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Ogawa, Tatsuhiko; Hirata, Yuho; Matsuya, Yusuke; Kai, Takeshi
Computer Physics Communications, 316, p.109758_1 - 109758_15, 2025/11
Times Cited Count：0 Percentile：0.00A track structure simulation model, ITSART Ver.2, has been developed to simulate the transport of arbitrary ions in arbitrary materials, accounting for every atomic interaction on an event-by-event basis. Unlike conventional track structure models, which are typically designed for therapeutic particle beams or bio-molecular targets, ITSART Ver.2 uniquely enables track structure calculations for any ion-material combination across an energy range from 10 eV/n to 1 TeV/n. To validate the developed model, the energy-angular distributions of secondary electrons, ion stopping ranges, radial dose distributions, and microscopic dose distributions calculated by ITSART Ver.2 were benchmarked against literature data. The unique features of ITSART Ver.2, including kinetic modeling of secondary electrons above 1 keV, modeling of secondary electron angular distribution, consideration of momentum transfer to target atoms, and interface with an atomic de-excitation model, resulted in calculations that were consistent with the benchmarking data. Furthermore, this benchmarking calculation demonstrated that ITSART Ver.2 can reproduce target-specific quantities such as Auger electron production and penumbra radial dose, which cannot be simulated with conventional codes that approximate the target as water. The capability of ITSART Ver.2 to perform track structure calculations under unconventional conditions paves the way for simulating various irradiation eff ects, such as reactor material irradiation damage, semiconductor device degradation, and other complex interactions.
Ogawa, Tatsuhiko; Labonnote, N.*
Nuclear Instruments and Methods in Physics Research B, 567, p.165791_1 - 165791_20, 2025/10
Times Cited Count：0 Percentile：0.00The general-purpose particle and heavy ion transport code system, PHITS, developed by the Japan Atomic Energy Agency, was validated against the SINBAD, an internationally recognized benchmark experiment archive for radiation shielding. Unlike the previous PHITS benchmark against SINBAD, which primarily focused on shielding experiments for proton accelerators, this study conducted benchmarking for double-differential neutron yields, activation, residual dose, and microdosimetric quantities induced by protons, electrons, ions, and pions. This allowed for the use of models and databases not previously employed in validation studies, leading to the discovery of previously overlooked issues. While PHITS calculations generally agreed with experimental data within a factor of two, a detailed comparison revealed the need for improvements in several areas. These include: the inability of the high-energy hadron cascade model to calculate the angular momentum of residual nuclei, the underestimation of neutrons below 100 MeV in pion-induced reactions by the same model, the underestimation of proton-rich nuclei by the evaporation model, and the underestimation of high-energy secondary neutrons by the heavy-ion reaction model. These findings will be used as guidelines for future improvements to PHITS.
Ogawa, Tatsuhiko
Annals of Nuclear Energy, 216, p.111256_1 - 111256_12, 2025/06
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)A novel robust method has been developed to simulate the performance of composite neutron sources composed of an alpha-emitting actinide and a light nucleus with low neutron separation energy. This method is based on the JENDL-5 cross-section data library and the Monte-Carlo radiation transport code PHITS. In contrast to previously devised methods, this approach can predict various quantities of the sources, such as actinide grain size dependence, absolute neutron emission intensity, energy spectra of neutrons and parasitic photons, neutron multiplicity, and time structure, with little approximation. The accurate calculation of stopping power of alpha rays in actinide grains and light elements, as well as the use of (
,n) reaction evaluated cross sections, which is one of the unique features of PHITS Ver.3.34 and its later versions, are the essences of the method. This method allows for the calculation of quantities important for practical applications, such as detection signal frequency, coincidence event rate, and the impact of parasitic gamma-rays.
