bluuebunny/crossref_metadata_2025 huggingface dataset:
3D modeling system of seismoacoustic monitoring results at the Nikolaevskoye field
Authors: Lomov Mikhail
Published: September 2020

The complexity of solving the problem of preventing natural and man-made disasters during intensive nature management is associated with the multifactorial nature of the conditions and causes of catastrophic events, significant variations in the properties and state of geospheres, and the lack of reliable criteria and precursors of dangerous dynamic phenomena.

The modern scientific approach to solving this problem consists in modeling processes that allow to adequately describe the state of changing natural and technical systems with subsequent verification of the results of theoretical research by instrumental methods. An even greater effect is brought by the combined use of natural and theoretical methods, united by a common ideology and maximally adapted to the conditions of the problem being solved, providing continuous multivariate monitoring of geophysical fields and processes in the geospheres.

In this regard, it seems very urgent to set up research work aimed at the development of scientific and methodological foundations and technical means for assessing and monitoring hazardous geomechanical processes to reduce the risk of man-made disasters during the development of mineral deposits.
Prognosys of dangerous geodynamic phenomena at the Kun-Manye field based on the analysis of digital elevation models
Authors: Usikov Vitaly
Published: September 2020

The Kuhn-Magnyo copper-nickel deposit is located in the southeast of the Aldan-Stanovoy shield. Based on the results of geological exploration, the object is assessed as promising. The ore field, within which the deposit is located, is confined to a complex junction of several regional tectonic structures. The area has an intensely dissected relief, increased seismicity. Therefore, an assessment of the possibility of dangerous geodynamic phenomena during its operation is required. This work describes its preliminary assessment based on the results of morphometry on digital elevation models (DEM). Several morphostructural elements have been identified that directly determine the geodynamics in the area of the earth’s crust containing the deposit. The result of the study revealed a potential hazard.
Neutron capture and total cross-section measurements of 155Gd and 157Gd at ANNRI in J-PARC
Authors: Kimura Atsushi , Nakamura Shoji , Iwamoto Osamu , Iwamoto Nobuyuki , Harada Hideo , Katabuchi Tatsuya , Terada Kazushi , Hori Jun-ichi , Shibahara Yuji , Fujii Toshiyuki
Published: September 2020

Neutron capture and total cross sections of 155Gd and 157Gd were measured with the neutron time-of-flight method in Accurate Neutron-Nucleus Reaction measurement Instrument at Material and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex using the NaI (Tl) spectrometer and Li-glass detectors. Preliminary cross sections were obtained in the neutron energy region from 4 meV to 100 meV. The derived cross sections agree with evaluated values in JENDL 4.0 and the experimental results by Mastromarco but were not consistent with those by Leinweber.
Measurement of the angular distribution of neutrons scattered from deuterium below 3 MeV
Authors: Pirovano Elisa , Nolte Ralf , Nyman Markus , Plompen Arjan
Published: September 2020

The differential cross section of neutron scattering on deuterium was investigated in the energy range from 400 keV to 2.5 MeV using the recoil detection method, irradiating with monoenergetic neutrons a proportional counter filled with deuterated gases. Comparing simulations of the transport of neutrons and recoil nuclei in the detector to the experimental pulse-height distribution, it was possible to establish a procedure for the determination of the coefficients of the Legendre expansion of the n-d angular distribution.
Measurements of cross sections for high energy neutron induced reactions on Co and Bi
Authors: Ndlovu Ntombizikhona , Maleka Peane , Bielewicz Marcin , Buffler Andy , Smit Frederick , Geduld Dieter , Mhlongo Sizwe , Lamula Thobeka , Dyosi Siyabulela , Nchodu Rudolph , Wiedeking Mathis , Ntshangase Sifiso , Strugalska-Gola Elzbieta , Herbert Mark , Masondo Vusumuzi
Published: September 2020

There are few experimental data for neutron cross-section libraries in (n,xn) reactions for various materials at energies above 20 MeV. For neutron energies above 20 MeV, these set of (n,xn) reactions are important for neutron fluence monitoring and spectra unfolding for future generation IV nuclear reactors. There were attempts to measure the cross-sections on natural cobalt and bismuth at incident neutron energies of about 90 MeV and 140 MeV. These measurements were made using the quasi-monoenergetic neutron facility at iThemba LABS, South Africa. In addition, at The Svedberg Laboratory facility in Sweden, similar experiments were performed on natural Yttrium. The measured cross-sections were compared with some of the few available data for neutron-induced reactions at high energies. Data collected from these two facilities, required corrections to be made for the contribution of the low energy tail (continuum) in the incident neutron spectrum. Preliminary results from iThemba LABS showed large discrepancy which we suspect was due to instability of the proton beam during the irradiations. Follow-up experiments are planned to accurately determine the uncertainty contributions, with additional data at other neutron energies.
Simulations of the measurement results of differential cross sections of n-p and n-d elastic scattering at CSNS Back-n WNS
Authors: Cui Zengqi , Bai Huaiyong , Jiang Haoyu , Hu Yiwei , Zhang Guohui , Fan Ruirui , Jiang Wei , Yi Han , Tang Jingyu , An Qi , Bao Jie , Bao Yu , Cao Ping , Chen Haolei , Chen Qiping , Chen Yonghao , Chen Yukai , Chen Zhen , Feng Changqing , Gao Keqing , Gu Minhao , Han Changcai , Han Zijie , He Guozhu , He Yongcheng , Hong Yang , Huang Hanxiong , Huang Weiling , Huang Xiru , Ji Xiaolu , Ji Xuyang , Jiang Zhijie , Jing Hantao , Kang Ling , Kang Mingtao , Li O , Li Chao , Li Jiawen , Li Lun , Li Qiang , Li Xiao , Li Yang , Liu Rong , Liu Shubin , Liu Xingyan , Luan Guangyuan , Mu Qili , Ning Changjun , Qi Binbin , Ren Jie , Ren Zhizhou , Ruan XiChao , Song Zhaohui , Song Yingpeng , Sun Hong , Sun Kang , Sun Xiaoyang , Sun Zhijia , Tan Zhixin , Tang Hongqing , Tang Xinyi , Tian Binbin , Wang Lijiao , Wang Pengcheng , Wang Qi , Wang Taofeng , Wang Zhaohui , Wen Jie , Wen Zhongwei , Wu Qingbiao , Wu Xiaoguang , Wu Xuan , Xie Likun , Yang Yiwei , Yu Li , Yu Tao , Yu Yongji , Zhang Linhao , Zhang Qiwei , Zhang Xianpeng , Zhang Yuliang , Zhang Zhiyong , Zhao Yubin , Zhou Luping , Zhou Zuying , Zhu Danyang , Zhu Kejun , Zhu Peng
Published: September 2020

