Relative yields have been measured in the 40-130 MeV bremsstrahlung induced reactions of 59Co. The experiments have been performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line γ-ray spectrometric technique. The bremsstrahlung photon flux has been calculated with the Geant4 program. The cross sections were calculated by using computer code TALYS-1.96 with different models and are found to be in good agreement with the experimental data.

The yields of photonuclear reactions in the Ag-107, In-113, and In-115 nuclei were measured. Monte Carlo simulations were performed using the Geant4 code, and the results were compared with the experimental values. The isomeric ratios of the yields in the reactions Ag-107(gamma, n)(106)m,g Ag and In-113(gamma, n)(112)m,g In were determined, and the cross sections for the reactions Ag-107(gamma, n)(106)g Ag and Ag-107(gamma, 2n)Ag-105 at an energy of 20 MeV were calculated based on the experimental data.

First nuclear activation experiments have been carried out using the new accelerator for relativistic particles NUCLOTRON in Dubna. The distribution of neutrons emitted during the irradiation with 0.65, 1.0 and 1.5 GeV protons from a lead target (empty set = 8 cm, 1= 20 cm) and moderated by surrounding paraffin of 6 cm thickness was studied with radiochemical sensors along the beam axis on top of the moderator. Small(139) Lasensors of approximately 1 g each were used to measure essentially the thermal neutron fluence at different depths near the surface: i. e. on top of the moderator, in 10 mm deep holes and in 20 mm deep holes, respectively. The reaction La-139 (n, gamma) La-140 (tau(1/2) = 40.27 h) was studied using standard procedures of gamma-ray spectrometry and data analysis The induced activity of La-140 increases strongly with the depth of the hole inside the moderator. Its activity distribution along the beam direction on top of the moderator has its maximum about 10 cm downstream the entrance of the protons into the lead and the activity increases about linearly with the proton energy. Some comparisons of the experimental results with model estimations based on the LAHET code are also presented. The experiments were carried out in the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna, Russian Federation.

The cross sections for the reactions 165 Ho(γ, n) 164 Ho, 165 Ho(γ, 3n) 162m Ho, 165 Ho(γ, 4n) 161 Ho, 165 Ho(γ, 5n) 160m1 Ho, 165 Ho(γ, 5n) 160 Ho, and 165 Ho(γ, 6n) 159 Ho were experimentally determined in the energy range from 50 to 110 MeV. Also, calculations were performed using the Geant4 code and the Talys program to determine the cross section of reactions in holmium samples. Calculation results are compared with the obtained experimental results. The dependence of the isomeric ratio 160m1 Ho/ 160 Ho on the electron energy has been measured.

In 2011–2012, experiments on the irradiation of the target assembly of “Quinta” setup containing 500 kg of metallic natural uranium with a deuteron beam showed that the average energy of the resulting neutrons increases with the energy of the incident deuterons. Thin-film breakdown counters (TFBC) were used to study the quantitative characteristics of this effect. The results of fission rates measurement in natU and 209Bi targets of the TFBC detectors located at different distances along the deuteron beam axis, experimental values of the natU/209Bi rates ratio and neutron integral fluxes at the energies above 1 and 20 MeV are presented. A comparison of the experimental and calculated results on the fragment fission rates is presented.

This paper shows the results from the experiment that was done in JINR (Joint Institute for Nuclear Research) Dubna. Thorium foil between two aluminum foils was irradiated inside Phasotron with 100 MeV protons. As a result - gamma spectra was obtained from the Th and aluminum foils and residual nuclei cross-sections were evaluated from the reaction. Also there was made a simulation analysis of the beam distribution inside the Th foil and particle escape from the target. The experimental cross-sections were compared with calculations made in Monte-Carlo simulation (MCNP 6.1).

Lead converter was irradiated with electron beams with energies of 60, 80 and 100 MeV. And holmium samples were irradiated with a flux of bremsstrahlung, which was formed in a lead converter. The rates of about 20 photonuclear reactions in 165Ho, which are induced by bremsstrahlung, were measured. Simulations to determine the fluence of electrons, photons, neutrons for holmium samples and the reaction rates for the obtained isotopes in the samples were performed using the Geant4 code. For those radionuclides that are determined in experimental measurements, the results were compared.

Four Monte-Carlo codes where tested to simulate bremsstrahlung spectra for accelerated electron beams at the energy range 4-20 MeV. All four codes give the same shape of the spectrum, in which in addition to the bremsstrahlung part there are characteristic energy lines of the target atom and an annihilation line of 0.511 MeV caused by secondary processes of the photoelectric effect and of electron-positron pair production. The absolute values of the energy spectrum have close magnitudes but it requires a more thorough study.