Matsuya, Yusuke; Yoshii, Yuji*; Kusumoto, Tamon*; Ogawa, Tatsuhiko; Onishi, Seiki*; Hirata, Yuho; Sato, Tatsuhiko; Kai, Takeshi
Physical Chemistry Chemical Physics, 27(14), p.6887 - 6898, 2025/04
Times Cited Count：2 Percentile：86.03(Chemistry, Physical)Radicals by water radiolysis play an important role in evaluating radiation-induced biological effects, such as DNA damage induction, chromosomal aberrations, and carcinogenesis. In the Particle and Heavy Ion Transport code System (PHITS), a track-structure simulation mode enabling the estimation of each atomic interactions in water and a chemical simulation code (PHITS-Chem) dedicated to electron beams that can simulate radical dynamics have been developed in our previous study. Here, we developed the PHITS-Chem code applicable to any ion species, considering a space partitioning method to detect radical reactions more efficiently and the 4D visualization function. The updated PHITS-Chem code was verified by comparing the simulated G values of proton beams, particle beams, and carbon ion beams to the corresponding values in the literature. We succeeded in intuitively evaluating the diffusion dynamics of radicals using the PHITS 3D drawing software, PHIG-3D. The time to calculate the G values was reduced (e.g., about 28 times faster) while maintaining its calculation accuracy. The developed PHITS-Chem code is expected to contribute to precise and intuitive understanding of the biological effects induced by radicals in ion-beam radiotherapy.
Sari, A.*; Meleshenkovskii, I.*; Ogawa, Tatsuhiko; Tran, K.-T.*; Jinaphanh, A.*; Jouanne, C.*; Zoia, A.*
Nuclear Instruments and Methods in Physics Research A, 1072, p.170168_1 - 170168_17, 2025/03
Electron accelerators cover a wide range of applications, from nuclear waste package assay and security-related tasks to radiation therapy. High-energy photons produced by electron Bremsstrahlung radiation might induce photonuclear reactions emitting secondary neutrons. In this paper, we perform a two-stage benchmark for Monte Carlo simulation of photoneutron fields from electron accelerators operating in the 4-20 MeV range. On the one hand, we benchmark three independently developed Monte Carlo codes, i.e., MCNP, TRIPOLI-4; and PHITS, using ENDF7u photonuclear data from the ENDF/B-VII.1 library. On the other hand, we benchmark two photonuclear data sub-libraries, i.e., ENDF7u and JENDL-5, as well as nuclear reaction models, using the PHITS code. Errors in ENDF7u for W-184 and Ta-181 cause unphysical shapes of the photoneutron energy spectra with the three codes. Questionable behaviors are also found with JENDL-5, which calls for further examinations in this recently released library. For the cases of heavy water and beryllium, the photoneutron energy spectra obtained with MCNP6 is invalidated. We identified that the problem stems from wrong treatment of the reference frame in using the ACE data files by MCNP and previous versions of PHITS. Results obtained for tungsten and tantalum show that photoneutrons are overall emitted in an isotropic manner. However, results obtained for heavy water and beryllium display different tendencies. This investigation should help Monte Carlo code users to refine the current validity domain of the latest releases of MCNP6, PHITS and TRIPOLI-4 for the simulation of photoneutrons.
Ogawa, Tatsuhiko; Hirata, Yuho; Matsuya, Yusuke; Kai, Takeshi; Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Furuta, Takuya; Abe, Shinichiro; Matsuda, Norihiro; et al.
EPJ Nuclear Sciences & Technologies (Internet), 10, p.13_1 - 13_8, 2024/11
The latest updates on PHITS, a versatile radiation transport code, focusing specifically on track-structure models are presented. Track structure calculations are methods used to simulate the movement of charged particles while explicitly considering each atomic reaction. Initially developed for radiation biology, these calculation methods aimed to analyze the radiation-induced damage to DNA and chromosomes. Several track-structure calculation models, including PHITS-ETS, PHITS-ETS for Si, PHITS-KURBUC, ETSART, and ITSART, have been developed and implemented to PHITS. These models allow users to study the behavior of various particles at the nano-scale across a wide range of materials. Furthermore, potential applications of track-structure calculations have also been proposed so far. This collection of track-structure calculation models, which encompasses diverse conditions, opens up new avenues for research in the field of radiation effects.
