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We studied cytotoxicity and accumulation of boron and lithium by cultured human fibroblasts and human and mouse skin melanoma cell cultures. The cytotoxicity of boron and lithium drugs was assessed by MTT tests in the boron and lithium concentration range of 10-640 μg/ml. Cell viability was significantly reduced after incubation with boron and lithium at concentrations >160 μg/ml. To assess accumulation of boron and lithium, the concentration of elements was measured using inductively coupled plasma atomic emission spectrometry. Melanoma cells more intensively accumulated lithium in comparison with boron. The results indicate the possibility of safe application of lithium salts in concentrations minimally required for successful neutron capture therapy. [ABSTRACT FROM AUTHOR]

We report on specific heat and magnetic properties of thin Gd sheets obtained by means of a cold rolling technique. At temperatures well below Curie temperature TC, the cold rolling has a minor impact on the specific heat CP. However, a well defined k-type anomaly of CP seen in the vicinity of TC in a polycrystalline Gd sample is markedly suppressed in the severely deformed samples. Depression of the λ peak is due to a large decrease of magnetization that presumably originates in a local magnetic anisotropy induced by the severe plastic deformation. Results of calculation of magnetocaloric effect from the CP and magnetization data indicate that the magnetocaloric effect gradually decreases as the degree of plastic deformation increases. This trend is further confirmed by the direct measurements of the adiabatic temperature change ΔTad. [ABSTRACT FROM AUTHOR]

Fundamentals of boron neutron capture therapy of malignant tumors are outlined, and the current status of the development of epithermal-neutron sources on the basis of charged-particle accelerators is surveyed. Attention is additionally given to a neutron source based on a charged-particle accelerator belonging to a new type—a tandem accelerator with vacuum insulation and a lithium neutron-producing target. [ABSTRACT FROM AUTHOR]

Three fragments of the Chelyabinsk meteorite have been investigated by Mössbauer spectroscopy in a temperature range of 300–830 K. They are found to contain iron in the composition of various minerals in different physicochemical and crystallographic states. Anomalous behavior of the temperature dependences of hyperfine magnetic fields on iron nuclei in all fragments is demonstrated. The results obtained are qualitatively explained within the concept of structural magnetic phase transitions, in which iron ions play a role of stabilization centers for new crystal structures in specific temperature ranges. [ABSTRACT FROM AUTHOR]

This study examines the application of machine learning algorithms, specifically the Random Forest regression model, to optimize the magnetocaloric effect in all- d -metal Heusler alloys. The model was trained using descriptors related to the mean properties of individual atoms, the properties of simple compounds in their ground state, and measures of chemical disorder. It demonstrated high accuracy in predicting structural properties, while exhibiting moderate accuracy in predicting magnetic properties. To identify optimal alloy compositions, a genetic algorithm was used to find those with the greatest differences in magnetization during martensitic transitions. Using this combined approach, the Ni–Co–Mn–Ti alloy system was thoroughly explored, resulting in the discovery of an alloy with a maximum magnetization difference. These results are consistent with previous research based on density functional theory and highlight the effectiveness of integrating machine learning with genetic algorithms for the discovery of new materials with outstanding magnetocaloric properties. The study emphasizes the need for further refinement of models capable of accurately predicting complex magnetic interactions, which is essential for fully leveraging the potential of all- d -metal Heusler alloys in practical applications. [ABSTRACT FROM AUTHOR]

Despite significant progress in the study of materials undergoing first-order magnetic phase transitions accompanied by the so-called giant magnetocaloric effect (MCE), Gd metal still remains the most widely used material in prototypes of magnetic refrigerators due to its significant MCE, good machinability and reasonable mechanical and chemical stabilities. Alloying of Gd enables fine-tuning the Curie temperature of Gd-based solid solutions (all show second-order phase transitions), for graded magnetocaloric materials. Commonly, Gd packed spheres are used as a magnetocaloric working substance in the active magnetic regenerator (AMR) cycle. In this work, we show that the optimized stacking parallel-plate geometry of AMR bed made of Gd is more effective for application at frequencies 1–10 Hz then the packed spheres. We also give a short review on magnetocaloric properties of cold-rolled Gd-X (X = Y, In, Zr, Ga, B) solid solutions. These materials can be produced in the form of thin (∼100 μm) foils/plates to ensure rapid heat exchange between to the heat transfer fluid. Although the magnetocaloric effect decreases in the as-rolled foils, it can be recovered by thermal treatment of the final stacked-plates regenerators. Gd-Y, Gd-In and Gd-Zr solid solutions have magnetocaloric properties, comparable to the MCE of pure Gd in a wide temperature working span up to 37 K, 36 K, and 16 K respectively, which makes them suitable magnetocaloric material systems for testing the fundamental heat exchangers geometries at ambient temperature and in frequencies of 1–10 Hz. [ABSTRACT FROM AUTHOR]

