The Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR) is one of the leading centers for neutron physics in the JINR Member States. FLNP scientists conduct research in the fields of condensed matter physics and nuclear reactions with neutrons, as well as to solve a wide range of applied problems using nuclear physics techniques. The basic facility of...
The parity violating effects in nuclear interactions is extremely enhanced in resonant neutron absorption processes via compound nuclear states for some of medium-heavy nuclei. The enhancement is explained as a result of the interference between parity-unfavored partial amplitudes of the compound nuclear process, which is referred to as "s-p mixing". The "s-p mixing" is expected to enhance the...
Abstract: Nuclear data of the (n, cp) reactions are important in the development of nuclear energy, the application of nuclear technology and the research of nuclear reaction theory. Based on the neutron sources of the 4.5 MV Van de Graaff accelerator of Peking University, EG-5 Van de Graaff accelerator of JINR, FLNP, HI-13 tandem accelerator of CIAE, and the CSNS Back-n, we have extended our...
The tagged neutron method (TNM) is currently being implemented at the Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, for neutron-nuclear physics research. This method utilizes the reaction d+t→α+n to produce neutrons with an energy of approximately 14 MeV, which are emitted simultaneously with α-particles in nearly opposite directions. Neutron tagging is achieved...
The Acceleration Effect (AE), the existence of which was recently predicted in [1], is a generalization of the previously discovered of optical Accelerating Matter Effect (AME) [2]. It consists in the fact that the result of the interaction of a wave with an accelerating object is a change in its frequency. The effect is proportional to the acceleration of the object and the time delay caused...
New short-range forces (SRF) are predicted in many theories beyond the Standard Model of particle physics in the form of weakly interacting scalar or pseudo-scalar bosons. For example, dark matter could be explained by the existence of a weakly interacting boson, and some theories with extra spatial dimensions predict such a particle. Neutrons are useful tools in searches for these SRFs due to...
One of the current problems of the Standard Model of Elementary Particle Physics is the about three sigma failure of the first-row unitarity test of the Cabbibo-Kobayashi-Maskawa matrix. A long-standing goal of the study of free neutron beta decay is a better determination of its upper left element ("Vud"). That is possible with measurements of the neutron lifetime and a correlation...
Neutron activation analysis due to its high accuracy, reproducibility and nondestructive nature is a technique widely used in the environmental, material, archeological, geological and nanotoxicological studies. Favorable features of neutron activation analysis will be highlighted in the presentation and the principal of its realization on the installation REGATA of the IBR-2 reactor will be...
Neutronic Characteristics of Metal Hydride Moderators and Their Applications in Microreactors
Energetic dependence of neutron-induced single event upsets, and its impact on atmospheric neutron SER prediction
The cross section of 6Li(n, t)4He reaction is adopted as standards up to 1 MeV due to its relatively high cross-section. However, in the neutron energy above 0.5 MeV, it was indicated that the cross section might be overestimated by evaluated data, such as ENDF/B-VIII.0 and JEFF-3.3 [1]. Besides, due to the high Q value (4.78 MeV), the 6Li(n, t)4He reaction is widely used in neutron detection...
The characteristics of various nuclear processes are rather simple to calculate in statistical model [1,2]. In particular, the transition-width distribution is described by the Porter–Thomas equation, there are no correlations between different partial widths, the strength function of $\beta$-transitions $S_\beta (E)$ depends smoothly on energy, and the ratios of the amplitudes for decay via...
The Back-n white neutron beam line, which uses back-streaming white neutrons from the spallation target of the China Spallation Neutron Source, is used for nuclear data measurements. A Micromegas-based neutron detector with two variants was specially developed to measure the beam spot distribution for this beam line. In this article, the design, fabrication, and characterization of the...
The neutron capture cross section data for $^{165}$Ho were measured at the Back-streaming White neutron beam line (Back-n) of China Spallation Neutron Source (CSNS) using total energy detection systems, which is comprise a set four C$_6$D$_6$ scintillator detectors coupled with pulse height weighting techniques.
The resonance parameters were extracted using the multilevel, multichannel...
A possibility of the test of T - invariance violation in neutron - nuclear interaction in the multiple mirror reflections of slow neutrons is considered. The reflections are assumed in a "whispering gallery" mode. It is shown that an expected effect may exceeds in magnitude a correspondent effect near p - wave resonance. The methodical features of such experiment are considered.