Differential cross-section data for the n-p and n-d elastic scattering (1H(n, el), 2H(n, el)) are collected and analyzed from EXFOR library. For En > 20 MeV, the experimental results for both reactions are scarce with large uncertainties and discrepancies in general. For En ≤ 20 MeV, the experimental results lack systematicness, most of which were measured around En = 14 MeV even though the differential cross sections of n-p scattering in 1 keV ≤ En ≤ 20 MeV region are recommended as standard. Taking these facts into account, more accurate and systematic measurements are planned. The experiments will be conducted using ΔE-E detectors of the Light-charged Particle Detector Array (LPDA) system at China Spallation Neutron Source (CSNS) Back-n White Neutron Source (WNS), and simulations are carried out. Using polyethylene and deuterated polyethylene as samples, both n-p and n-d scattering reactions are simulated along with the neutron-induced 12C background reactions, and the 2-D spectra and the counting rates of the ΔE-E detectors are obtained. According to the simulations, the applicable neutron energy range and positions of the detectors are recommended, and the beam time for the event and background measurements is suggested.
Determining spontaneous fission properties by direct mass measurements with the FRS Ion Catcher
Authors: Mardor Israel , Dickel Timo , Amanbayev Daler , Ayet San Andrés Samuel , Beck Sönke , Benyamin David , Bergmann Julian , Constantin Paul , Cléroux Cuillerier Alexandre , Geissel Hans , Gröff Lizzy , Hornung Christine , Kripko-Koncz Gabriella , Mollaebrahimi Ali , Miskun Ivan , Plaß Wolfgang R. , Pomp Stephan , Rotaru Adrian , Scheidenberger Christoph , Stanic Goran , Will Christian
Published: September 2020

We present a direct method to measure fission product yield distributions (FPY) and isomeric yield ratios (IYR) for spontaneous fission (SF) fragments. These physical properties are of utmost importance to the understanding of basic nuclear physics, the astrophysical rapid neutron capture process ('r process') of nucleosynthesis, neutron star composition, and nuclear reactor safety. With this method, fission fragments are produced by spontaneous fission from a source that is mounted in a cryogenic stopping cell (CSC), thermalized and stopped within it, and then extracted and transported to a multiple-reflection time-of-flight mass-spectrometer (MR-TOF-MS). We will implement the method at the FRS Ion Catcher (FRS-IC) at GSI (Germany), whose MR-TOF-MS relative mass accuracy (~ 10-7) and resolving power (~ 600,000 FWHM) are sufficient to separate all isobars and numerous isomers in the fission fragment realm. The system's essential element independence and its fast simultaneous mass measurement provide a new direct way to measure isotopic FPY distributions, which is complementary to existing methods. It will enable nuclide FPY measurements in the high fission peak, which is hardly accessible by current techniques. The extraction time of the CSC, tens of milliseconds, enables a direct measurement of independent fission yields, and a first study of the temporal dependence of FPY distributions in this duration range. The ability to resolve isomers will further enable direct extraction of numerous IYRs while performing the FPY measurements. The method has been recently demonstrated at the FRS-ICr for SF with a 37 kBq 252Cf fission source, where about 70 different fission fragments have been identified and counted. In the near future, it will be used for systematic studies of SF with a higher-activity 252Cf source and a 248Cm source. The method can be implemented also for neutron induced fission at appropriate facilities.
Incorporating a two-step mechanism into calculations of (p,t) reactions used to populate compound nucleus spin-parity distributions in support of surrogate measurements
Authors: Benstead James
Published: September 2020

The surrogate reaction method may be used to determine the cross section for neutron-induced reactions not accessible through standard experimental techniques by creating the same compound nucleus which the desired reaction would pass through, but via a different entrance channel. A variety of direct reactions have been employed in order to generate the required compound nuclei for surrogate studies.

