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Results from preliminary experimental research of neutron emission generated by a spherical plasma focus chamber filled with an equal-component deuterium-tritium mixture are presented. At a maximum current amplitude in the discharge chamber of ∼1.5 MA, neutron pulses with a full width at half-maximum of 75–80 ns and an integral yield of ∼1.3 × 1013 DT neutrons have been recorded.

Приводятся основные результаты работ по созданию экспериментальной базы, позволяющей безопасно проводить фундаментальные и прикладные исследования с тритийсодержащими средами в условиях неспециализированных лабораторий. Обсуждаются технические характеристики комплексов оборудования и установок, методические подходы, обеспечившие проведение исследований: явления мюонного катализа ядерных реакций синтеза; свойств лёгких экзотических ядер на границе нейтронной стабильности; явления «сверхпроницаемости» трития через металлы V группы и проницаемости водорода через конструкционные материалы, в том числе содержащие радиогенный Не; взаимодействия конструкционных материалов с изотопами водорода, включая тритий при давлении до 300 МПа.

A search for the muon-catalyzed fusion (MCF) reaction d+d → 4He+γ in the ddμ muonic molecule was performed using the experimental MCF installation TRITON and NaI(Tl) detectors for γ quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR phasotron to detect γ quanta with an energy of 23.8 MeV. The first experimental estimation for the yield of radiative deuteron capture from the ddμ state J=1 was obtained at a level of ηγ≤2×10−5 per one fusion.

A design of the deuterium high-pressure target is presented. The target of a 76-cm3 volume is intended to study muon-catalyzed fusion reactions in ultrapure D2 (the concentration of impurities with Z > 1 is under 0.2 ppm) at temperatures of 80–800 K and up to 150-MPa pressures. The operation of the main target systems is described: the generation and purification of deuterium gas, refrigeration, heating, evacuation, control, and automated data acquisition. The target was used to determine the parameters of the muon-catalyzed fusion reactions in ultrapure D2 at temperatures of 300 to 800 K and pressures up to 150 MPa.

A high strength pearlitic-sorbitic steel (DIN 1.1200/K08500) and a metastable austenitic stainless steel (DIN 1.4301/AISI 304) were tensile tested in H2–O2 gas mixtures of high total gas pressures without any prior precharging and in inert environment after gaseous precharging in different H2–O2 gas mixtures. Tests at various total pressures revealed that the effect of oxygen to suppress hydrogen environment embrittlement is a function of oxygen partial pressure and not of total oxygen content. For steel 1.1200 tested at room temperature the threshold O2 partial pressure was 30–40 kPa whereas for steel 1.4301 tested at −50 °C a partial pressure of 160 kPa was not sufficient to influence embrittlement effects. Reviewing literature results in the context of this work revealed that threshold partial pressures vary by at least 3 orders of magnitude depending on steel grade and temperature. For tests in inert environment after gaseous precharging threshold O2 partial pressure was one order of magnitude lower compared to tests in H2–O2 gas mixtures.

By means of muon catalysis we study the phenomena in a pt-fusion, which have been previously investigated in the only experiment and now are at the frontier of nuclear few-body physics. The experiment is aimed at measuring the yields of the reaction products: γ-quanta, conversion muons and e + e − pairs. As a result we plan to measure the pt-fusion partial product yields (first time for e + e − pairs) with accuracy not worse than 10%, and this will enable us to obtain the nuclear reaction rates in M1 and E0 transitions in A = 4 system.

The design of deuterium high-pressure target of 76 cm3 volume developed to study muon catalyzed fusion in diffusion-pure deuterium over an 80–800 K temperature range at up to 150 MPa pressure is presented.

Experiments on the study of the muon catalyzed fusion (μCF) process in a double D/T mixture of hydrogen isotopes in the temperature range 300–800 K at densities 0.3–0.5 LHD are performed at the JINR phasotron. The values of the effective μCF parameters (cycling rate λ c , neutron yield Y n , muon losses w) are obtained. Tentative dtμ-molecule formation rates on D2 and DT molecules (λ dtμ−d and λ dtμ−t ) are obtained for different mixture temperatures and densities. The results obtained show that λ dtμ−t increases with temperature, but its value is smaller than theoretical predictions.

