Based on an idea by Carlo Rubbia, the n_TOF facility has been operating during the last 20 years at CERN. n_TOF is a spallation neutron source, driven by the 20 GeV/c proton beam from the CERN PS accelerator. A massive Lead spallation target is feeding two experimental areas set at 185 meters (EAR1, horizonal with respect to the proton beam direction) and at 20 meters (EAR2, in the vertical...
From fission yield measurements to evaluation: correlations of multi-observable analysis
S.M. Cheikh 1, G. Kessedjian 1, A. Chebboubi 1, O. Serot 1 and C. Sage 2
1 CEA, DES, IRESNE, DER, SPRC, LEPh, Cadarache center, F-13108 Saint Paul lez Durance, France
2 LPSC, Université Grenoble-Alpes, CNRS/IN2P3, 38026 Grenoble, France
Topics for submission: Fission yield evaluation
Keywords: fission...
LA-UR-21-28456
We have extended significantly our description of fission by examining a larger set of observables and more nuclei. We extract neutron and proton numbers of fission fragments, their spins and fission fragments relative orbital angular momentum and their correlations, investigate neutrons emitted at or shortly after scission, excitation energy sharing mechanism, total kinetic...
Since 2016 the Nuclear Data Section of the International Atomic Energy Agency (NDS/IAEA) has encouraged the development of new codes for processing evaluated nuclear data for applications. The main motivation has been the need for improving processing methods and avoiding common failure modes. In the frame of this effort, the NDS/IAEA has supported the development of the processing system...
In nuclear medicine, the positron emitting $^{86}$Y (14.7 h) is an emerging imaging isotope for use in combination with the $\beta$$^-$ emitting therapeutic radionuclide $^{90}$Y (2.7 d), the pair being commonly called as a matched theranostic pair [1]. To produce the radionuclide $^{86}$Y via the $^{86}$Sr(p,n) reaction in a pure form, 96.4% enriched thin $^{86}$SrCO$_3$ targets were...
The $^{35}$Cl radiative capture rate is important in a number of applications. The long-lived radionuclide $^{36}$Cl is a by-product of the activation of $^{35}$Cl present in graphite moderated reactors both in the fuel cladding and as an impurity in nuclear graphite (< 2 ppm by mass). Reliable predictions of the amount of $^{36}$Cl present in the large volume of irradiated nuclear graphite...
A. Chebboubi1, D. Bernard1, V. Vallet1, G. Kessedjian1, O. Méplan2, Y.H. Kim3, U. Köster3, Ch.E. Düllmann4,5,6, F. Géhin1, M. Houdouin-Quenault1,2, O. Litaize1, C. Mokry4,6, M. Ramdhane2, J. Runke4,5 ,C. Sage3, O....
For safe use of nuclear reactor core, slowing down of neutrons and reaction rates inside the core should be predicted accurately. They have made tremendous efforts to improve the calculation methods and the nuclear data for the prediction. However, the calculated neutron spectrum and the reaction rates have been validated only by post irradiation measurement of gamma rays. As an in-situ...
- Istituto Nazionale di Fisica Nucleare, Sez. di Bari, Bari, Italy
- Università degli studi di Bari, Dipartimento Interateneo di Fisica, Bari, Italy
- Istituto Nazionale di Fisica Nucleare, Sez. di Perugia, Perugia, Italy
- Istituto Nazionale di Astrofisica, Osservatorio Astronomico d’Abbruzzo, Teramo, Italy
- Istituto Nazionale di Fisica Nucleare, Sez. di Bologna, Bologna, Italy
6....
Neutron capture cross-section measurements are of great interest for various nuclear data applications, such as the slow neutron capture (s-) process of nucleosynthesis in stars, innovative nuclear technology or medical applications. The neutron energy range of interest varies depending on the application and, hence, pulsed white neutron sources combined with the time-of-flight (TOF) technique...
Nuclear data evaluation is a process that takes a long time partly due to resonance identification having to be performed manually by expert nuclear data evaluators. This procedure is laborious, time-consuming, and irreproducible from evaluator to evaluator. Additionally, it is well-documented that a systematic evaluation of the uncertainty on the evaluated cross section is unreliably low....
GALILEE-1 is the new verification and processing system for evaluated data, developed at CEA.
We have already presented in the past the reconstruction and Doppler broadening of cross-sections implemented in the GTREND module of GALILEE-1. The results obtained are of very good quality and we can explain the discrepancies observed with respect to other processing codes such as NJOY and PREPRO....
As engineering discussions of the feasibility of new reactor systems, it is necessary to evaluate the impact of the fuels and materials for the neutronics characteristics such as criticality, conversion rate, and fuel balance. It is important to perform the validation of 233Th and 233U nuclear data for a thorium-based nuclear reactor, because those nuclear data contribute...
Nuclear medicine has proven to be a much needed medical specialty in order to diagnose and treat several diseases, among them, cardiovascular diseases and cancer, the first and the second causes of mortality worldwide, respectively [1]. Several international agencies recommend to study of new routes and new facilities for producing radioisotopes with application to nuclear medicine as a...
As engineering discussions of the feasibility of new reactor systems, it is necessary to evaluate the impact of the fuels and materials for the neutronics characteristics such as criticality, conversion rate, and fuel balance. It is important to perform the validation of 232Th and 233U nuclear data for a thorium-based nuclear reactor, because those nuclear data contribute...
We present our first results for a microscopic simulation of symmetric boost fission in terms of the antisymmetrized molecular dynamics (AMD), which incorporates the mean-field effects (as the TDDFT) via SLy4 effective interaction as well as stochastic 2-nucleon collisions similar to the cascade model. Due to these features, AMD is capable of obtaining not only the “expectation value” or...
In the previous version of nuclear data processing code NECP-Atlas reported in the last ND-2019, the code could process the evaluated nuclear data into application libraries of typical formats with the conventional processing methods. NECP-Atlas is under continuous development and verification during the past years. Several new capabilities have been developed in the code.
(1) The code is...
Nuclear reactors are copious sources of antineutrinos. This is the main reason why reactors have played a key role in the discovery of the neutrino and in the study of neutrino oscillation phenomena. The comparison of the neutrino flux measurements performed at short baselines with the improved conversion procedure by Huber [1] and Mueller [2] led to the discovery of the so-called reactor...
FOOT (FragmentatiOn Of Target) is an applied nuclear physics experiment with the aim of performing high precision cross section measurements for fragmentation reactions of interest in Hadrontherapy and Radioprotection in Space. An in-depth knowledge of the physical and biological effects caused by nuclear fragments is in fact of great interest for both the improvement of Hadrontherapy...
$^{32}$Si is an extremely rare, naturally occurring radioactive isotope. With its half-life ($\textit{T}$$_{1/2}$) of approximately 150 years $^{32}$Si would be one of the suitable candidates for radiometric dating in the range of 100–1000 years, where an appropriate dating nuclide is still missing (Fig. 1a).
The fact that the application of this nuclide for dating has been very limited so far...
In proton therapy, Positron Emission Tomography (PET) range verification, which is based on the detection of the short-lived (online monitoring) or the long-lived (offline monitoring) $\beta^{+}$ emitters produced in the body of the patient, has been proved to be a well-suited technique to monitor the beam range $^{[1]}$. This technique requires the comparison of the observed activity...
A. Algora1,2, V. Guadilla3, J. L. Tain1, M. Fallot4, M. Estienne4, A. Porta4, L. Giot4, L. Le Meur4, A. Beloeuvre et al. for the DTAS Jyvaskyla Collaboration
1)Instituto de Física Corpuscular, CSIC-Univ. de Valencia, E-46071 Valencia, Spain
2)Institute of Nuclear Research (ATOMKI), P.O. Box 51, H-4001 Debrecen, Hungary
3)Faculty of Physics, University of Warsaw, 02-093, Warsaw,...
Criticality safety analysis is needed at various stages of the nuclear fuel cycle, including the back-end of the fuel cycle, i.e. reprocessing, transport, storage and final disposal of spent nuclear fuel (SNF). In the past, criticality safety assessments for SNF management for out-of-reactor applications assumed that the fuel is in its most reactive condition, which is usually prior to...
Although protontherapy is advantageous over more traditional radiotherapy from the point of view of dose delivery and sparing of organs at risk, its full potential has not been reached yet [1]. A lot of effort is focused on proton range verification techniques to improve dose localization. Several of these techniques profit from the secondary emission induced by protons to identify the proton...
A resolved resonance region evaluation of 140,142Ce has been carried out by Oak Ridge National Laboratory. Requested by the US Nuclear Criticality Safety Program, this evaluation is based on recent high-resolution transmission and capture high-resolution measurements of natCe and 142Ce conducted at JRC-GEEL at the Geel Linear Accelerator facility, as well as recently measured thermal constants...
Particle therapy is a promising and rapidly developing methodology of modern tumor treatment. In order to reach its full potential, however, it requires detailed verification that the clinical target volume receives the planned dose while sparing surrounding healthy tissues.
Although the applicability of in-beam positron emission tomography and prompt gamma rays has already been demonstrated...
The self-shielding effect in the unresolved resonance region has a large impact on the fast- and intermediate-spectrum reactors. The probability table method is widely used for continuous-energy Monte Carlo calculation codes to treat the effect. In this method, a table provides the probability distribution of the cross-section for a nuclide in the given energy grid points. The table is...
The neutron induced total, elastic, and capture cross sections of 63,65Cu iso- topes were selected for evaluation in the resolved and unresolved resonance energy ranges by the National Criticality Safety Program to resolve discrepancies related to benchmark performance. This is especially evident for the series of ZEUS benchmarks in which copper is used as a reflector. Because copper is also...
Boron Neutron Capture Therapy (BNCT) is facing a renaissance with the development of accelerator-based neutron sources in different countries [1,2]. These facilities can be placed in hospitals, overcoming the main barrier in the expansion of this promising therapy, which up to now has been only performed at research reactors. BNCT is the only external radiotherapy option which is selective at...
