bluuebunny/crossref_metadata_2025 huggingface dataset:
Indirect measurements of neutron-induced reaction cross sections at heavy-ion storage rings
Authors: Sguazzin M. , Jurado B. , Pibernat J. , Swartz J. A. , Grieser M. , Glorius J. , Litvinov Yu. A. , Reifarth R. , Blaum K. , Alfaurt P. , Ascher P. , Audouin L. , Berthelot C. , Blank B. , Bruckner B. , Dellmann S. , Dillmann I. , Domingo-Pardo C. , Dupuis M. , Erbacher P. , Flayol M. , Forstner O. , Freire-Fernández D. , Gerbaux M. , Giovinazzo J. , Grévy S. , Griffin C. J. , Gumberidze A. , Heil S. , Heinz A. , Kurtulgil D. , Leckenby G. , Litvinov S. , Lorentz B. , Méot V. , Michaud J. , Perard S. , Petridis N. , Popp U. , Ramos D. , Roche M. , Sanjari M.S. , Sidhu R.S. , Spillmann U. , Steck M. , Stöhlker Th. , Thomas B. , Thulliez L. , Versteegen M.
Published: May 2023

Neutron-induced reaction cross sections of unstable nuclei are essential for understanding the synthesis of heavy elements in stars and for applications in nuclear technology. However, their measurement is very complicated due to the radioactivity of the targets involved. We propose to circumvent this problem by using the surrogate reaction method in inverse kinematics, where the nucleus formed in the neutron- induced reaction of interest is produced by a reaction involving a radioactive heavy-ion beam and a stable, light target nucleus. The probabilities as a function of the compound-nucleus excitation energy for γ-ray emission, neutron emission and fission, which can be measured with the surrogate reaction, are particularly useful to constrain model parameters and to obtain more accurate predictions of the neutron-induced reaction cross sections of interest. Yet, the full development of the surrogate method is hampered by numerous long- standing target issues, which can be solved by combining surrogate reactions with the unique and largely unexplored possibilities at heavy-ion storage rings. In this contribution, we describe the developments we are carrying out to measure for the first time simultaneously γ-ray emission, neutron emission and fission probabilities at the storage rings of the GSI/FAIR facility. In particular, we will present the first results of the proof of principle experiment, which we performed in June 2022 at the Experimental Storage Ring (ESR) of GSI/FAIR.
Measurement of Photoneutron Yields Using the RPI LINAC and Assessment of Evaluated Photoneutron Data for Tantalum and Beryllium
Authors: Epping Brian , Rapp Michael , Barry Devin , Daskalakis Adam , Danon Yaron , Blain Ezekiel , Brand Peter , Bretti Michael , Gray Matthew , Krusieski Larry , Kerdoun Azeddine , Block Robert , Landsberger Sheldon
Published: May 2023

A new experiment configuration was designed, developed, and implemented to measure photoneutron yields using the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) at the RPI Gaerttner LINAC Center. The experiment configuration includes a new target assembly that converts the LINAC electron beam into a high energy bremsstrahlung photon flux incident upon a sample material of interest. The photons excite nuclei in the sample of interest, which can subsequently emit neutrons (photoneutrons). The photoneutrons emitted in the direction of the detector system travel through a series of collimated vacuum pipes before reaching a pair of proton-recoil high-energy neutron detectors. The signals generated by the neutron detectors are processed using a digital data acquisition system and subsequently analyzed to determine the energy-dependent photoneutron yield from the sample of interest. The new experiment configuration was used to perform proof-of-concept experiments to measure the photoneutron yields from samples of tantalum and beryllium. The measured results were then compared against the results from Monte Carlo simulations of the detailed experiment configurations to perform preliminary assessments of evaluated photoneutron data libraries.
233U(n,γ) measurements at LANSCE
Authors: Leal-Cidoncha Esther , Couture Aaron , Rusev Gencho , Bond Evelyn M. , Fry Cathleen , Ullmann John , Bredeweg Todd
Published: May 2023

Uranium-233 plays an important role in the Th-U fuel cycle, which has been proposed as an alternative to the U-Pu fuel cycle due to its reduced amount of transuranium elements. The available experimental 233U(n,γ) cross section data in the literature are scarce, [1–3]. In 2008, the 233U(n,γ) cross section was investigated at LANL using the DANCE detector combined with a PPAC, however the statistics in the keV regime were inadequate for a reliable extraction of the cross section at 100 keV. An accurate measurement of the 233U(n,γ) cross section is required by the NCSP to complete the neutron-induced cross section data; a new evaluation reported the need of 233U capture data.

The challenge in this measurement lies in the difficulty of measuring capture cross section data due to the competing capture and fission channels. Fission reactions are around one order of magnitude more likely than capture for 233U. The accuracy in the capture cross section measurement relies on the discrimination between the γ-rays produced in capture and fission reactions, for which an experimental setup combining capture and fission detectors is needed.

Following this requirement, a new measurement has been performed at LANSCE combining the γ-ray array DANCE with the neutron detector NEUANCE to identify fission and neutron-capture events.