Muon catalyzed fusion in deuterium was studied by the MCF collaboration at JINR phasotron. The measurements were carried out with a high-pressure deuterium target at the JINR phasotron in the temperature range 300–800 K at densities ≃0.5 LHD. The first experimental results for ddμ-molecule formation rate λ ddμ in the temperature range 400–800 K with deuterium density 0.5 LHD are presented.

The quasi-isentropic compressibility of helium and deuterium plasmas at pressures of up to 1500–2000 GPa has been measured using devices with spherical geometry and an X-ray diagnostic complex comprising three betatrons and a multichannel imaging system with electro-optic gamma detectors. A deuterium density of 4.5 g/cm3 and a helium density of 3.8 g/cm3 have been obtained at pressures of 2210 and 1580 GPa, respectively. The internal energy of a deuterium plasma at the indicated pressure is about 1 MJ/cm3, which is about 100 times greater than the specific energy of condensed chemical explosives. Analysis of the obtained data shows that the degree of helium ionization under the achieved plasma compression parameters is about 0.9.

The quasi-isentropic compressibility of a helium plasma has been measured using a spherical experimental chamber, as well as an X-ray diffraction complex consisting of three betatrons and a multichannel optoelectronic system for the detection of X-ray images. The density of the compressed helium plasma of about 8 g/cm3 has been obtained in the experiment at a pressure of 5000 GPa. Analysis of the data indicates that helium at the measured parameters is in a single ionized state.

The paper presents research results related to the impact of high-pressure hydrogen (80 MPa) and radiogenic 3He and their synergetic effect on mechanical properties and structure of CrNi40MoCuTiAl alloy within the temperature range from room temperature to 873K.The samples of three different 3He concentrations have been prepared for research: ≈ 30, ≈ 80 and ≈ 190 appm. The buildup of 3He has been fulfilled using «tritium trick» technique.The tests at room temperature have shown the increasing conventional yield strength (σ0.2) and decreasing plasticity characteristics (total elongation Δ5 and reduction of area E) depend on 3He concentration increasing. However at 873 К test temperature the alloy with the maximum 3He (≈ 190 appm) concentration turned out to be more plastic than the alloy with 3He ≈ 30 and 80 appm concentration.

The low-lying spectra of 8He and 10He nuclei were studied in the 3H(6He, p)8He and 3H(8He, p)10He transfer reactions. The 0+ ground state (g.s.) of 8He and excited states, 2+ at 3.6–3.9 MeV and (1+) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μb/sr, respectively. Some evidence for a 8He state at about 7.5 MeV was obtained. We discuss a possible nature of the nearthreshold anomaly above 2.14 MeV in 8He and relate it to the population of a 1− continuum (soft dipole excitation) with a peak value at about 3 MeV. The lowest energy group of events in the 10He spectrum was observed at ∼ 3 MeV with a cross section of ∼ 140 μb/sr. We argue that this result is consistent with the previously reported observation of 10He providing the new 10He g.s. position at about 3 MeV

Hydrogen environment embrittlement (HEE) of several heats of austenitic stainless steels was measured by slow strain rate tensile testing in hydrogen atmosphere at different temperature–pressure combinations. The relative reduction of area decreased (means increasing hydrogen embrittlement) in the following order: 20 °C/10 bar > 20 °C/700 bar > −50 °C/10 bar > −50 °C/400 bar ≈ −80 °C/200 bar. An assessment of the most severe error sources revealed that tensile tests in hydrogen can be performed with a very high repeatability and reproducibility with a total deviation of about 10% with respect to the relative reduction of area (RRA = RA H2 /RA He ). Higher deviations in RRA are due to local deviations in metallurgy and chemical composition, which are very sensitive to HEE. Screening tests of several austenitic SS at 20 °C/700 bar show decreasing HEE with increasing Ni content. For RRA > 90%, a minimum Ni content of >11.5 wt% is required.