The slow neutron capture ($s$-) process is responsible for the formation of half of the elements heavier than iron in the Universe. Despite the long time scale of this process, the long half-life of some isotopes throughout the $s$-process reaction flow creates branching points that lead to the division of the nucleosynthesis path. ${79}$Se ($t_{1/2} = 3.27 \times 10^5$ y [1]) represents one...
The Generalised Nuclear Database Structure is a new standard for representing reaction and decay data in nuclear data libraries and is slated to replace the legacy ENDF-6 format. GNDS is designed to be both human readable and easy to work with so that downstream code developers can create software that supports GNDS. The specifications for GNDS-1.9 were published in 2020; this version...
The SANDA H2020-EURATOM project, Supplying Accurate Nuclear Data for energy and non-energy Applications, brings together the majority of the European nuclear data community (35 partners from 19 countries), infrastructures and resources to produce accurate and reliable nuclear data tools including data, codes and methodologies that can be used to simulate, analyse, optimize, exploit and...
In the unresolved resonance region (URR), cross sections for neutrons interacting with nuclei have resonances that cannot be measured nor predicted, hence only statistical values are provided. Often, proper simulations by neutronic transport codes require special data and handling in the URR to account for the variation in the cross sections in this region. The current methodology used to...
The slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances heavier than iron in the universe. Neutron capture cross sections on stable isotopes are a key nuclear physics input for s-process studies. The $^{72}\mathrm{Ge}(n,\gamma)$ Maxwellian-Averaged Cross Section (MACS) has an important influence on production of isotopes between Ge and...
Silicon is of great applied interest in the semiconductor industry and in detectors for physics experiments. An increased understanding of neutron induced charged particle producing reactions on silicon is particularly significant not only for basic physics but also for applications.
In the present work, an optimal set of optical model potential parameters is obtained for the n+28,29,30Si...
The EXFOR database is the major source to retrieve experimental data as input for nuclear data evaluations. It aggregates decades worth of international nuclear data measurements. EXFOR is specifically designed to store experimental data as it was reported by the experimentalists, with limited corrections made as needed. For this reason, the database does not store the subjective alterations...
The Advanced Fuel Cycle Programme funded by the UK Government through the Department for Business, Energy & Industrial Strategy revolves around developing capability and capacity for nuclear while seeking to reduce costs across the nuclear lifecycle, to ensure that nuclear can play a part in delivering secure, low-carbon energy in the global market. This includes the development of Advanced...
Monte Carlo simulation tools make use of models to describe the physics of everything that surrounds us. For such tools to be reliable, models as close to reality as possible need to be implemented in the simulation. Nuclear reaction cross-sections play an essential role in simulations for radiation protection in space. Therefore, a GSI-ESA-NASA collaboration project created a collection of...
The knowledge about prompt neutrons and $\gamma$-rays spectral characteristics in nuclear fission is essential to understand the nuclear de-excitation process of fission fragments [1,2]. Preferably, these observables should be known in correlation with fragment properties like mass and kinetic energy.
Typical multi-parameter experiments require long measurement times and efficient detector...
The availability of reliable, up-to-date and well-structured nuclear data libraries, with user-friendly visualization and retrieval interfaces, is a valuable tool for both nuclear specialists in the applications fields and nuclear physics researchers.
The International Atomic Energy Agency (IAEA) has been coordinating the international network of Nuclear Structure and Decay Data evaluators...
The damage due to cosmic rays is a serious concern for astronauts, electronics, and spacecraft. Although the cosmic ray flux is comprised mostly of protons and helium nuclei, there is a non-negligible component comprised of heavy-ions up to and including iron nuclei. The importance of the heavy-ion component is enhanced because the damage due to ionization goes as $Z^2$. In addition to the...
New U-235 and U-238 evaluations [1-3] were undertaken within the OECD/NEA Data Bank CIELO Project [4] and were adopted for the ENDF/B-VIII.0 library [5], which was released in 2018. Since then, several reports and publications were released that showed serious discrepancies with the light water reactor (LWR) performance of the previous ENDF/B-VII.1 library [6] in criticality studies as the...
Current fieldable spectroscopy techniques often use single detector systems heavily impacted by interferences from intense background radiation fields. These effects result in low-confidence measurements that can lead to misinterpretation of the collected spectrum. To help improve interpretation of the fission products and short-lived radionuclides produced in a composite sample, a...
The n_TOF Collaboration operates the neutron time-of-flight facility at CERN [1], based on a 20 GeV/c pulsed proton beam impinging on a lead target employing water to moderate the spallation neutrons. The facility is characterized by a high-instantaneous neutron beam intensity, high energy resolution and a wide neutron energy spectrum, spanning from sub-thermal to GeV. The first experimental...
The Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA) is a flexible experimental facility being designed at SCK CEN, Mol, Belgium. It is conceived to operate both in sub-critical mode, as an Accelerator Driven System, and in critical mode, as a lead-bismuth cooled fast reactor.
In order to comply with MYRRHA reactor design requirements, uncertainties must be...
The galactic cosmic ray (GCR) background presents creates a hostile, high-dose environment for astronauts and the electronics they rely. While the GCR spectrum extends to 10’s of GeV/nucleon, much of the dose in electronics is attributable to the final slowing of heavy ion at the end of their path, e.g., the “Bragg peak”, and the location and magnitude of the Bragg peak is in turn highly...
Radiation shielding and calculation are essential for the construction and operation of accelerator facilities. High energy gamma-rays in accelerators can produce secondary neutrons, which can penetrate through shielding materials and produce additional dose rate by activating accelerator components; thus, the double differential cross sections (DDXs) of photoneutron are very essential....
Studies of neutron-induced reactions are of considerable significance, both for their importance to basic research in nuclear physics and for practical applications in nuclear technology, medicine and industry. Thallium is widely used in electronics, pharmaceuticals, fiber optics, infrared detectors and nuclear medicine. However, little information is available in literature for neutron...
Nuclear fusion is a complex process involving a complete re-arrangement of quantum systems with many degrees of freedom. Heavy ion fusion exhibits a strong entrance channel dependence at near fusion barrier energies and could be reasonably explained by coupled channels formalism [1,2] that explicitly includes the effects of internal degrees of freedom. Though tremendously successful in...
The production of useful and high-quality nuclear data requires experimental measurements with high precision and extensive information on uncertainties and possible correlations. When performing experimental measurement data analysis, the physicist uses many external parameters (detector efficiencies, distance of flight, …) in addition to the raw data. All the steps of the data processing...
The artificial production of radionuclides has considerable significance for many different applications. Recently, we observe increasing interest in the field of nuclear medicine, with $^{44g}$Sc being one of the promising nuclides for positron emission tomography. Besides its direct production routes by irradiating suitable targets like Sc or Ti with charged particles, $^{44}$Ti is in the...
Experimental data on photoneutron spectrum for reaction of 16.6MeV mono-energetic polalized photons on medium-heavy mass targets were obtained at BL-01, NewSUBARU, Hyogo, Japan. The data consists of low energy neutrons having energy distribution similar to tail of Maxwellain and relatively high energy ones originated from decay of pre-equilibrium status. In this presentation, quantities...
The new detection device for measurements of light ions (p, d, t, α) emitted as products of the
nuclear reactions induced by fast neutrons was recently developed at the Nuclear Physics Institute of
the Czech Academy of Sciences. The device consists of the vacuum chamber and rotational table with
the detection telescopes composed of two Si detectors for dE–E charged particle recognition. It is...
Prompt fission $\gamma$ rays (PFG) account for 40% of the total $\gamma$ heating in the core of a typical fast reactor, which in turn constitutes about 10% of the total energy release in fission [1]. Therefore, precise knowledge about multiplicities and $\gamma$-ray energies is important. Prompt fission $\gamma$ rays are commonly defined as those emitted in coincidence with fission fragments,...
The prediction of prompt neutron spectra of the photon-induced reactions on the 238U and 232Th targets are needed in the treatment of experimental data of the reactions induced by quasi monochromatic γ-ray beams produced in laser Compton-scattering at the NewSUBARU synchrotron radiation facility.
Unfortunately any experimental information concerning both the fission fragments and the prompt...
We have added the multipole humped fission barriers model into the Unified Hauser-Feshbach and Exciton Model for Fission Nuclei (FUNF). With the help of the MINUIT, we optimized the parameters of FUNF to reproduce the cross-section of neutron-induced $^{238}U$. The double-humped fission barrier can be used to explain the low energy resonance structure of $n+^{238}U$ fission cross-section at low energy.
The Langevin approach has been widely used in the study of fission. In this approach, the fission process is described as the time evolution of the shape deformation of the nucleus, and the fragment mass and kinetic energy distributions can be calculated. The physical inputs for the Langevin equation are the potential energy of deformation and two transport coefficients: the inertia and the...
A robust description of the process of nuclear fission is essential to many research domains ranging from nuclear energy, national security, and nuclear data. However, owing to the nuclear many-body problem, a description of fission based on nucleon-nucleon interactions is unfeasible given current computational limitations, which has led to a number of alternative methods that greatly reduce...
Abstract
In order to reduce the uncertainties in the design and operation of accelerator-driven systems (ADSs), high-precision nuclear data for neutron- and proton-induced reactions on a variety of isotopes in the energy range below 200 MeV are necessary. As the important component of the spent fuel of current nuclear power plants, U isotopes will be loaded into ADSs to produce energy and...
Improving the prediction of TSL on-the-fly based on deep neural networks using experimentally measured double differential data and dynamic structure factor
Vaibhav Jaiswal$^{1,*}$, Arthur Pignet$^2$, and Luiz Leal$^1$
$^1$Insititut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France
$^2$MINES ParisTech, PSL - Research University, Centre for Material Forming...
Reflectors play an important role at reactor and spallation neutron sources, providing a means for otherwise lost neutrons to be potentially re-directed towards the neutron science instruments. Such materials typically surround the moderating volume, but can also be placed in the neutron beam extraction area. We present developments of improved modelling methods such as including crystallite...