In this work, a previously developed (p,t) reaction model has been extended to incorporate a two-step reaction mechanism, which takes the form of sequential neutron transfer. This updated model is applied to the 92Zr(p,t)90Zr reaction and is found to modify the strengths of the previously predicted populated levels. It is planned that this improved (p,t) model will be used to attempt to constrain cross section predictions for a number of (n,γ) reactions in future, as well as provide a possible comparison against other surrogate studies utilising different direct reactions such as (p,d).
Monte Carlo simulation of γ and fission transfer reactions using extended ℛ-matrix theory
Authors: Bouland Olivier
Published: September 2020

This paper comes back on the accuracy of the surrogate-reaction method (SRM) historically used for neutron-induced average partial cross sections inference from measured surrogate-reaction probabilities. The SRM level of performance is examined in relation to a reasonably accurate reference calculation performed with the 𝒜𝒱𝒳𝒮ℱ-ℒ𝒩𝒢 code [1] through a challenging test case : the 240Pu* compound system. This paper argues on some ingredients of the reference calculation [2] and returns some hints about the failure now well-known of the neutron-induced γ average cross section inference. It shows also that in some special cases, the SRM can be poorly accurate also in terms of neutron-induced fission average cross section inference.
Angular distributions and anisotropy of fission fragments from neutron-induced fission of239Pu,237Np, andnatPb in energy range 1–200 MeV
Authors: Vorobyev A.S. , Gagarski A.M. , Shcherbakov O.A. , Vaishnene L.A. , Kuz’mina T.E. , Barabanov A.L.
Published: September 2020

This work summarizes some results of a series of experiments aimed at the investigation of energy dependence of anisotropy of fission fragments (FFs) in (n,f) reactions for neutron energies from low to intermediate. Angular distributions of FFs from the neutron-induced fission of239Pu,237Np, andnatPb have been measured in the energy range 1–200 MeV at the neutron TOF spectrometer GNEIS based on the spallation neutron source at 1 GeV proton synchrocyclotron of the Petersburg Nuclear Physics Institute (Gatchina, Russia). The anisotropies of FFs deduced from the measured angular distributions are presented. In the neutron energy range above 20 MeV the results have been obtained for the first time in our works. The experimental data for FF anisotropy in237Np(n,f) are compared with calculations based on "adapted" TALYS software.
Neutron Multiplicity Correlations with Fission Fragment Mass and Energy from 239Pu(n,f)
Authors: Göök Alf , Hambsch Franz-Josef , Oberstedt Stephan
Published: September 2020

There exists experimental evidence for strong fluctuations of the average neutron multiplicity from resonance to resonance in 239Pu(n,f). These fluctuations have been shown to impact nuclear reactor benchmarks by reducing the criticality. The fluctuating neutron multiplicity can be explained as a consequence of the competition between direct fission and the (n,γf) process. However, there is also evidence for fluctuations of the fission fragment mass yields from resonance to resonance. The mass yield fluctuations may also contribute to fluctuations of the neutron multiplicity averaged over all fission fragment masses. In order to model the contribution to the neutron multiplicity fluctuations by the fission fragment mass yield fluctuations new data on the correlations between fission fragment properties and neutron multiplicities are in need. We present experiments carried out to determine prompt neutron multiplicity correlations with fission fragment masses and total kinetic energies in the reaction 239Pu(n,f). The experiment has been performed at the GELINA facility at JRC-Geel. A twin position-sensitive Frisch-grid ionization chamber is used for fission fragment identification via the double kinetic energy technique. An array of scintillation detectors is employed for neutron counting. Correlations between average neutron multiplicities and fission fragment properties have been measured with improved resolution in both mass and TKE, compared to data from the literature.
A comprehensive study of spallation models for proton-induced spallation product yields utilized in transport calculation
Authors: Iwamoto Hiroki , Meigo Shin-ichiro , Matsuda Hiroki
Published: September 2020

In order to understand the current status of the predictive performance of spallation models and issues towards further improvement, a comprehensive study of the proton-induced spallation product yields was conducted. In this study, four kinds of the latest spallation models (i.e. INCL++/ABLA07, INCL++/GEMINI++, INCL4.6/GEM, and CEM03.03), utilized in Monte Carlo particle transport calculation, are employed, and six pieces of cross section data measured at GSI, RIKEN, and J-PARC are used for comparison. As a result, the INCL++/ABLA07 calculations are in general agreement with the GSI and RIKEN experimental data, whereas some discrepancies are observed especially in the comparisons with the J-PARC experiments. Finally, several key issues inherent in each spallation model are described.
The cosmic ray detector for the NICA collider
Authors: Bielewicz Martin , Grodzicka-Kobylka Martyna , Maksiak Bartosz , Mianowski Slawomir , Pszczel Damian , Sibczynski Pawel , Stepaniak Joanna , Swiderski Lukasz , Szczesniak Tomasz , Linczuk Maciej , Wielanek Daniel , Kisiel Adam , Kasprowicz Grzegorz , Pozniak Krzysztof , Zabolotny Wojciech , Romaniuk Ryszard , Chlopik Arkadiusz , Bancer Aleksandr , Grodzicki Krystian , Dudzinski Adam , Jaworska Elzbieta , Strugalska-Gola Elzbieta , Szuta Marcin , Peryt Marek J. , Roslon Krystian , Rybczynski Maciej , Wlodarczyk Zbigniew , Stefanek Grzegorz , Kankiewicz Pawel , Synfeld-Kazuch Agnieszka , Milewicz Michalina-Zalewska
Published: September 2020

Multi-Purpose Detector (MPD) is a main part of a new Ion Collider fAcility (NICA) located in Dubna, Russia. To increase MPD functionality, it was proposed to add an additional muon trigger system for off-beam calibration of the MPD sub-detectors and for rejection of cosmic ray background during experiments. The system could also be very useful for astrophysical observations of cosmic showers initiated by high energy primary particles. This article describes the main goals of MCORD detector and the early stage of MCORD design, based on plastic scintillators with silicon photomultiplier photodetectors (SiPM) for scintillation readout and electronic system based on MicroTCA standard.
Current status of the verification and processing system GALILÉE-1 for evaluated data
Authors: Coste-Delclaux Mireille , Jouanne Cédric , Mounier Claude
Published: September 2020