We report on the magnetic and magnetocaloric properties of Terbium ribbons subjected by cold rolling. The magnetic entropy change ΔS = 8.66 J/(kg·K) and adiabatic temperature change ΔT = 4.38 K for a bulk sample of Terbium in an external magnetic field change of 1.9 T are larger by about 12% and 26% respectively, than those values of cold rolled Terbium. The changes are fully reversible and can be fully restored by an additional annealing. [ABSTRACT FROM AUTHOR]

Systematic studies of magnetic entropy change ΔSm and adiabatic temperature change ΔTad have been performed for ferromagnetic shape memory alloys Ni2 + xMn1−xGa (0.18 ≤ x ≤ 0.27) undergoing coupled magnetostructural phase transition from ferromagnetic martensite ↔ paramagnetic austenite. The magnetic entropy change calculated from isothermal magnetization measurements has the highest value (for the magnetic field change of ΔH = 5 T), ΔSm = −29 J/kg K, in a Ni2.20Mn0.80Ga composition. The decrease in ΔSm observed in the alloys with the larger Ni excess (0.22 ≤ x ≤ 0.27) is attributed to the progressive reduction in both the saturation magnetization and the total entropy change at the martensitic transition temperature. The adiabatic temperature change ΔTad measured upon heating in the Ni2 + xMn1−xGa (0.18 ≤ x ≤ 0.27) alloys does not exceed 0.8 K (for the magnetic field change of ΔH = 1.85 T). A higher value of ΔTad measured upon cooling has been explained as caused by the contribution of the structural subsystem to ΔTad, i.e., to a partial magnetic field-induced structural transformation that has, for the given magnetic field change, an irreversible character in the alloys studied. [ABSTRACT FROM AUTHOR]

A new type of accelerator, namely, an electrostatic tandem accelerator with vacuum insulation, being distinguished by a high acceleration rate of charged particles and a large surface area of accelerating electrodes, was proposed, manufactured, and put into operation to obtain a proton beam with a 2-MeV energy and a direct current up to 10 mA. The influence of breakdowns on the electric strength of high-voltage components of the accelerator is studied in the work. [ABSTRACT FROM AUTHOR]

An epithermal neutron source based on a tandem accelerator is being constructed at the Budker Institute of Nuclear Physics for use in neutron capture therapy at a cancer clinic. A lithium neutron-generating target obtained by deposition of lithium onto the target substrate is one of the key elements of the facility. The effect of residual gas on the lithium layer composition has been investigated using a secondary-ion mass spectrometer. [ABSTRACT FROM AUTHOR]

The phase diagrams of magnetically ordered Heusler alloys with the inversion of the exchange interaction have been studied using the phenomenological Landau theory of phase transitions. It has been shown that the shape of the phase diagrams in these alloys depends on the magnitudes and signs of the phenomenological parameters in the Landau functional. At certain magnitudes and signs of the parameters of the Landau functional, the phase diagrams have thermodynamic paths that allow one to explain the experimentally observed sequences of the phase transitions in the Heusler alloys. [ABSTRACT FROM AUTHOR]

The results of direct measurements of the magnetic field induced entropy change in the Ni_{2.19}Mn_{0.81}Ga alloy are presented. It is shown that the largest entropy change in the magnetic field 2.6 T is equal to 11 J/kgK. The experimental data are compared with the theoretical results, obtained with the help of the statistical and molecular field theory. [ABSTRACT FROM AUTHOR]