A massive lead spallation target was irradiated with 660 MeV protons to generate a secondary neutron field. The field was studied via measurement of the residual nuclei generation in the lead activation samples located inside the target. Experimental results were compared with the Monte Carlo simulations using Geant4 and MCNPX 2.7.0 codes. The comparison shows a general agreement between experiment and simulation and thus serves as a validation of the utilized codes, high-energy nuclear models (ICLXX_HP, BIC_HP, BERT_HP, and INCL4.2) and nuclear data libraries (ENDF/B-VII.1), which can be used for the development of the subcritical accelerator-driven systems in the future.

At the Joint Institute for Nuclear Research (JINR) we are involved in the Accelerator-Driven-System (ADS) research. We perform experiments with assemblies composed of a spallation target and a subcritical blanket irradiated with high-energy proton or deuteron beams that generate high-energy neutron fields by spallation and fission reactions. In this paper, three uranium assemblies are presented: Energy plus Transmutation (E+T), QUINTA and BURAN. We discuss the results of the E+T and QUINTA irradiations by 1.6 GeV deuterons and 660 MeV protons, respectively. We have focused on the regions close to the primary beam passage through the targets. The field has been measured using activation detectors of 209 Bi, 59 Co, and nat Pb. Monte Carlo simulations using MCNPX 2.7.0 have been performed and compared to the experimental results. We discovered that the field intensity near the primary beam is very dependent on the precision of the accelerator beam settings. Therefore, a Monte Carlo-based study of the influence of the uncertainty of primary proton beam parameters on experimental result accuracy of the QUINTA assembly has been carried out. The usage of MCNPX 2.7.0 in the future BURAN irradiations has been assessed.

Calorimetric experiments have been performed to analyze different thick targets of U-nat, C, Pb material, irradiated by 660 MeV protons at the Phasotron accelerator facility, Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The method of online temperature measurement has been compared with MCNPX 2.7.0 simulation and selected with Ansys Transient Thermal Simulation to compare measured temperature with the simulated one. Thermocouples type T and E have been used as a temperature probe. Many different positions have been measured for each target. Temperature results are following very well the processes inside of the cylinders. Changes of heat deposition caused by drops of the proton beam intensity are displayed very well as a jagged line shown in almost every chart. Accurate temperature changing measurement is a very modest variation of how to observe inner macroscopic behavior online.

We used the phasotron of the Laboratory of Nuclear Problems at JINR to irradiate isotopically pure Bi-209 target with 660 MeV protons. Cross sections of the fragment production with mass numbers 24 <= A <= 210 u were measured for the first time using the direct gamma-spectrometry method with a high-resolution HpGe detector. The gamma lines of the fragments have been identified, and the cross sections determined by the DEIMOS code. The results of the measured nuclide cross section have been parametrized in terms of a three-parameter equation in order to reproduce the real isobaric distribution. Fission and spallation mass yields have been reconstructed on the base of charge distribution of reaction products. The main reaction results have been compared with other experimental data obtained from the proton-induced reaction at 600 MeV as well as with theoretical model calculations using the CRISP code.

Independent and cumulative production cross sections for radioactive nuclear fragments from the deuteron-irradiation of isotopically enriched lead (Pb-204, (206)pb, Pb-207, and Pb-208) targets were obtained for the first time. The experiment has been performed with a 4.4 GeV deuteron beam from the Nuclotron of the Laboratory of High Energy Physics (LHE), Joint Institute for Nuclear Research (JINR) at Dubna. The production cross sections of target fragments were determined by off-line 7-ray spectroscopy. Charge dispersion and massyield distributions were deduced from these data. The results are discussed in terms of the relative importance of different reaction mechanisms (evaporation-spallation, fission and multifragmentation). Comparison of our results with the data from the reaction induced by protons of about the same kinetic energy per nucleon, has been performed. The coexistence of the different decay modes in the formation of the reaction residues, such as spallation, fission and multifragmentation is suggested.

The activation experiment was performed using the accelerated beam of Phasotron accelerator at the Joint Institute for Nuclear Research (JINR). The natural uranium spallation target QUINTA was irradiated with protons with energy 660 MeV. Monte Carlo simulations of neutron production were performed using the Geant4 code. The number of leakage neutrons from the sections of the uranium target surrounded by the lead shielding and the number of leakage neutrons from lead were determined. The total number of fissions in the setup QUINTA was determined. Experimental values of reaction rates for the produced nuclei in the I-127 sample were obtained and several values of reaction rates were compared with the results of simulations. Experimentally determined fluence of neutrons in energy interval 10-175 MeV using the (n,xn) reactions in the I-127(NaI) sample was compared with the results of simulations. Possibility of transmutation of the long-lived radionuclide I-129 in the QUINTA setup was estimated.