This measurement will provide results of the 233U capture-to-fission ratio in the Resolved and Unresolved Resonance regions.
Neutron Capture Cross Section Measurement and Resonance Analysis of 107Pd Using ANNRI at MLF/J-PARC
Authors: Nakano Hideto , Katabuchi Tatsuya , Terada Kazushi , Kimura Atsushi , Nakamura Shoji , Endo Shunsuke , Rovira Gerard , Kodama Yu
Published: May 2023

The neutron capture cross sections of 107Pd were measured using the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) at the Japan Proton Accelerator Research Complex (J-PARC). Capture γ-rays were detected with a NaI(Tl) spectrometer. The incident neutron energy was determined by the time-of-ﬂight method. The preliminary cross section was derived from thermal to resonance energy region. In the resonance region, resonance parameters were derived by resonance analysis using REFIT code. The resonance parameter was close to the value of JENDL-4.0.
Cross Section Measurements and Theoretical Study of the 174,176Hf(n,2n)173,175Hf Reactions
Authors: Vlastou R. , Kalamara A. , Serris M. , Chasapoglou S. , Frantzis C. , Tsivouraki E. , Kokkoris M. , Krokidi K. , Axiotis M. , Harissopulos S. , Lagoyannis A.
Published: May 2023

Experimental cross section measurements for the 176Hf(n,2n)175Hf and 174Hf(n,2n)173Hf reactions were carried out, using the activation technique. The neutron beam energy in the range of 15.3-20.3 MeV was produced via the 3H(d,n)4He reaction at the 5.5 MeV Tandem Van de Graaf accelerator laboratory of NCSR “Demokritos”. A thin metallic foil of natural Hf was used, while for the determination of the neutron flux at the target position, reference foils of Al were placed at the front and back of the Hf target. The irradiations were continuous for ~24-48 hours, leading to a total neutron fluence of 1010-1011 n/cm2 and a BF3 detector was used for monitoring the neutron flux during the irradiations. After the end of each irradiation, the activity of the Hf target and the Al reference foils were measured off-line by two HPGe detectors. The 176Hf(n,2n)175Hf reaction has been corrected for the contribution of the 177Hf(n,3n)175Hf and 174Hf(n,γ)175Hf reactions. Statistical model calculations based on the Hauser-Feshbach theory have also been performed using the EMPIRE 3.2.3 code. The predictions have been compared with the data of the present work as well as with data from literature.
Using the Monte-Carlo method to analyze experimental data and produce uncertainties and covariances
Authors: Henning Greg , Kerveno Maëlle , Dessagne Philippe , Claeys François , Dari Bako Nicolas , Dupuis Marc , Hilaire Stephane , Romain Pascal , de Saint Jean Cyrille , Capote Roberto , Boromiza Marian , Olacel Adina , Negret Alexandru , Borcea Catalin , Plompen Arjan , Paradela Dobarro Carlos , Nyman Markus , Drohé Jean-Claude , Wynants Ruud
Published: May 2023

The production of useful and high-quality nuclear data requires measurements with high precision and extensive information on uncertainties and possible correlations. Analytical treatment of uncertainty propagation can become very tedious when dealing with a high number of parameters. Even worse, the production of a covariance matrix, usually needed in the evaluation process, will require lenghty and error-prone formulas. To work around these issues, we propose using random sampling techniques in the data analysis to obtain final values, uncertainties and covariances and for analyzing the sensitivity of the results to key parameters. We demonstrate this by one full analysis, one partial analysis and an analysis of the sensitivity to branching ratios in the case of (n,n’γ) cross section measurements.
Target mass dependence of photoneutron spectrum for 16.6 MeV photons on medium-heavy mass targets
Authors: Sanami Toshiya , Tran Tyuet Kim , Yamazaki Hiroshito , Itoga Toshiro , Kirihara Yoichi , Namito Yoshihito , Sakaki Yasuhito , Miyamoto Shuji , Asano Yoshihiro
Published: May 2023

We measured neutron energy spectra for the photonuclear reactions of 16.6 MeV linearly polarized photons on Pb, Au, Sn, Cu, Fe and Ti. The spectra for each target show dependence on the target mass, as well as on the angle between the directions of neutron emission and polarization. The components show angular dependence were extracted from the spectra for each target and compare with the excited levels of residual nuclei. Based on the data, we discuss a plan for further experiments to clearly observe the features of the spectra.
Nuclear data - an essential tool in nuclear astrophysics
Authors: Langanke Karlheinz
Published: May 2023

Nuclear processes play an essential role for the evolution of many astrophysical objects and they are key to the origin of the elements in the Universe. Our understanding of the Universe has benefitted from the tremendous progress in nuclear physics which became possible due to novel experimental facilities and improved instrumentation as well as due to advances in theoretical modelling. The talk exemplifies this progress for three selected topics: solar and stellar hydrostatic burning, neutron-star mergers as a site of heavy-element production by the r-process and the influence of electron capture on nuclei for the core-collapse in massive stars leading to supernova explosions.
Present status of an R-matrix analysis code AMUR for cross-section evaluation in resolved resonance region
Authors: Kunieda Satoshi
Published: May 2023

An R-matrix analysis code AMUR is being progressed in terms of the correction on the experimental conditions to the theoretical calculations. In this work, new broadening options are presented both for cross-sections and angular distribution with given energy resolution. The code is also under development to analyze the J-PARC/ANNRI measurement with the double-bunch mode. In the final part, let me focus on understanding of the R-matrix theory itself, in which a role of distant poles is discussed in the simultaneous analysis of the same compound nucleus.
New developments in fission studies within the time-dependent density functional theory framework
Authors: Bulgac Aurel
Published: May 2023

We have extended significantly the microscopic description of the fission process by examining a larger set of observables. We extract neutron and proton numbers of fission fragments, their spins and fission fragment relative orbital angular momentum and their correlations, investigate neutrons emitted at or shortly after scission, excitation energy sharing mechanism, total kinetic energy of fission fragments, and the entanglement entropy. I will present a short overview of our simulations obtained with two independent nuclear energy density functionals.
Fission-fragment yields measured in Coulomb-induced fission of 234,235,236,238U and 237,238Np with the R3B/SOFIA setup
Authors: Chatillon A. , Boutoux G. , Gorbinet T. , Grente L. , Martin J.-F. , Pellereau E. , Taieb J. , Alvarez-Pol H. , Audouin L. , Ayyad Y. , Bélier G. , Benlliure J. , Caamaño M. , Casarejos E. , Cortina-Gil D. , Ebran A. , Farget F. , Fernández-Domínguez B. , Heinz A. , Johansson H. T. , Jurado B. , Kelić-Heil A. , Kurz N. , Laurent B. , Loeher B. , Nociforo C. , Paradela C. , Pietri S. , Prochazka A. , Ramos D. , Rodríguez-Sànchez J. L. , Rodriguez C. , Rossi D. , Simon H. , Tassan-Got L. , Toernqvist H. , Vargas J. , Voss B. , Weick H.
Published: May 2023

