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The paper presents the measured cumulative yields of 44 Ti for nat Cr, 56 Fe, nat Ni and 93 Nb samples irradiated by protons at the energy range 0.04–2.6 GeV. The obtained excitation functions are compared with calculations of the well-known codes: ISABEL, Bertini, INCL4.2+ABLA, INCL4.5+ABLA07, PHITS, CASCADE07 and CEM03.02. The predictive power of these codes regarding the studied nuclides is analyzed.

The possibility of verifying benchmark experiments which are necessary for design validation of the blankets of the TIN-ST thermonuclear neutron source based on the I-2 proton accelerator using neutrons from the reaction 7Li(p, n) is analyzed. It is shown that modern software and databases are effective in calculating the neutron spectra for two types of thorium blankets: solid-state and molten-salt. The hardware and procedures used to develop an adequate idea of the spectral characteristics of the neutron fluxes from plasma and accelerator sources are examined. The results can become the basis for designing micromodels of blankets for subsequent verification benchmark experiments.

The work is devoted to a quantitative comparison of different inorganic scintillators to be used in neutron-radiation inspection systems. Such systems can be based on the tagged neutron (TN) method and have a significant potential in different applications such as detection of explosives, drugs, mines, identification of chemical warfare agents, assay of nuclear materials and human body composition [1] – [3] . The elemental composition of an inspected object is determined via spectrometry of gammas from the object bombarded by neutrons which are tagged by an alpha-detector built inside a neutron generator. This creates a task to find a quantitative indicator of the object identification quality (via elemental composition) as a function of basic parameters of the $\gamma$ -detectors, such as their efficiency, energy and time resolutions, which in turn are generally defined by a scintillator of the detector. We have tried to solve the task for a set of four scintillators which are often used in the study of TN method, namely BGO, ${\rm LaBr}_{3}$ , LYSO, NaI(Tl), whose basic parameters are well known [4] – [7] .

The paper presents the 207Bi production cross-sections measured by the direct gamma-spectrometry technique in the samples of lead enriched with isotopes 208, 207 and 206, as well as in the samples of natural lead and bismuth, irradiated by protons of 11 energies in the range from 0.04 to 2.6 GeV. The obtained experimental results are compared with the previous measurements, with the TENDL-2019 data-library evaluations and the simulated data by means of the high-energy transport codes MCNP6.1 (CEM03.03), PHITS (INCL4.6/GEM), and Geant4 (INCL++/ABLA). The observed discrepancies between model predictions and experimental data are discussed.

The problems of the metrological certification of beams of high-energy heavy charged particles (HCPs) and protons that will be used in the study—as well as testing for radiation resistance—of promising products of semiconductor micro- and nanoelectronics, solid-state microwave electronics, and micromechanical systems are considered. One of the main requirements for such beams is ensuring the desired range of linear energy transfer (LET). Two methods for changing the LET are considered, one of which is based on using the ions of various types (16O, 22Ne, 40Ar, 56Fe, 84Kr, 136Xe, 209Bi), and the other is based on using ion of the same type (197Au), but with different energies. The advantages of using both methods are considered and the problems arising when using the second method are analyzed. © 2019, Pleiades Publishing, Ltd.

The potentialities of tagged neutron method (TNM) for explosives detection are examined on the basis of an idealized geometrical model. The model includes ING-27 14 MeV neutron generator with a built-in α-detector, a LYSO γ-detector and samples of material to be identified of approximately 0.3 kg each: explosives imitators (trinitrotoluene - TNT, tetryl, RDX and ammonium nitrate), legal materials (sugar, water, silk and polyethylene). The samples were unshielded or shielded by a paper layer of various thicknesses. The experimental data were interpreted by numerical simulation using a Poisson distribution of signals with the statistical parameters defined experimentally. The detection parameters were obtained by a pattern classification theory and a Bayes classifier.