Stainer, T.*; Ogawa, Tatsuhiko; 6 of others*
EPJ Web of Conferences, 302, p.07003_1 - 07003_10, 2024/10
Times Cited Count：0 Percentile：0.00(Computer Science, Interdisciplinary Applications)The NEA Data Bank is an international reference centre for computer codes, nuclear and thermochemical data which has traditionally used simple file servers, and even DVDs, to deliver valuable content to end users across the globe. With the recent implementation of a self hosted GitLab system at the NEA it has enabled the Data Bank to streamline delivery, automate processes and testing, while empowering code owners and developers with a secure platform to collaborate and develop codes. In this paper we present the NEA Git-Lab system with some concrete examples of codes such as Kraken, PHITS and FISPACT-II taking advantage of many of the services and functionalities provided by GitLab. We illustrate methodologies on how to work effectively with third party software in a position of being a custodian of code, rather that a code owner, providing DevSecOps as a service.
Garnaud, L.*; Ogawa, Tatsuhiko; 7 of others*
EPJ Web of Conferences, 302, p.07004_1 - 07004_14, 2024/10
Times Cited Count：1 Percentile：97.81(Computer Science, Interdisciplinary Applications)Photoneutrons, produced by photonuclear reactions, appear in diverse applications using high-energy gamma sources, electron accelerators, or nuclear reactors. Monte Carlo particle-transport codes typically simulate their emission, characterize their fields, and evaluate their impact on nuclear systems. This work aims to compile a compendium on photoneutron simulation using MCNP6, PHITS, and TRIPOLI-4. Each code runs with both ENDF/B-VIII.0 and JENDL-5 nuclear data libraries. We investigate photoneutron fields from 50 naturally isotopic elements, ranging from reaction energy threshold up to 30 MeV (the Giant Dipole Resonance regime). These fields are characterized by photoneutron current, energy spectrum, and angular distribution. This paper details results for the initial five elements: deuterium, beryllium, carbon, nitrogen, and oxygen, ordered by increasing atomic number. This compendium will serve as a valuable resource for users to understand code capabilities and limitations, for developers to improve neutron-emitting photonuclear reaction sampling, and for all photoneutron researchers, including nuclear data evaluators and experimental physicists.
Costantini, J.-M.*; Ogawa, Tatsuhiko
Quantum Beam Science (Internet), 8(3), p.20_1 - 20_16, 2024/08
A novel Coulomb spike concept is applied to the radiation damage induced in LiF and SiO
with about the same mass density (
2.65 g cm
) by 
Ni and 
Kr ions of 1.0-MeV/u energy for about the same electronic energy loss (10 MeV/um). The distribution of ionizations and electrostatic energy gained in the electric field by the ionized atoms is computed with the PHITS code for both targets. Further, the atomic collision cascades induced by these low energy hot ions of about 500 eV are simulated with the SRIM2013 code. It is found that melting is reached in a small volume for SiO due to the energy deposition in the subthreshold events of nuclear collisions induced by the Si and O ions. For LiF, the phonon contribution to the stopping power of the lighter Li and F ions is not sufficient to induce melting, even though the melting temperature is lower than for SiO. The formation of amorphous domains in SiO is likely after fast quenching of the small molten pockets, whereas only point defects may be formed in LiF.
Meleshenkovskii, I.*; Van den Brandt, K.*; Ogawa, Tatsuhiko; Datema, C.*; Mauerhofer, E.*
European Physical Journal Plus (Internet), 139, p.565_1 - 565_9, 2024/07
Times Cited Count：1 Percentile：28.73(Physics, Multidisciplinary)Fast neutron inelastic scattering is a promising non-destructive assay technique for various analytical applications. As an active neutron interrogation technique, its performance is a function of various different factors and parameters that require optimization. Monte Carlo simulation codes are indispensable for such tasks. However, the internal simulation routines implemented in such codes can rely on different physical models that can yield discrepancies in the simulation results. In this work we conduct an intercomparison of PHITS and Geant4 codes performance in application to fast neutron inelastic scattering simulations. The goal of this paper is twofold. First, we explain the differences in code configuration with respect to gamma and neutron transport, as well as internal simulation routines. Second, we conduct a performance assessment of the two codes using two different measurement configurations. One configuration consisted of a source of gamma-rays in a broad energy range (100 keV - 9000 keV) and a CeBr
detector. The other configuration consisted of a monoenergetic 2.5 MeV fast neutron source, Fe, Nd, Dy, B targets and a CeBr detector. Selected simulation configurations were chosen with a goal to compare the performance differences in neutron energy distribution, produced prompt gamma-rays and energy deposition in CeBr detector between the two codes. Results of our study reveal a good coherence of both codes performance in the application of fast neutron inelastic scattering simulations. The simulation geometries and observed differences are described in detail.