Samples of stainless steel 12Cr18Ni10Ti with radiogenic helium were subjected to mechanical tests with a constant extension rate. The presence of {sup 3}He does not markedly affect the strength characteristic, but significantly decreases plasticity of steel. The presence of hydrogen enhances the embrittlement of steel, containing {sup 3}He. The diffusion coefficient of hydrogen does not change significantly in the presence of helium, but the traps for hydrogen, which occur due to the presence of helium, delay the kinetics of a steady state flux onset at helium concentration of 50 appm. (authors)

Application of hydrogen isotopes in different fields of fundamental physics obtained by RFNC-VNIIEF in the last decade are presented. Gas-handling systems for scientific experiments, some technologies and designs of the setup key elements are described, and results obtained with the developed equipment are outlined. (authors)

We present some results of studying the influence of high-pressure hydrogen (80 MPa), radiogenic 3He (with concentrations up to 130 appm), and their joint action on the mechanical properties and structure of 12Kh18N10T steel in the temperature range from 293 to 873 K. We describe the procedure of tests of specimens containing 3He. It has been established that the joint action of hydrogen and 3He affects slightly the ultimate strength of the specimens. Saturation of steel with radiogenic 3He by the method of “tritium trick” increases its yield strength. Hardening of the steel caused by helium increases with temperature and 3He concentration and, at 873 K, is accompanied by substantial embrittlement. We also present results of the fractographic analysis of specimens tested under different conditions.

Automated system feeding into ion source hydrogen isotopes as molecules with preset ratio of the fluxes is described. The control system automatically maintained the working parameters and provided graphic and digital representation of the controlled processes. Theradio-frequency (RF) ion source installed at the axial injection line of the cyclotron produced ion beams of HD + , HT + , DT + , D 2 H + , etc. At a several months DT + beam acceleration the tritium consumption was less than 108 Bq/hr. The intensity of a 58.2 MeV triton beam (T + ions) extracted from the cyclotron chamber was about 10 nA.

The paper presents results of tritium-structural materials interaction modeling by simultaneous exposure to radiogenic helium-3 and hydrogen (both dissolved and external). This method of synergetic effect of radiogenic helium-3 and hydrogen is a radiation-safe technique to study the tritium impact on mechanical properties of structural materials. Applicability of the method is illustrated by technique and research results on the impact of high-pressure hydrogen (80MPa), helium-3 (concentration ∼140appm) and their synergetic (hydrogen+ 3 He) effecs on mechanical properties of CrNi40MoCuTiAl alloy in temperature range from 20 to 600°C. It has been shown that joint effect of radiogenic helium-3 and hydrogen on mechanical properties of alloy can not be represented as the result of a simple summation of helium and hydrogen embrittlement. Proposed technique of synergetic impact of radiogenic helium-3 and hydrogen allows more correct simulation and investigation in the tritium impact on mechanical properties of materials than individual research in helium or hydrogen embrittlement.

The technical approach, equipment and software developed during the creation of measurement and control systems for two complexes are described. The first one is a complex that prepares the gas mixture and targets of the 'TRITON' facility. The 'TRITON' facility is designed for studying muon catalyzed fusion reactions in triple mixtures of H/D/T hydrogen isotopes over wide ranges of temperature and pressure. The second one is 'ACCULINNA' - the liquid tritium target designed to investigate the neutron overloaded hydrogen and helium nuclei. These neutron-overloaded nuclei are produced in reactions of tritium beams on a heavy hydrogen and tritium target.

For the experiment on the measurement of the electron antineutrino magnetic moment we suggest a new approach to the tritium source design, namely, a configuration of annular cells filled with TiT{sub 2} that are stacked into a hollow cylinder. Detectors are mounted in the hole inside.We present results of the optimization of geometrical and physical parameters of the source with respect to its experimental effectiveness and safety guaranty at all stages of its lifecycle. We discuss the choice of the construction materials and specify technological issues relevant to radiation purity of the source, being of the special concern in the experiment on the electron antineutrino magnetic moment measurement.

The superpermeability phenomenon was suggested to use in fusion machines to separate the fuel mixture from helium ashes, to arrange in-vessel fuel recirculation contours and effective evacuation of...

The results of calculated and experimental studies of the influence of some parameters (the temperature and time of tritiation and aging, the cooling rate after tritiation) on the helium-3 concentration in metals are given. It has been experimentally found that the hydrogen concentration in O3 mm samples of 12Cr18Ni10Ti steel, which were saturated with hydrogen at 773 K and 50 MPa, makes up ∼ 0.6 of the equilibrium hydrogen concentration immediately after cooling to room temperature and ∼ 0.5 after 5000-hour aging.