In this work the stress-temperature phase diagrams of a cubic ferromagnet with positive constant anisotropy and an external elastic stress along [001] axis are investigated. [ABSTRACT FROM AUTHOR]

A hot target plasma is obtained in the end cell of the AMBAL-M device with the use of an end gas-discharge plasma source. A fairly high longitudinal electron current flowing from the plasma source to the plasma receiver is detected experimentally. The electron current is studied in the region in front of the input magnetic mirror, where the longitudinal electric field is directed outward from the mirror. Different models for plasma description are considered, and possible plasma instabilities are discussed. It is shown that a fairly high longitudinal electron current in the region where the electric field accelerates electrons results in the generation of the flow of fast electrons responsible for the current in the mirror system. © 2000 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

A tandem accelerator with vacuum insulation has been proposed and developed in the Budker Institute of Nuclear Physics. Negative hydrogen ions are accelerated by the positive 1 MV potential of the high voltage electrode, converted into protons in the gas stripping target inside the electrode, and then the protons are accelerated again by the same potential. The potential for high voltage and intermediate electrodes is supplied by the sectioned rectifier through a sectioned bushing insulator with a resistive divider. In this work, we propose a radical improvement of the accelerator concept. It is proposed to abandon the separate placement of the accelerator and the power supply and connect them through the bushing insulator. The source of high voltage is proposed to be located inside the accelerator insulator with high voltage and intermediate electrodes mounted on it. This will reduce the facility height from 7 m to 3 m and make it really compact and attractive for placing in a clinic. This will significantly increase the stability of the accelerator because the potential for intermediate electrodes can be fed directly from the relevant sections of the rectifier. [ABSTRACT FROM AUTHOR]

In this work we report on the results of investigation of the magnetocaloric effect in Gd100-xYx (x = 0, 5, 10, 15) cold rolled ribbons. It is shown that the magnetocaloric effect exists within a wide temperature interval 258-295 K and is comparable with magnetocaloric effect observed in bulk samples of pure gadolinium. The value of the magnetocaloric effect in the rolled samples is reduced as compared with the bulk samples and strongly depends on the degree of the plastic deformation. Heat treatment procedures can restore the values of the magnetocaloric effect in the cold rolled ribbons up to initial ones. Thus, cold rolling is proposed to be a promising technique for producing thin forms of magnetocaloric materials for heat exchangers of magnetic cooling devices, modifying microstructure of the materials and related magnetic properties. [ABSTRACT FROM AUTHOR]

The magnetocaloric effect (MCE) in samples of the Gd2In compound has been studied by the direct method in temperature range of 4–240 K in magnetic fields of Bitter coil up to 14 T. The maximum detected value of the inverse MCE at cryogenic temperatures in the 1st-order metamagnetic phase transition (PT) is ∆Tad = − 0.5 K at T0 = 45 K in the field of 1.8 T. The MCE in this temperature range changes sign with increasing of the magnetic field up to 5 T, and the direct MCE is observed with further increasing of the field. The kinetic arrest of the 1st-order metamagnetic PT is observed on the temperature dependence of magnetization in the steady magnetic field of 5 T. The direct MCE in the Curie temperature Tc = 200 K increases with increasing of the magnetic field, and the effect maximum shifts to higher temperatures. The maximum detected value of the direct MCE is ∆Tad = 7.8 K at T0 = 215 K in the field of 14 T. [ABSTRACT FROM AUTHOR]

A new method has been proposed for obtaining a beam of monoenergetic neutrons with almost arbitrary energies. The production of the beam for the calibration of a dark-matter detector with liquid argon as a working medium has been described. [ABSTRACT FROM AUTHOR]