Low energy fission of 234,235,236,238U and 237,238Np radioactive beams, provided by the GSI/FRS facility, has been studied using the R3B/SOFIA setup. The latter allows, on an event-by-event basis, to simultaneously identify, in terms of their mass and atomic numbers, the fissioning nucleus in coincidence with both fission fragments after prompt-neutron emission. This presentation reports on new results on elemental, isobaric and isotopic yields.
Independent isotopic fission yields of 252Cf spontaneous fission via mass measurements at the FRS Ion Catcher
Authors: Waschitz Y. , Amanbayev D. , Spătaru A. , Mardor I. , Dickel T. , Cohen E. O. , Aviv O. , Ayet San Andrés S. , Balabanski D. L. , Beck S. , Bergmann J. , Brencic Z. , Constantin P. , Dehghan M. , Geissel H. , Gröf L. , Hornung C. , Kalantar-Nayestanaki N. , Kripko-Koncz G. , Miskun I. , Mollaebrahimi A. , Nichita D. , Plaß W. R. , Pomp S. , Scheidenberger C. , Solders A. , Stanic G. , Wasserheß M. , Vencelj M. , Zhao J.
Published: May 2023

We present first preliminary results of a novel method for measuring independent isotopic fission yields (IIFYs) of spontaneous fission (SF) via direct mass measurements, at the FRS Ion Catcher (FRS-IC) at GSI. Fission products were generated from a 252Cf source installed in a cryogenic stopping cell, and were identified and counted with the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the FRS-IC, utilizing well-established measurement and data analysis methods. The MR-TOF-MS resolves isobars unambiguously, even with limited statistics, and its non-scanning nature ensures minimal relative systematic uncertainties amongst fission products. The analysis for extracting IIFYs includes isotope-dependent efficiency corrections for all components of the FRS-IC. In particular, we applied a self-consistent technique that takes into account the element-dependent survival efficiencies in the CSC, due to chemical reactions with the buffer gas. Our IIFY results, which cover several tens of fission products in the less-accessible high-mass peak (Z = 56 to 63) down to fission yields at the level of 10−5, are generally similar to those of the nuclear database ENDF/B-VII.0. Nevertheless, they reveal some structures that are not observed in the database smooth trends. These are the first results of a planned campaign to investigate IIFY distributions of spontaneous fission at the FRS-IC. Upcoming experiments will extend our results to wider Z and N ranges, lower fission yields, and other spontaneously-fissioning actinides.
Experimental Prompt Fission Neutron Spectra Comparisons for the 235,238U(n, f) and 239Pu(n, f) Reactions
Authors: Devlin Matthew , Kelly Keegan J. , Gomez Jaime A. , O’Donnell John M. , Neudecker Denise , Haight Robert C. , Bennett Eames , Fotiades Nikolaos , Ullmann John , Wu Ching-Yen , Henderson Jack , Henderson Roger , Buckner Matthew Q.
Published: May 2023

The Chi-Nu project to measure prompt fission neutron energy spectra for the major actinides has now completed two measurements, for neutron-induced fission of 239Pu and 235U for incident neutron energies from 1 to 20 MeV, and has almost completed the prompt fission neutron spectrum measurement for 238U. In addition, similar data have been taken for spontaneous fission in some other isotopes, and a measurement of fission neutron spectra from 240Pu(n, f ) is in progress. These measurements are done at the same facility, with the same equipment and analyzed in a similar way. A useful way to look at such data is to examine ratios of the prompt fission neutron spectra among actinides, as some of the experimental uncertainties involved in these data are the same from isotope to isotope, making the ratios of fission neutron spectra less dependent on the experimental and analysis details. We discuss here the ratios of prompt fission neutron spectra between 239Pu(n, f ) and 235U(n, f ) , as well as the evolution of the mean fission neutron energy for 239Pu(n, f ) and 235,238U(n, f ) with increasing incident neutron energy.
Charge polarization calculated with a microscopic model for the ﬁssion fragments of U-236
Authors: Ebata Shuichiro , Okumura Shin , Ishizuka Chikako , Chiba Satoshi
Published: May 2023

We investigated theoretical methods to estimate the charge polarization of the ﬁssion fragments. The method is based on the microscopic mean-ﬁeld model with the nucleon degree of freedom, and is represented in the three-dimensional coordinate space for dealing with any nuclear deformation. We employed the Skyrme eﬀective interaction for the calculations and uranium-236 as a target nucleus. We reported static and dynamic methods in which the potential energy surface of the ﬁssioning nucleus concerning the quadrupole and octupole deformations are used. Although the static method deduced the charge polarization which indicates the nuclei with the magic number and the octupole deformation, the quantities are not consistent with the existing data library (Wahl’s systematics). The dynamic method with the iso-energy initial condition on the potential energy surface showed the ﬁnite charge polarization of light and heavy ﬁssion fragments which is consistent with the data library. Furthermore, it indicates that the charge polarization has energy dependence of the initial states of the dynamic method.
Photofission and photoneutron cross sections for 238U and 232Th
Authors: Filipescu Dan , Wang Hongwei , Fan Gongtao , Nishio Katsuhisa , Ohtsuki Tsutomu , Gheorghe Ioana , Stopani Konstantin , Tudora Anabella , Suzaki Fumi , Hirose Kentaro , Inagaki Makoto , Bjørøen Marianne , Lui Yiu-Wing , Ari-izumi Takashi , Miyamoto Shuji , Utsunomiya Hiroaki
Published: May 2023