Experimental data on the shock compression, temperature, and absorptivity of gaseous deuterium with an initial density close to its value in the liquid state were obtained on a spherical explosion shock-wave generator in a pressure range of 80–90 GPa. The obtained results are compared with the existing experimental and theoretical data.

A computerized system for monitoring and controlling the gas-mixture preparation complex of the TRITON installation is described. The installation is designed for experimental investigations of muon-catalyzed fusion in triple mixtures of hydrogen isotopes H/D/T over wide ranges of temperature and pressure. The system is used to control the entire complex of gas-mixture preparation, the target parameters, and the gas-mixture composition, as well as to carry out radiation monitoring. Good performance characteristics, the high reliability of the system, and the possibility of its rapid adaptation to new tasks have been demonstrated in physics experiments.

Measurement and control systems of two instrumentation complexes for experimental studies using hydrogen isotopes are described. The first of these, the complex that prepares the gas mixture of the Triton facility, is designed for studying the muonic catalysis of nuclear fusion reactions in triple mixtures of H/D/T hydrogen isotopes over wide ranges of temperature and pressure. The second, the Prometheus complex, is designed for studying the phenomena of tritium accumulation and transmission by metals and other structural materials.

Photoluminescence (PL) spectra and Raman scattering spectra of Si–SiO x systems, prepared by radio frequency magnetron sputtering method and thermal annealed at 1150°C for creation of Si nano-crystallites, were investigated as a function of Si content and Si nano-crystallite sizes. It was shown that the PL spectrum of such systems consists of several bands with peak positions at 1.32–1.34, 1.42–1.58, 1.77, 2.05 and 2.30 eV. The dependencies of these PL band parameters on concentration and size of Si nano-crystallites in the Si–SiO x system have been investigated and analyzed. The nature of radiative optical transitions for all PL bands is discussed.

A cryogenic tritium target and computer-controlled equipment providing for feeding/recovering tritium into/from the target cell and radiation monitoring in technological lines and in workrooms is described. The tritium target set-up showed reliable operation in experiments done with a 58.3 MeV triton beam focused on a 5 mm spot at intensity approaching 3×107 s−1. The t+t elastic scattering cross-section was obtained in a wide angular range.

Photoluminescence (PL) spectra and their temperature dependence, as well as PL excitation and Raman spectra of Si–SiO x systems prepared by RF magnetron sputtering were investigated as a function of Si content. It was shown that PL spectrum of such systems consists of several bands. The correlation of shift of peak position of the lower-energy band from 1.38 to 1.54 eV with the change of size of Si nanocrystallites from 5 to 2.7 nm was observed. It was assumed that this PL band is connected with carrier recombination inside Si nanoparticles or with radiative transitions between a Si band and an interface level. It was shown that peak positions of the other observed bands (at 1.7, 2.06 and 2.32 eV) do not depend on the sizes of Si nanocrystallites. It was suggested that they are connected with silicon oxide defects based on the increase of intensities of these bands with increasing silicon oxide content. It was also shown that the excitation of PL is mainly due to light absorption in silicon nanocrystallites. Participation of hot carriers in excitation of defect-related bands was assumed.

TheseparatorACCULINNAwasupgradedtoachievenewexperimentalrequirements.Thebeamlinewasextendedbynewion-opticalelementsbeyondthecyclotronhall.Thenewarrangementsyieldmuchbetterbackgroundcondi-tions.Theintensitiesof 6 Heand 8 Heradioactivebeamsproducedinfragmentationof35AMeV 11 Bionswereincreaseduptoafactorof10.Theupgradedbeamlinewasusedinexperimentstostudythe 5 Hresonancestatespopulatedinthet þt reaction.Acryogenicliquidtritiumtargetwasdesignedandinstalledattheseparatorbeamline. 2002ElsevierScienceB.V.Allrightsreserved. PACS:25.70.Mn;29.25.RmKeywords:Radioactive ion beams;Productiontarget;Profileddegrader;Liquidtritiumtarget 1.IntroductionTheseparatorACCULINNA[1]isinoperationsince1996.Highintensityprimarybeamsof 7 Li, 11 B, 13 C, 15 Nand 18 Owithenergyvaluesrangingbetween32and50AMeVaredeliveredbytheU-400Mcyclotrontotheproductiontargetoftheseparator.Thesecondarybeamsof 6 Heand 8 Henucleiwithenergiesofabout25AMeVallowedustogainnewinsightsintothestructureofneutronhalonucleithroughthestudyofone-andtwo-neutrontransferreactionsmadewithhydrogenandheliumtargets[2–5].Suchbeamsofferfavor-ableconditionsfortheproductionofsofarun-knownparticle-unstablenucleibeyondtheneutrondripline.Forthispurposeonecoulduseone-stepone-proton and two-neutron transfer reactionsoccurringwheneither