Metal hydrides have a variety of mechanical, thermal, and neutronic properties that are ideal for applications to nuclear technologies. As a result, zirconium hydride has been used in the fuel of TRIGA reactors for over half a century. More recently, calcium hydride (CaH${}_{2}$), a saline hydride, has been investigated and shows promise for use as a moderator in microreactors. As of yet,...
The medical cyclotrons intended to produce medical isotopes are relatively widespread. Nowadays, it is popular to place small and compact accelerators directly to hospitals. This approach simplifies handling with produced radiopharmaceuticals, but it imposes radiation safety measures during production. Radiation protection issues are gaining on importance especially as production increases on...
Fission product yields play an important role for nuclear reactor fuel cycle, nuclear reactor
decay heat, and nuclear reactor waste inventory. Multiple techniques have been used to determine
fission product yields for many decades to support reactor design. For our purposes, we will be
performing $\gamma$-ray spectroscopy on $\beta$-decaying fission products following a prompt fission...
Nuclear data is critical for many modern applications from stockpile stewardship to cutting edge scientific research. Central to these pursuits is a robust pipeline for nuclear modeling as well as data assimilation and dissemination. We summarize the ongoing nuclear data efforts at Los Alamos for medium mass to heavy nuclei. We begin with a discussion of a novel toolkit for model parameter...
Among the photo-nuclear reactions of light nuclides, the photo-disintegration of deuterium, $^2{\mathrm H}(\gamma,{\mathrm n})^1{\mathrm H}$, is arguably the most important one for nuclear systems with heavy/light water. In multiplying/critical systems, this reaction is also a source of delayed neutrons due to the delayed gamma emission of certain fission products. Therefore, it is important...
Short-lived radionuclides, i.e., radioactive isotopes with half-lives less than 100 Ma, were present in the proto-solar cloud and during the early phases of the formation of our Solar system. The origin of individual short-lived radionuclides is still under debate. Due to the comparatively short half-lives, these isotopes are nowadays not present in cosmic samples, but are recognizable as...
Accurate gamma production in capture reactions is critical for simulation of nuclear reactor applications. This includes modeling of strength functions and level densities and calculating cross sections from resonance parameters. To improve this work, the Rensselaer Polytechnic Institute (RPI) 16-segment gamma-multiplicity NaI(Tl) detector at the Gaerttner Linear Accelerator Center (LINAC) has...
Around half of the elements heavier than iron are produced via the slow neutron capture process ($s$-process), whereby a seed nucleus undergoes a series of neutron captures and beta decays, with the timescales of the captures being slower than those of beta decays. The $s$-process is further subdivided into several different components which occur in different types of stars. Of particular...
Centro Nacional de Aceleradores (CNA) is a joint interdisciplinary research center from Universidad de Sevilla, Junta de Andalucía and CSIC (Spanish National Research Council) open to external users. CNA has six different facilities, namely: a 3 MV Pelletron tandem accelerator, an 18/9 MeV Cyclotron accelerator, a 1 MV mass spectrometer accelerator, a PET/CT scanner, a 200 kV radiocarbon...
For the improvement of Generation IV nuclear reactors simulation, accurate evaluated data are required. Among others, a reaction of interest is the neutron inelastic scattering as it modifies the energy distribution of neutrons. In the context of the innovated Th/U cycle and for a better knowledge of the neutron inelastic scattering on thorium 232, experiments have been performed at...
It is well ascertained since the late '50, that the vast majority of the elements above the iron peak are synthesized in stars, via sequences of neutron captures and β-decays. Among the nucleosynthesis mechanisms, the slow (s-)process represents one of the better known and is very effective into modelling the stellar evolution. Thanks to the high accuracy of the nuclear data available in the...
How elements are made in the Universe is an open long-standing question. Several processes are invoked to explain the observed elemental abundances in our Solar System [1] and in our Galaxy [2].
Complex simulations of astrophysical events are used to study the origin of the heavy elements and quantify the contribution of the r-process to the observed elemental abundances [3]. This process...
The fast neutron fission cross sections of 233,235,238U and 239,240,241Pu were evaluated for the JENDL-5 library up to 200 MeV. The experimental fission cross sections and their ratios in the EXFOR library were reviewed with the source articles. Additionally, Poenitz’s data compiled in his GMA database were reviewed. We found about 160 datasets are archived with the...
The new Device for Indirect Capture Experiments on Radionuclides at LANSCE: Efforts on measuring the resonance(s) responsible for the extremely large 88Zr(n,g) cross section
A. Stamatopoulos1, P. Koehler1, E. Bond2, T. A. Bredeweg2, A. Couture1, B. DiGiovine1, M. E. Fassbender2, A. C. Hayes-Sterbenz3, G. Keksis2, A. Matyskin2, K. Parsons4, G. Rusev2, J. Ullmann1, C. Vermeulen2
- Physics...
According to the Nuclear Data High Priority Request List published by the Nuclear Energy Agency (http://www.oecd-nea.org/dbdata/hprl/), values of cross sections used in nuclear technology should be known with uncertainties between 1% and 5%, while cross sections of key isotopes involved in s- and r-processes must be known with uncertainties of about 1%.
The uncertainty associated with the...
Iron is an important structural and shielding material that appears in many applications. Nuclear reaction data of iron have been addressed within the Subgroup-40 (CIELO) of the OECD/NEA Data Bank [1]. The resulting evaluated data files from the BNL/IAEA collaboration for the iron isotopes [2] were included in the ENDF/B-VIII.0 library [3] and performed well in criticality benchmarks....
The new generation of radioactive ion beam facilities will allow the production of unstable nuclei far away from the valley of stability. In the very neutron-rich region, the beta-decay energy window is much larger than the neutron separation energy of the daughter nucleus. Thus, delayed neutron emission after beta decay becomes a prevalent decay mode. To obtain information about the nuclear...
Cross-sections for neutron-induced interactions with molybdenum, in particular for the neutron capture reaction, play an important role in various fields ranging from nuclear astrophysics to safety assessment of conventional nuclear power plants and the development of innovative technologies. It is found as a pollutant in pre-solar silicon carbide grains and it has a crucial role in stellar...
Neutron induced reaction cross section measurements are often performed relative to a neutron cross-section standard. Thus, the accuracy of the neutron standards determines the accuracy of the neutron cross section measurements. The $^{235}$U(n,f) cross section is widely used as reference reaction, while it is considered as standard at 0.0253 eV (thermal energy), between 7.8 and 11 eV and from...
While nuclear data play an important role in nuclear physics applications, it has become important to have a better understanding and try to minimize their uncertainties. In particular, there is a need for precision neutron-induced fission cross section measurements on fissile nuclei. Neutron-induced fission cross sections are typically measured as ratios, with a well-known standard in the...
Pulsed neutron beams are a valuable tool in nuclear physics, but their applications are strongly restricted by the limited number of neutron sources available worldwide [1]. These neutron beams, suitable for "time of flight" (TOF) experiments, can be characterized by their time resolution, the intensity per pulse, and the frequency or repetition rate.
In terms of neutron production,...
Three-body break-up channels play an important role in light nuclear systems even at low incident energies. In standard two-body R-matrix theory these processes can only be treated approximatively for instance by using sequential decay models. We will present a novel three-body R-matrix formalism that is based on a proposal by Glöckle [1]. In this framework the Faddeev equations are solved by...
Energy resolutions of pulsed neutrons are one of the important parameters for nuclear data measurement by TOF method. The energy resolutions are a facility-specific parameters, and has been evaluated experimentally and numerically at various TOF facilities using pulsed neutrons.
KURNS-LINAC is an L-band electron linear accelerator with maximum acceleration voltage of 46 MeV established at...
Abstract
Neutron production through α-induced nuclear reactions is a key issue in several fields. Specifically, (α,n) reactions are interesting in nuclear astrophysics as a source of neutrons for the slow neutron capture nucleosynthesis (the s-process) [TAI16] and in the α-particles capture process (the α-process) [WOO92, BLI17]. Other fields of interest include the neutron-induced...
V. Alcayne a), A. Kimura b), E. Mendoza a), D. Cano-Ott a), T. Martinez a), E. González-Romero a), A. Pérez de Rada a), and the n_TOF collaboration c)
a) Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), E-28040 Madrid, Spain
b) Japan Atomic Energy Agency (JAEA), Tokai-mura, Japan
c) Conseil Européen pour la Recherche Nucléaire, CERN, Switzerland
The safe and...
Reactor antineutrino energy spectra are the subject of active experimental researches nowadays, either through large reactor neutrino experiments, short baseline neutrino experiments at research reactors or through dedicated nuclear physics measurements of the properties of the fission products. The summation method relies on the use of nuclear data to build the reactor antineutrino energy...
Nucleon inelastic scattering to the continuum can be adequately described through the exciton or quantum mechanical multistep direct (MSD) and multistep compound (MSC) pre-equilibrium models, as they account not only for the high energy component of particle emission spectrum, but also it provides initial conditions of the formed Compound Nucleus (CN).
It was previously shown that an ...
The Nuclear Data Production System (NDPS) is an experimental system for measuring nuclear data by use of neutron Time-of-Flight detection systems built at Daejeon, Korea. The RAON (Rare isotope Accelerator complex for ON-line experiment) provides deuterons and protons up to 98 MeV and 83 MeV, respectively. They are accelerated by a superconducting driver LINAC and are delivered to the neutron...
Working Party on International Nuclear Data Evaluation Co-operation Subgroup 47 (WPEC SG47) entitled "Use of Shielding Integral Benchmark Archive and Database for Nuclear Data Validation" was started in June 2019 with the objectives to promote a more systematic and wider use of shielding benchmark experiments in nuclear data and transport code validation and development, to provide feedback on...
The GAINS spectrometer operating at the GELINA neutron source (EC-JRC-Geel) is one of the best known setups within the nuclear data community. It provides reliable, high resolution $\gamma$-production cross-section data of importance both for the fundamental nuclear physics research and its many applications. The story of this spectrometer started around 2000 with just 2 large volume HPGe...