Ionic substitution is considered to be an effective approach to modify functional characteristics of hexagonal ferrites. To this aim, solid solutions with iso- and aliovalent substitution of iron by aluminum and titanium, respectively, are prepared by the solid-phase synthesis. The influence of the Al3+–Ti4+ substitution on the structure and properties of BaFe12–xAlxO19, BaFe12–yTiyO19 is studied. The prepared solid solutions are studied by scanning electron microscopy and X-ray microanalysis, powder XRD, vibration magnetometry, and differential scanning calorimetry. The crystal structure data confirm that the synthesized samples are characterized by the hexagonal phase, the P63/mmc space group. The samples are shown to consist of 1-10 µm flat hexagonal crystals. The influence of substitution on their magnetic properties is determined. The substitution of Fe3+ magnetic ions by Al3+ and Ti4+ ions decreased the Curie point of the solid solutions. Since magnetic characteristics can be tuned by introducing Al3+ and Ti4+, this effect can be used to control the optimization of magnetic characteristics in BaFe12–xAlxO19, BaFe12–yTiyO19 solutions to solve applied problems. [ABSTRACT FROM AUTHOR]

The results of measurements of the luminescence spectrum of lithium when it is irradiated with a proton beam with an energy of 2 MeV are presented. The operational diagnostics for monitoring the position of the proton beam on a lithium target, which is used in neutron generation, has been developed and put into operation. [ABSTRACT FROM AUTHOR]

The electric strength of ceramic insulators was tested at a dedicated high-voltage vacuum facility and the electric strength of a vacuum-insulated tandem accelerator with redesigned feedthrough insulators was studied. Based on the results of the investigations and the upgrade the voltage in the accelerator was increased from 1.00 to 1.15 MV; the operating mode was achieved without high-voltage breakdowns. [ABSTRACT FROM AUTHOR]

Abstract— Diagnostics have been developed for measuring the efficiency of stripping a beam of negative ions in a gas stripping target of a tandem charged particle accelerator. The coefficient of ion-electron emission during the bombardment of copper by protons with an energy of 1 MeV was measured. A bending magnet with a horizontal nozzle was installed, which made it possible to place a Faraday cup and receive a stream of neutrals formed on it as a result of incomplete stripping of negative ions in the stripping target. Diagnostics of the efficiency of the gas stripping target were put into operation on the basis of measuring the current of electrons emitted from the surface of a Faraday cup during its bombardment by a directed stream of neutrals and the proton current by a non-contact current sensor. [ABSTRACT FROM AUTHOR]

The expression of marker proteins of acute kidney injury after administration of high doses of lithium carbonate was assessed to evaluate the possibility of lithium use in neutron capture therapy. In mice with implanted skin melanoma B16, the expression of Kim1 (kidney injury molecule 1) and NGAL (neutrophil gelatinase-associated lipocalin) proteins in the kidneys was evaluated immunohistochemically 15, 30, 90, 180 min, and 7 days after peroral administration of lithium carbonate at single doses of 300 and 400 mg/kg. An increase in the expression of the studied proteins was found in 30 and 90 min after administration of 400 mg/kg lithium carbonate, however, 7 days after the drug administration, the expression returned to the level observed in the control group. It can be suggested that single administration of lithium carbonate in the studied doses effective for lithium neutron capture therapy will not significantly affect the renal function. [ABSTRACT FROM AUTHOR]

The development of a medical facility for boron neutron capture therapy at Budker Institute of Nuclear Physics is under way. The neutron source is based on a tandem accelerator with vacuum insulation and lithium target. The proposed accelerator is conceived to deliver a proton beam around 10 mA at 2.3 MeV proton beam. To deliver a therapeutic beam for treatment of deep-seated tumors a typical Beam Shaping Assembly (BSA) based on the source specifications has been explored. In this article, an optimized BSA based on the 7 Li(p,n) 7 Be neutron production reaction is proposed. To evaluate the performance of the designed beam in a phantom, the parameters and the dose profiles in tissues due to the irradiation have been considered. In the simulations, we considered a proton energy of 2.3 MeV, a current of 10 mA, and boron concentrations in tumor, healthy tissues and skin of 52.5 ppm, 15 ppm and 22.5 ppm, respectively. It is found that, for a maximum punctual healthy tissue dose seated to 11 RBE-Gy, a mean dose of 56.5 RBE Gy with a minimum of 52.2 RBE Gy can be delivered to a tumor in 40 min, where the therapeutic ratio is estimated to 5.38. All of these calculations were carried out using the Monte Carlo MCNP code. [ABSTRACT FROM AUTHOR]