This paper describes the current status of GALILÉE-1 that is the new verification and processing system for evaluated data, developed at CEA. It consists of various components respectively dedicated to read/write the evaluated data whatever the format is, to diagnose inconsistencies in the evaluated data and to provide continuous-energy and multigroup data as well as probability tables for transport and depletion codes. All these components are written in C++ language and share the same objects. Cross-comparisons with other processing systems (NJOY, CALENDF or PREPRO) are systematically carried out at each step in order to fully master possible discrepancies. Some results of such comparisons are provided.
Resonance evaluation of Gadolinium isotopes
Authors: Leal Luiz , Sobes Vladimir , Rocchi Federico , Roubtsov Danila , Chow Jimmy , Massimi Cristian
Published: September 2020

The objective of this paper is to present the results of an evaluation of the gadolinium isotopes with the main focus on the isotopes155Gd and157Gd. The evaluations were carried out in the resolved resonance region using the Reich-Moore formalism. The originality on the155Gd and157Gd evaluations is the addition of new high-resolution capture cross section measurements performed at the neutron time-of-flight, n_TOF facility for enriched samples and the statistical analysis of the resonance parameters. The resonance analysis was performed with the multilevel R-matrix code SAMMY together with the generalized least-squares technique based on the Bayes’ theory.
Uncertainties of calculated coincidence-summing correction factors in gamma-ray spectrometry
Authors: Semkova V. , Otuka N. , Plompen A.J.M.
Published: September 2020

Uncertainty propagation to the γ-γ coincidence-summing correction factor from the covariances of the nuclear data and detection efficiencies have been formulated. The method was applied in the uncertainty analysis of the coincidence-summing correction factors in the γ-ray spectrometry of the 134Cs point source using a p-type coaxial HPGe detector.
Analysis of the time-of-flight neutron scattering cross-section data for light water measured at the SEQUOIA spectrometer, Spallation Neutron Source (SNS)
Authors: Jaiswal Vaibhav , Leal Luiz , Kolesnikov Alexander I.
Published: September 2020

Thermal neutron scattering cross-section data for light water available in the major nuclear data libraries observes significant differences especially at reactor operating temperatures. During the past few years there has been a renewed interest in reviewing the existing thermal scattering models and generating more accurate and reliable thermal scattering cross sections using existing experimental data and in some cases based on Molecular Dynamics (MD) simulations. There is a need for performing new time-of-flight experiments at high temperatures and pressures, to have a better understanding of the physics involved in the scattering process that could help improve the existing TSL data.

Lack of experimental thermal scattering data for light water at high temperatures led to a new measurement campaign within the INSIDER project at the Institut de radioprotection et de sûreté nucléaire (IRSN). Double differential scattering cross section for light water have been measured at the SEQUOIA spectrometer based at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, United States. Several measurements have been carried out at different temperatures and pressures corresponding to liquid light water. Measurements at five different incident neutron energiesEi(8, 60, 160, 280 and 800 meV) have been carried out to help exploring different regions of the frequency spectrum. This paper presents the analysis of the dynamic structure factor and the derived frequency spectrum of light water. The analysis of the experimental data would provide one with better confidence, the behavior of thermal scattering cross sections for light water at high temperatures, knowledge of which is very important for the design of novel reactors as well as existing pressurized water reactors.
MicroMegas-based detectors for time-of-flight measurements of neutron-induced reactions
Authors: Gunsing F. , Belloni F. , Berthoumieux E. , Diakaki M. , Dupont E. , Ferrer-Ribas E.
Published: September 2020

MicroMegas detectors are versatile gaseous detectors which are used for ionizing particle detection. A MicroMegas detector consists of two adjacent gas-filled volumes. One volume acts as a drift region with an electric field operating in the ionization chamber regime, the second volume is the amplification region acting as a parallel-plate avalanche counter. The use of the microbulk technique allows the production of thin, radiation resistant, and low-mass detector with a highly variable gain. Such MicroMegas detectors have been developed and used in combination with neutron time-of-flight measurements for in-beam neutron-flux monitoring, fission and light-charged particle reaction cross section measurements, and for neutron-beam imaging. An overview of MicroMegas detectors for neutron detection and neutron reaction cross section measurements and related results and developments will be presented.
First steps toward the development of SONATE, a Compact Accelerator driven Neutron Source
Authors: Thulliez Loïc , Letourneau Alain , Schwindling Jérôme , Chauvin Nicolas , Sellami Nadia , Ott Frédéric , Menelle Alain , Annighöfer Burkhard
Published: September 2020