A specific objective of the recent IAEA Coordinated Research Project on Photonuclear Data and Photon Strength Functions (Code F41032; Duration 2016-2019) has been to measure photonuclear cross-section data where needed, for unexplored nuclei and cases of discrepant existing data. A dedicated experimental campaign has been conducted at the laser Compton-scattering γ-ray source of the NewSUBARU synchrotron radiation facility of SPring8, Japan, where photoneutron reactions for 11 nuclei from 9Be to 209Bi have been investigated in the Giant Dipole Resonance energy region. The measurements followed the development of a flat-effi ciency moderated neutron detection array and the associated neutron-multiplicity sorting techniques. The IAEA CRP campaign has been followed at NewSUBARU by new measurements of photofission and photoneutron reactions on 238U and 232Th in the energy range of 5.87 MeV – 20.14 MeV. The neutron-multiplicity sorting of high-multiplicity fission neutron coincidence events has been performed using a dedicated energy dependent, multiple firing statistical treatment. The photoneutron (γ, xn) and photofission (γ, fxn) reactions have been discriminated by considering a Gaussian distribution of prompt-fission-neutrons (PFN) multiplicities predicted by the evaporation theory. We here provide preliminary experimental (γ, n), (γ, 2n) and (γ, F) cross sections, average energies of PFN and of photoneutrons emitted in (γ, n) and (γ, 2n) reactions, as well as the mean number of PFN per fission act. The new 238U cross sections are compared with recent statistical-model calculations performed with the EMPIRE code on existing data.
The n_TOF NEAR Station Commissioning and first physics case
Authors: Stamati M. E. , Torres-Sánchez P. , Pérez-Maroto P. , Cecchetto M. , Goula S. , Mastromarco M. , Chasapoglou S. , Beltrami C. , Chiesa D. , Manna A. , Mucciola R. , Patronis N. , Praena J. , Guerrero C. , Colonna N. , Mengoni A. , Massimi C. , Aberle O. , Alcayne V. , Altieri S. , Amaducci S. , Amar Es-Sghir H. , Andrzejewski J. , Babiano-Suarez V. , Bacak M. , Balibrea J. , Bennett S. , Bernardes A. P. , Berthoumieux E. , Bosnar D. , Busso M. , Caamaño M. , Calviño F. , Calviani M. , Cano-Ott D. , Casanovas A. , Castelluccio D. M. , Cerutti F. , Cescutti G. , Chiaveri E. , Colombetti P. , Console Camprini P. C. , Cortés G. , Cortés-Giraldo M. A. , Cosentino L. , Cristallo S. , Di Castro M. , Diacono D. , Diakaki M. , Dietz M. , Domingo-Pardo C. , Dressler R. , Dupont E. , Durán I. , Eleme Z. , Fargier S. , Fernández-Domínguez B. , Finocchiaro P. , Fiore S. , Furman V. , García-Infantes F. , Gawlik-Ramięga A. , Gervino G. , Gilardoni S. , González-Romero E. , Gunsing F. , Gustavino C. , Heyse J. , Jenkins D. G. , Jericha E. , Junghans A. , Kadi Y. , Katabuchi T. , Katabuchi T. , Knapová I. , Kokkoris M. , Kopatch Y. , Krticka M. , Kurtulgil D. , Ladarescu I. , Lederer-Woods C. , Lerendegui-Marco J. , Lerner G. , Martínez T. , Masi A. , Mastinu P. , Matteucci F. , Maugeri E. A. , Mazzone A. , Mendoza E. , Michalopoulou V. , Milazzo P. M. , Murtas F. , Musacchio-Gonzalez E. , Musumarra A. , Negret A. , Oprea A. , Pavón-Rodríguez J. A. , Pellegriti M. G. , Perkowski J. , Petrone C. , Piersanti L. , Pirovano E. , Pomp S. , Porras I. , Protti N. , Quesada J. M. , Rauscher T. , Reifarth R. , Rochman D. , Romanets Y. , Romano F. , Rubbia C. , Sánchez A. , Sabaté-Gilarte M. , Schillebeeckx P. , Schumann D. , Sekhar A. , Smith A. G. , Sosnin N. V. , Spelta M. , Tagliente G. , Tarifeño-Saldivia A. , Taríro D. , Terranova N. , Urlass S. , Valenta S. , Variale V. , Vaz P. , Vescovi D. , Vlachoudis V. , Vlastou R. , Wallner A. , Woods P. J. , Wright T. , Žugec P. ,   n_TOF Collaboration
Published: May 2023

The NEAR Station is a new experimental area developed at the n_TOF Facility at CERN. The activation station of NEAR underwent a characterization of the beam following the installation of the new n_TOF Spallation Target. The commissioning of the neutron beam comprises a set of simulations made with the FLUKA code and experimental verification. The experimental determination of the neutron spectrum was made using activation techniques with three separate set-ups. Two set-ups were based on the Multi-foil Activation technique (MAM-1 and MAM-2), and the third set-up relied on the process of neutron moderation and activation of a single material (ANTILoPE). The three set-ups are presented. Also the present plans and future perspectives of the activation station of NEAR are discussed.
Design study of benchmark experiment for large-angle scattering cross section for non-solid target with 14 MeV neutron
Authors: Araki Sota , Fukui Kazuki , Rosidah Maemunah Indah , Miyazawa Rio , Tamaki Shingo , Kusaka Sachie , Murata Isao
Published: May 2023

Accuracy of large-angle scattering cross section in nuclear data has a large contribution on precision of neutron transport calculation in fusion reactor design. In the previous research, benchmark experiments for a solid target were carried out, however, non-solid targets, which are enclosed in a container, could not be dealt with. This is because we were not able to remove the effect due to existence of the container in the previous method. In this study, we performed design study of advanced benchmark experiment for large-angle scattering cross section especially for a non-solid target in a container. In addition, we also carried out benchmark experiments for silicon, which is important for the fusion reactor, however, is one of the elements that are difficult to obtain a solid target. In conclusion, we successfully developed an advanced benchmark experimental method for non-solid targets and verified it numerically by Monte Carlo calculation. In addition, we also found experimentally that large-angle scattering cross section of silicon is underestimated in JENDL-4, ENDF-B/VIII and JEFF-3.3.
WPEC/SG46 Exercise on Target Accuracy Requirement
Authors: Cabellos Oscar , Hursin Mathieu , Palmiotti Pino
Published: May 2023