The BaFe12–x(Ti,Mn,In,Ga)xO19(x = 1, x = 7) HEOs are prepared by a solid-phase synthesis. Correlations between the chemical composition (degree of Fe substitution), structural parameters, and magnetic characteristics are studied. Magnetic characteristics of the BaFe12–x(Ti,Mn,In,Ga)xO19 (x = 1, x = 7) HEOs are studied in a wide range of fields and temperatures. The measured IR reflectance spectra of the samples contain features caused by phonon vibrations. The dependence of characteristics of phonon lines on the concentration x is qualitatively analyzed; the obtained spectra are compared with those of a single-crystal BaFe12O19 sample. [ABSTRACT FROM AUTHOR]

Large single crystals of high-entropy oxides with the M-type hexaferrite structure, the chemical composition of which can be described by the formula BaFe12–x(Ti, Mn, In, Ga)xO19, are obtained for the first time by spontaneous crystallization from a solution. The actual compositions of the samples are determined: BaFe1.20Ti0.22Mn0.76In0.58Ga0.23O19, BaFe8.71Ti0.44Mn1.16In1.25Ga0.44O19, BaFe7.14Ti0.57Mn1.77In1.79 Ga0.73O19, BaFe5.6Ti0.64Mn2.48In2.52Ga0.76O19. These crystals have a special shape for hexaferrites and are characterized by a fairly uniform distribution of elements in their structure. A significant quantitative difference in the ability of various metal ions to transfer from a melt to a growing crystal is found. A change in the initial ion concentration in the solution has practically no effect on this ability. The influence of crystal compositions on their unit cell parameters is considered. Some increase in these parameters correlates with a decrease in the iron content in the samples. This is mainly due to an increase in the weighted average ionic radius of ions forming the crystals. The configuration mixing entropies within the sublattice formed by Fe, Ti, Mn, In, and Ga for the target compositions and the compositions of actually obtained crystals are calculated and compared. [ABSTRACT FROM AUTHOR]

We report a study of the effect of magnetic field on the structural organization and sensory properties of thin titanyl phthalocyanine (TiOPc) layers deposited by vacuum thermal evaporation. It is shown that magnetic field (directed perpendicular to the substrate surface) does not affect the phase composition of the layers which are represented by II-triclinic and I-monoclinic crystal modifications in both cases. The crystallites of both phases demonstrate preferential orientations, the angles between molecular planes and the substrate are 62.53° and 5.30°, respectively. The 2D GIXD study shows that magnetic field significantly improves the crystallinity of obtained thin layers; the conductivity increases by ~10 times, but the sensory response to ammonia does not change. Irradiating the layer obtained in magnetic field by fast neutrons (fluence 3·1014 cm–2) decreases the conductivity by two orders of magnitude. This effect is not observed in the parallel experiment without magnetic field. [ABSTRACT FROM AUTHOR]

The tandem accelerator with vacuum insulation has been proposed and developed in Budker Institute of Nuclear Physics. Negative hydrogen ions are accelerated by the positive 1 MV potential of the high-voltage electrode, converted into protons in the gas stripping target inside the electrode, and then protons are accelerated again by the same potential. A stationary proton beam with 2 MeV energy, 1.6 mA current, 0.1% energy monochromaticity, and 0.5% current stability is obtained now. To conduct Boron Neutron Capture Therapy it is planned to increase the proton beam current to at least 3 mA. The paper presents the results of experimental studies clarifying the reasons for limiting the current, and gives suggestions for modifying the gas stripping target in order to increase the proton beam current along with the stability of the accelerator. [ABSTRACT FROM AUTHOR]

For the development of boron neutron-capture therapy of malignant tumors, a source of epithermal neutrons on the basis of a tandem accelerator with a vacuum insulation and a lithium target was created and launched. With the aim of optimizing the neutron-producing target, various structure materials were irradiated with a proton beam. The results obtained bymeasuring the dose rate and radiation spectrum upon the absorption of 2-MeV protons are presented, and the choice of tantalum for an optimum material of the target substrate was explained. [ABSTRACT FROM AUTHOR]

