Nuclear Reaction Products Research Articles

Computational and Experimental Simulation of Static Memory Cells of Submicron Microcircuits under the Effect of Neutron Fluxes

The simulation of reversible single events in test samples of static memory microcircuits with design norms of 0.5, 0.35, 0.25, and 0.1 μm under the effect of neutron fluxes with various energies is performed. It is shown theoretically and experimentally that reversible single events can occur in modern microelectronics and nanoelectronics products under the effect of a fission-spectrum neutron flux caused by the passage of primary recoil atoms and nuclear reaction products along the microcircuit surface perpendicularly to the electric current lines in the near-drain transistor area. A series of irradiation experiments of static memory circuits with design norms of 0.35 μm is interpreted based on the proposed model.

Nuclear Reactions under Irradiation of Deuterated Structures by X Rays

Measurements of emission from nuclear reaction products (neutrons and protons) have been carried out appearing in the deuterated structures of textured CVD diamond, palladium, titanium, and zirconium under irradiation with a beam of X rays using independent methods (neutron detector based on He-3 counters, Si surface-barrier semiconductor detectors and CR-39 track detector). The possibility of enhancement of both DD reaction and multi-particle deuterium fusion by the beam of X rays with energy ranging 20–30 keV in solid deuterated targets has been established. Analysis of X-ray fluorescence spectra of the target bombarded by beams of ions has revealed “additional” peaks, the occurrence of which cannot be related to any of the known elements, and requires separate study.

High-speed gas neutron detector for thermometry of thermonuclear plasma

Abstract The article deals with the problem of measuring the temperature T i of ions in D–T plasma. To measure T i , it is proposed to use a gaseous proportional counter operating in the current mode. For the selection of current pulses it is proposed to use the property of products of nuclear reactions which are the alpha-particle and the residual nucleus to form the braking peak of ionization when stopped (so called Bragg’s effect). Neutron energy distribution consists of events characterized by current pulses with two peaks — due to the alpha particle and the residual nucleus. This selection method allows excluding the so-called “wall effect”, i.e. events that do not fully fit into the volume of the counter. As has been shown such kind of neutron detector can achieve an energy resolution of about 10 − 3 .

Study of Luminescence in Noble Gases and Binary Kr-Xe Mixture Excited by the Products of 6Li(n,α)T Nuclear Reaction

At the present time the direct nuclear energy conversion into optical radiation is realized in gas media in which filling of energy levels takes place in the low-temperature plasma (nuclear-excited plasma) induced by ionizing radiation. The research of optical radiation of the nuclear-excited plasma induced by products of nuclear reactions is interest for development of an alternative outlet method of energy from the nuclear reactor, creation of control and regulating bodies for parameters of nuclear reactors as well as creation of one of diagnostics of high-temperature plasma in fusion reactors. The purpose of this work was to obtain new experimental data about processes of nuclear energy conversion into optical radiation with the optimal gas media having high coefficient of nuclear energy conversion into optical radiation and also with a possibility of outlet method of energy from the nuclear reactor core. In this article, description of the reactor experimental bench (LIANA) and the experiment scheme, the irradiating ampoule device (AD) with surface source of charged particles is provided, and the procedure of reactor experiment is presented. This paper presents the results of the reactor experiments of studying the spectral-luminescent characteristics of unary noble gases (Ne, Ar, Kr, Xe) and binary Kr-Xe gas mixture in a 200–975 nm spectral range with ionization gaseous media by products of 6Li(n,α)T nuclear reaction under irradiation at research water-cooled heterogeneous reactor (the IVG.1M).

Detection of atomic nuclear reaction products via optical imaging

In this paper we propose a new method for measuring the cross section of low yield nuclear reactions by capturing the products in a cryogenically frozen noble gas solid. Once embedded in the noble gas solid, which is optically transparent, the product atoms can be selectively identified by laser induced fluorescence and individually counted via optical imaging to determine the cross section. Single atom sensitivity by optical imaging is feasible because the surrounding lattice of noble gas atoms facilitates a large wavelength shift between the excitation and emission spectrum of the product atoms. The tools and techniques from the fields of single molecule spectroscopy and superresolution imaging in combination with an electromagnetic recoil separator, for beam and isotopic differentiation, allow for a detection scheme with near unity efficiency, a high degree of selectivity, and single atom sensitivity. This technique could be used to determine a number of astrophysically important nuclear reaction rates.

