using a system of 18 scintillation detectors based on bismuth germanite Bi 4 Ge 3 O 12 (BGO) located around the sample. As a result of the studies carried out, the yields of two transitions for the reaction of tagged neutrons with 16 O, nine transitions for the reaction with 31 P, and nine transitions for the reaction with 32 S were measured for the first time. The angular anisotropy of the γ-radiation accompanying the inelastic scattering of neutrons with an energy of 14.1 MeV on 31 P nuclei was also measured for the first time.

The results of determining the mass concentration of carbon in soil are discussed. The measurements were made on a facility operating according to the tagged neutron method, which consists of irradiating samples with 14 MeV fast neutrons and detecting the characteristic spectra of gamma rays from inelastic neutron scattering at specific time ranges between neutron emission and arrival of the γ-quantum signal. The values of the accuracies of the measurements have been estimated, the standard deviation of the repeated measurements for concentrations of carbon of 1–3

The prototype of polarized deuteron source was made for the Van de Graaff accelerator of the Czech Technical University in Prague with aim to create full scale setup for producing polarized neutron beam for experiments on measurement Δσ_L and Δσ_T , longitudinal and transversal spin asymmetries in transmission polarized neutron beam through frozen polarized deuteron target. It is based on Kaminsky’s experiment on channeling deuterons through a magnetized Ni single crystal foil of 1–2 μm. It is proposed to use the reaction T (d,n)^4 He with polarized deuterons of an energy 150–200 keV. For a nonchanneled beam (the goniometer in a random position), the tensor polarization measurements were carried out with a TiT target. Our result is P_zz = - 0.10 ± 0.02 . This result indicates that deuterium atoms that have passed outside the channels also become polarized due to the capture of polarized electrons from the nickel crystal.

The SPASCHARM experiment is aimed at a systematic study of the nucleon spin structure and the spin dependence of the strong interaction of antimatter and matter with matter at energies up to 45 GeV. As part of the first stage of the experiment, the study of the spin properties of hadrons will take place in a beam of negatively charged hadrons on existing beamline 14 at the operating SPASCHARM setup at the U70 facility. At the second stage, the production of polarized beams of protons and antiprotons is envisaged in beamline 24A of the U-70 accelerator facility. A polarized antiproton beam will certainly become a unique beam in the world. It is planned to measure single-spin asymmetries in dozens of reactions, both on hydrogen and on various nuclei. At the SPASCHARM facility, it is also possible to measure the transverse polarization of hyperons and elements of the spin density matrix of vector mesons. The spin structure of the nucleon will be investigated in the study of quarkonium production to determine the contribution of gluons to the proton spin. The presence of two types of polarized beams and eight types of nonpolarized beams (π ± , K ± , p , p̅ , d , C ), in combination with a polarized target, expands the range of studies of polarization phenomena and enhances the uniqueness of the project.

Tagged neutrons with an initial energy of 14.1 MeV scattered on a carbon sample are measured within the framework of the TANGRA project. Angular distributions of neutrons are obtained for elastic scattering and scattering to the first excited state of 12 C with an energy of 4.44 MeV. Results are compared to experimental data from other authors and model calculations performed using a coupled channels model with a deformed optical potential.

Учебное пособие написано на основе курса лекций «Свойства атомных ядер», читаемом для студентов магистратуры на физическом факультете МГУ им. М.В. Ломоносова. В пособии разбираются как фундаментальные, так и прикладные аспекты физики нейтрона и нейтронной физики и демонстрируется их связь с более общими проблемами ядерной физики. Рассмотрены такие вопросы, как свойства нейтрона, основные типы ядерных реакций взаимодействия нейтронов с атомными ядрами, а также роль нейтронов в астрофизических процессах. Представлен обзор источников нейтронов, а также изложены некоторые вопросы, связанные с практическим использованием нейтронов. Пособие рассчитано на студентов нефизических специальностей, а также людей, интересующихся современными проблемами физики.

In the framework of TANGRA-project at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear research in Dubna (Russia), two experimental setups (Fig. 1) have been designed and tested for investigation of 14-MeV neutron-induced nuclear reactions on a number of important for nuclear science and engineering isotopes. As a source of 14-MeV “tagged” neutrons we are using the VNIIA ING-27 steady-state portable neutron generator with embedded in its vacuum tube 64-pixel charge-particle detector. The “Romashka” system is an array of up-to 24 hexagonal NaI(Tl)-crystal scintillation probes, while the “Romasha” array consists of 18 cylindrical BGO-crystal detectors of neutrons and gamma-rays. In addition to these detectors there is a HPGe gamma-ray spectrometer and a number of Stilbene detectors that can be added for high-resolution gamma-ray spectrometry and neutron-gamma detection. The main characteristics of the neutron-induced nuclear reaction products can be investigated by commissioning the detectors in suitable for these experiments’ geometries. Both setups can be used for doing basic and applied scientific research, because they permit simultaneously to measure the energy, angle and multiplicity distributions of gamma-rays and neutrons, produced in the competitive neutron-induced nuclear reactions (n, n’γ), (n,2n), (n, xnγ) and (n, f) in pure or complex substances.