One of the charged-particle accelerators with relatively low energy and relatively high current is the vacuum-insulated tandem accelerator proposed for boron neutron capture therapy and planned for use in a number of other applications requiring a more remote location of the neutron-generating target from the accelerator. In this work, the phase portrait of the ion beam and its dependence on the ion beam current and the strength of the magnetic lens focusing the beam of negative hydrogen ions on the input of the accelerator are measured. It is shown that the modernization of the magnetic lens contributed to the reduction of the spherical aberration of the lens and improved the quality of the negative ion beam. It has been established that the ion beam emittance increases with increasing current, and the space charge affects the phase portrait of the ion beam in the low energy transport path. To compensate for the action of the space charge on the phase portrait of the proton beam, the strength of the magnetic lens is changed. The obtained experimental data indicate that the proton beam can be transported to the site of the planned location of the neutron-generating target without adding focusing elements. [ABSTRACT FROM AUTHOR]

The influence of nonmagnetic impurities (Y ) on the magnetocaloric effect (MCE) in the Heusler alloy Ni50Mn34In16Y in which ferromagnetic and antiferromagnetic coupling coexists in the martensitic state is investigated by means of ab initio and Monte Carlo simulations. Different impurity configurations are considered. Either Mn on the Mn sublattice or Ni on the Ni sublattice is substituted randomly by Y or substitution may occur simultaneously on both sublattices. The magnetic and magnetocaloric properties are obtained as a function of temperature and magnetic field using a mixed type of Potts and Blume--Emery--Griffiths model where the model parameters are obtained from ab initio calculations. When varying the impurity concentration, the shape of the magnetization curves is drastically changed at the martensitic transformation temperature due to the complex competing magnetic interactions. We show that the inverse MCE effect increases if Mn is substituted by Y compared with Y substituting for Ni. For example, the alloy system Ni50Mn32.75Cu1.25In16 where 5 at% Mn is replaced by Cu exhibits an inverse MCE which is twice as large compared with Ni50Mn34In16. Such predictive simulations may be used to design Heusler composites which display larger MCEs. [ABSTRACT FROM AUTHOR]

The kinetics of magnetic and structural domains and relaxation of magnetization and strain under an external stress and a magnetic field in ferromagnetic Ni-Mn-Ga alloys close to a structural phase transition on the basis of time-depending Ginzburg-Landau equation with a thermal noise were theoretically investigated. The influence of an external magnetic field on the kinetics of structural domains was established to have the same influence as the stress has but not so great. The evolution of structural domain pictures was obtained. One type of structural domains was established to prevail in an alloy under an external stress or a magnetic field with time. The time dependencies of magnetization and strain were calculated. [ABSTRACT FROM AUTHOR]

Boron neutron capture therapy (BNCT) can become an instrument for patients with malignant neoplasms of the rectum and colon. Here we evaluate the effectiveness of BNCT performed at the accelerator based epithermal neutron source at G. I. Budker Institute of Nuclear Physics, Siberian Division of Russian Academy of Sciences, in relation to subcutaneous xenografts of human colon adenocarcinoma SW-620 in SCID mice. Utilization of BNCT with boronоphenylalanine (BPA) and sodium borocaptate (BSH), which were injected intravenously into the retroorbital sinus, resulted in a significant decrease in tumor volumes compared to the control group (no radiation). [ABSTRACT FROM AUTHOR]

The electron distribution function over longitudinal energies in the startup plasma of the end cell of the AMBAL-M device is measured with a small-size movable electrostatic analyzer. It is found that, in the region where a substantial longitudinal current flows, the electron distribution function over longitudinal energies has a plateau in the 150–350-eV energy range. © 2000 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

A proton beam (2 MeV and 1.6 mA) has been obtained on a tandem accelerator with vacuum insulation. Experimental results are given that outline the reasons for current limits, and approaches to increasing the current of a proton beam are proposed. [ABSTRACT FROM AUTHOR]