Facilities providing bright thermal neutron beams are of primary importance for various research topics such as condensed matter experiments, neutron-imaging or medical applications. Currently these are mainly spallation sources and nuclear reactors. However, these later facilities are ageing and the political context does not favor the building of new ones. This is the case in CEA-Saclay (France), where the Orphee reactor is planned to shutdown in 2019. Therefore, another local facility, affordable by one country, able to provide high brilliance neutron beams has to be built. At CEA-Saclay, a compact accelerator driven neutron source, SONATE, is investigated in taking advantage of the IPHI accelerator able to deliver a 3 MeV proton beam with an intensity up to 100 mA. In the future, SONATE is foreseen to operate with 20 MeV protons to increase the neutron brightness. In addition to the difficulties to operate such high intensity accelerators, the other challenges regard the target-moderator-reflector (TMR) design which is crucial to maximize the neutron flux at the detector location. At CEA-Saclay, several experiments were performed between 2016 and 2019 with the IPHI accelerator. Geant4 simulations were also developed. They demonstrate the feasibility of such concept and enable to find the best TMR configuration for the future SONATE facility. These developments are reported in this article.
Laser-driven neutrons for time-of-flight experiments?
Authors: Millán-Callado M.A. , Guerrero C. , Quesada J.M. , Gómez J. , Fernández B. , Lerendegui-Marco J. , Rodríguez-González T. , Domingo-Pardo C. , Tarifeño-Saldivia A. , Benlliure J. , Cortina D. , Martín L. , Peñas J. , Cano-Ott D. , Martínez T.
Published: September 2020

Neutron beams, both pulsed and continuous, are a powerful tool in a wide variety of research fields and applications. Nowadays, pulsed neutron beams are produced in conventional accelerator facilities in which the time-of-fight technique is used to determine the kinetic energy of the neutrons inducing the reactions of interest.

In the last decades, the development of ultra-short (femtosecond) and ultra-high power (> 1018W/cm2) lasers has opened the door to a vast number of new applications, including the production and acceleration of pulsed ion beams. These have been recently used to produce pulsed neutron beams, reaching fluxes per pulse similar and even higher than those of conventional neutron beams, hence becoming an alternative for the pulsed neutron beam users community. Nevertheless, these laser-driven neutrons have not been exploited in nuclear physics experiments so far.

Our main goal is to produce and characterize laser-driven neutrons but optimizing the analysis, diagnostic and detection techniques currently used in conventional neutron sources to implement them in this new environment. As a result, we would lay down the viability of carrying out nuclear physics experiments using this kind of sources by identifying the advantages and limitations of this production method.

To achieve this purpose, we plan to perform experiments in both medium (50TW@L2A2, in Santiago de Com-postela) and high (1PW@APOLLON, in Paris) power laser facilities.
The prototype dosimetry system to protect MPD electronic equipment at the new NICA collider
Authors: Bielewicz Marcin , Chlopik Arkadiusz , Bancer Aleksandr , Dudzinski Adam , Jaworska Elzbieta , Rzadkiewicz Jacek , Roslon Krystian , Dunin Nikita , Milewicz-Zalewska Michalina
Published: September 2020

The Multi-Purpose Detector (MPD) is a main detection system of the new collider located in Dubna, Russia (Nuclotron-based Ion Collider fAcility -NICA). During the work, the Slow Control electronic equipment which is located on the MPD surface and on the special platform near the MPD body, an accidental irradiation caused by the NICA’s failure or its abnormal functioning may occur. Thus, there is a risk of destroying the electronics by a radiation exposure in the platform area, and in the consequence the emergency/fast switch off of the MPD sub-detectors might become impossible. We present the preliminary dosimetry system i.e. the method of prevention of such situation by the continuous monitoring on the Slow Control electronics on the platform. System will be alarming when the radiation levels threshold will be surpassed.
Measurement of leakage neutron spectra with D-T neutrons and evaluated nuclear data
Authors: Han Rui , Chen Zhiqiang , Tian Guoyu , Nie Yangbo , Shi Fudong , Zhang Suyalatu , Zhang Xin , Liu Bingyan , Sun Hui
Published: September 2020

Benchmarking of evaluated neutron nuclear data libraries was performed for ∼14.8 MeV neutrons on the several targets, such as gallium, graphite, silicon carbide, uranium and tungsten samples. The experiments were performed at China Institute of Atomic Energy (CIAE). The neutron leakage spectra from the samples were measured at 60◦ and 120◦ by a TOF technique with a BC501A scintillation detector. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL3.1, JENDL-4.0 and the new release ENDF/B-VIII.0, JEFF-3.3 evaluated nuclear data libraries and so on. There have some difference between experiments and simulations for the elastic and inelastic contributions in the partial energy range. And the discrepancies of the neutron leakage spectra in the MCNP simulations originate simply from the differences in the spectra distributions of the neutron reaction channels in the evaluated nuclear data libraries.
Ratio of spectral averaged cross sections measured in standard 252Cf(sf) and 235U(nth,f) neutron fields
Authors: Schulc Martin , Kostal Michal , Capote Roberto , Novak Evzen , Burianova Nicola , Simon Jan
Published: September 2020

The results of systematic evaluations of spectrum averaged cross section (SACS) measurements in the fission neutron fields of 252Cf and 235U are presented. The data form a complete database of high-threshold experimental SACS measured in the same installation under the same conditions and using the same high purity germanium gamma spectrometer. This is crucial to reduce the uncertainty of the ratio and the data scattering and therefore, to minimize discrepancies compared to cross section measured under different conditions in different laboratories. This new dataset complements and extends earlier experimental evaluations. The total emission of the 252Cf neutron source during the experiments varied from 9.5E8 to 4.5E8 neutrons per second. The emission was derived in accordance to the data in the Certificate of Calibration involving absolute flux measurements in a manganese sulphate bath. Concerning 235U fission neutron field, the irradiations were carried out in a specifically designed core assembled in the zero power light water LR-0 reactor. This special core has a well described neutron field. After the irradiation, the low volume irradiated samples to be measured by gamma spectrometry were placed directly on the upper cap of a coaxial high purity germanium (HPGe) detector in a vertical configuration (ORTEC GEM35P4). High volume samples were homogenized and strewn into the Marinelli beaker. The HPGe detector is surrounded by the lead shielding box with a thin inner copper cladding and covered with rubber for suppression of background signal and bremsstrahlung. The experimental reaction rates were derived for irradiated samples from the Net Peak Areas (NPA) measured using the semiconductor HPGe detector. The measured reaction rates are used to derive the spectrum-averaged cross sections. Furthermore, measured reaction rates are also compared with MCNP6 calculations using various nuclear data libraries, in particular IRDFF evaluations.
Uncertainties on radiation source terms of MINERVA (MYRRHA Phase 1) beam dump
Authors: Stankovskiy Alexey , Bisogni Dario , Çelik Yurdunaz , Fiorito Luca , Van den Eynde Gert
Published: September 2020