Since the foundation of Back-n beam line in CSNS, the capture cross section of $^{197}Au(n,\gamma)$ had been measured twice. Considering the lower energy zone and high level of background of previous results, however, we aim to process the yield result to 1 MeV, and analyze the resonance parameters: resonance peak, Gamma width and incident neutron width from 1 eV to 2 keV that belongs to the...
The n+d reaction is one of the most fundamental three-body nuclear reactions, which is an important platform for examining the nucleon-nucleon interaction. The wave-packet continuum discretization approach is developed to solving three-nucleon scattering equations within a modified Faddeev-AGS equation framework, which is based on the discretization representation of the three-body continuum...
Efficient and practical neutron detectors are crucial in many areas, including national security, medicine, crystallography, and astronomy. As commonly used neutron detectors, 3He-gas-filled proportional counters still play an irreplaceable role in neutron fluence monitoring. 3He tubes are used directly to detect the thermal neutron, but the measurable neutron energy range is often extended by...
The final accuracy of the evaluations relies on the quality of the experimental datasets
being used. But, conversely, the quality of the experimental datasets relies on the quality of the
standards used as reference. Big improvements have been done in the last decade, after the
IAEA launched an international project for the “Maintenance of the Neutron Cross-Sections
Standards”, adopting...
A nanosecond tagged neutron technology (NTNT) is based on the space-time analysis of events produced by the 14 MeV neutrons which time of escape, energy, and direction of movement is known by the recording of the accompanying alpha-particle. The development by FSUE VNIIA of the high-intensity generator of tagged neutrons promoted the extension of the applications of tagged neutrons. Currently,...
Model of experiments for applied research at the Nica facility are developed and manufactured. Model includes two ionization chambers IK-1, IK-2, strip and phosphor chambers for measure profile with coordinate and intensity of beam and various sample holders with different geometry. At those chambers, the materials of electrodes are used different, at the IK-1 it is foil-clad fiberglass, for...
Cosmic muon-induced fast neutrons are one of the main sources of neutron background in deep underground environments. Due to the high energy and low flux of cosmic muons, it is challenging to directly measure the neutron yield. According to the Weizsäcker-Williams virtual photon method, when the energy transfer is less than one-tenth of the kinetic energy of the lepton, the Coulomb excitation...
Neutron-induced reaction 6Li(n,t)4He plays an important role in nuclear energy and nuclear data evaluation. The cross section of 6Li(n,t)4He has been adopted as standard in the energy range of 0.0253eV–1.0MeV [1], and is commonly used as reference for other cross section measurements. Previous works have shown non-negligible discrepancies in cross section results [2,3,4], and the angular...
The TANGRA project is aimed at studying the inelastic scattering of 14.1 MeV neutrons from the ING-27 neutron generator on various atomic nuclei using the tagged neutron method. To register gamma rays from the interaction of neutrons with nuclei, we use HPGe and LaBr3(Ce) detectors. To perform high-precision measurements, the energy calibration and counting efficiency of the detectors were...
The 1H(n, n)1H reaction is important for fundamental physics research, neutron cross-section standards, and nuclear data evaluation. However, there are few differential cross-section data for this reaction in several MeV neutron energy regions. The relative differential cross sections of the 1H(n, n)1H reaction was measured at the Back-n white neutron source of the China Spallation Neutron...
Gamma and neutron imaging are crucial non-destructive testing techniques which have been widely used in nuclear safety, national security, materials characterization, and cultural heritage preservation. While the hit position reconstruction algorithms are key issues to improve the image fidelity and accuracy. A 2D planar neutron and gamma imaging system based on a monolithic lithium glass...
In the scope of the “TANGRA” (TAgged Neutrons and Gamma RAys) project established at the Frank Laboratory of Neutron Physics (JINR, Dubna), several experimental setups of different configurations [1] were devised and employed to study the inelastic scattering of neutrons with an energy of 14 MeV on atomic nuclei using the tagged neutron method [2].
One of “TANGRA” setups utilizes two...
A previous experiment performed at JRC-Geel on prompt fission neutrons (PFN) in correlation with fragments from spontaneous fission of 252Cf was repeated using an improved setup and much better statistics. The experiment lasted 3 months and 68×106 coincident events were collected. In this new experiment PFN spectra and angular distributions (in the laboratory system) are selected in a narrow...
The study of the dynamics of heavy nuclei fission remains a relevant problem in modern nuclear physics. One of the key questions in this field is the identification of the mechanism of spin formation of the fission fragments, which is still insufficiently studied. In this work, based on studies [1,2], a modelling of the potential energy of the compound fissile system has been performed to...