Si/SiGe/SiGe:C/SiGe/Si heterostructures are investigated by Raman spectroscopy, electroreflectance method, and secondary-neutral mass spectrometry. It is shown that doping of a SiGe layer lying between undoped SiGe layers with C (1.5%) leads to almost complete stress relaxation in the doped layer. It is found that high-temperature photon annealing is responsible for a partial stress relaxation in the lower SiGe buffer layer. However, such annealing increases the Si content in this layer. Low-temperature treatment in the radio-frequency (RF) hydrogen plasma leads to considerable stress relaxation in the lower buffer layer without varying its composition. The results obtained from the electroreflectance and secondary-neutral-mall spectra correlate with the Raman spectroscopy data.

Photoluminescence (PL), photoluminescence excitation (PLE), and Raman spectra of Si–SiOx layers were measured as a function of Si content. Samples were prepared by co-sputtering of Si and SiO2 and post-annealing. The average size of Si nanoparticles was estimated from Raman measurements. It was shown that, in general, the PL spectra consist of two bands with maxima in the 'red' and 'green' spectral ranges. The 'red' PL band is complex and contains two (IR and red (R)) components. The shift of the peak position of the IR component from 1.38 to 1.54 eV correlates with the decrease of the Si nanoparticle size from 5 to 2.7 nm. It was shown that this PL component could be ascribed to carrier recombination in silicon nanoparticles. The R component of the 'red' band as well as the 'green' band have similar dependences of the peak positions and intensities on the Si content and can be ascribed to defect-related luminescence. It was concluded that the light absorption in silicon nanocrystallites plays the main role in PLE process. Hot-carrier participation in the excitation of defect-related bands was deduced.

This paper presents a schematic design of Tritium Fuel Cycle for Muon-Catalyzed Intense Neutron Source (MC INS) capable of producing monochromatic 14 MeV neutrons. Based on the assumption that the fuel mixture should be used in a liquid phase the different approaches arc proposed to incorporate a DT cell (synthesizer) into the MC INS facility The estimations of total tritium inventory in the MC INS facility are given The calculations of the DT cell operation temperature regime using the code FLOW 3D are presented. It is shown the capability to remove the thermal energy released in the DT cell of the proposed design. The MC INS design is analyzed from the viewpoint of tritium safety requirements.

An experiment aimed at directly detecting antineutrino-electron scattering by using a 40-MCi tritium β-active source will make it possible to lower the present-day laboratory limit on the neutrino magnetic moment by two orders of magnitude. The experiment brings together novel unique technologies in studying rare processes of neutrino-electron scattering: (i) an artificial source of antineutrinos from tritium decay of 40-MCi activity with the antineutrino flux density of about 6×1014 cm−2 s−1 and (ii) new types of detectors capable of detecting electrons of energy down to about 10 eV, namely, a silicon cryogenic detector based on the ionization-into-heat conversion effect and a high-pure germanium detector with an internal signal amplification in the electric field. A compact installation located at a specially equipped underground laboratory (≤100 mwe) will provide favorable background conditions for running the experiment. With a background level of about 0.1 event/(kg keV d) and detector assembly masses of 3 and 5 kg for the silicon and germanium ones, respectively, a limit of μ ν ≤3±10− μ B on the electron-antineutrino magnetic moment will be obtained within 1 to 2 years of data acquisition. The status of the experiment and the state of the art are presented.