In the framework of Phase I of the MYRRHA project implementation, the superconducting linear accelerator with proton beam parameters 100 MeV, 4 mA is going to be built. To stop the beam, a beam dump based on Al-6061 alloy is designed. The evaluation of radiological impact of an accidental radioactivity release requires the reliable estimates of primary radiation source terms with associated uncertainties. The article addresses the propagation of nuclear data uncertainties through beam dump activation calculations. The Total Monte Carlo approach was used to generate large number of random excitation functions for residual products of proton interactions with materials of Al-6061 alloy. The residual products do not impose any feedback on proton and neutron spectra in the beam dump, moreover the calculation of the production rates is sufficient to obtain uncertainties on final activities. This significantly accelerates the uncertainty quantification allowing to study the convergence of mean and higher moments (variance, variance of variance) for individual nuclides.
Comparison between measurement and calculations for a 14 MeV neutron water activation experiment
Authors: Andreoli F. , Angelone M. , Colangeli A. , Besi Vetrella U. , Fiore S. , Flammini D. , Del Prete P. , Loreti S. , Mariano G. , Mazzitelli G. , Moro F. , Pagano G. , Pietropaolo A. , Pillon M. , Terranova N. , Villari R. , Naish J. , Nobs C.R. , Packer L.W.
Published: September 2020

The nuclear heat loads due to gamma rays emitted from the decay of 16N and delayed neutrons from17N, generated by the activation of water in cooling circuits, are critical for ITER design. The assessment of nuclear heating from activated water is complex; it requires temporal and spatial dependent transport and activation calculations taking into account variation of irradiation, water flow conditions and cooling circuits’ parameters. A water activation experiment has been recently conducted at the14 MeV Frascati Neutron Generator (FNG) in order to validate the methodology for water activation assessment used for ITER and to reduce the safety factors applied to the calculation results, which have a large impact on the schedule, commissioning and licensing. Water circulating inside an ITER First Wall (FW) mock-up was irradiated with 14 MeV neutrons and then measured using a large CsI scintillator detector. The system consists of a closed water loop where the cooling water, transiting through an ITER FW mock-up, is irradiated by FNG. The induced 16N activity via 14 MeV neutrons interactions with 16O via the 16O(n,p)16N reaction is measured in a dedicated counting station via an expansion volume. The water then passes to a much larger holding delay tank, and after several 16N half-lives decay time, it is then recirculated and exposed again to neutrons in the ITER First Wall (FW) mock-up. The measured 16N activity is obtained measuring the emitted characteristic 6.13 and 7.12 MeV gamma-rays. Calculations were performed in an accurate model of the FW mock-up using the MCNP Monte Carlo code and FENDL-3.1 nuclear data library to obtain the predicted flux impinging on the water. The EASY-2007 inventory code was used to predict the 16N activity. In this work, a comparison between measurements and calculations is reported together with associated uncertainty analysis.
Nuclear data sensitivity analysis and uncertainty propagation in the KYADJ whole-core transport code
Authors: Wu Qu , Peng Xingjie , Shi Guanlin , Yu Yingrui , Li Qing , Wang Kan
Published: September 2020

Nuclear data sensitivity analysis and uncertainty propagation have been extensively applied to nuclear data adjustment and uncertainty quantification in the field of nuclear engineering. Sensitivity and Uncertainty (S&U) analysis is developed in the KYADJ whole-core transport code in order to meet the requirement of advanced reactor design. KYADJ aims to use two-dimension Method of Characteristic (MOC) and one-dimension discrete ordinate (SN) coupled method to solve the neutron transport equation and achieve one-step direct transport calculation of the reactor core. Developing sensitivity and uncertainty analysis module in KYADJ can minimize deviations caused by modeling approximation and enhance calculation efficiency. This work describes the application of the classic perturbation theory to the KYADJ transport solver. In order to obtain uncertainty, a technique is proposed for processing a covariance data file in 45-group energy grid instead of 44-group SCALE 6.1 covariance data which is extensively used in various codes. Numerical results for Uncertainty Analysis in Modelling (UAM) benchmarks and the SF96 benchmark are presented. The results agree well with the reference and the capability of S&U analysis in KYADJ is verified.
Benchmarking of FLUKA production cross sections of positron emission tomography isotopes for in-vivo range verification in hadron therapy
Authors: Aricò Giulia , Battistoni Giuseppe , Cerutti Francesco , Horst Felix , Mairani Andrea , Schuy Christoph , Weber Uli , Ferrari Alfredo
Published: September 2020