Neutron inelastic scattering is one of the major nucleon-nucleus interactions in the fast energy range, and its cross section constantly increases above the threshold energy of the first excited state up to a few MeV. Since the inelastic scattering process changes the momentum of interacting neutrons and produces characteristic gamma-rays, high quality nuclear data for this process are...
Neutron beams have been utilized not only in the basic science, but also in the various industry sectors such as nuclear power, aerospace, defense industry, and semiconductor industry, over the past decades. Although the needs for the nuclear data using the neutron beam extensively have been increased worldwidely, however, it is still insufficient, in particular for the high energy...
The Nuclear Data Production System (NDPS) which is a neutron time-of-flight (TOF) experimental facility of RAON is under construction. The proton and deuteron beams are accelerated up to 83 and 98 MeV, respectively. The proton beams bombarded with a thin Li target will produce mono-energetic neutrons, and continuous-energy neutron spectra will be generated by colliding deuteron beams to a...
For thorough understanding resonant theories and cause of discrepancies among different cross-section measurements, development of an R-matrix analysis code AMUR is being progressed.
The code is organized by “theoretical” and “experimental” classes based on the object-oriented framework. In the theoretical class, with sharing the same compound nucleus, the independent distant poles can...
Christian Brazell
10/15/21
TAMU-LLNL
LLNL-ABS-827556
ND2022
Surrogate Modeling for Fission Cross Sections, Criticality Studies, and Uncertainty Quantification
ABSTRACT
Computational methods have advanced to the point where, in many cases, the main source of uncertainty in neutronics calculations comes from the underlying Nuclear Data (ND). Assessing the impact of the underlying uncertainties...
Abstract
The leakage neutron spectra measurements have been done on benchmark spherical assembly-nickel sphere with diameter of 50 cm and copper cube with an edge of 48.4 cm. The Cf-252 neutron source was placed into the centre of nickel sphere and copper cube. The proton recoil method was used for neutron spectra measurement using spherical hydrogen proportional detectors (HPD) with pressure...
In the field of radiation detection using Ge detectors, pulse pile-up rejection processing (PUR) is widely used. PUR reduces the distortion of the spectrum shape but it causes further increase of dead time. Many papers have been written on the dead time losses with PUR and methods to correct the influence [1],[2]. The proposed correction methods presuppose that the timing of pulses is random....
Beta-delayed neutron emission is a dominant decay mode for the very neutron-rich nuclei. With the opportunities offered by new generation radioactive beam facilities, we can perform experiments with a larger and more exotic pool of isotopes. This enabled us to revisit the conventional views on the fundamentals of beta delayed neutron emission. However, new data and improved models are...
MONNET is a fast neutron source based on a tandem-accelerator, located at the Geel (BE) site of the Joint Research Centre (JRC). It became operational in 2020. MONNET may deliver intense neutron beams in the energy range from $30~\text{keV}$ to $10.1~\text{MeV}$ and from $12.8~\text{MeV}$ to $24~\text{MeV}$. Neutrons are produced with protons or deuterons on lithium, tritium or deuterium...
Phenomenological optical model potentials (OMPs) have played an essential role in scattering calculations for several decades. Despite their successes, none have had their parametric uncertainty fully quantified, making reliable extrapolation difficult. To address this gap, we have developed a generic OMP uncertainty quantification framework that leverages Markov-Chain Monte Carlo for OMP...
Non-light water reactor (non-LWR) concepts under development throughout the industry are significantly different from traditional LWR designs with respect to geometry, materials, and operating conditions. These differences result in significant differences with respect to the reactor physics behavior of non-LWRs as compared to LWRs. Given the limited operating experience with non-LWRs, the...
The goal of the U.S. Nuclear Criticality Safety Program’s (NCSP) Thermal/Epithermal eXperiments (TEX) is to design and conduct new critical experiments to address high priority nuclear data needs from the nuclear criticality safety and nuclear data communities. The first set of five TEX experiments, using layers of plutonium-aluminum Zero Power Physics Reactor (ZPPR) plates stacked with...
The Gogny-based QRPA approach developed in CEA, DAM, DIF [1] can be applied to spherical as well as to axially deformed nuclei, from light (i.e. oxygen) to superheavy elements [2]. For electric and magnetic dipole modes, intensive computational efforts have been made to produce a large-scale data set of gamma-ray strength functions with as little as possible phenomenological corrections. The...
It has been proposed to design and build an modular, a simple and effective cosmic ray detector (muon detector) that can be used both in laboratory measurements and in great physics experiments. The main goal of this system is to provide information from cosmic muons that pass the other detector in both in-beam and off-beam experiments for testing and calibration. Moreover, observation of...
Shanghai Light Source has been operated since 2009 to provide synchrotron radiations to 40 beamlines of the electron storage ring at a fixed electron energy, 3.5 GeV. The Shanghai Laser Electron Gamma Source (SLEGS) is approved as one of 16 beamlines in the Phase II project in 2016 to produce energy-tunable gamma-ray beams in the inverse Compton slant-scattering of laser photons from a 100 W...
Nuclear structure and inelastic scattering have key roles in the study of the origin of elements in the Universe as well as in the modern medical treatments. A precise knowledge of reaction rates and particle absorption are of fundamental importance in the mass aggregation mechanism of r-process and increase the accuracy of radio isotopes production and radiation therapies. The theoretical...
Evaluated Means and Uncertainties, or EMU, is a new suite of tools for generating statistical realizations of nuclear data libraries encoded in the Generalized Nuclear Database Structure (GNDS). Built upon the For Updating Data and Generating Evaluations (FUDGE) package from LLNL, EMU is capable of reading and generating realizations of nearly any accessible nuclear data library, whether they...
The first excited $1/2^+$ state in $^9$Be has been observed as a sharp peak just above the $^8$Be+$n$ threshold energy in the photo-disintegration cross section of $^9$Be. Since the size of the peak has a strong influence on the reaction rate of the $^9$Be synthesis, experimental data have been investigated [1, 2].
We performed calculations using an $\alpha+\alpha+n$ three-cluster model [3,...
The laser Compton slant-scattering is a key technique to achieve the energy tunability in producing gamma-ray beams at synchrotron radiation facilities operated at a fixed electron energy. A pioneering attempt was made of generating MeV gamma-ray beams in the slant-scattering at 70 – 110o in the UVSOR-II electron storage ring [1]. The Shanghai Laser Electron Gamma Source (SLEGS) is dedicated...
A new setup is being prepared in Centrum Výzkumu Řež for the measurement of prompt capture and inelastic gammas coming from neutron interactions. These gammas are important for safety during reactor operations (worker’s protection or radiation damage) or have applications in many areas like element identification in soil and space.
The setup consists of an aluminum sphere with a 50 cm diameter...
The giant dipole resonance (GDR) is one of the most well-known collective excitation modes since the dawn of research on nuclear physics. The origin of GDR is a collective motion of neutrons against protons inside the nucleus. Since its discovery in the photoabsorption cross section, extensive theoretical studies have been done to reveal the nature of such electric dipole excitation. The...
The Generalized Nuclear Database Structure (GNDS) is an international nuclear data format meant to replace the half-century-old Evaluated Nuclear Data Format (ENDF-6). The current version of the specifications as defined by the Working Party on Evaluation Co-operation (OECD/NEA/WPEC) Expert group on GNDS (EGGNDS), includes specifications for the treatment of the unresolved resonances region...
First-forbidden beta decays play an important role in several domains of physics. First, in astrophysics, where nuclear data such as the half-life govern stellar evolution and nucleosynthesis [1]. Second, they are of interest for nuclear reactors physics as first highlighted in 2014 [2]. In first-forbidden $\beta$-decays, the form factor of the leptonic spectra are not equal to one as for...
The transfer function of a zero-power thermal reactor was successfully measured by means of a pile noise experiment at low frequency. During a month-long experimental campaign, neutron fluctuations were acquired using excore fission chambers in a sub-critical state of the reactor. The analysis made use of the Cross-Power Spectral Density (CPSD) methodology. Firstly, the prompt neutrons kinetic...
The non-proliferation issues caused by the civilian use of highly enriched uranium (HEU) were solved by using of several international agreements. Accordingly, efforts were made to reconstruct existing research reactors for using of low enriched uranium (LEU) and to encourage the usage of LEU in the development of new research reactors and other nuclear facilities, such as subcritical systems...
Condition-based monitoring (CBM) techniques are widely being adopted for maintenance activities in nuclear power plants. Asset operational data are collected by smart sensors mounted on and around the components. The sensed data is often gathered and processed by a monitoring and diagnostic center to garner various component fault signatures. These fault signatures are subsequently used as...
The FLUKA general purpose radiation transport Monte Carlo code being developed and maintained by CERN has adopted modern software development standards including a formal quality assurance process. This includes the FLUKAVAL testing framework that takes into account the specific needs of testing a Monte Carlo radiation transport simulation code.
FLUKAVAL is a...
All the cross sections of neutron-induced reactions, angular distributions, energy spectra, and double-differential cross sections for n+ 107, 109Ag reactions are calculated and analyzed below 20 MeV by using UNF code. The isomeric cross sections are also calculated. Furthermore the theoretical results are compared with the available experimental data and the evaluated results in ENDF/B-Ⅷ.0,...
Abstract:
Accuracy of large angle scattering cross section in nuclear data have a large influence on precision of neutron transport calculation in fusion reactor design. In previous research, benchmark experiments for solid target were carried out, however, non-solid targets, which are covered by a casing, could not be dealt with. This is because we could not remove the casing effect in the...
The predicted reactor antineutrino flux is an important ingredient for particle physics measurements and neutrino-based safeguards applications, ranging from neutrino oscillation measurements to monitoring reactor fuel and operations. Over the past decade, comparisons between predictions and reactor neutrino experiments have revealed significant discrepancies which have motivated new neutrino...