The response function of the BGO, NaI (Tl) and LaBr3(Ce) scintillation detectors to monoenergetic gamma quanta was built on the basis of Monte Carlo simulations using the GEANT4 toolkit and calibration measurements with gamma radiation sources of different energies. The response function consists of seven components: the first six constitute the detector’s response to a direct hit of monoenergetic gamma radiation and depend on the properties of the detector (size, material, energy resolution, etc.), and the seventh component represents the effect of surrounding materials on the measured gamma spectrum. For each component of the function, the analytical form of the energy dependence is determined and its parameters are found when registering gamma quanta with energies in the range from 0.3 MeV to 10 MeV.

Using the tagged neutron method at the "TANGRA" facility at Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research based on the ING-27 standard neutron generator, a study of the 14.1 MeV inelastic neutron scattering reaction on different nuclei was carried out. The angular distributions of g-quanta accompanying inelastic neutron scattering on atomic nuclei were measured. This article presents a GEANT4-based program that allows calculating the interaction of fast neutrons with matter and simulating the experiment and also presenting the results of the experiment in a convenient and visual form. Using the written program, optimal target parameters were determined. The algorithm used by the program is given in this work. The general description of the experimental installation, data collection and processing systems is given.

The work is devoted to determining the response function of the detector NaI(Tl) for g -quanta with energy of 4.43 MeV, formed during inelastic scattering of neutrons with energy of 14.1 MeV on the nuclei 12C. In gamma spectrometry, output pulses are recorded, the amplitudes of which are proportional to the energy lost in the detection medium by incident photons. One of the main tasks of radiation detection is to restore radiation characteristics from signals measured at the outputs of detectors. For this, it is necessary to know, first of all, the general characteristics of detectors as converters of radiation into signals. The main characteristic of the detector is its response function, which can be defined as the probability that a particle with given properties generates a certain signal in the detector that will be registered by the device. The article presents the results of modeling the response function of a scintillation detector based on a NaI(Tl) crystal for gamma radiation from inelastic fast neutron scattering in order to study the mechanism of its formation.

Scintillation NaI(Tl) crystals are typically utilized at room temperature for detection of energetic photons in high energy and nuclear physics research, non-destructive analysis of materials testing, safeguards, verification of nuclear treaty, geological exploration and therapeutic imaging. The present work provides a new geometry for the source-to-detector combination. A special order cubic detector with rectangular cavity was used. The mathematical expressions of the path-lengths traveled by the incident photon as well as the geometrical solid angle were derived. The detector efficiency was determined for an axially positioned standard point-like gamma-ray source using the analytical efficiency transfer technique. Geant4 Monte Carlo simulation code was also used to predict the detector response under the calibration geometry. The analytical efficiency transfer and Geant4 simulation results were compared with those obtained experimentally and a good agreement between them was shown.

A study of the reaction of inelastic scattering of 14.1 MeV neutrons by 23 Na nuclei was carried out at the TANGRA facility using the tagged neutron method. In this work, the energies of visible g-transitions are determined, the yields of g -quanta are obtained, the angular distributions of g -quanta for 23 Na are measured. The results obtained are in good agreement with the data of other published experimental works.

In the frame of TANGRA-project at JINR-FLNP (Dubna) we measured the gamma-rays resulting from the inelastic scattering of 14.1 MeV neutrons on magnesium. As a source of neutrons we used ING-27 portable neutron generator of VNIIA (Moscow) where the neutrons are produced in a d-t fusion-fission nuclear reaction, H(d,n)He. The α-particles were registered by a 64-pixel Si charge particle detector embedded in ING-27 vacuum chamber. The sample tested was a 10cm-thick plastic cube filled with MgO powder. The gamma-rays from the interaction of neutrons with the sample we registered by a Romashka-type Fe-protected array, consisted of 22 hexagonal NaI(Tl) scintillator prisms. The analog signals form all the αand γdetectors were collected in list-mode, simultaneously, by a computerized 32-channel data acquisition system (DAQ) from JINR AFI-electronics, which was used, also, for digitizing and storing the waveforms on the computer hard-drive for further off-line analysis with CERN-ROOT modular scientific software toolkit. Using the time-correlated associated particle method (TCAPM), also known as tagged neutron method (TNM), the influence of the background radiation on the collected gamma-ray spectra was

Low cost scintillation detectors as compared with HPGe detectors are considered to be one of most important radiation detection tools. Therefore, these detectors can be manufactured in different shapes and work at room temperature without any cooling systems, which added an extra advantage to it. This work presents a study of a cubic detector with a rectangular cavity in different experimental setup geometries, using standard point-like gamma-ray sources, where the efficiency of the detector in these geometries was the target to be studied. According to this aim, the data from the experimental measurements was used to determine the detector efficiency. An analytical calculation of the detector efficiency was done by using a new mathematical expression, this mathematical expression depends on the efficiency transfer technique and effective solid angle calculations. To support the mathematical model, the source-to-detector arrangement was simulated by Geant4 Monte Carlo code. All the compared efficiency results were found to be promising and trusted based on the calculated deviation percentages.