Protons and carbon ions have been extensively used for radiotherapy treatments, and in comparison to conventional radiotherapy, they allow a more conformal dose to the target tumor, especially in case of deep-seated tumors. However, the accuracy of hadron therapy treatments is affected by uncertainties in the particle range calculations. Several techniques are under development for in-vivo range verification, one of which consists on measuring the activity distributions of positron emitters, such as 10C, 11C and 15O, which are produced in the patient body during proton and carbon ion treatments. A comparison between measured and expected positron emitter activity distributions can provide information on the quality of the delivered treatment and accuracy of the particle range calculations. In this work the FLUKA production cross sections for 10C, 11C and 15O originated from proton and carbon ion beams in carbon and oxygen targets were compared with experimental data, at low and therapeutic energies.
Systematic review on infection and disease caused byThelazia callipaedain Europe: 2001–2020
Authors: do Vale Beatriz , Lopes Ana Patrícia , da Conceição Fontes Maria , Silvestre Mário , Cardoso Luís , Coelho Ana Cláudia
Published: September 2020

Cases of thelaziosis byThelazia callipaedahave been increasing considerably in Europe throughout the 21st century, with recent emphasis on Eastern Europe. A systematic review was conducted using defined search terms across three major databases and, additionally, with the examination of the references of the 56 articles selected. Available information about epidemiological and clinical features of all cases of thelaziosis byT.callipaedain companion animals, wildlife and humans was extracted, evaluated and subjected to qualitative and quantitative analysis. In all cross-sectional studies about dogs, cats and red foxes, males were more frequently infected than females (dogs:p = 0.0365; cats:p = 0.0164; red foxes:p = 0.0082). Adult dogs seem to be more prone to infection (p < 0.0001), as well as large-sized dogs (p < 0.0001), and companion animals that live exclusively outdoors (p < 0.0001). Dogs and red foxes involved in these cross-sectional studies harboured significantly more female than male nematodes (p < 0.0001). Thelaziosis byT.callipaedais far from controlled in Europe. Only through updated epidemiological data, knowledge improvement and awareness can correct diagnosis and appropriate treatment and prevention be ensured to tackle this zoonosis.
Gram-Scale Robust Synthesis of 1-Chloro-2,3-dimethyl-4-phenylnaphthalene: A Promising Scaffold with Three Contiguous Reaction Positions
Authors: Tanabe Yoo , Moriguchi Kento , Kono Taro , Seko Shinzo
Published: September 2020

A three-step reaction sequence for the gram-scale synthesis of 1-chloro-2,3-dimethyl-4-phenylnaphthalene was developed. (i) Stereoselective dichlorocarbene addition to methyl angelate afforded methyl (1S*,3S*)-2,2-dichloro-1,3-dimethylcyclopropane-1-carboxylate (78% yield, >98% purity, distillation). (ii) Addition reaction of two molar amounts of PhLi afforded (1S*,3S*)-2,2-dichloro-1,3-dimethylcyclopropyldiphenylmethanol (81% yield, >98% purity, recrystallization). (iii) Key SnCl4-mediated benzannulation produced the desired product (83% yield, >98% purity, recrystallization) with three contiguous reaction sites. Five derivatization examples including benzylic reactions and cross-couplings at the pendant Cl-position are demonstrated. Some relevant distinctive benzannulations are also discussed.
Quantifying Experiences with Telepractice for Aphasia Therapy: A Text Mining Analysis of Client Response Data
Authors: Jacobs Molly , Briley Patrick , Ellis Charles
Published: September 2020

Measures of satisfaction following treatment for aphasia have been limited. The challenge associated with reduced verbal output among many persons with aphasia (PWA) has reportedly been a key reason measures of treatment satisfaction have been limited. A novel approach to measure treatment satisfaction is the use of content analysis (CA), which uses the presence of certain words, themes, or concepts to explore outcomes such as treatment satisfaction particularly among individuals who generate limited output. CA utilizes responses and response patterns to assign meaning to client responses. The aim of this study was to use CA to measure posttreatment satisfaction with a telepractice approach for aphasia treatment. Seventeen PWA received 12 treatment sessions over a 6-week period. At the conclusion of the treatment, CA was utilized to explore patient satisfaction with this treatment approach. The participants reported an overall positive sentiment for the telepractice approach. Two primary topics emerged which were healthcare provider and healthcare delivery, where text analysis revealed discussion of these topics to be centered around being “helpful” and “being effective.” This study demonstrated that CA can be an effective approach for determining satisfaction with aphasia treatment particularly among PWA with limited verbal abilities.
Elastic, magnetoelastic, magnetopiezoelectric, and magnetodielectric characteristics of HoAl3(BO3)4
Authors: Bilych I. V. , Kolodyazhnaya M. P. , Zhekov K. R. , Zvyagina G. A. , Fil V. D. , Gudim I. A.
Published: September 2020

The main elastic moduli and piezoelectric modulus have been measured in holmium alumoborate single crystals. The renormalization of the permittivity, piezoresponse, and sound velocities, driven by the nematic-like paramagnetic phase in the sample, is considered. A significant variability of the results is detected, which is caused, presumably, by the fact that, under the action of external fields, the motion trajectory of the nematic-like phase’s director depends on random defects of thermoelastic origin. It is shown that above 5 K, the temperature dependences of the studied parameters are well-described using holmium ion’s known ground multiplet spectrum, formed by the interaction with the crystal field. Changes in the C44-mode velocity in the sub-Kelvin temperature range are measured.
Electrical and thermal conductivity of FeNi at low temperatures
Authors: Khadzhay G. Ya. , Vovk S. R. , Vovk R. V. , Gevorkyan E. S. , Zubenko N. S. , Kislitsa M. V. , Chishkala B. O. , Feher A. , Kollar P. , Fuzer J.
Published: September 2020