Gamma spectra processing is one of the most time-consuming stages of instrumental neutron activation analysis. Since spectra contain a large number of multiplets, their processing by classical mathematical methods leads to high uncertainty in the areas of full energy peaks. In this case, it is necessary to perform manual fitting of peak boundaries. This process is planned to be automated using...
Fast-timing measurement of nuclear excited states using Labr3 detectors has gained a lot of attention in experimental nuclear physics. This is because that the lifetime information is more sensitive to the intrinsic nuclear structure than the level energy. In this talk the speaker will briefly introduce the idea of constructing a fast-timing detector array by LaBr3 detector coupled with...
A compact time-of-flight neutron spectrometer was developed as a part of the BM@N setup at the Nuclotron accelerator (JINR). The aim of the spectrometer is study of neutron emission from target spectator decay in heavy-ion collisions at 2 – 4 A GeV. The neutron spectra are measured at large angles in the energy range of 2 – 200 MeV using small flight path of 20 – 30 cm. Neutron detectors are...
Beryllium, zirconium, and bismuth play crucial roles in nuclear science and technology: beryllium serves as a neutron reflector and moderator, zirconium is widely used in reactor structural materials, and bismuth is essential in accelerator-driven systems and lead-bismuth-cooled reactors. Accurate nuclear data for these materials are critical for shielding, reactor design, and nuclear safety...
The main goal of the TANGRA (TAgged Neutrons and Gamma RAys) project at the Frank Laboratory of Neutron Physics (JINR, Dubna) is to study the interaction of 14.1 MeV neutrons with various nuclei. One of the experimental setups developed within the project consists of an array of 20 EJ-200 plastic scintillators and is designed to study the angular distributions of neutrons and γ-rays resulting...
The neutron total cross sections ( σtot ) are of great value in nuclear reactor design, nuclear theory models, nuclear applications and other fields. Thulium ( 169Tm ) is a crucial neutron absorbing material, and the σtot of 169Tm are highly useful for nuclear reactor design. However, there are only a few experimental σtot of 169Tm in EXFOR and no data in the energy between 10 keV and hundreds...
Current microscopic nuclear data face two major challenges: significant discrepancies among datasets from different sources and missing data points at specific energy levels. To maximize the utilization of existing data, this study proposes constraining differential experimental results through integral experiments, thereby enhancing data consistency and completeness.
Our investigation...
The relative deviation of the thermal capture cross-section of 242Pu in the mainstream nuclear database is more than 10%, and the uncertainty of its capture cross-section in the intermediate and fast neutron region is over 30%. In this paper, the thermal capture cross-section measurement of 242Pu was carried out based on activation method. The irradiation experiment was carried out on the...
In the burgeoning age of artificial intelligence (AI) and advanced technologies, neural networks have emerged as powerful tools, revolutionizing various scientific domains. This lecture, "Recent Progress of Neural Networks in Nuclear Structures," explores the intricate workings of these algorithms and their transformative impact on nuclear physics.
We begin by examining the fundamental...
In accelerator-driven subcritical nuclear system (ADS) simulations, spallation and transmutation reaction models are typically employed due to the lack of the database in medium-to-high energy range. However, some model deviations have been identified, particularly in high-energy neutron-induced reactions on actinide nuclides. This paper presents a comprehensive verification of the current...
Air pollution is the world's most pressing environmental crisis It is responsible for more than 7 million deaths annually, the bulk of which – 70 per cent – occurs in Asia-Pacific region. Air pollution in these countries is several times higher than WHO guideline for safe air. Heavy metals (HM) are among the most dangerous environmental pollutants. In most European countries, the need to study...
Recent progress of the phycical design for the the Ultra-cold Neutron Source at CSNS
A concept is presented for an ultracold neutron (UCN) source with a superfluid helium converter placed in the thermal column of the WWR-K research reactor (Almaty, Kazakhstan). Similar source designs are employed in the existing TRIUMF project (Vancouver) [1] and the proposed project at the WWR-M reactor (Gatchina) [2]. The main distinguishing features of our concept are more efficient systems...
Extensive production and application of gold nanoparticles leads to contamination of aquatic and terrestrial ecosystems, creating risks for consumers of plant products. The effects of gold nanoparticles in concentration range of 1-100 mg/L applied in two routes on Mentha spicata L. plants, soil and human health was investigated. k0-neutron activation analysis was used to determine gold...