The results of a comprehensive study by the methods of IR absorption, Raman scattering, photoluminescence (PL), and electron spin resonance (ESR) of SiOx films prepared by thermal evaporation of SiO in a vacuum are presented. The nature of structural transformations occurring on annealing the films is determined. Annealing in the temperature range 300–600°C gives rise to a PL band at 650 nm, presumably related to structural defects in SiOx film. Raising the annealing temperature further leads to healing of such defects and quenching of the PL band. Silicon precipitates pass from the amorphous to the crystalline state on being annealed at Tann=1100°C, which gives rise to a new PL band at 730 nm. ESR spectra of Pb centers were recorded at the interface between randomly oriented silicon nanocrystallites and SiO2.

This paper describes the system being designed to study the processes of hydrogen isotopes (or their mixtures) interaction with a solid body at pressures up to 500 MPa. Hydrogen isotopes pressure is produced by a thermodesorption source based on vanadium dihydride. Gas is sampled through an intermediate volume. Gas chromatograph is used to analyze the gas for isotopic composition. Possibility of the system development is exemplified by temperature dependencies of equilibrium desorption pressures for vanadium dihydride in a pressure range up to 500 MPa obtained using available equipment.

The results of the design study of an advanced scheme for the 14-MeV intense neutron source based on muon-catalyzed fusion ({mu}CF) are presented. A pion production target (liquid lithium) and a synthesizer [liquid deuterium-tritium (D-T) mixture] are considered. Negative pions are produced inside a 17/7 T magnetic field by an intense (2-GeV,12-mA) deuteron beam interacting with the 150-cm-long, 0.75-cm-radius lithium target. Muons from the pion decay are collected in the backward direction and stopped in the D-T mixture of the synthesizer. The synthesizer has the shape of a 10-cm-radius sphere surrounded by two 0.03-cm-thick titanium shells. At 100 {mu}CF events/muon, it can produce up to 10{sup 17}n/s of 14-MeV neutrons. A quasi-isotropic neutron flux up to 10{sup 14} n/cm{sup 2}.s{sup -1} can be achieved in the test volume of {approx}2.5 l with an irradiated surface of {approx}350 cm{sup 2}. The thermophysical and thermomechanical analyses show that the technological limits are not exceeded.

The paper presents a schematic design of a Tritium Fuel Cycle for Muon-Catalyzed Intense Neutron Source (MC INS) capable of producing 14 MeV neutrons. Based on the assumption that the fuel mixture should be used in a liquid phase different approaches are proposed to incorporate a DT cell (synthesizer) into the MC INS facility. Estimations of the total tritium inventory in the MC INS facility are given. The calculations of the DT cell operation temperature regime using the code FLOW-3D(R) are presented. The capability to remove the thermal energy released in the DT cell of the proposed design is shown. The MC INS design is analyzed from the viewpoint of tritium safety requirements.

Experimental study on muon catalyzed dt fusion in a triple mixture of hydrogen isotopes (H/D/T) was carried out at the JINR phasotron. The measurements have been performed at various temperatures and densities with liquid and gaseous H/D/T mixtures. Results are presented for the main characteristics of the dtμ cycle. A reduction of the number of dt fusions is observed when hydrogen is added to the D/T mixture, This is mainly due to muon loss to the pt and pd cycles, which have a high sticking probability. We also observe an increase of the cycle rate when the temperature of the H/D/T mixture rises. This confirms the theoretical prediction.

Equilibrium pressures of protium and deuterium desorption over a two-phase area of monohydride-vanadium dihydride were measured. Temperature measurement range was 300–635 K and the pressure range 1–500 MPa. Obtained temperature-dependences of fugacities within the given measurement range are: lgf(MPa) = −2152/T+ 6.6 and lgf(MPa) = −2575/T + 7.4 for protium and deuterium, respectively. The values of enthalpy and entropy for vanadium dihydride phase formation were calculated from obtained relations. Using expressions obtained for fugacities and literature data on hydrogen imperfection the pressures, which can be obtained with vanadium dihydride employed in thermodesorption hydrogen sources, were estimated. Taking into account that due to deterioration in strength properties of the used structural materials, the heating temperature of the load-bearing body is limited to ∼973 K, maximal calculated pressure, which can be obtained with such sources as ≈1820 MPa for protium and ≈2220 MPa for deuterium.