Recently, a second Target Accuracy Requirements (TAR) exercise is 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 and fuel cycle design. The goal is to provide the NEA/HPRL with new requirements of “nuclear data uncertainty reduction”
Use of nickel sphere and copper cube with 252Cf neutron source in the centre for test of nuclear data libraries ENDF/B-VII.1, ENDF/B-VIII.0, JEFF- 3.3, BROND- 3.1
Authors: Jansky Bohumil , Rejchrt Jiri , Novak Evzen , Schulc Martin , Kostal Michal , Blokhin Anatoly
Published: May 2023

The leakage neutron spectrum measurements have been done on benchmark spherical assembly-nickel sphere with a diameter of 50 cm and a copper cube (block) with dimensions of 49.5 x 49.5 x 48 cm3 in Research Centre Rez (RC Rez). The 252Cf neutron source was placed into the centre of nickel sphere and copper cube. The proton recoil method was used for the neutron spectrum measurement using spherical hydrogen proportional detectors (HPD) with pressure of 400 and 1000 kPa (diameter of detectors is 4 cm) and scintillation stilbene (ST) detector (diam. of 1 x 1 cm). The neutron energy range of spectrometer is from 0.04 MeV to 1.3 MeV for HPD and from 1 MeV to 12 MeV for ST. The adequate MCNP neutron spectrum calculations based on data libraries ENDF/B-VII.1, ENDF/B-VIII.0, JEFF-3.3, BROND-3.1 were done and compared with the experiment, i.e., calculation to experiment ratio C/E was determined.
Variance minimisation on a quantum computer of the Lipkin-Meshkov-Glick model with three particles
Authors: Hobday Isaac , Stevenson Paul , Benstead James
Published: May 2023

Quantum computing opens up new possibilities for the simulation of many-body nuclear systems. As the number of particles in a many-body system increases, the size of the space if the associated Hamiltonian increases exponentially. This presents a challenge when performing calculations on large systems when using classical computing methods. By using a quantum computer, one may be able to overcome this difficulty thanks to the exponential way the Hilbert space of a quantum computer grows with the number of quantum bits (qubits). Our aim is to develop quantum computing algorithms which can reproduce and predict nuclear structure such as level schemes and level densities. As a sample Hamiltonian, we use the Lipkin-Meshkov-Glick model. We use an efficient encoding of the Hamiltonian onto many-qubit systems, and have developed an algorithm allowing the full excitation spectrum of a nucleus to be determined with a variational algorithm capable of implementation on today’s quantum computers with a limited number of qubits. Our algorithm uses the variance of the Hamiltonian,⟨H⟩2 − ⟨H⟩2, as a cost function for the widely-used variational quantum eigensolver (VQE). In this work we present a variance based method of finding the excited state spectrum of a small nuclear system using a quantum computer, using a reduced-qubit encoding method.
Thermal scattering law for ice based on neutron time-of-flight experiments carried out at the SEQUOIA spectrometer at the Oak Ridge National Laboratory
Authors: Jaiswal Vaibhav , Leal Luiz , Kolesnikov Alexander I.
Published: May 2023

Precise estimation of neutron thermalization in moderators relies on high-fidelity thermal scattering cross-section data governed by the thermal scattering law (TSL). The Institut de Radioprotection et de Sûreté Nucléaire (IRSN) has been working on the development of improved TSL for light water ice. Many polymorphic phases of light water ice exist depending on the thermodynamic conditions. The most common type of ice at standard pressure and temperature below water freezing point (273.15 K) is ice-Ih. It is essential to have high-resolution experimental double differential data for developing and/or validating TSL for moderator materials.Existing experimental double-differential scattering data for ice-Ih are extremely sparse and of limited quality. New high-quality double-differential measurements for ice-Ih over multiple temperatures and incident neutron energies would directly support the validation and improvement of ice-Ih TSL models for criticality safety applications.

Series of time-of-flight (TOF) inelastic neutron scattering experiments on ice-Ih at temperatures starting at 271 K and down to 6 K, have been carried out at the SEQUOIA spectrometer at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL), United States. The experiments have been performed for incident neutron energies, Ei= 11, 55, 160, 250, and 600 meV, to explore different excitation energies in the vibrational phonon spectrum. This paper presents the thermodynamic conditions and the details of the TOF measurements on ice-Ih and the derived phonon spectrum from the experimentally measured double differential data. A study of the variation of the phonon spectrum of ice-Ih as a function of temperature is highlighted, and a preliminary TSL evaluation is developed based on the experimental phonon spectrum.
Pulsed-Neutron Die-Away Experiments for Plastics and Neutron Thermal Scattering Laws
Authors: Siefman Daniel , Coleman Shauntay , Northrop Jordan , Zywiec William , Holmes Jesse , Zerkle Michael , Heinrichs David , Percher Catherine
Published: May 2023

Pulsed-neutron die-away (PNDA) experiments 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 decay-time eigenvalue. The eigenvalue can be extracted from the experimental measurements of the neutron flux and used as an integral parameter in validation. For certain materials and geometric configurations, the eigenvalue is heavily influenced by thermal neutron scattering of only the target material. For that reason, a PNDA experiment can have a higher sensitivity to TSLs than is commonly available in critical experiments. Herein, we present results for a series of new PNDA experiments conducted at Lawrence Livermore National Laboratory with plastic materials, e.g. high-density polyethylene and Lucite. We compare the experimental integral parameters to simulated results and report trends in the biases. We evaluate the bias with different Monte Carlo transport codes (MCNP6.2 and Mercury) and show no significant differences between the results of the two codes.
Effect of supergravity field on the behavior of suspended dross in hot dip Al-Zn and purification
Authors: Chu Rensheng , Wang Zhe , Sun Ningjie , Deng Xiaoxuan , Ma Changwen , Guo Zhancheng
Published: May 2023