The necessity to operatively concern the growing needs of the BN-600 reactor support as well as the commissioning of the BN-800 reactor which also has a task of scientific support have led to the necessity of a new generation simulation support code development. This new generation code would make it possible to flexibly consider actual demands of scientific support of both reactors. In future...
Evaluation of Neutron Data Standards have been a critical component of ENDF/B library releases which is currently coordinated by the IAEA. The latest Neutron Data Standards were released in 2017 [1] and were adopted for the ENDF/B-VIII.0 library [2]. Since very early on, the Neutron Data Standards have been derived using the Bayesian GMA code originally developed by W. Poenitz with an...
Abstract
The Blackshaw-Murray[1] elastic kernel represents the effect of neutron up-scattering caused by thermal motion of target nuclei and resonance elastic scattering on the multigroup scattering matrices. A first implementation of this model was proposed by Ouisloumen and Sanchez and made available in proprietary cross-sections libraries of the PARAGON and APOLLO lattice codes.[2]...
The main objective of the article is development of a digital platform for visualization and processing of nuclear data.
It is based on the idea of saving the experience accumulated over many years of working with libraries of nuclear-physical data for various purposes. The main task is to provide users with open and convenient access to various types of nuclear data archives for conducting...
Recently, an advanced neutronics lattice code called Kylin-2 has been developed by Nuclear Power Institute of China. In order to develop multi-group library for Kylin-2, a fission product depletion chain simplification method was proposed in this paper to generate burnup data for the multi-group library. This method constructed two quantitative contribution functions based on the thought of...
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\textbf{\large Regression analysis of experimental reaction
cross-section data of $^{241}$\emph{Am}(n, 2n)$^{240}$\emph{Am}}\...
Fast neutron induced nuclear reaction cross section data are necessary for both nuclear energy technology and the study of nuclear physics research. The information of (n,2n) cross sections is quite essential in nuclear reactor technology as a significant portion of the fission neutron spectrum lies above the threshold of (n,2n) reaction for most structural materials. Furthermore, the...
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\title{\myfont{\textbf{Comparison of binding energy from Atomic Mass Evaluation (AME-2020) with statistical model...
Lately, novel radiation therapy methods using advanced laser technologies with ultra-high dose rates (“FLASH”), such as laser-accelerated particle beams and laser-driven ionizing radiation in pulses, with time spans from fs to ns started to emerge, having encouraging results in numerous studies concerning toxicity characterization [1,2]. Significant parameters of radiation therapies like high...
The COG suite of criticality benchmarks has been formally expanded to 3,368 to cover the entire energy range from thermal to fast neutron spectra under a variety of reflector and moderator conditions and fissile materials. The number of benchmark cases in each of these six major categories is summarized in Table 1.
Table 1. Number of Benchmark Cases.
Category Number of...
In order to compare the ENDF/B-VIII.0 and CENDL-3.2 Fe-56 nuclear data, 28 iron sensitive models were selected from the International Criticality Safety Benchmarking Experiments Evaluation Program. There are 21 highly enriched models and 7 plutonium mental models. The benchmark models were modeled in MC program and k_{eff} calculated with ENDF/B-VIII.0, with a hybrid ENDF/B-VIII.0 with...
The status of the two neutronics international benchmark projects sanctioned by the Organisation for Economic Co-operation and Development Nuclear Energy Agency (OECD NEA), the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP), was last directly discussed with the international nuclear data...
Accurate nuclear data for neutron capture reactions of minor actinides (MA) are required to estimate the production and the transmutation rates due to their preponderant role in the study and design of transmutation systems related to nuclear waste management. Since its construction in 2009, continuous research efforts have been carried out to measure neutron-induced reactions at the Accurate...
The Chernobyl accident in 1986 deposited radioisotopes like $^{137}$Cs over large parts of Europe. Having a half-life of 30.2 years, $^{137}$Cs is still present in nature, including in mushrooms as well as wild boars, and has become an integrated part in many natural food chains.
In this article, we describe our facility UGGLA (Uppsala Generic Gamma Lab). UGGLA is designed to measure...
The compact accelerator-driven fast neutron sources represent cheaper and smaller alternative to research nuclear reactors. They can be used (as a primary or supplementary tool) for many research activities realized at the nuclear reactors, such as the isotope production, sub-surface exploration, material research, neutron activation analysis, nuclear data provisioning, boron neutron capture...
Based on the statistical theory of light nucleus reactions, the description of the complicated emission processes of proton and light composite charged particles are further improved through considering the effects of Coulomb barriers both in incident and different outgoing reaction channels. Moreover, the analysis of the reaction channels including the sequential and simultaneous emission...
A small modular reactor (SMR) employing calcium hydride (CaH2) as a moderator have attracted attention to the passive safety and economic efficiency. Some integral experiments should be carried out to validate nuclear data of CaH2, however, no integral experiment by reactor for the validation have been reported. As the first integral experiment by reactor, a series of...
For the JENDL development we analyzed the iron in-situ experiment at the DT neutron source facility FNS in JAEA with the two-dimensional Sn code DORT and the latest nuclear data libraries: JENDL-4.0, ENDF/B-VIII.0 and JEFF-3.3. As a result, we found that the result with ENDF/B-VIII.0 reproduced the measured data worse than those with JENDL-4.0 and JEFF-3.3. Here we investigate this issue.
The...
The $^{235}$U(n,f) cross section is one of the most important cross-sections in many applications, and it is a standard at the thermal neutron energy point (0.025 eV), and from 0.15 MeV to 200 MeV. Above 100 MeV, it also plays an important role in understanding fundamental nuclear physics processes, as it can be related to the properties of excited nuclear matter. Above 50 MeV, however, the...
A series of benchmark experiments with thin targets was carried out at ITEP in 1994 - 2009 in support of subcritical systems with an external neutron source (Accelerator Driven Systems, ADS) [1-3].
The cross sections for the formation of residual products of nuclear reactions were determined by the activation method ͟using precision γ-spectrometry. Thin samples made of material considered...
The group of CSNS White Neutron Source (Back-n) has developed a prototype TPC for the physical experiments. The main design goal of white neutron source TPC is to measure the neutron induced light charged particle emitting nuclear reactions, and at the same time, it takes into account many applications such as fission cross section measurement, beam spot measurement and neutron radiography. At...
EXFOR (EXchange FORmat) database contains experimental nuclear reaction data compiled by the NRDC (Nuclear Reaction Data Centers) network. The network strictly regulates data format, rules of compilation, distribution of work and data exchange between data centers. The data dissemination is not regulated by the network - this includes output data formats, various database services, software...
It is an open question in the fields of nuclear reactions to study the mechanism of reactions induced by the weakly bound nuclei at different incident energies with various target nuclei and calculate the reaction cross sections. The structure of weakly bound nuclei, which is easily broken up, plays an important role in their induced reaction and is thought to be the main reasons for their...
The $^{235}$U(n,f) cross section is one of the most important neutron cross-section standards, and therefore it is recognized as a convenient reference for several other reaction cross-section measurements at thermal energy and between 0.15 MeV and 200 MeV. Outside these energy ranges the cross section is either not well known nor measured yet, as for example above 200 MeV, where evaluations...
In the operation of nuclear reactors, the kinetic behaviour of the neutron population is driven by the delayed neutrons. The delayed neutrons fraction is thus one of the key parameters associated to nuclear safety.
The kinetic parameters (delayed neutrons fraction and generation time) of the LR-0 reactor operated by Centrum výzkumu Řež were measured by CEA using a current-mode neutron noise...
Across the nuclear data pipeline, it is important to drive improvements in validation and verification. One powerful tool in this process, for evaluation through applications, is simply visualizing the data. The ability to visualize nuclear data exists in many forms already, ranging from the legacy but robust tools in NJOY [1] (PLOTR and VIEWR) to the NEA’s Java-based Nuclear Information...
Fission reactions investigated in inverse kinematic at relativistic energies have proven
to be a powerful technique to get access to a large variety of non stable heavy nuclei
[1] but also to fully identify, for the first time, in atomic and mass number both fission
fragments [2]. These systematic investigations made possible to establish the role of
proton shells in the asymmetric fission...
The comprehensive experimental nuclear reaction data compilations were pioneered at the Metallurgical Laboratory (University of Chicago) and Los Alamos National
Laboratory [1,2] for the Manhattan Project needs. In 1947 many Manhattan Project alumni moved to a newly created Brookhaven National Laboratory to work on nuclear physics research and data compilations [3,4] in support of nuclear...
The thermal scattering laws (TSLs) take into account the crystalline structure and atomic motions of isotopes bound in materials. This paper presents the CINEL code, which was developed to generate temperature-dependent TSLs for solid, liquid and free gas materials of interest for nuclear reactors.
CINEL is able to calculate TSLs from the phonon density of states (PDOS) of materials under...
It is reasonable to believe that in the not-too-distant future, quantum computing will revolutionize our ability to model and understand atomic nuclei and their interactions, and will find applications well beyond basic research. Advances in technologies that allow the production of quantum hardware with a larger number of qubits and significantly smaller error rates are still a few years...
An effort is now underway to produce a new evaluation of the neutron cross section standards.
It is important to maintain experimental programs to increase the quality and extend the database
for the neutron cross section standards in order to improve evaluations of them that will be used to convert cross section measurements made relative to those standards.
Measurements have been made for...
The average energy and multiplicity of prompt $\gamma$-rays from near thermal neutron induced fission of $^{235}$U have been measured using the STEFF detection setup at both the high-flux ILL research reactor and the neutron time-of-flight facility n_TOF. As highlighted by the NEA High Priority Request List, these quantities are of importance to the heating of non-fuelled elements of a...
Abstract
Thermal neutron cross sections of hydrogenous materials are a fundamental ingredient for the simulation and design of, amongst other things, neutron moderators at research centres and nuclear reactors. However, experimental thermal cross sections are available for just a handful of materials (see, e.g., Ref. 1]). In order to match the level of detail in modern Monte Carlo nuclear...