The experimental measurement data on the fine structure of beta-decay strength function Sβ(E) in spherical, transitional, and deformed nuclei are analyzed. Modern high-resolution nuclear spectroscopy methods made it possible to identify the splitting of peaks in Sβ(E) for deformed nuclei. By analogy with splitting of the peak of E1 giant dipole resonance (GDR) in deformed nuclei, the peaks in Sβ(E) are split into two components from the axial nuclear deformation. In this report, the fine structure of Sβ(E) is discussed. Splitting of the peaks connected with the oscillations of neutrons against protons (E1GDR), of proton holes against neutrons (peaks in Sβ(E) of β+/EC-decay), and of protons against neutron holes (peaks in Sβ(E) of β–-decay) is discussed.

The fission rates of natural uranium and thorium were measured in the particle field of Quinta, a 512 kg natural uranium target–blanket sub-critical assembly. The Quinta assembly was irradiated with deuterons of energy 4 GeV from the Nuclotron accelerator of the Joint Institute for Nuclear Research (JINR), Dubna, Russia. Fission rates of uranium and thorium were measured using Gamma spectroscopy and fission track techniques. The production rate of 239Np was also measured. The obtained experimental results were compared with Monte Carlo predictions using the MCNPX 2.7 code employing the physics and fission–evaporation models of INCL4–ABLA, CEM03.03 and LAQGSM03.03. Some of the neutronic characteristics of the Quinta are compared with the “Energy plus Transmutation (EpT)” subcritical assembly, which is composed of a lead target and natU blanket. This comparison clearly demonstrates the importance of target material, neutron moderator and reflector types on the performance of a spallation neutron driven subcritical system.

Three photo plates derived with spectrograph LNP JINR with constant magnetic field [1] have been investigated using the Microscope Automatic Scanning MAS [2]. Electron internal conversion (ICE) spectrograms of two erbium (Er P-2, Er P-8) and one Ho fractions has been measured. More detailed analysis gave us the possibility to obtain some new lines (see table) in addition to many earlier existing lines in 160Dy [3]. For that investigations it is necessary to increase the speed with which microscopic objects are measured are described. These efforts include the modernization of the MAS automatic scanning microscope and the development of programs to reach an initial point and for carrying out automatic point-to-point linear transitions with a specified step. The error in realizing a transition to a given point with specified coordinates is shown to amount to 1 µm.

The isoscaling behavior of the fragment production cross section was studied for reactions with deuterons on enriched lead targets ( 204 Pb, 206 Pb, 207 Pb, 208 Pb). The information about the reaction mechanism as well as the origin of the residues in the mass range 20 ≤ A ≤ 100 were obtained. During the analysis it was found the same behavior of the reactionmechanism as in the reactions with deuteron on enriched tin isotopes ( 112 Sn, 118 Sn, 120 Sn, 124 Sn). In the present article the estimation of the temperature and the symmetry energy coefficient of composite systems was done.

The experimental study of the beam power gain for deep-subcritical uranium target assembly Quinta (mass of natural uranium 512 kg) under relativistic protons, deuterons and carbon nuclei irradiation is presented. The Quinta assembly was irradiated with 0.66 GeV protons, 1, 2, 4, and 8 GeV deuterons and 24, 48 GeV carbon nuclei from the Phasotron and Nuclotron accelerators at the Joint Institute for Nuclear Research (JINR), Dubna. The beam power gain values obtained for the target assembly Quinta were extrapolated for a quasi-infinite uranium target using the results of the R.G. Vasilkov et al. [1]. The obtained results can be used in the ADS reactor design.

The flux of secondary neutrons generated in collisions of the 660 MeV proton beam with the massive natural uranium spallation target was investigated using a set of monoisotopic threshold activation detectors. Sandwiches made of thin high-purity Al, Co, Au, and Bi metal foils were installed in different positions across the whole spallation target. The gamma-ray activity of products of (n,xn) and other studied reactions was measured offline with germanium semiconductor detectors. Reaction yields of radionuclides with half-life exceeding 100min and with effective neutron energy thresholds between 3.6 MeV and 186 MeV provided us with information about the spectrum of spallation neutrons in this energy region and beyond. The experimental neutron flux was determined using the measured reaction yields and cross-sections calculated with the TALYS 1.8 nuclear reaction program and INCL4-ABLA event generator of MCNP6. Neutron spectra in the region of activation sandwiches were also modeled with the radiation transport code MCNPX 2.7. Neutron flux based on excitation functions from TALYS provides a reasonable description of the neutron spectrum inside the spallation target and is in good agreement with Monte-Carlo predictions. The experimental flux that uses INCL4 cross-sections rather underestimates the modeled spectrum in the whole region of interest, but the agreement within few standard deviations was reached as well. The paper summarizes basic principles of the method for determining the spectrum of high-energy neutrons without employing the spectral adjustment routines and points out to the need for model improvements and precise cross-section measurements.