Verification of neutron fission cross-sections of minor actinides from some recently available evaluated nuclear data libraries was carried out by comparison of the reaction rates calculated by the MCNP6.1 computer code to the experimental values. The experimental samples, containing thin layers of 235U, 237Np, 238,239,240,241Pu, 242mAm, 243Cm, 245Cm, and 247Cm, deposited on metal support and foils of 235U (pseudo-alloy 27Al + 235U), 238U, natIn, 64Zn, 27Al, and multi-component sample alloy 27Al + 55Mn + natCu + natLu + 197Au, were irradiated in the channels of the tank containing fluorine salts 0.52NaF + 0.48ZrF4, labelled as the Micromodel Salt Blanket, inserted in the lattice centre of the MAKET heavy water critical assembly at the Institute for Theoretical and Experimental Physics, Moscow. This paper is a continuation of earlier initiated scientific-research activities carried out for validation of the evaluated fission cross-sections of actinides that were supposed to be used for the quality examination of the fuel design of the accelerator driven systems or fast reactors, and consequently, determination of transmutation rates of actinides, and therefore, determination of operation parameters of these reactor facilities. These scientific-research activities were carried out within a frame of scientific projects supported by the International Science and Technology Center and the International Atomic Energy Agency co-ordinated research activities, from 1999 to 2010. Obtained results confirm that further research is needed in evaluations in order to establish better neutron cross-section data for the minor actinides and selected nuclides which could be used in the accelerator driven systems or fast reactors.

Computational and experimental studies of the possibility of determining the fissile and matrix materials by means of differential neutron attenuation are presented. The time response of 235U fission under the action of 14 MeV neutrons from an ING-07T pulsed neutron generator, fabricated by VNIIA, on a 70-liter steel container holding uranium in graphite, iron and polyethylene matrices is analyzed. It is shown that milligram quantities of 235U can be detected and the matrix type and density as well as the location of fissile material inside a container can be determined.©2013 Springer Science+Business Media New York.

The analysis of various non-destructive methods to control fissile materials (FM) in large-size containers filled with radioactive waste (RAW) has been carried out. The difficulty of applying passive gamma-neutron monitoring FM in large containers filled with concreted RAW is shown. Selection of an active non-destructive assay technique depends on the container contents; and in case of a concrete or iron matrix with very low activity and low activity RAW the neutron radiation method appears to be more preferable as compared with the photonuclear one.

The Radiation Test Facility (RTF) is under construction at the Institute for Theoretical and Experimental Physics to control the electronics under irradiation of particles that imitate cosmic rays (protons, carbon, aluminum, iron, tin, bismuth, and uranium). For the norms of radiation safety of personnel and users of the RTF to be observed, a local shielding and beam dump must be designed. Simulations of the dose rates around the designed shielding and beam dump are carried out in the present work.

The work is devoted to illegal materials detection via tagged neutron method (TNM). The detection of hazardous substances is based on recording of gamma radiation from a neutron-irradiated object and analysis of its elemental composition. As against other neutron radiation methods the TNM enables to obtain 3D distribution of elements in the inspected area. The results of experimental part of the research show operational capabilities (probabilities of missing and false alarm) of a portable TNM inspection system when inspecting small hand-luggage-type objects.

The paper concerns potential of numerical simulation for assessment of characteristics of tagged neutron device. The CERN Geant4 code and TPT2 (Toolkit for Particle Transport) code developed in VNIIA were used to simulate the γ-neutron transport in components of the tagged neutron device and recording of ionizing radiation by the scintillation detector. The numerical simulation was corrected and validated by experimentations with the model of the device of the same geometry, type of detector, materials. At first, we obtained a spectral response of LYSO scintillator under γand neutron radiation and satisfied that it was close to the measured data. Using the detector response, the instrumental spectra of the tagged neutron device including the neutron generator, LYSO scintillating detector and tetryl/sugar as an object of interrogation were calculated. A good agreement of coefficients of decomposition of experimental and calculated spectra let us validate that Geant4 and TPT2 codes can be used for the reliable numerical simulation of various configurations of the tagged neutron device.

This works presents results of activation-aided determination of threshold reaction rates in 92 209Bi, natPb, 197Au, 181Ta, 169Tm, natIn, 93Nb, 64Zn, 65Cu, 63Cu, 59Co, 19F, and 12C samples and in 121 27Al samples. All the samples were aligned with the proton beam axis inside and outside the demountable 92-cm thick Pb target of 15-cm diameter assembled of 23 4-cm thick discs. The samples were placed on 12 target disks to reproduce the long axis distribution of protons and neutrons. In June 2006, the target was exposed for 18 hours to a 800-MeV proton beam extracted from the ITEP U-10 accelerator. The proton fluence and the proton beam shape were determined using the 27Al(p,x)7Be monitor reaction. The reaction rates were determined by the direct gamma-spectrometry techniques. In total, 1196 gamma-spectra have been measured, and about 1500 reaction rates determined. The measured reaction rates were simulated by the MCNPX code using the following databases: ENDF/B6 for neutrons below 20 MeV, MENDL2 for 20-100 MeV neutrons, and MENDL2P for proton cross sections up to 200 MeV. An acceptable agreement of simulations with experimental data has been found., Comment: 4 pages, 5 figures, 3 tables, only pdf file, to be published in Proc. Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France, April 22-27, 2007