The rapid neutron capture (r-process) is one of the main mechanisms whereby elements heavier than iron are synthesized, and is responsible for the creation of the heaviest stable isotopes of the actinides. Kilonova emissions are modeled as being largely powered by the radioactive decay of species synthesized via the r-process and in principle, observations of these offer insight into...
In nuclear physics the term meta-stable state refers to an excited state with an unusually long half-life, which can sometimes be even longer than that of the corresponding ground state. As a result, these states are often considered to be nuclei in their own right and, together with the corresponding ground state nuclei, they are referred to as isomers. The yields of...
In recent years, molten salt reactor (MSR) concepts have seen renewed interest both within academia and emerging industry. Several widespread reactor concepts are developed, sharing the feature that the fissile fuel is dissolved in a molten fluoride or chloride salt which remains liquid over a wide temperature range at atmospheric pressure. One of the attractive features of MSRs is precisely...
Nuclear mass measurements give access to nuclear binding energies, which reflect the sum of interactions among its constituent nucleons. Certain double differences of neighboring nuclei binding energies provide $\delta$V$_{pn}$, the average interaction strength of the last one or two protons with the last one or two neutrons [1].
We will present highly-accurate mass measurements of the...
Currently, reaction measurements on fission products are being planned by the Nuclear Science PG at both Argonne Nat. Lab and at FRIB (Facility for Rare Isotopes, Michigan State). These indirect experiments produce specific short-lived nuclei via beta decay, and the subsequent neutron and gamma emission are studied. Some initial experiments found a surprising overabundance of gamma emission....
The design of neutron sources, using Monte-Carlo radiation transport codes, relies on the usage of thermal scattering libraries in the ACE format. These libraries are derived from models of neutron interactions in the materials of interest. We report here on the development of such libraries for applications related to cold and very-cold neutron sources [1]. For this purpose, we have used...
N. Jovancevic$^1$, D. Knezevic$^2$, A.M. Sukhovoj$^3$, L.V. Mitsyna$^3$ M. Krmar$^1$,
$^1$) Department of Physics, Faculty of Science, University of Novi Sad, Serbia \
nikola.jovancevic@df.uns.ac.rs\
$^2$) Institute of Physics Belgrade, University of Belgrade, Belgrade, Serbia\
$^3$)Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russian...
Recently, a second Target Accuracy Requirements (TAR) exercise has been launched in the framework of the WPEC/S46 on “Efficient and Effective Use of Integral Experiments for Nuclear Data Validation”. The TAR exercise aims at quantifying nuclear data needs (in terms of uncertainty reduction) to meet target accuracies on specific integral parameters. These target accuracies are driven by reactor...
Nuclear data evaluation principally relies on adjustments of nuclear parameters on differential experiment data. To add another source of information, one may use integral experiments data. Usually, this process is applied on multi-group cross sections, with the help of deterministic transport code. However, nuclear data obtained are often biased toward the integral experiment studied, or the...
Uranium Carbide (UC) is a nuclear fuel material, whose crystal binding may affect doppler broadening of epithermal neutron absorption resonances and scattering behavior of thermal neutrons. Currently, there is no Thermal Scattering Law (TSL) evaluation for UC in the ENDF/B-VIII.0 database. Ab-initio lattice dynamics (AILD) techniques are used to calculate the phonon spectrum using...
The N=Z=50 isotope $^{100}\text{Sn}$ has long been of interest from theoretical and experimental perspectives because it is the heaviest self-conjugate doubly-magic nucleus. Despite the significant progress in the last decade, the challenge of reaching it in experimental facilities remains to date. Systematic measurements of ground state masses and isomer excitation energies in its vicinity...
Recommended 2$\beta$(2$\nu$) half-lives and their systematics [1] are examined in the framework of a semi-empirical approach. Impacts of nuclear deformation, transition energy, and forbidden decay on half-live values were observed. These findings were used to predict T$_{1/2}$ for 35 isotopes of interest. Current results are compared with other theoretical and experimental works.
[1] B....
Hydrogen fluoride (HF) is a material commonly used in nuclear fuel processing and manufacturing. As HF is commonly used directly in conjunction with various forms of uranium, an accurate representation of the thermal cross sections is vital to criticality safety. To generate the thermal scattering cross sections for HF, a classical molecular dynamics (MD) simulation of the flexible HF system...
The Auger-emitting nuclides $^{119}Sb$ (for which $^{119m}Te$ is a generator) and $^{117m}Sn$ are promising candidates for the treatment of small tumors and for use in radiosynoviorthesis, but there is little information available regarding the formation of these nuclei when targets are bombarded with high energy protons in large-scale isotope production facilities. A more precise cross...
A better quantitative understanding of $\beta$-delayed neutron emission rates and spectra is relevant for nuclear structure, astrophysics, and reactor applications: $\beta$-delayed neutrons provide valuable information on the $\beta$-decay process, are needed in network calculations for understanding the stellar nucleosynthesis process, and can improve the understanding of the kinematics and...
Abstract
In fusion reactor design, neutron leaks intensively from blanket material through a gap. In this streaming phenomenon, back scattering cross section is known to be very crucial. In the present study, the author’s team carried out a new experiment for benchmarking the large-angle scattering cross section of tungsten using a DT neutron source of OKTAVIAN facility, Osaka University,...
In recent years there has been resurgence in the field of thermal scattering law (TSL) evaluations and experiments. This comes after years that this field was dormant with little updates to ENDF evaluations. Evaluated TSL is based on atomistic calculations that in most cases results in a phonon spectrum that can be processed to create the scattering kernel for use in applications. The...
Japanese Evaluated Nuclear Data Library version 5 (JENDL-5) was released in 2021. JENDL-5 is intended to extend its generality from JENDL-4.0 by covering a wide variety of nuclear data for applications not only to nuclear design and decommissioning, but also to radiation-related fields. Overview of JENDL-5 and a future plan for the next of JENDL-5 are presented.
JENDL-5 includes up-to-date...
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\title{Additional reaction mechanisms to statistical $\alpha$-emission and the related optical-potential validation}
\author{V.~Avrigeanu} \email{vlad.avrigeanu@nipne.ro}
\author{M.~Avrigeanu}
\affiliation{Horia Hulubei National Institute for...
Around half of the nuclei heavier than iron are created via the rapid neutron capture process (r-process). For nuclear masses $A>100$, there are two main peaks in the r-process elemental solar system abundances, located at $A\sim 130$ and $A\sim 195$, which are associated with the neutron shell closure during the $(n,\gamma)$ $\leftrightarrow$ $(\gamma ,n)$ equilibrium. In contrast, the...
The even-A stable Xe isotopes are placed in a mass region where a variety of nuclear phenomena emerge. In particular, $^{126}$Xe and $^{128}$Xe exhibit characteristics of transitional nuclei, a possible critical point in the shape transition from spherical to γ-soft, O(6)-like nuclei [1].
In order to probe the structure and collectivity of $^{126,128}$Xe, their properties were studied in...
The availability of reliable nuclear data with quantified uncertainties is essential for basic and applied science. The last decade has seen much progress in the development of theory tools that allow us to achieve more accurate evaluations for compound (statistical) nuclear reactions. Integrated nuclear structure and reaction descriptions provide the basis for achieving consistent evaluations...
Neutronics study is the backbone for the reactor Physics design. In both, fission and fusion reactor neutrons play an important role to the generation of electricity, by the conversion of their kinetic energy to heat energy. Fission neutrons have a maximum energy 2-3 MeV, while fusion neutrons coming from D-T plasma have a maximum energy of ~ 14.6 MeV. The Dynamics of fusion reactor neutrons...
Pulsed-neutron die-away experiments (PNDA) can be useful benchmarks to validate neutron thermal scattering laws (TSLs). The experiment uses a neutron generator to impinge a short (~10-4 s) mono-energetic neutron pulse on a target sample. After the pulse, the neutron population within the sample moderates and reaches thermal equilibrium with a fundamental spatial mode and characteristic...
New evaluations of neutron-induced nuclear reactions on $^{54,56,57,58}$Fe through the CIELO [1] international collaboration were adopted by the ENDF/B-VIII.0 [2] library, released in 2018. These evaluations were performed by adjusting model inputs to reproduce available experimental data above neutron resonance regions. Since the latest release, two new experimental data sets are available;...
Improved current measurements for ionization chambers using the ULCA: A benchmark experiment to determine the F-18 half-life
Ole Nähle1), Dietmar Drung 1), Karsten Kossert 1), Hansjörg Scherer1), Marcell Péter Takács 1)
1) Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
Corresponding author’s e-mail: ole.j.naehle@ptb.de
Ionization chambers play an...
Since its introduction, the so-called surrogate-reaction method (SRM) has motivated the development and improvement of theories in connection to direct reactions. A recent paper~\cite{bou:20} has shown that the assimilation of experimental probabilities in the neutron cross section evaluation process can still be better estimated using tools resulting from the efforts made over the two last...
Thermal scattering law for ice based on neutron time-of-flight experiments carried out at the SEQUOIA spectrometer at the Oak Ridge National Laboratory
Vaibhav Jaiswal$^{1,*}$, Luiz Leal$^1$, and Alexander I. Kolesnikov$^2$
$^1$Insititut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France
$^2$Neutron Scattering Sciences Division, Oak Ridge National Laboratory,...
As the main output of CENDL project, the updated Chinese Evaluated Nuclear Data Library, CENDL-3.2 released in June 2020, which contains the neutron reaction data file which contained 272 materials, and the evaluated activation, fission yields, decay data and photonuclear data file are also included CENDL-3.2.
Out of all 272 materials, the data for 135 materials are totally new，partly updated...
JENDL-5 contains several sub-libraries to contribute to various applications. This presentation outlines the deuteron and alpha ones.
Nuclear data on neutron-production reactions induced by deuteron are required in the fields of design of accelerator-based neutron sources. In such facilities, ($d,xn$) reactions on Li, Be, or C are employed to generate neutron beams. We have recently developed...