Instrumental neutron activation analysis was used to determine the content of more than 30 chemical elements in moss, soil and leaves samples collected in seven Moscow parks, Russia. To determine Cd, Pb and Cu atomic absorption spectrometry was applied. In general, in moss samples used to assess air pollution the content of elements increased with exposure time, except alkali element (K, Cs...
Hao Xu1, Jie Feng1,2, Mingyang Zhu1, Bingzhan Shi1, Guoqiang Zhang3, Jinguang Wang4, Yifei Li4, Xin Lu4,5,6, Wenchao Yan1,2, Liming Chen1,2
1State Key Laboratory of Dark Matter Physics, Key Laboratory for Laser Plasmas (MoE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China, haoxu001@sjtu.edu.cn.
2 Collaborative Innovation Center of IFSA, Shanghai Jiao...
This study presents numerical and analytical investigations aimed at optimizing the measurement of ultracold neutron (UCN) loss factors on various materials using the gravitational [1] spectroscopy method. The optimization of experimental setup geometry was performed through numerical simulations, allowing for the determination of optimal parameters to enhance measurement accuracy. Within the...
Fast neutron radiography offers distinct advantages over conventional X-ray radiography, demonstrating significant developmental potential and broad application prospects in strategic fields including national defense, aviation, aerospace, and nuclear energy. As a critical performance indicator for imaging systems, spatial resolution has been extensively studied through theoretical simulations...
Neutron spectra and fast neutron fluence rate measurement for the Atomospheric Neutron Irradiation Spectrometer at CSNS
An optimized k₀-neutron activation analysis (k₀-NAA) method, incorporating cyclic irradiations of short-lived radionuclides (SLRNs), was developed at the Dalat Research Reactor (DRR). This study presents the precise characterization of reactor parameters using a fast irradiation facility, rigorous sample preparation, and advanced calibration of HPGe detector-based gamma-ray spectrometry for...
The report is devoted to the problem of interaction of slow neutrons with matter moving with acceleration. The possibility of transformation of the neutron dispersion law due to the general effect of acceleration is considered. The Acceleration effect consists of that the result of the interaction of a particle with any object moving with acceleration should be a change in its frequency ω and...
Development status of the neutron detectors for instruments at China Spallation Neutron Source
Nanodispersed media, such as nanodiamond powders, are efficient diffuse reflectors of low-energy neutrons [1]. This is due to the intense coherent elastic scattering of such neutrons on individual nanoparticles of a few nanometers in size. Such reflectors can be used for quasi-specular reflection of cold neutrons [2] and in the design of very cold neutron sources for their directed extraction...
It is already well known that Fe-Ga alloys possess increased values of the magnetostriction constant. This characteristic has been studied in a wide range of gallium concentration (up to 35 at.%) [1, 2] and the presence of two peak of magnetostriction at 19 and 27 at.% of gallium has been established. At present, work is underway to analyze the influence of certain structural phases on the...
For the first time, the author proposed the concept of a new direction in the field of cold (cryogenic) neutron moderators for research neutron sources of low, medium and high power and intensity, which is based on the use of a universal cryogenic neutron moderator based on hydrocarbons. It is shown that the successful development of fundamentally new methods, installations, devices and...
The treated and untreated wastewaters are widely used for irrigation in many developing countries. They often contain not only organic compounds, but also various metals that are both essential (zinc, copper) and potentially hazardous (chromium, nickel) for human health. Since plants, including leafy vegetables, can accumulate metals both in their roots and edible parts, this can be dangerous...
A new high-brilliance ultracold neutron (UCN) source is planned to be created for the FLNP JINR pulsed reactor. It is planned to carry out a series of investigations using VCNs, which are essential for the design of the main elements of this UCN source. For this purpose, a test VCN channel at the third channel of the IBR-2M reactor will be built. This will allow us to obtain a VCN beam with a...
The new direction in medicine that emerged in the second half of the ХХ century –medical elementology – opens fundamental basis for the development and use of new methods of diagnosis and treatment of various diseases, including oncological ones, as well as for solving many other problems facing modern medicine. The subject of research in this new direction consists of four points:
- study of...
The investigation of neutron-induced fission independent yields of actinides is critically important for both the efficient utilization of nuclear energy and nuclear physics research. The fission spectrometer based on the velocity-kinetic energy method consists of a Time Of Flight (TOF）detector and a Frisch-Grid Ionization Chamber (FGIC), achieving mass yield distribution with a mass...