This work is aimed at experimental determination of independent and cumulative yields of radioactive residual product nuclei in the intermediate energy proton-irradiated thin targets made of highly isotopic enriched and natural lead ( 206,207,208,nat Pb), bismuth ( 209 Bi), and highly isotopic enriched iron ( 56 Fe). 5972 independent and cumulative yields of radioactive residuals nuclei have been measured in 55 thin Pb and Bi targets irradiated by 0.04, 0.07, 0.10, 0.15, 0.25, 0.6, 0.8, 1.2, 1.4, 1.6, and 2.6GeV protons. Besides, 219 yields have been measured in 0.3, 0.5, 0.75, 1.0, 1.5, and 2.6GeV proton-irradiated Fe target. In both cases, the protons were extracted from the ITEP U-10 synchrotron. The measured data are compared with experimental results obtained elsewhere and with theoretical calculations by seven codes. The predictive power was found to be different for each of the codes tested, but was satisfactory on the whole in the case of spallation products. At the same time, none of the codes can describe well the product yields throughout the whole product mass range, and all codes must be further improved.

This work is devoted to the differential die-away technique that is widely used for active detection of fissile materials via pulsed neutron generators. The technique allows direct detection of milligram quantities of uranium-235 and plutonium-239 in objects with volumes up to several cubic meters. Our group has demonstrated this technique, creating a special installation based on the commercially produced ING-07T pulsed neutron generator. The installation includes eight proportional 3 He -counters mounted inside a polyethylene moderator with a cadmium filter, as well as a polyethylene chamber into which a 70-liter container is loaded for inspection. Preliminary testing showed that the minimum detectable mass of unshielded uranium-235 is ∼3 mg, using a 5.108 n/s neutron yield and 8 min measurement time. When the container is filled with neutron absorbing materials, e.g., iron, the minimum detectable mass increases to ∼30 mg. Use of borated screens further increases the minimum mass that can be detected. The tested installation and/or its modifications can be used for control and detection of fissile materials in various applications from luggage inspection to control containers with nuclear fuel cycle radioactive wastes.

Capabilities of the Tagged Neutron (TN) method for detection and identification of explosives materials (EM) are explored using an idealized geometrical model that includes a 14 MeV neutron generator with an integrated alpha detector, a gamma-ray detector based on BGO/LYSO crystals, and irradiated samples in the form of simulated EM (TNT, tetryl, RDX, etc.) or benign material (BM) such as cotton, paper, etc. Research was carried out under the framework of computational simulations of neutron physics processes by Monte Carlo methods as well as experimental measurements using an ING-27 neutron generator produced by VNIIA. The work resulted in a comparison between measured and simulated ROC (receiver operating characteristics) curves obtained via integration of analytically expressed functions of irradiation time, mass, and type of EM and BM. Experimental results indicate that 0.3 kg of tetryl simulant located 45 cm from the neutron generator is detected in 97% of cases after a one minute measurement, with the false-alarm rate being highly dependent on the type of BM present: from ∼0% in the case of water to ∼5% in the case of silk. Comparison of simulated and experimental data for these results shows they are in agreement in cases where the simulations account for neutron scattering from the object and background effects.

This work presents results of activation-aided determination of threshold reaction rates (RRs) in 92 samples of 209 Bi nat Pb 197 Au, 181 Ta, 169 Tm, nat In, 93 Nb, 64 Zn, 65 Cu, 63 Cu, 59 Co, 19 F, and 12 C and in 121 samples of 27 Al. All the samples are aligned with the proton beam axis inside and outside the demountable 92-cm-thick Pb target of 15-cm diameter assembled of 23 4-cm-thick discs. The samples are placed on 12 target disks to reproduce the long axis distribution of protons and neutrons. The target was exposed to an 800-MeV proton beam. The total number of protons onto the target was (6.0 ± 0.5) ×10 15 . The RRs were determined by the direct gamma spectrometry techniques. In total, 1196 gamma spectra have been measured, and about 1500 RRs have been determined. The measured RRs were simulated by the MCNPX and SHIELD codes. A generally acceptable agreement of simulations with experimental data has been found.