Suspended dross is becoming the main factor affecting the surface quality of hot-dip coated steel. Hence, this paper developed a new method for its removal from industrial hot-dip Al–Zn (AZ) baths by using a supergravity field, whose effect on it was analyzed. The supergravity field forced the suspended dross to the top layer, and stratification occurred. As the gravitational constant (G) increased, the pure alloy ratio in the hot-dip AZ matrix increased and the suspended dross became more intensively confined in the top layer; at G = 1000, the pure alloy ratio reached 87.3%, with almost no suspended dross. A new shape factor for the suspended dross was proposed to determine via kinetic calculations its movement behavior under the supergravity field. The calculation results were consistent with the experimental data, laying the foundation for the separation and removal of suspended dross in hot-dip AZ baths by the supergravity field.
Gewichtsveränderungen bei Pflegeheimbewohner*innen:
Eine retrospektive Analyse von Routinedaten
Authors: Graeb Fabian , Wolke Reinhold , Reiber Petra , Essig Gundula , Berger Bianca
Published: May 2023

Hintergrund Ungewollte Gewichtsverluste und daraus resultierende
Mangelernährung sind unter anderem mit steigendem Alter,
Morbidität und Pflegebedürftigkeit assoziiert. Somit
könnte ein allmählicher Gewichtsrückgang als weiteres
physiologisches Alterssymptom erscheinen.

Fragestellung und Methodik Anhand von Routinedaten aus sechs
Pflegeeinrichtungen soll der Frage nachgegangen werden, wie sich das Gewicht
über drei Jahre (t0-t6) bei 540 hochaltrigen,
pflegebedürftigen Bewohner*innen entwickelt, welche Faktoren ein
stabiles Gewicht begünstigen und ob sich auch in dieser Gruppe eine
Assoziation von Gewichtsverlusten und Mortalität zeigt.

Ergebnisse Im ersten Halbjahr verlieren 24,2% (n=112)
mindestens 5% ihres Körpergewichtes, 31,1%
(n=144) weisen ein Mangelernährungsrisiko auf. Bis t4
(N=308) sind 57,5% (n = 177) gewichtsstabil,
wobei ein niedrigeres Alter und Pflegegrad eher positiv, Klinikaufenthalte eher
negativ mit den Gewichtsverläufen assoziiert sind. Die Cox Regression
zeigt ein signifikant steigendes Mortalitätsrisiko mit zunehmendem Alter
(HR 1,032; p<0,001), akuten Schmerzen (HR 10,321; p<0,001),
einem Gewichtsverlust von≥5% des Körpergewichtes im
ersten Halbjahr (HR 2,024; p<0,001) sowie bei hohem Pflegegrad (HR
1,872; p<0,001) und Ischämischen Herzkrankheiten (HR 1,491;
p=0,008). Ein initial höherer BMI (HR ,964; p=0,013) ist
dagegen mit einem reduzierten Risiko assoziiert.

Schlussfolgerung Es deutet sich an, dass die beobachteten Gewichtsverluste
zumindest anteilig einem physiologischen Alterungsprozesses zuordnen lassen. Ein
besonderes Augenmerk bei Interventionen (präventiv oder kurativ) ist
demzufolge in der Gruppe hochaltriger, pflegebedürftiger Menschen auf
den Erhalt der Lebensqualität zu legen.
Liebe Leserinnen und Leser
Authors: Bischoff Stephan C.
Published: May 2023

„Ernährungstherapie ohne Grenzen“ ist das Motto der
diesjährigen deutschsprachigen Tagung „ernährung
2023“ in Bregenz im Dreiländereck
Österreich/Deutschland/Schweiz. Der Ort könnte kaum
besser gewählt werden, denn genau diese drei Länder bzw. deren
ernährungsmedizinische Fachgesellschaften richten diese Tagung vom 1.-3.
Juni 2023 aus. Das Programm wurde bereits im letzten Heft der Aktuellen
Ernährungsmedizin vorgestellt und verspricht ein
vielfältiges und spannendes Angebot an Themen
M2Q oder doch etwas Anderes? Der Einfluss verschiedener
Aufgreifkriterien auf die Prävalenzschätzung chronischer
Erkrankungen mit ambulanten GKV-Diagnosedaten
Authors: Epping Jelena , Stahmeyer Jona T. , Tetzlaff Fabian , Tetzlaff Juliane
Published: May 2023

Ziele Zur Ermittlung der Prävalenz von chronischen Erkrankungen
auf Basis von ambulanten Krankenkassendaten wird häufig auf eine
wiederholte Nennung einer Diagnose im Laufe eines Jahres
zurückgegriffen, meist in zwei oder mehr Quartalen (M2Q). Dabei bleibt
bisher unklar, ob sich die Prävalenzschätzungen stark
verändern, wenn anstatt zwei Nennungen in unterschiedlichen Quartalen
nur eine Diagnosenennung oder wenn andere Festlegungen als Aufgreifkriterium
angewendet werden. Ziel dieser Studie ist daher die Anwendung unterschiedlicher
Aufgreifkriterien und die Analyse der Auswirkungen dieser Aufgreifkriterien auf
die Prävalenzschätzungen auf Basis von ambulanten
Diagnosedaten.