A comprehensive analysis of soil elemental content in the Nile Delta, Egypt, was conducted using advanced analytical techniques, including Inductively Coupled Plasma Atomic Emission Spectrometry (ICP–AES) and Inductively Coupled Plasma Mass Spectrometry (ICP–MS). A total of 55 elements were analyzed across 53 soil samples. Of these, 10 major elements (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, and P)...
There are several instruments on the flight bases of the IREN facility that are used to carry out measurements on the transmission, capture and scattering of neutrons on samples.
The analysis of experimental data, the assessment of the possibility of conducting, and the planning of experiments with IREN beams require knowledge of the facility parameters: the absolute fluxes of resonance and...
$ICP-MS$ method has been used for analyses [1] of the elemental and isotope composition (64 elements) of bones of dinosaurs, South mammoths, prehistoric bear and archanthropus as well as the samples of surrounding soils; everything collected in different parts of Uzbekistan. A high concentration of uranium we detected in the bones of dinosaurs (122mg/kg), South mammoth (220mg/kg), prehistoric...
The church of Transfiguration of Our Saviour on the Nereditsa Hill is one of the earliest Old Russian buildings, raised in 1198 by order of Knyaz of Novgorod Yaroslav Vladimirovich. The church was included in the UNESCO list of World Heritage sites in 1992. During the World War II, the monument was partially destroyed. As a result, almost the entire painting crumbled, with the exception of a...
The energy distributions and absolute yields of the long-range alpha particles and the tritons in thermal neutron induced ternary fission of 235U were measured using a twin-gridded ionization chamber. The experimental result shows that the long-range alpha particles and the tritons can be separated obviously in the cathode amplitude vs anode amplitude two-dimensional spectrum, and the absolute...
Conventional photon and neutron bimodal imaging systems suffer from inherent limitations such as different imaging beam geometry, leading to challenges in direct fusion of transmission image and system complexity. While the single-source-single-detector configuration based on a compact electron linear accelerator proposed by Tsinghua University addresses imaging beam geometry issue, it remains...
To get more data concerning the geochemistry and mineralogy of the Danube River tributaries mainly from the Eastern Serbian sector and to elucidate the status quo of sedimentary material, Instrumental Neutron Activation Analysis (INAA) and X-Ray Diffraction (XRD) were used in tandem to investigate 10 samples of unconsolidated bottom sediments, two samples collected at 1.5 and 7.5 m below the...
The Multi-purpose Time Projection Chamber (MTPC) prototype has been successfully developed and commissioned at the CSNS Back-n white neutron beamline. As a novel detection system, its primary design objective focuses on precise measurement of light charged particle emissions in nuclear reactions, while maintaining versatile capabilities for multiple applications including fission cross-section...
This work presents the results of a comprehensive study that applied complementary physico-chemical methods to 29 mural fragments from the Vladychnaya Palata in the Novgorod Kremlin. Plaster samples were subjected to neutron activation analysis (NAA) at the WWR-K research reactor (Institute of Nuclear Physics, Kazakhstan) to determine elemental composition. The pigment composition of the...
Determination of radiosensitivity for plant species is important in order obtain desirable plant characteristics. As a rule, median lethal dose(LD50) is considered as appropriate dose to obtain the highest mutation frequency [1].
Such a task for fast neutrons (FN) is a complex challenge due to the unique properties of neutron radiation, the biological variability of the plant, the difficulty...
Neutron capture reactions play a crucial role in nuclear physics research, as their cross-section measurements provide critical data for nuclear structure studies and nuclear databases, while also enabling the examination of symmetries and conservation laws in nuclear reactions. To meet the requirement for neutron capture cross-section measurements at the back-streaming neutron facility...
Crystallographic texture (or crystallographic preferred orientation) is an inherent property of polycrystalline materials, which defines the anisotropy of their bulk physical properties. Textures are formed during inelastic deformation processes, crystallization, recrystallization, etc. They are also influenced by structural phase transformations, which may be studied in situ. Such experiments...
To establish a comprehensive and reliable nuclear database for neutron-induced processes, the development of accelerator-driven system (ADS) technology is essential. Despite many efforts have been made, accurate measurements of light charged ions (LCIs), including protons, tritium, and α particles, at zero degrees in the beam direction remain challenges. Conventional detectors often fail to...
Abstract
The effect of neutron irradiation on the structural, optical, and electronic properties of doped strained heterostructures with AlGaAs/InGaAs/GaAs and AlGaAs/InGaAs/AlGaAs quantum wells was experimentally studied. Heterostructures with a two-dimensional electron gas of different layer constructions were subjected to neutron irradiation in the reactor channel with the fluence range of...