The electrical resistivity and thermal conductivity as functions of temperature, for an equiatomic Fe–Ni system are studied. The samples were obtained from nickel and iron powders by a 10 min electroconsolidation at a temperature of 1100 °C, pressure 35 MPa, and current ∼5 kA, and studied in the range of 4.2–300 K. It was found that the electrical and thermal conductivity of the electroconsolidated sample is significantly higher than that of samples with the same composition, obtained by melting. It was revealed that in the investigated range of 4.2–300 K, an electroconsolidated sample’s resistivity as a function of temperature is determined by electrons scattering by defects and phonons, and the scattering of electrons by phonons can be approximated with high accuracy by the Bloch–Grüneisen–Wilson formula.
Low-temperature mechanical properties and thermally activated plasticity parameters of the CrMnFeCoNi2Cu high entropy alloy
Authors: Tabachnikova E. D. , Shapovalov Yu. O. , Smirnov S. N. , Gorban’ V. F. , Krapivka N. A. , Firstov S. A.
Published: September 2020

The mechanical properties of a high-entropy CrMnFeCoNi2Cu alloy with an FCC lattice have been studied in a broad temperature range (4.2–350 K). The microhardness and Young’s modulus were measured at 300 K for two structural states. The temperature dependences of the yield strength, deforming stress, and strain rate sensitivity have been obtained. It was found that a high-strength state is realized in the alloy while maintaining high plasticity, over the entire temperature range. Empirical estimates of microscopic plasticity parameters and internal and effective stresses have been obtained using the thermally activated deformation model.
Physical vapor deposition of a polyamorphic system: Triphenyl phosphite
Authors: Beasley M. S. , Kasting B. J. , Tracy M. E. , Guiseppi-Elie A. , Richert R. , Ediger M. D.
Published: September 2020

In situ AC nanocalorimetry and dielectric spectroscopy were used to analyze films of vapor-deposited triphenyl phosphite. The goal of this work was to investigate the properties of vapor-deposited glasses of this known polyamorphic system and to determine which liquid is formed when the glass is heated. We find that triphenyl phosphite forms a kinetically stable glass when prepared at substrate temperatures of 0.75–0.95Tg, where Tg is the glass transition temperature. Regardless of the substrate temperature utilized during deposition of triphenyl phosphite, heating a vapor-deposited glass always forms the ordinary supercooled liquid (liquid 1). The identity of liquid 1 was confirmed by both the calorimetric signal and the shape and position of the dielectric spectra. For the purposes of comparison, the glacial phase of triphenyl phosphite (liquid 2) was prepared by the conventional method of annealing liquid 1. We speculate that these new results and previous work on vapor deposition of other polyamorphic systems can be explained by the free surface structure being similar to one polyamorph even in a temperature regime where the other polyamorph is more thermodynamically stable in the bulk.
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W emitted terahertz power from photoconductive antennas based on rhodium doped InGaAs
Authors: Kohlhaas R. B. , Breuer S. , Liebermeister L. , Nellen S. , Deumer M. , Schell M. , Semtsiv M. P. , Masselink W. T. , Globisch B.
Published: September 2020

We investigate photoconductive terahertz (THz) emitters compatible with 1550 nm excitation for THz time-domain spectroscopy (TDS). The emitters are based on rhodium (Rh) doped InGaAs grown by molecular beam epitaxy. InGaAs:Rh exhibits a unique combination of ultrashort trapping time, high electron mobility, and high resistivity. THz emitters made of InGaAs:Rh feature an emitted THz power of 637 μW at 28 mW optical power and 60 kV/cm electrical bias field. In particular for a fiber coupled photoconductive emitter, this is an outstanding result. When these emitters are combined with InGaAs:Rh based receivers in a THz TDS system, 6.5 THz bandwidth and a record peak dynamic range of 111 dB can be achieved for a measurement time of 120 s.
Threshold photoelectron spectroscopy of the HO2 radical
Authors: Tang Xiaofeng , Lin Xiaoxiao , Garcia Gustavo A. , Loison Jean-Christophe , Fittschen Christa , Röder Anja , Schleier Domenik , Gu Xuejun , Zhang Weijun , Nahon Laurent
Published: September 2020

We report a synchrotron radiation vacuum ultraviolet photoionization study of the hydroperoxyl radical (HO2), a key reaction intermediate in combustion and atmospheric chemistry as well as astrochemistry, using double imaging photoelectron photoion coincidence spectroscopy. The HO2 radical is formed in a microwave discharge flow tube reactor through a set of reactions initiated by F atoms in a CH4/O2/He gas mixture. The high-resolution threshold photoelectron spectrum of HO2 in the 11 eV–12 eV energy range is acquired without interferences from other species and assigned with the aid of theoretically calculated adiabatic ionization energies (AIEs) and Franck–Condon factors. The three vibrational modes of the radical cation HO2+, the H–O stretch, the H–O–O bend, and the O–O stretch, have been identified, and their individual frequencies are measured. In addition, the AIEs of the X3A″ ground state and the a1A′ first excited electronic state of HO2+ are experimentally determined at 11.359 ± 0.003 eV and 11.639 ± 0.005 eV, respectively, in agreement with high-level theoretically computed results. Furthermore, the former AIE value provides validation of thermochemical networks used to extract the enthalpy of formation of the HO2 radical.