Methodik Für acht ausgewählte chronische Erkrankungen
wurde die administrative Prävalenz auf Basis der ambulanten
ärztlichen Diagnosen im Jahr 2019 ermittelt. Dabei wurden fünf
verschiedene Aufgreifkriterien verwendet: (1) einmalige Nennung, (2) zweimalige
Nennung (auch im selben Quartal oder Behandlungsfall), (3) Nennung in mindestens
zwei Behandlungsfällen (auch im selben Quartal), (4) Nennung in zwei
Quartalen und (5) Nennung in zwei aufeinander folgenden Quartalen. Für
die Analysen wurden die Daten der im Jahr 2019 durchgehend bei der AOK
Niedersachsen versicherten Personen verwendet (n=2 168 173).

Ergebnisse In Abhängigkeit von der Diagnose und der Altersgruppe
zeigten sich teilweise größere Unterschiede zwischen den
Prävalenzschätzungen bei den Kriterien der wiederholten Nennung
einer Diagnose verglichen mit der einmaligen Nennung. Diese Unterschiede in den
ermittelten Prävalenzen fielen insbesondere unter Männern und
jüngeren Versicherten recht deutlich aus. Bei der Anwendung der
zweimaligen Nennung (Kriterium 2) unterschieden sich die Ergebnisse nicht von
der Prävalenz, die durch Nennung in mindestens zwei
Behandlungsfällen (Kriterium 3) oder zwei Quartalen (Kriterium 4)
ermittelt wurde. Die Anwendung des strengen Kriteriums von zwei aufeinander
folgenden Quartalen (Kriterium 5) führte zur weiteren Verringerung der
ermittelten Prävalenz.

Schlussfolgerung Die Nutzung der Kriterien der wiederholten Nennung einer
Diagnose, die sich zunehmend als Standard zur Diagnosevalidierung in
Krankenkassendaten durchsetzt, führt zu einem teilweise deutlichen
Absinken der Prävalenz. Auch die Definition der Studienpopulation
(z. B. wiederholter Kontakt zu niedergelassenen Ärzt:innen in
zwei aufeinander folgenden Quartalen als zwingende Bedingung) kann die
Prävalenzschätzung stark beeinflussen.
Enterale Ernährungstherapien beim pädiatrischen M.
Crohn Anwendungen und Wirkweise
Authors: Hörning André , Schmidt-Choudhury Anjona
Published: May 2023

Die Inzidenz chronisch-entzündlicher Darmerkrankungen (CED), insbesondere
des Morbus Crohn, nimmt weltweit deutlich zu. Externe Umweltfaktoren,
einschließlich der alltäglichen westlich-industrialisierten
Ernährung, welche sich u. a. durch einen hohen Anteil
prozessierter industriell hergestellter Lebensmittel auszeichnet, spielen eine
Schlüsselrolle im Pathomechanismus der Krankheit.

Ernährungsspezifische Maßnahmen nehmen seit jeher eine zentrale
Rolle bei der Behandlung der CED ein. Der erfolgreiche Einsatz der exklusiven
enteralen Ernährung (EET), die als Induktionstherapie der ersten Wahl
bei pädiatrischem Morbus Crohn (MC) gilt, spricht deutlich für
einen Zusammenhang zwischen Ernährung und CED. Die EET wird alleinig
oder im Verlauf der Erkrankung und auch beim hochaktiven MC in Kombination mit
Immunmodulatoren eingesetzt. Einziger Nachteil dieser hocheffizienten
Ernährungstherapie ist die Geschmacksmonotonie, die eine reduzierte
Therapieadhärenz mit sich bringt. Die intestinale Mikrobiota und deren
Stoffwechselaktivität (Mikrobiom) scheinen ebenso eine wichtige Rolle
für die Pathogenese zu spielen, da Kinder und Jugendliche mit Morbus
Crohn oder Colitis ulcerosa diesbezüglich häufig
ausgeprägte Veränderungen aufweisen. Es ist bekannt, dass die
Zusammensetzung der intestinalen Mikrobiota stark von der Ernährung
beeinflusst wird. Auch die EET kann durch Ausschluss potenziell
schädlicher Nahrungsbestandteile die Darmmikrobiota modifizieren und zur
mukosalen Heilung führen.

Diätetische Interventionen könnten demnach eine sehr
nebenwirkungsarme Möglichkeit darstellen, den MC zu behandeln und der
Manifestation bei genetisch prädisponierten Individuen
möglicherweise sogar vorzubeugen. Auf der Grundlage der
Nährstoffzusammensetzung der EET hat daher die Suche nach einer
geschmacklich verbesserten und gleichzeitig wirksamen Diät begonnen, die
Ergebnisse dieser alternativen Ernährungsstrategien erscheinen
vielversprechend.

Dieser Übersichtsartikel soll den Wirkmechanismus der exklusiven
enteralen Eliminationsdiät und moderner ernährungsmedizinischer
Therapiestrategien aufzeigen sowie den aktuellen Stand der wissenschaftlichen
Erkenntnisse, die deren Wirksamkeit bei der Behandlung des pädiatrischen
MC belegen, zusammenfassen. Insbesondere sollen dabei die möglichen
pathophysiologischen Mechanismen, die der Remissionsinduktion und -erhaltung
zugrunde liegen, auch im Hinblick auf Veränderungen des Darmmikrobioms
beleuchtet werden.
Kammer mit Hürden
Authors: Hommel Oliver
Published: May 2023

Grün-Schwarz hält Wort im Ländle: Die Pflegekammer in Baden-Württemberg kommt*. Allerdings sind vorab einige Hürden zu nehmen!
Dexmedetomidine Opioid Sparing Effect in Mechanically Ventilated Children (DOSE): Trial of Fentanyl versus Fentanyl + Dexmedetomidine for Maintenance of Sedation
Authors: Becker Mara L. , Fischer Gwenyth , Hornik Chi D. , Alibrahim Omar , Iheagwara Kelechi , Abulebda Kamal , Bass Andora L. , Irby Katherine , Subbaswamy Anjali , Zivick Elizabeth E. , Sweney Jill , Stormorken Anne G. , Barker Erin E. , Mahadaveiah Shruthi , Lutfi Riad , McCrory Michael C. , Costello John M. , Ackerman Kate G. , Munoz-Pareja Jennifer C. , Feger Bryan J. , Dean J. Michael , Hanley Daniel F. , Greenberg Rachel G. , Avadhani Radhika , Thompson Richard E. , Benjamin Daniel K. , Hornik Christoph P. , Zimmerman Kanecia O.
Published: May 2023

Objectives This article observes the mean daily dose of fentanyl required for adequate sedation in critically ill, mechanically ventilated children randomized to receive dexmedetomidine or placebo.