The specific geometry of small angle neutron scattering spectrometer YuMO, a central
hole along the neutron beam direction through the two scattering detectors reaching to direct
beam detector (DBD) located at 35 meters from moderator [1-3]
DBD importance return to determine the transmittance of the sample as a function of
wavelength, due to peculiarities of normalization when the ratio...
The work presents application of the particle detection techniques developed in the field of High-Energy Physics (HEPh) to neutron detection. This area has been growing rapidly over the past decade due to ongoing developments at CERN, JINR and other research centers.
Mictro-Pattern Gaseous Detectors (MPGD), such as GEMs, or Gas Electron Multiplier, Micro-Megas, micro-RWELL, micro-GROOVE,...
Physical Design of a High-Brightness Neutron Source Target Station Using 100 MeV Protons on a Tantalum Target
147,149Sm are slow neutron capture (s-process) nuclides in nuclear astrophysics, whose (n,γ) cross-section are the important input parameters in nucleosynthesis net calculation in the Samarium (Sm) region. Additionally, 149Sm is a fission product of 235U with 1% yield, and its neutron resonance parameters play a critical role in reactor neutronics. According to the available nuclear evaluation...
The damage effect caused by high energy particles, especially Single Event Upset (SEU), is one of the major factor of failure in SRAM-based FPGA components, for applications in harsh radiation environments, such as space-borne payloads and ground-based large scale particle experiments. With the advancement of the integrated circuit industry, in nowadays the feature size of high-performance...
Abstract:
With the advancement of science and technology, the field of Inertial Confinement Fusion (ICF) has entered a new era where fusion yields are sufficiently high to enable nuclear measurements to provide multidimensional information encompassing spatial, temporal, and spectral dimensions. Nevertheless, neutron yield remains one of the most critical parameters of concern in the...
Time-Resolved Prompt Gamma Neutron Activation Analysis (T-PGAA) is an innovative nuclear analytical technique that combines the advantages of Neutron Resonance Capture Analysis (NRCA) and Prompt Gamma Activation Analysis (PGAA). It exhibits high sensitivity and exceptional isotopic resolution capabilities. T-PGAA holds significant potential in diverse fields such as lunar soil analysis,...
In this work the results of modeling and simulating the burnup of the IBR-2M pulsed fast reactor in the Monte Carlo software package. A three-dimensional geometric model of the reactor has been developed, including an active zone with 64 fuel assemblies, a PO-3 reactivity modulator, a control and protection system, and a liquid metal sodium coolant. Critical calculations and simulation of the...
The current polyethylene-moderated 3He neutron detector suffers from low detection efficiency and a dependence on the neutron energy and emission angle, which hinders the accurate measurement of critical data for astrophysical modeling, such as (α, n), (γ, n) cross sections, and β-delayed neutron emission probabilities. To address this, a novel detector design was proposed, using a large...
With the development of ultra-short and ultra-intense laser technology, laser driven plasma electron acceleration is becoming increasingly mature. Compared with traditional RF acceleration, this acceleration method has significant characteristics - an acceleration gradient three orders of magnitude higher. It is precisely because of its ultra-high acceleration gradient that the accelerated...
The NEPTUN reactor is a pulsed periodic research reactor under development with a sodium coolant and a core based on neptunium nitride fuel. The reactor is designed for experiments using extracted beams. Average thermal power is 10-15 MW, pulse half-width is 200 μs, pulse frequency is 10 Hz, time-average thermal neutron flux density is ~1014 cm−2·s−1. The reactor vessel and its core are...
The development of a design for a new, high-class reactor, NEPTUNE, is required to effectively continue the neutron research program once the IBR-2M's service life ends and to satisfy new needs. This reactor, like the IBR-2M, will be unique, more powerful, and competitive among other facilities in the world. It will be a tool for physicists, biologists, and creators of new substances and...
The dispersed moderating agent for cryogenic moderators of the IBR-2M reactor is produced by the formation of droplets and subsequent freezing in liquid nitrogen. The heat exchange between the droplet and liquid nitrogen leads to intensive local boiling of the liquid nitrogen, resulting in vapor cushioning and heat exchange. This phenomenon is known as the Leidenfrost inverse effect.
The...
The Department of Spectrometers Complex (DSC) of IBR-2 plays an important role in maintaining the efficiency and development of the experimental facilities at the IBR-2 reactor. One of the directions of DSC is the development and creation of wide-aperture neutron detectors based on the 6LiF/ZnS(Ag) scintillator. As part of the modernization of the scientific installations of the IBR-2 reactor,...