Ogawa, Tatsuhiko; Iwamoto, Yosuke
Nuclear Instruments and Methods in Physics Research B, 549, p.165255_1 - 165255_4, 2024/04
Times Cited Count：2 Percentile：57.55(Instruments & Instrumentation)Atomic defect is one of the critical factors that determines the irradiation effects in materials. The atoms are recoiled by the impulse of incoming radiation, which changes the mechanical, electrical and chemical properties of the target materials. Methods to calculate atomic displacement based on nuclear reaction cross sections and Rutherford scattering cross sections were proposed but they were dedicated to calculation of the defect density in macroscopic scale whereas some phenomena are attributed to the topological arrangements of defects in microscopic scale. Application of a track-structure calculation model, ITSART implemented to a general-purpose radiation transport code PHITS for calculation of the topological arrangement of radiation-induced defects is proposed in this study. To verify the defect production calculated by ITSART, DPA (Displacement Per Atom) cross section in Cu was calculated and compared with literature data. The agreement indicates the accuracy of ITSART for calculating atomic displacement. By using the same methodology to a smaller volume, the defects in SiO exposed to 600 MeV proton beam was calculated. PHITS users can make use of the outputs by forwarding them to other tools, such as molecular dynamics codes, to analyse the further evolution of the defects.
Hirata, Yuho; Kai, Takeshi; Ogawa, Tatsuhiko; Matsuya, Yusuke; Sato, Tatsuhiko
Nuclear Instruments and Methods in Physics Research B, 547, p.165183_1 - 165183_7, 2024/02
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)The luminescence efficiency of the phosphors for swift ions is known to decrease because of the quenching effects. To obtain the precise dose distributions using phosphor detectors, understanding the mechanisms of quenching effects is mandatory. Here, we developed a new model for estimating the luminescence intensity of phosphors based on the track-structure modes for arbitrary materials implemented in PHITS. The developed model enabled the simulation of the quenching effects of the BaFBr detector and was verified by comparing the results to the corresponding measured data. The present model is expected to contribute to developing phosphor detectors worldwide.
Ogawa, Tatsuhiko; Hashimoto, Shintaro; Sato, Tatsuhiko
Journal of Nuclear Science and Technology, 61(1), p.68 - 73, 2024/01
Times Cited Count：3 Percentile：50.10(Nuclear Science & Technology)The gamma de-excitation model of the general-purpose radiation transport code Particle and Heavy Ion Transport code System (PHITS), called the Evaluated Nuclear Structure Data File (ENSDF-)-Based Isomeric Transition and isomEr production Model (EBITEM) has been upgraded with focus on precise neutron capture reaction simulation. The first de-excitation subsequent to neutron capture of numerous nuclei, which was formerly simulated by a model based on the single particle model, is calculated using the Evaluated Gamma Activation File (EGAF). The database used for further de-excitation, ENSDF, retrieved in 2013, was replaced with Reference Input Parameter Library 3 (RIPL-3) to consider internal conversion. The internal conversion process was interfaced with the atomic de-excitation model to assess the emission of Auger electrons and fluorescent X-rays. The spectra of gamma-rays from neutron capture reactions calculated by the upgraded EBITEM correlate better with the evaluated cross section data than those of the previous version.
Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuya, Yusuke; Matsuda, Norihiro; Hirata, Yuho; et al.