Methods We conducted Dexmedetomidine Opioid Sparing Effect in Mechanically Ventilated Children (DOSE), a multicenter, double-blind, randomized, placebo-controlled, dose-escalating trial. We enrolled children aged 35 weeks postmenstrual to 17 years (inclusive) admitted across 13 pediatric multidisciplinary and cardiac intensive care units. Adequate sedation was based on a State Behavioral Score and Richmond Agitation-Sedation Scale of –1 or lower. Only the first two dexmedetomidine dosing cohorts opened for enrollment, due to early trial closure during the coronavirus 2019 pandemic. Thirty children were randomized over 13 months and included in the analyses.

Results Demographic and baseline characteristics were not different between dexmedetomidine and placebo cohorts. Similarly, mean daily fentanyl use was not different, using an unadjusted mixed regression model that considered treatment, time, and a treatment-by-time interaction. Adverse events and safety events of special interest were not different between cohorts.

Conclusion The DOSE trial revealed that dexmedetomidine added to fentanyl does not impact safety and may not spare fentanyl use in critically ill children, although the trial did not meet its recruitment goals, due to early closure during the coronavirus 2019 pandemic. More rigorous inpatient pediatric trials like DOSE that study critically ill, mechanically ventilated children are needed. Despite the many obstacles faced, the DOSE trial presents challenges from which the greater research community can learn and use to optimize future therapeutic trials in children.
A theoretical study of the time-resolved x-ray absorption spectrum of the photoionized BT-1T cation
Authors: Schnack-Petersen Anna Kristina , Pápai Mátyás , Coriani Sonia , Møller Klaus Braagaard
Published: May 2023

The time-resolved x-ray absorption spectrum of the BT-1T cation (BT-1T+) is theoretically simulated in order to investigate the charge transfer reaction of the system. We employ both trajectory surface hopping and quantum dynamics to simulate the structural evolution over time and the changes in the state populations. To compute the static x-ray absorption spectra (XAS) of the ground and excited states, we apply both the time-dependent density functional theory and the coupled cluster singles and doubles method. The results obtained are in good agreement between the methods. It is, furthermore, found that the small structural changes that occur during the reaction have little effect on the static XAS. Hence, the tr-XAS can be computed based on the state populations determined from a nuclear dynamics simulation and one set of static XAS calculations, utilizing the ground state optimized geometry. This approach can save considerable computational resources, as the static spectra need not to be calculated for all geometries. As BT-1T is a relatively rigid molecule, the outlined approach should only be considered when investigating non-radiative decay processes in the vicinity of the Franck–Condon point.
Predicting layered itinerant magnetic Fe3SiSe2 with spontaneous valley polarization
Authors: Qiao Lei , Fang Le , Lv Qingyun , Xu Shaowen , Jia Fanhao , Wu Wei , Picozzi Silvia , Pyatakov Alexander P. , Reimers Jeffrey R. , Ren Wei
Published: May 2023

Density functional theory calculations are performed to systematically investigate the electronic and magnetic properties of few-layer and bulk Fe3SiSe2 (FSS). We predict that the bulk FSS has a metallic ground state and a layered structure displaying intralayer ferromagnetic ordering and interlayer antiferromagnetic ordering. The itinerant magnetism in the FSS was determined by the Stoner criterion. Predictions of the absence of unstable phonon modes and a moderate cleavage energy of only 28.3 meV/Å2 suggest the possibility of stabilizing FSS in a monolayer form. The calculated spin–orbit coupling facilitates not only a large magnetocrystalline anisotropy energy, around 500 μeV/Fe, but also spontaneous valley polarization in odd-numbered layer systems. These systems have net magnetic moments as the magnetic moments of AFM-ordered layers are not fully compensated in the odd-numbered layer case and are predicted to show 2D metallic behaviors. The magnitude of the valley polarization in odd-numbered layered systems decreases from 18 meV with layer number but is absent in even-layered structures, thus showing an odd–even oscillation effect. Experimental realization of this bidimensional metallic magnet is, therefore, expected to widen the arena of two-dimensional materials that show exotic phenomena.
Suppression of skyrmion Hall effect via standing surface acoustic waves in hybrid ferroelectric/ferromagnetic heterostructures
Authors: Chen Chao , Wei Dahai , Sun Liang , Lei Na
Published: May 2023

Magnetic skyrmion is a promising information carrier for its low critical driven current density, topological stability, and small size, which has been proposed for various devices such as racetrack memory and logic gates. However, the skyrmion Hall effect originating from Magnus force leads to transverse motion, which hinders the development of skyrmionic device applications. Here, we propose artificial tracks built by standing surface acoustic waves (SSAWs) to suppress the skyrmion Hall effect through micromagnetic simulations. We systematically study the dynamics of an isolated skyrmion under SSAWs and driven currents in a prototype of the ferromagnetic skyrmion system. The skyrmion Hall angle changes from 80° to 0°, where the skyrmion motion is along the driven current. An analytical model considering magnetoelastic energy induced by SSAWs is developed, and a linear relation between the current density and the critical SSAW amplitude to eliminate the skyrmion Hall effect is achieved. Furthermore, a reconfigurable multichannel skyrmion racetrack is constructed through the change of SSAW wavelengths. Our work opens a feasible route for the suppression of skyrmion Hall effect via SSAWs.