Initial operation of the recoil mass spectrometer EMMA at the ISAC-II facility of TRIUMF

The Electromagnetic Mass Analyser (EMMA) is a new vacuum-mode recoil mass spectrometer currently undergoing the final stages of commissioning at the ISAC-II facility of TRIUMF. EMMA employs a symmetric configuration of electrostatic and magnetic deflectors to separate the products of nuclear reactions from the beam, focus them in both energy and angle, and disperse them in a focal plane according to their mass/charge (m/q) ratios. The spectrometer was designed to accommodate the gamma-ray detector array TIGRESS around the target position in order to provide spectroscopic information from electromagnetic transitions. EMMA is intended to be used in the measurement of fusion evaporation, radiative capture, and transfer reactions for the study of nuclear structure and astrophysics. Its complement of focal plane detectors facilitates the identification of recoiling nuclei and subsequent recoil decay spectroscopy. Here we describe the facility and report on commissioning efforts.

Active Target for α-Particle Condensation Studies in 16O

An active target has been developed for studying the Hoyle like states in 16O. It is a position and time sensitive detector system based on the Low-Pressure Multy-Wire Proportional Chamber (LPMWPC) technique and Si detectors. The few Torr pressure of methyl ((OCH3)2CH2) serves as a working gas for the LPMWPC operation, and the oxygen atoms of the methyl molecules serve as an experimental target. The main advantage of this new target-detector system is a high sensitivity to the low-energy, highly ionizing particles, produced after photodisintegration of 16O, and the insensitivity to the γ-rays and low ionizing particles, which allows one to detect only the products of the nuclear reaction, which are studied. The threshold energies for detection of α particles and 12C nuclei are about 50 keV and 100 keV, respectively. Temporal and positional resolution of the LPMWPC modules was investigated with the use of the α-particle source. This paper discusses the architecture of the active target and the test results of the prototype MWPC detector. This installation has been constructed to study the cluster states at 15.1 MeV in 16O using the proton beams from the Yerevan proton cyclotron and the Compton backscattered photon beams of the ELI-NP facility.

Radiative Characteristics of Xe2Cl* Molecules under High-Energy Electron Pumping of Xe–CCl4 and Ar–Xe–CCl4 Gas Mixtures with a Low CCl4 Content

Spontaneous and stimulated emissions of Xe2Cl* triplex molecules upon excitation of Xe–CCl4 gas mixtures with a low CCl4 content by a pulsed high-energy electron beam have been experimentally studied. The electron energy is 150 keV, and the pump current pulse duration and amplitude are 5 ns and 5 A, respectively. Emission of an Xe2Cl excimer molecule in the wavelength range of 430–650 nm is shown to consist of 13 narrow vibrational bands with half-widths Δλ ~ 14 nm peaking at 399, 413, 431, 451, 472, 492, 510.3, 534.9, 540.9, 551.7, 564.4, 581.6, and 603 nm. Under the given pumping conditions, a regime of weakly amplified spontaneous emission is implemented at the energy deposition to the gas of ~200 W/cm3 on the axis of a 50‑mm cell and the electron beam pumping in the wavelength range of 450–550 nm. Spontaneous emission of the 42Г–12Г band of a Xe2Cl* excimer molecule at λmax = 486 nm was amplified by a factor of 60 in a 100‑cm cell under pumping of a dense 3He–Xe–CCl4 gas mixture by the 3He(n, p)3T nuclear reaction products at the energy deposition to the gas of ~5 mJ/cm3 in a cavity with the mirror reflections of ~99.4% (totally reflecting mirror) and 98.5% (output mirror).

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЯ НАЧАЛЬНОГО ЭТАПА ОКИСЛЕНИЯ АУСТЕНИТНОЙ СТАЛИ 12Х18Н10Т В ВОДЯНОМ ПАРЕ

The paper presents the results of the study of the initial stage of oxidation of austenitic steel 12X18H10T in water vapor, which were obtained using a method of research of thin surface layers of steel, based on the analysis of nuclear reaction products in the interaction of oxygen with accelerated ion beams. Austenitic 18 % chromium steel 12X18H10T is one of the structural steels used in reactor installations with heavy liquid metal coolant (HLMC) in the region is relatively high (T<350 °C) temperatures. In test benches and experimental installations the temperature area of use of this steel is much wider. Studies of this steel, especially in the field of low temperatures or short time intervals of exposure of samples, where there are significant methodological difficulties, are of some scientific interest. In addition, the study of the oxidation of structural steels directly in gaseous media, including water vapor, are of great practical importance. It is because these modes of oxidation are used as special technological operations of formation of oxide films on the individual elements and the equipment of the first circuits of nuclear power plant (NPP) with HLMC on the basis of lead and its alloys.

A setup to develop novel Chemical Isobaric SEparation (CISE)

Gas catchers are widely used to thermalize nuclear reaction products and subsequently extract them for precision measurements. However, impurities in the inert stopping gas can chemically react with the ions and thus influence the extraction efficiency. So far, chemical reactions in the gas-catcher have not been investigated in detail. Therefore, we are currently building a new setup to develop Chemical Isobaric SEparation (CISE) with the aim to understand the chemistry inside the gas-catcher and to explore its potential as a new technique for separation of isobars. In this paper, we give a short description of the setup together with the ion transportation studies performed via ion-optics simulations.