Mofan Zhang1,2
1China Spallation Neutron Source
2Indiana University, zhangmo@iu.edu
Parity Violation (PV) effects in p-wave resonances of compound nucleus has always been the interest of the NOPTREX (Neutron Optical Parity and Time-Reversal EXperiment) collaboration since it may shine lights on the search of Time-Reversal Invariant Violation (TRIV) in the same resonances that exhibit a...
The development of polarized neutron technology is pivotal for advancing studies in material science and fundamental physics, particularly in probing magnetic structures and symmetry violations. At the China Spallation Neutron Source (CSNS), significant progress has been made in the design and implementation of polarized 3He neutron spin filters (NSFs) based on spin-exchange optical pumping...
This study analyzes the differences in the operation and heat distribution of single-beam and multi-beam Accelerator-Driven Systems (ADS) through burn-up simulation calculations. Compared to conventional single-beam configurations, the multi-beam ADS achieves a flat neutron flux and heat distribution, effectively suppressing radial power peaking. The distributed spallation target design in...
Accelerator Driven Subcritical system is believed to be the best candidate for nuclear waste transmutation. In the design scheme of ADS plant with one target, high-intensity external neutrons are concentrated in the center of the core which will result in a high power peak factor. To solve the challenges, a Multi-Beam Accelerator Driven Subcritical（MB-ADS） system is proposed. The spallation...
Neutron sources have been widely applied in numerous fields, ranging from detection technology to medicine and laboratory astrophysics due to their unique features of electrical neutrality and deep penetration capability. Currently, there are two main mechanisms for the generation of neutrons assisted by lasers, i.e., photonuclear reactions (γ, n) and beam-target nuclear reactions. Compared...
The report presents a project of a high brilliance ultracold neutron (UCN) source, which is planned to be constructed at FLNP JINR. It details the concept of the proposed source, the progress made in designing its key components, and the challenges that need to be overcome. A potential research program on this source is also discussed.
As part of this project, it is initially planned to...
As one of the important auxiliary devices for neutron scattering instruments, sample environment provides various experimental conditions to enhance the research capabilities of the instruments. The sample environment at the Chinese Spallation Neutron Source (CSNS) has been providing in-situ experimental services since the commissioning of the instrument in 2018. It has evolved from initially...
Polarized neutrons serve as a critical probe in nuclear physics to investigate spin-dependent interactions and nuclear dynamics. Polarized neutron enables precise studies of nuclear forces, include probing nuclear structure, analyzing reaction mechanisms and resolving nucleon internal spin-quark distributions via deep inelastic scattering. Challenges persist in achieving high polarization...
The Back-n white neutron facility is a comprehensive experimental platform that serves a wide spectrum of research goals, including nuclear data measurement, experiments in nuclear physics and astrophysics, calibration of neutron detectors, investigation of neutron radiation effects, and applications in archaeology, among others. Operational since 2018, this beamline has facilitated over 300...
In connection with the assumption that sterile neutrinos are right neutrinos, an analysis of the current experimental situation in neutron decay for right currents was performed. As a result of the analysis, it was found that there is an indication of the existence of a right vector boson W_R with a mass M_(W_R )=304_(-20)^(+24) GeV, and a mixing angle with W_L: ζ = -0.039±0.014. It is shown...
Information from existing studies on heavy metal concentrations in mosses is an invaluable resource for international negotiations on heavy metal pollution. Results from moss studies help investigate both spatial and temporal trends of heavy metals in atmospheric sediments. Besides, these studies allow the identification of places with high levels of atmospheric pollutants that spread over...
A new high-brilliance ultracold neutron source at the IBR-2 pulsed reactor is currently being developed at the FLNP JINR. Work on the project of a new type of UCN source requires conducting of a series of methodical experiments with very cold neutrons, which are currently not feasible at JINR. Therefore, at the first stage of work on the project, it is planned to create a test VCN channel. It...
The work is devoted to the creation of a new ultracold neutron source based on superfluid helium for researches in the field of physics of fundamental interactions at the PIK reactor. This source is aimed at obtaining a world record UCN density of 2200 cm-3.
For this source we have developed and implemented the whole scope of technologies allowing us to make UCN sources based on superfluid...