In electrostatic tandem charged particle accelerators, gas stripping targets are used to convert negative ions into positive ones. Partial ionization of the gas by ions leads to the formation of an undesirable beam of stripping gas ions in the accelerating channels. In this work, the current of a beam of argon ions produced in a tandem accelerator with vacuum insulation was measured by mass spectroscopy. It is shown that the current of argon ions is 2000 times smaller than the current of the proton beam. The reliability of the measurements is provided by visualization of an argon ion beam on the surface of a lithium target and is also confirmed by an experiment with increased gas injection and an estimate of the possible contribution of the proton beam. It is shown that such a small value of the argon ion current does not pose a danger either as a source of additional heating of a lithium target, or as an additional load of a high-voltage power supply, and therefore does not require the previously proposed means for its suppression. [ABSTRACT FROM AUTHOR]

A neutron source composed of a tandem accelerator with vacuum insulation and a lithium target is used to develop the boron neutron capture therapy and other applications. The dependence of the proton beam size on the target surface on the beam current is measured with thermocouples inserted inside the target and with a infrared camera. It is found that there is no appreciable influence of the spatial charge on the proton beam transport to a distance of 5 m from the accelerator to the target, which simplifies the neutron source operation. [ABSTRACT FROM AUTHOR]

An epithermal neutron source based on a compact tandem accelerator is being built at the Budker Institute of Nuclear Physics for use in neutron capture therapy at a cancer clinic. It is expected that a lithium neutron-generating target will act as a neutron source. An original technique for determining the thickness of the lithium layer is proposed, and the measured radial distribution of the evaporated lithium layer thickness is presented. [ABSTRACT FROM AUTHOR]

The production of a deuteron beam in a vacuum-insulated tandem accelerator and the generation of fast neutrons from a lithium target have been investigated. The possibility of using a source of fast neutrons for radiation testing of materials and for fast-neutron therapy is discussed. [ABSTRACT FROM AUTHOR]

A method for producing elemental boron nanoparticles with a size of less than 100 nm by ultrasonic dispersion in a liquid medium and subsequent cascade fractionation is described. The resulting boron nanoparticles were used as a target for boron neutron capture therapy (BNCT). According to the results of an experimental preclinical study of BNCT with the synthesized boron nanoparticles, neutron irradiation for 1 h of T98G human glioma cells pre-incubated in a medium with boron nanoparticles (10, 20, and 40 ppm in terms of boron-10 isotope) leads to a significant suppression of cell viability. [ABSTRACT FROM AUTHOR]

We studied the effect of applied tensile stresses on magnetic properties of Fe- and Co-rich amorphous glass-coated microwires. Rising of magnetic anisotropy field upon tensile stress in Co-rich glass-coated microwires is described by a linear dependence. Furthermore, decrease of magnetic susceptibility upon tensile stress is observed in Co-rich microwires. A monotonous increase in the coercivity and the switching field upon tensile applied stress is observed for as-prepared Fe-rich microwire. Stress induced magnetic bistability consisting of transformation of hysteresis and onset of rectangular hysteresis loop upon tensile stress, σ , of about 22.5 MPa is observed in stress-annealed Fe-rich microwires. Such stress-induced magnetic bistability results in considerable growing of coercivity and remanent magnetization in stress-annealed Fe-rich microwires. The rising in the coercivity and the switching field upon applied tensile stresses in stress-annealed Fe-rich microwires with stress induced magnetic bistability (at σ > 22.5 MPa) is roughly described by the σ ½ dependence, as previously reported for the wires with spontaneous magnetic bistability. Consequently, stress-annealing of Fe-rich microwire allows beneficial enhancement of the stress dependence of coercivity. Observed dependencies are discussed considering stress dependence of the magnetostriction coefficient in Co-rich glass-coated microwires, internal stresses redistribution and domain structure rearrangement in stress-annealed Fe-rich microwires upon applied tensile stresses. Image 1 • Linear increase in the magnetic anisotropy field upon stress in Co-rich microwires. • Decrease in the magnetic susceptibility upon applied stress in Co-rich microwires. • Observation of stress induced magnetic bistability in stress-annealed Fe-rich microwires. • Enhanced stress dependence of coercivity in stress-annealed Fe-rich microwires. • Observation of σ ½ dependence of switching field in stress-annealed Fe-rich microwires. [ABSTRACT FROM AUTHOR]