Infological models of the ENDF-format nuclear data

Issues involved in the infologic modeling of the ENDF-format nuclear data libraries for the purpose of converting ENDF files into a relational database have been considered. The transfer to a relational format will make it possible to use standard readily available tools for nuclear data processing which simplify the conversion and operation of this data array. Infological models have been described using formulas of the “Entity (List of Attributes)” type. The proposed infological formulas are based on the physical nature of data and theoretical relations. This eliminates the need for a special notation to be introduced to describe the structure and the content of data, which, in turn, facilitates the use of relational formats in codes and solution of nuclear data evaluation problems. The concept of nuclear informatics has been formulated based on relational DBMS technologies as one of the tools for solving the “big data” problem in modern science and technology. The organizational and technological grounds for the transfer of ENDF libraries to a relational format are presented. Requirements to the nuclear data presentation formats supported by relational DBMS are listed. Peculiarities of the infological model construction, conditioned by the hierarchical nature of nuclear data, are identified. The sequence for the ENDF metadata saving is presented, which can be useful for the verification and validation (testing of the structural and syntactical validity and operability) of both source data and the procedures for the conversion to a relational format. Formulas of infological models are presented for the cross sections file, the secondary neutron energy distributions file, and the nuclear reaction product energy-angle distributions file. A complete array of infological models for ENDF libraries and the generation modules of respective relational tables are available on a public website.

Emission of noble gases and their mixtures with lithium excited by the products of the 6Li(n,α)3H nuclear reaction

AbstractResearch results of luminescence spectra of noble gases and Ar–Xe, Ar–Kr, and Kr–Xe mixtures under the excitation by products of nuclear reaction in the core of a stationary nuclear reactor with 0.87 × 1014 n/cm2s thermal neutron flux are described in the article. The emission spectra of noble gases are similar to the obtained spectrum under the excitation by the 40Ar+7 ion beam from the DC-60 accelerator. Bands in spectra of the binary mixtures of noble gases are connected with the radiation on heteronuclear ion molecule transitions. The appearance of the lines of alkali metal atoms at the temperature increase of gas chamber is explained by sputtering of the lithium layer via nuclear reaction products as well as ionized and excited particles of the buffer gas.

Ion beam measurements for the investigation of TiN thin films deposited on different substrates by vacuum arc discharge

Titanium nitride thin films were deposited on different substrates using vacuum arc discharge system. Simultaneous ion beam analysis measurements including elastic backscattering (EBS) and nuclear reaction analysis (NRA); were applied for both composition analysis and thickness measurements of the prepared TiN films. Experimental conditions have been optimized to avoid overlapping of peaks of different nuclear reactions products, especially those related to interaction between ion beam and light elements present in totally different substrates. Independent compliment measurements utilizing time-of-flight elastic recoil detection analysis (TOF-ERDA), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) measurements were also applied to verify the experimental findings obtained by EBS and NRA measurements. The results have shown that all prepared TiN films have N/Ti ratio of around 1, with low levels of contamination elements.

Расчетно-экспериментальное моделирование обратимых сбоев ячеек статической памяти субмикронных микросхем при воздействии потоков нейтронов

AbstractThe simulation of reversible single events in test samples of static memory microcircuits with design norms of 0.5, 0.35, 0.25, and 0.1 μm under the effect of neutron fluxes with various energies is performed. It is shown theoretically and experimentally that reversible single events can occur in modern microelectronics and nanoelectronics products under the effect of a fission-spectrum neutron flux caused by the passage of primary recoil atoms and nuclear reaction products along the microcircuit surface perpendicularly to the electric current lines in the near-drain transistor area. A series of irradiation experiments of static memory circuits with design norms of 0.35 μm is interpreted based on the proposed model.

Излучательные характеристики молекул Xe-=SUB=-2-=/SUB=-Cl-=SUP=-*-=/SUP=- при накачке пучком быстрых электронов газовых смесей Xe-CCl-=SUB=-4-=/SUB=- и Ar-Xe-CCl-=SUB=-4-=/SUB=- с низким содержанием CCl-=SUB=-4-=/SUB=-