Fluctuation in the observed resonance decay widths is often characterized by the Porter-Thomas distribution, or the chi-square distribution. Compound nucleus reaction modelings, in which the Gaussian Orthogonal Ensemble (GOE) is involved as a propagator, have been successfully applied to study the properties of fluctuation in the S-matrix (or the cross section). In the GOE models, the...
With the rise of interest in thermal neutron scattering data for advanced reactor, criticality safety, and shielding applications, new experimental data is required both for evaluations of new materials or for re-evaluations (or validations) of previously evaluated materials. New experimental data is evaluated in a 3-step process: 1) computing the phonon characteristics (e.g....
Following the release of JEFF-3.3 in late 2017, the JEFF coordination group took a step back to review its goals for a new major release, JEFF-4: for users, in terms of fields of application and performance, and within the project to modernize the methods for the production, testing and benchmarking of its evaluated files. Given the broad range of applications of a nuclear data library and the...
VESUVIO is a spectrometer at the ISIS Neutron and Muon Source, Rutherford Appleton Laboratory (United Kingdom) that allows the measurement of the total cross-section of a sample material by the transmission and time of flight techniques, over a range of five decades in energy (10$^{-3}$ to 10$^{2}$ eV). At the same time, it allows a precise determination of the effective temperature of each...
A segmented total energy detector (sTED) for (n, γ) cross section measurements at n_TOF EAR2
V. Alcayne1, D. Cano-Ott1, E. González-Romero1, T. Martínez1, E. Mendoza1, A. Sánchez-Caballero1, J. Balibrea2, C. Domingo-Pardo2, J. Lerendegui2 and n_TOF collaboration3
1CIEMAT, Spain
2IFIC CSIC-UV, Spain
3CERN, Switzerland
The neutron time-of-flight facility n_TOF [1] is characterised by its high...
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\title{Role of direct interactions in $(d,p)$ and $(d,2p)$ reactions}
\author{M.~Avrigeanu} \email{marilena.avrigeanu@nipne.ro}
\author{C.~Costache}
\author{V.~Avrigeanu}
\affiliation{Horia Hulubei National Institute for Physics and Nuclear...
The safe management of the spent nuclear waste (SNF) requires a special effort of characterization, since its isotopic composition is the key to its transport, handling and storage by means of the decay heat, gamma emission and neutron emission it produces due to radioactive decay.
The effort is being done in the frame of the EU EURAD project (European Joint Programme on Radioactive Waste...
Radionuclide monitoring involves measurements of the concentrations of radioactive particles and noble gases in air, soil, and liquid samples. After collection and appropriate treatment of the samples, γ and β emissions are measured by means of Ge detectors and β counters, respectively. Quantification of such spectra relies heavily on up-to-date evaluations of the nuclear structure and decay...
NJOY+NCrystal is an open source tool which can be used to generate thermal neutron scattering libraries in a format that supports both coherent and incoherent elastic components for crystalline solids. The tool is based on a customized version of NJOY2016 [1] which calls the thermal scattering software NCrystal [2] for the calculation of the elastic components. The libraries can both be...
The CONRAD computer code is being developed by the nuclear data group of CEA Cadarache by since mid-2000. It was originally designed to analyse neutron-induced reactions in the resonance energy range and then, was extended to higher energies (several MeV) treatment with inclusion of charged-particles penetration factor. In the resonance range, nuclear models implemented in the CONRAD program...
Nuclear data processing is the procedure devoted to the conversion of evaluated nuclear data into libraries suitable for specific final applications such as neutron transport or inventory calculations. AMPX is the modular processing code of SCALE Code System that takes basic cross section data in Evaluated Nuclear Data File format to provide both multigroup and continuous energy libraries for...
FUDGE (For Updating Data and Generating Evaluations) is an open-source code that supports reading, visualizing, checking, modifying, and processing nuclear reaction and decay data. For ease of use the frontend of FUDGE is written in Python while C and C++ routines are employed for computationally intensive calculations.
FUDGE has been developed primarily at Lawrence Livermore National...
Knowing the half-life of a radioactive isotope as precisely as possible is crucial for many research areas, for example nuclear astrophysics, nuclear energy technology or environmental research. Radionuclides with half-lives of hundreds to millions of years are particularly important, not only because of their significance in the relevant scientific field but also because of their potential...
Abstract
The ELECTR module of NJOY is designed to produce complete and accurate multigroup electroatomic cross sections from ENDF/B-IV, -V -VI or -VII data[1]. It will also work with the newer formats developed for ENDF/B-VII. ELECTR produces restricted cross sections consistent with a solution of the multigroup Boltzmann-Fokker-Planck (BFP) equation. Total, elastic, inelastic (collision...
A comprehensive reevaluation of $^{239}$Pu transport cross sections from subthermal energies up to 30 MeV within the INDEN collaboration is presented. Softer prompt fission neutron spectra (PFNS) for thermal neutron-induced fission with an average energy of 2.08 MeV from the IAEA evaluation is combined with new resonance parameters and new nubar evaluation to preserve the good criticality...
Initially born out of the needs of the ESS Detector Group to enhance the realism of thermal neutron scattering in Geant4-based detector design studies, the NCrystal project has grown into a generic backend for such modelling -- which is both flexible, efficient, and available under a liberal open source license. In this contribution we present the project, including both design philosophy, an...
Fission-product yields are one of the most fundamental pieces of nuclear data associated with nuclear fission, and they play an important role in fundamental neutrino science, nuclear energy, nuclear medicine, and national security. One of the most straightforward and reliable ways to determine fission-product yields is via detection of the characteristic γ rays emitted following the β decay...
The latest evaluated nuclear data libraries, including ENDF/B-VIII.0, TENDL2019, all have two formats, the Evaluated Nuclear Data File (ENDF-6) nuclear data format, and the Generalised Nuclear Database Structure (GNDS). The first official public documentation of all of the options for storing data in GNDS was released by the Working Party on International Nuclear Data Evaluation...
The Full Law Analysis Scattering System Hub (FLASSH) is an advanced code which evaluates the thermal scattering law (i.e. TSL, S($\alpha$,$\beta$)) for thermal scattering cross sections and resonance Doppler broadening. These features in the cross section are both fundamentally driven by target atom vibrations, which are impacted by the nature of the chemical binding and temperature of the...
The evaluation state-of-the-art according to the $^{239}$Pu(n,2n) angular-integrated reaction cross section is well synthesized by Fig.1, enclosed, on which are drawn from one side, experimental data and on the other side, some major evaluated curves. Recent evaluations, by contrast to the old JEF-2.2 data file, remain consistent except near threshold and at energies above the maximum of the...
The NJOY nuclear data processing system is widely used for pointwise and multigroup neutronic and photonic cross sections production from Evaluated Nuclear Data Files (ENDF). Current restriction to neutral particles-induced evaluations limits the scope of the system's mission to applications related to fission and fusion reactor design, licensing and safety analysis, stockpile stewardship...
Radiative neutron-capture cross sections are of pivotal importance in many fields such as nucleosynthesis studies or innovative reactor technologies. A large number of isotopes have been measured with high accuracy, but there are still a large number of relevant isotopes whose cross sections could not be experimentally determined yet, at least with sufficient accuracy and completeness, owing...
Reliable and precise nuclear decay data are essential in many applications. In radionuclide metrology, decay data are input parameters in calculations related to radioactivity measurements, when absolute or relative standardisation methods are used. This is why the metrology community, especially in Europe, has carefully evaluated decay schemes and atomic and nuclear data for the last 50...
Neutron-induced cross sections on fissile nuclei such as $^{239}$Pu are important for defense and energy applications, as well as for basic science. The quality of these values rely on two basic pillars: a) the availability of high-quality, curated experimental data. Within this context, it is essential to constantly update the existing database with the new experiments carried out in...
An efficient neutron detection system with good energy resolution is required to correctly characterize decays of neutron-rich nuclei where beta-delayed neutron emission is a dominant decay mode. Precision neutron spectroscopy instrumentation is essential to probe nuclear structure effects in neutron-rich nuclei in new generation radioactive beam facilities. A new high-resolution neutron...
This paper describes methods for processing and use of thermal neutron scattering data in OpenMC. OpenMC relies on NJOY to process thermal scattering ENDF evaluations into ACE files, which are then converted to HDF5 files by OpenMC's Python API. This process is fully automated with OpenMC producing an NJOY input deck containing appropriate options for each module and covering every temperature...
Few data exist regarding the yields and the six group time spectra of delayed neutrons from the photofission reaction on actinides. In 1966, Nikotin et al. published data for the photofission of 232Th, 235U, 238U and 239Pu induced by Bremsstrahlung photons with an endpoint energy at 15 MeV. In 1970, Kull et al. presented data for the...
Accurately describing the scattering behavior of thermal neutrons can guarantee the accuracy of neutronics calculation. The thermal neutron scattering law (TSL) data is used to describe the scattering property of a materials. In this work, some efforts have been made to improve the accuracy of TSL data. The anisotropic displacement parameters method is used to remove the cubic approximation in...
A dedicated model for low-energy (<150 MeV/n) deuteron nuclear reactions has been a long-standing shortcoming of FLUKA [1-3], a general-purpose code for the Monte Carlo simulation of radiation transport. In view of the recently increasing interest in deuteron transport (e.g. for radioisotope production in medical applications [4-5] and for nuclear fusion studies [6]), a model for...
In high-intensity proton accelerator facilities such as Accelerator Driven System (ADS) and the spallation neutron source, it is crucial to evaluate the damage of beam-interception materials and accelerator components, such as a magnet coil. The displacement per atom (dpa) is used as a damage index, which is derived by integrating the particle flux and the displacement cross section based on...
All cross sections, angular distributions, energy spectra, and double-differential cross sections for n + 58,60,61,62,64, nat.Ni reactions are consistently calculated and analyzed in the incident neutron energies from 0.001 to 200 MeV by using nuclear theoretical models, including the optical model, the unified Hauser-Feshbach theory and the exciton model, the improved Iwamoto-Harada model,...