The results of experimental investigation into Fe2Ti1 –xVxSn alloys (x = 0, 0.06, 0.15, and 0.2) are presented. It is established from the temperature dependences of the electrical conductivity, Seebeck coefficient, and thermal conductivity that the studied compositions exhibit the transport properties typical of semiconductors, while the partial substitution of titanium atoms by vanadium atoms leads to a change in the conductivity from p-type to n-type; the undoped Fe2TiSn sample possesses the best thermoelectric characteristics. [ABSTRACT FROM AUTHOR]

Highlights • Magnetic and transport properties of as-prepared Mn 2 CoGa were studied. • No difference between magnetic properties of annealed and as-prepared Mn 2 CoGa was found. • The first report on transport properties of Mn 2 CoGa. Abstract Magnetic and transport properties of as-prepared Mn 2 CoGa polycrystalline Heusler alloy were investigated. Results of magnetic measurements were found to agree well with literature data, i.e., the studied Mn 2 CoGa is a ferrimagnet with magnetic moment of 2.03 μ B /f.u. and a high Curie temperature T C = 728 K. Measurements of transport properties revealed that electrical resistivity ρ of Mn 2 CoGa is anomalously large (∼250 µΩ·cm at room temperature) and demonstrates a complex temperature dependence. Specifically, in the measured temperature interval from 80 K to 375 K, the electrical resistivity is proportional to T 2 up to T ∼ 200 K while at higher temperatures ρ can be fitted by ρ(T) = A + B ·exp(− CT) expression. These changes in the scattering mechanisms are accompanied by a change of the magnetoresistance sign from positive at T below ∼200 K to negative at higher temperatures. [ABSTRACT FROM AUTHOR]

A modified wire scanner and a new methodical approach were used to measure the profile, current, and phase portrait of a negative hydrogen ion beam injected into a tandem accelerator with vacuum insulation. The effect of the space charge and spherical aberration of the focusing lenses on the negative hydrogen ion beam is revealed. Recommendations are given, whose implementation will make it possible to increase the current of the proton beam from 5 to 10 mA in the accelerator, which is sufficient for boron neutron capture therapy of malignant tumors. [ABSTRACT FROM AUTHOR]

We have studied the magnetic properties and domain wall dynamics in Fe-rich microwires subjected to stress-annealing. The hysteresis loops of Fe-rich microwires were considerably affected by stress-annealing. We obtained drastic decrease in coercivity and change in the character of hysteresis loops from rectangular to linear in stress-annealed Fe-rich microwires. For the wires after stress-annealing at variable temperatures we obtained a graded magnetic behavior with local hysteresis loops shapes and features (coercivity, remanent magnetization) changing along the sample length. In the samples subjected to local stress-annealing we created an artificial source of domain wall injection allowing the manipulation of domain wall dynamics. The observed stress-induced anisotropy could be related to the internal stress relaxation after annealing and the interplay of compressive “back-stresses” arisen after stress annealing and axial internal stresses. [ABSTRACT FROM AUTHOR]

Magnetostriction of a non-modulated martensite was measured for Ni 2.27 Mn 0.73 Ga ferromagnetic shape memory alloy in steady magnetic fields μ 0 H up to 10 T at temperatures below room temperature and in μ 0 H  ≤ 1 T at temperatures above room temperature. Linearity of the longitudinal magnetostriction λ || observed at high fields μ 0 H  > 6 T implies that the magnetostriction is associated with a 3 d electron band. The anisotropic magnetostriction obtained in a magnetic field μ 0 H  = 1 T at T  = 4.2 K is ∼16 ppm and decreases down to 3 ppm with the increase in temperature. The volume magnetostriction is positive but very small (∼0.6 ppm) under these conditions. In the region of the magnetostructural phase transition the longitudinal and volume magnetostriction showed a complex sigh-changing behavior which depends on the strength of applied magnetic field. Thermal expansion coefficient α of Ni 2.27 Mn 0.73 Ga in the martensitic state was measured to be α ∼13 × 10 −6  K −1 which is comparable with the thermal expansion coefficient of a non-stoichiometric Ni 2.19 Mn 0.81 Ga single crystal. [ABSTRACT FROM AUTHOR]