AbstractSpontaneous and stimulated emissions of Xe_2Cl* triplex molecules upon excitation of Xe–CCl_4 gas mixtures with a low CCl_4 content by a pulsed high-energy electron beam have been experimentally studied. The electron energy is 150 keV, and the pump current pulse duration and amplitude are 5 ns and 5 A, respectively. Emission of an Xe_2Cl excimer molecule in the wavelength range of 430–650 nm is shown to consist of 13 narrow vibrational bands with half-widths Δλ ~ 14 nm peaking at 399, 413, 431, 451, 472, 492, 510.3, 534.9, 540.9, 551.7, 564.4, 581.6, and 603 nm. Under the given pumping conditions, a regime of weakly amplified spontaneous emission is implemented at the energy deposition to the gas of ~200 W/cm^3 on the axis of a 50‑mm cell and the electron beam pumping in the wavelength range of 450–550 nm. Spontaneous emission of the 4^2Г–1^2Г band of a Xe_2Cl* excimer molecule at λ_max = 486 nm was amplified by a factor of 60 in a 100‑cm cell under pumping of a dense ^3He–Xe–CCl_4 gas mixture by the ^3He( n , p )^3T nuclear reaction products at the energy deposition to the gas of ~5 mJ/cm^3 in a cavity with the mirror reflections of ~99.4% (totally reflecting mirror) and 98.5% (output mirror).

Charged Particle Trajectories in the MAVR High-Resolution Magnetic Spectrometer

Charged-particle trajectories in the MAVR high-resolution magnetic spectrometer [1] are simulated. The latter has been constructed at the U400 accelerator for purifying the incident beam and identifying the products of nuclear reactions induced by the beams of stable and radioactive nuclei. In this paper we present the MAVRPC software package, aimed at reconstructing the spectrometer focal plane, optimizing the fields of quadrupole and dipole magnets, and estimating the solid-angle acceptance for secondary particles.

Review of Neutron Diagnostics Based on Fission Reactions Induced by Fusion Neutrons

Neutrons are an exceptional diagnostic signature in magnetic fusion experiments with high temperature plasma. A part of neutron detection methods relies on detecting nuclear reactions products, initiated by neutrons. Among different possibilities, the neutron-induced fission reactions can be used. These methods use the specific properties of the radioactive decay phenomena induced by neutrons of heavy elements like uranium or thorium. The neutron-induced fission reactions produce energetic fission fragments that can be detected in a special type of ionization chambers that has one of electrode covered with fissionable material. A fission reaction may be also adapted to neutron detection by activation method. A dedicated target-sample made from fissionable isotope (like 235U, 238U, 232Th), irradiated by neutrons, is the source of prompt and delayed neutrons. The decay curve of delayed neutrons can be registered almost immediately after irradiation by fusion neutrons, with a delay resulting exclusively from the time of transport of the samples to the measuring set-up. The yield of a fusion neutron source can be calculated from that measurement. Fission phenomena and fissionable materials are applicable in plasma neutron diagnostics. The lecture gives the introduction to the nuclear fission process and the particular attention is done to the phenomenon and physics of delayed neutrons which are generated during the fission reaction. Examples of delayed neutrons activation set-up and fission chambers dedicated for tokamaks are presented.

Evaluation of the radiation hazard for ion-beam analysis with MeV external proton beams (X-IBA)

Abstract MeV ion beams which are extracted into air or He atmosphere are used in many labs for proton-induced X-ray emission (PIXE), proton induced gamma ray emission (PIGE) or Rutherford backscattering (RBS) to analyze samples which are difficult or impossible to handle in vacuum. When MeV proton beams are extracted into air through thin Kapton foils or nowadays thin silicon nitride membranes, the protons will interact with air, as well as elements present in the analyzed samples. Typically the range of MeV protons in air is several cm, in Helium atmosphere several 10 cm and in human skin around 100 µm. Besides the severe radiation hazard in case of a direct exposure of skin with protons, there are a manifold of nuclear reactions or inelastic proton scattering processes which may cause activation of air and target materials but also prompt radiation. The radiation hazard associated with the direct and scattered beam, nuclear reaction products and radionuclide production in air have been discussed in a publication by Doyle et al. in 1991 which was used as a reference in several later publications. I have reevaluated the radiation hazards for external proton beams with up to 4.5 MeV using proton reaction cross sections taken from the JANIS book of proton induced cross sections. The radionuclide production in air is about 3 orders of magnitude lower compared to values given in the 1991 publication. Radionuclide production as well as generation of prompt alpha, gamma and neutron radiation in target materials for elements up to molybdenum is also evaluated.

Evidence of 9Be + p nuclear reactions during 2ωCH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas

The intensity of 9Be + p nuclear fusion reactions was experimentally studied during second harmonic (2ωCH) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H+ ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9Be + p interaction, were observed with fast ion loss detectors, γ-ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9Be(p, d)2α and 9Be(p, α)6Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.

Efficiency of high-purity germanium detector at characteristic gamma energies of 198Au and 58Co and covariance analysis

Naturally occurring 197Au and 58Ni foils were subjected to the neutron irradiation by placing them in a dry tube-I of Kalpakkam Mini reactor to produce gamma emitting 198Au and 58Co nuclear reaction products. The efficiency study of high-purity germanium detector corresponding to characteristic gamma energies 0.4118 and 0.8107 MeV of 198Au and 58Co was carried out by the methods of calibration of 152Eu and covariance.