Nuclear data in the different libraries (ENDF/B, JEFF, JENDL, CENDL) for the description of the outgoing particles are very often expressed as averaged distributions. This is the case, for example, of the (n,2n) reaction, for which we find only one energy distribution with a multiplicity equal to 2. The situation is quite similar for neutron capture (n,g) with an average photon number and an...
The neutron total cross section data of 9Be plays an important role in nuclear structure model of light nuclei and nuclear power installations. A measurement of the neutron total cross section of 9Be in the 1eV-30MeV energy region has been carried out using time-of-flight method and transmission method by the neutron total cross-sectional spectrometer (NTOX) based on the multi-layer fast...
Due to the introduction of several novel applications of He implantation, e.g. in materials of future fusion reactors [1 and in optical waveguides [2, 3], the need for elemental analysis of helium has recently increased dramatically. Depth profiling of helium can be realized by several ion beam analysis methods. Proton elastic backscattering spectrometry (p-EBS) is a basic method for such...
Modern theoretical studies and industrial applications related to the design, radiation protection, and reliability of nuclear facilities, medical applications, as well as space research and exploration are relying on extensive simulations and modeling. Computer codes realizing various semi-classical and quantum molecular dynamics (QMD) approaches are often employed to make up for the lack of...
Nuclear data for alpha particle induced reactions on 58,60,61,62,64,nat.Ni plays an important role in the application of nuclear techniques like charged particle activation analysis, medical isotope production, estimation of neutron yield and residual activity of accelerator components or simulation of radiation damage. All cross sections of α-induced reactions, angular distributions, energy...
The reduction of the uncertainties of neutron capture and fission cross sections of major and minor actinides is important for the improvement of the design of nuclear reactors and the optimization of nuclear waste management strategies, especially in life extension and higher burnup scenarios. In particular, neutron capture on $^{240}$Pu is the responsible for the formation of $^{241}$Am, via...
Nuclear data libraries are an essential part of ensuring the safety, reliability, and effectiveness of nuclear reactors, nuclear medicine, and the Nation’s nuclear weapons stockpile, as well as being an essential resource for scientists studying nuclear astrophysics, nuclear structure, archeology, and many other subjects. These nuclear data libraries, which have been constructed from...
The recent advancements in the field of nuclear medicine can be fairly attributed to the efficient methods for the production of the promising radionuclides in sufficient amounts with high purity. This work covers the theoretical aspects related to production of two potentially useful radionuclides; 110mIn (T½ = 69.1 min) and 193mPt (T½ = 4.33 d). Analysis of the excitation functions is...
The charge independence of nuclear forces implies that in describing nuclear structure we do not have to distinguish between neutrons and protons. This symmetry is broken by electromagnetic interaction leading to a vast field of investigation aimed at clarifying the coupling between strong and electromagnetic forces. That is why, after so many decades since the first formulation of the nuclear...
Preliminary assessment of the dose due to potential atmospheric release from MINERVA Proton Target Facility (PTF) being designed at SCK CEN has identified isotopes of Iodine (notably 125I, 126I and 131I) as major contributors [1]. Iodine is a volatile element and its retention in the structures is limited. Therefore, its production in the PTF actinide ISOL (Isotope Separation On-Line) targets...
In this paper, we present the interesting details of our attempts to create a basic evaluated nuclear data file for $^{232}$Th(n, 2n)$^{231}$Th reaction cross section, in the Indian context [1]. The work presented in this paper on nuclear data evaluation process includes performing our own Indian measurements of this
nuclear reaction data with detailed covariance analysis and including them in...
EXFOR (EXchange FORmat) and NSR (Nuclear Science References) databases contain experimental nuclear reaction and comprehensive bibliography information since the beginning of nuclear science developed within the framework of the NRDC (Nuclear Reaction Data Centers) network and under the auspices of the USNDP (US Nuclear Data Program). The both databases include compilations of original...
The Nuclear Physics Institute of the Czech Academy of Sciences operates several fast neutron generators. The generators are based on the reaction of accelerated protons (U120M cyclotron, energy of protons up to 35 MeV) with the lithium and beryllium targets. The produced quasi-monoenergetic and continuous neutron spectra with energies up to 33 MeV have been well characterized.
The neutron...
The global semi-macroscopic alpha-nucleus optical potential developed in 2002 [1] has been widely used in calculations of alpha-nucleus reactions, especially since it was implemented in the nuclear reaction code TALYS.
The result of the widespread use of the global semi-microscopic alpha optical potential in calculations of reaction cross sections of medium- and heavy mass nuclei that have...
For solid moderators, the incoherent approximation has been widely used to calculate thermal neutron scattering laws at different temperatures. The only input needed in the incoherent approximation is the phonon density of states. Traditionally, the phonon densities of states are calculated by fitting the interatomic force constants to experimental data, such as low-temperature inelastic...
Accurate simulations of the radionuclide inventories and measurable quantities such as activity, dose rates and decay heat are made possible by means of carefully evaluated decay data (DD). In an automated compilation of a DD library of more than 3800 nuclides, the DD files could notably suffer from: misreading of data from the sources, omitting of the emitted particle spectra during the...
In the Universe, the observed elements heavier than iron (Fe) are mostly produced by neutron-capture processes in the stars. These processes are defined as s (slow) and r (rapid) processes. The experimental measurement of the neutron capture cross sections is an actively working task, since it is an essential element in the stellar reaction rates calculations and thus, the possibility of...
More accurate neutron capture cross-section data for $^{239}$Pu are required for the design of new critical nuclear systems such as Gen IV reactors and Accelerator Driven Systems (ADS) and for the operation of thermal reactors, especially when loaded with MOX fuels. Therefore, the capture cross-section of $^{239}$Pu is included in the NEA/OCDE High Priority Request List [1].
At present...
Optical model is one of the most fundamental theoretical models in nuclear reaction theory. It is applied widely in various nuclear reaction calculations. The microscopic optical potential (MOP) is generated theoretically based on the nucleon-nucleon interaction, which has no free parameters and does not depend on experimental data. The MOPs for nucleon, 2,3H, 3,4,6He and 6,7Li are obtained in...
Reliable uncertainty estimation of both the unfolded experimental data and of the theoretical model is utmost to obtain adequate Chi-square estimation when fitting model parameters to the experimental gamma-ray spectra. To do that, preparation steps of experimental spectra had already been presented in Ref. [1] with complete uncertainty estimation. The obtained unfolded spectrum can then be...
The DEMO Oriented Neutron Source DONES is a neutron irradiation facility for experimental tests of DEMO reactor structural materials. It is intended to irradiate the materials at typically 5 - 20 dpa/fpy to damage dose levels of around 50 dpa over 3 years. The neutron fluence on the samples in the specimen
capsules in the High-Flux Test Module (HFTM) is a fundamental parameter for...
The FOOT (FragmentatiOn Of Target) collaboration aims at improving the accuracy of treatment planning in hadron therapy by studying the behavior of the used particle beams. Typical beams of protons or carbon ions can interact with the nuclei constituting the human body, thus leading to nuclear fragmentation with significative neutron productions. While nuclear fragments are an important source...
Neutron is one of the most produced secondary particle by medical and industrial accelerators, but it remains difficult to detect due to its neutral charge. Neutrons also require a particular attention in radiation protection due to their long range and their high relative biological effectiveness (RBE) [1]. For instance, in hadron therapy, ion beams can generate multiple neutrons both in the...
Graphite has been of significant scientific interest since the inauguration of nuclear technology, through the search for a high-purity grade to be used as a neutron moderator in Chicago-Pile 1, the first nuclear reactor. Currently, the Very High-Temperature Gas-Cooled Reactor is graphite-moderated and uses graphite as a significant structural component. Furthermore, nuclear graphite is a...
The Detector for Advanced Neutron Capture Experiments (DANCE) is a
4-$\pi$ BaF$_{2}$ array located at the Los Alamos Neutron Science
Center (LANSCE) dedicated to performing neutron capture experiments for
a wide range of applications from nuclear astrophysics to nuclear energy
to national security. The unique combination of high neutron flux, high efficiency, high segmentation, and moderate...
The recently developed multiband dispersive optical model with soft rotator nuclear model couplings is used to build a regional potential for fissile actinides. The model allows coupled-channel calculations for odd-A targets considering rotational bands built on vibrational states. Those complex vibrational states are characterized by a coupling of single-particle excitations with the...
An important part of medical applications of ionizing radiation are included in nuclear medicine. This is based on the use of radioisotopes as radiation sources and allows the both medical diagnostic and treatment of the main diseases with the greatest social impact, such as cancer, cardiovascular problem and brain diseases [1]. The two main challenges to improve and develop new therapies...
The analysis of level densities and photon strengths has been bedeviled by misconceptions and physics errors that have persisted for over 50 years. In this talk I will discuss deficiencies in the Constant Temperature (CT) level density model as described by Gilbert and Cameron. This model describes the “total” level density using a nonphysical back shift parameter. I will show that every...
Over the past decade, forbidden non-unique beta transitions have been identified to be of critical importance in several fundamental physics topics, such as the modelling of antineutrino flux from nuclear reactors or from the Earth, and the background modelling in dark matter experiments. The decay half-lives of long-lived beta-emitting radionuclides, which exhibit a high degree of...
A characterisation of spent nuclear fuel (SNF) is essential for a safe, secure, ecologic and economic handling, transport, interim storage and final disposal of SNF assemblies. Several quantities are of importance: neutron and γ-ray emission rates and spectra, decay heat and the inventory of fissile nuclides. These sources can only be obtained by theoretical calculations. Evidently, the...
Neutron capture cross-sections are an essential ingredient for many research fields, particularly for nuclear reactor technologies and astrophysical studies. Therefore, a big effort is being made worldwide with the aim of improving neutron-beam facilities, detection systems and sample production techniques with the goal of getting new or more accurate nuclear data.
However, ineluctable...