Impact of ANIS Beam Parameters on Single Event Burnout Testing in SiC Power Devices
Investigation of Background Calculation Methods for CSNS Neutron Scattering Spectrometer
At the 11-m flight path of the IREN facility the measurements of the differential cross sections of the Br (n, γ) and Cl (n, γ) reactions were carried out in region of the low-lying p-wave resonances of bromine at the 0.88 eV incident-neutron energy and chlorine at 398 eV, correspondingly. The purpose of the experimental γ-quanta angular distributions obtaining is search of the asymmetry of...
In series of the photo-fission reactions, namely, 235, 238U(γ, f), 232Th(γ, f), 242Pu(γ, f) we have found that some part of the fission fragments (FFs) are presumably born in the state of the fission isomer with the yield Y ≈ 10–3/binary fission and with the lifetime τisom > 400 nsec [1, 2]. A binary break-up of such fragments was observed...
This report presents the results of a study on the SLED (SLAC Energy Doubler) system effect installed on the first accelerating section feeder of the LUE-200 of the IREN facility on the energy spectrum of electrons. This work is based on analytical calculations of the LUE-200 accelerator beam dynamics conducted by BINP SB RAS specialists in 2020.
In regions such as Pabna, Bangladesh, where groundwater is the primary source of drinking water, arsenic contamination in both soil and groundwater poses a significant threat to human health.
Neutron Activation Analysis (NAA) is a highly sensitive and precise analytical technique capable of detecting and quantifying trace levels of arsenic, even at concentrations as low as parts per billion...
In nuclear reaction induced by slow and resonant neutrons on 35Cl nucleus followed by proton emission, the forward–backward effect was investigated. In the frame of the model of mixing states of compound nucleus with the same spin and opposite parities, cross sections, angular correlations and asymmetry coefficients were evaluated. Using theoretical calculations, measurement of...
Numerical modeling of the interaction of fast and thermal neutrons with semiconductor microcrystals (InSb, InAs, GaAs) was conducted using the GEANT4 software environment. The study aimed to determine the rates of nuclear reactions (elastic and inelastic scattering, radiative capture) and analyze the influence of secondary fission products on the radiation resistance of semiconductor...
Monte Carlo-based Study on Signal and Noise Characteristics of BNCT-SPECT Systems
Prompt fission neutron spectra (PFNS) of 241Am(n,F), 242mAm(n,F) and 243Am(n,F) are obtained at 10-5 <En <20 MeV. The methods of analysis of integral PFNS for americium nuclides were elaborated via comprehensive analysis of 233,235,238U(n,F) and 239,240Pu(n,F) PFNS data [1, 2]. Average PFNS energies of 241,242m,243Am(n,F) are strictly correlated with fission chances contributions...
Research progress of 3MeV high-frequency pulse proton accelerator
The Neutrino-4 collaboration improved the detector in the first neutrino laboratory at SM-3 reactor. Also, we have been creating a new neutrino laboratory at the same reactor to study light sterile neutrinos. In the Neutrino-4 experiment, an oscillation effect was observed at a confidence level of 2.7σ, which is in good agreement with the gallium anomaly and the result of the BEST experiment,...
With the continuous development of neutron sources in various fields, achieving efficient miniaturization of accelerator-based neutron sources has become a research hotspot. Traditional large-scale neutron sources devices are limited by their large size and high energy consumption, restricting their feasibility in small laboratories and field applications. Therefore, designing a compact and...
In [1-3] the virtual mechanism of ternary fission of the compound nucleus $(A, Z)$, formed by the capture of the thermal neutron by target-nucleus $(A-1, Z)$ as the two-stage process was suggested. At the first stage light particle $(A-A_{LP},Z-Z_{LP})$ with kinetic energy close to the Coulomb barrier height is emitted from the nucleus $(A, Z)$ with the forming of the virtual state of the...
The neutron instrument complex "Neutron Beta Decay" will be located on the beam of polarized cold neutrons on the GEK-3 N0 channel. The installation is designed to measure the asymmetries of neutron beta decay with a relative accuracy of 0.1%. The basis of the installation is a superconducting solenoid that creates a magnetic field in a uniform region of 0.35 T. Electrons and protons appeared...
Khafizov R. U. a, Kolesnikov I.A. a, Nikolenko M.V. a, Tarnovitsky S.A. a, Tolokonnikov S. V. a, Torokhov V.D. a, Trifonov G.M. a, Solovei V.A. a, Kolkhidashvili M.R. a, Konorov I.V. b
a NRC «Kurchatov Institute», Russia, khafizov_ru@nrcki.ru
b Technical University of Munich, Munich, Germany
The report considers the time spectra of double and triple coincidences of the neutron...