Journal of Nuclear Science and Technology, 61(1), p.127 - 135, 2024/01
Times Cited Count：183 Percentile：99.97(Nuclear Science & Technology)The Particle and Heavy Ion Transport code System (PHITS) is a general-purpose Monte Carlo radiation transport code that can simulate the behavior of most particle species with energies up to 1 TeV (per nucleon for ions). Its new version, PHITS3.31, was recently developed and released to the public. In the new version, the compatibility with high-energy nuclear data libraries and the algorithm of the track-structure modes have been improved. In this paper, we summarize the upgraded features of PHITS3.31 with respect to the physics models, utility functions, and application software introduced since the release of PHITS3.02 in 2017.
Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Sato, Kaoru*; Tsutsumi, Masaki*; Tanaka, Yoshimasa*; Ogawa, Yasunobu*; Sato, Tatsuhiko
Space Weather, 21(12), p.e2023SW003651_1 - e2023SW003651_11, 2023/12
Times Cited Count：2 Percentile：33.46(Astronomy & Astrophysics)Comprehensive understandings of their global impact on the atmosphere require whole pictures of spatio-temporal distributions of the ionization due to them. We estimate the altitude profiles of the ionization rate during the space weather event occurred in September 2017 by using the Particle and Heavy Ion Transport code System (PHITS) with input of the particle fluxes obtained by satellites. The estimates are then compared with measurements of the ionization altitude, ionization intensity, and electron density by the radars in the polar region such as the PANSY radar at Syowa Station and the EISCAT in Tromso, Norway. We conclude that the PHITS simulation results reproduce those ionizations measured by ground-based instruments with inputs of observed ionization sources by satellites within a factor of 2.
Hirata, Yuho; Kai, Takeshi; Ogawa, Tatsuhiko; Matsuya, Yusuke*; Sato, Tatsuhiko
Japanese Journal of Applied Physics, 62(10), p.106001_1 - 106001_6, 2023/10
Times Cited Count：5 Percentile：46.17(Physics, Applied)Optimization of semiconductor detector design requires theoretical analysis of the process of radiation conversion to carriers (excited electrons) in semiconductor materials. We, therefore, developed an electron track-structure code that can trace an incident electron trajectory down to a few eV and simulate many excited electron productions in semiconductors, named ETSART, and implemented it into PHITS. The accuracy of ETSART was validated by comparing calculated electron ranges in semiconductor materials with the corresponding data recommended in ICRU Report 37 and obtained from another simulation code. The average energy required to produce a single excited electron (epsilon value) is an important value that describes the characteristics of semiconductor detectors. Using ETSART, we computed the epsilon values in various semiconductors and found that the calculated epsilon values cannot be fitted well with a linear model of the band-gap energy. ETSART is expected to be useful for initial and mechanistic evaluations of electron-hole generation in undiscovered materials.
Sato, Tatsuhiko; Matsuya, Yusuke*; Ogawa, Tatsuhiko; Kai, Takeshi; Hirata, Yuho; Tsuda, Shuichi; Parisi, A.*
Physics in Medicine & Biology, 68(15), p.155005_1 - 155005_15, 2023/07
Times Cited Count：11 Percentile：88.01(Engineering, Biomedical)In this study, we improved the microdosimetric function implemented in PHITS using the latest track-structure simulation codes. The improved function is capable of calculating the probability densities of not only the conventional microdosimetric quantities such as lineal energy but also the numbers of ionization events occurred in a target site, the so-called ionization cluster size distribution, for arbitrary site diameters from 3 nm to 1 um. As a new application of the improved function, we calculated the relative biological effectiveness of the single-strand break and double-strand break yields for proton irradiations using the updated PHITS coupled with the simplified DNA damage estimation model, and confirmed its equivalence in accuracy and its superiority in computational time compared to our previously proposed method based on the track-structure simulation.
Constantini, J.-M.*; Ogawa, Tatsuhiko; Gourier, D.*
Journal of Physics; Condensed Matter, 35(28), p.285701_1 - 285701_12, 2023/04
Times Cited Count：0 Percentile：0.00(Physics, Condensed Matter)A novel analysis of luminescence is presented on the basis of virtual photon spectra (VPS) produced by charged particles (electrons or ions) passing by luminescent species such as defects or impurities, in wide band-gap ionic-covalent solids. The electron-energy dependence of experimental luminescence spectra of sapphire (-AlO) is discussed in relation to the computed VPS for the primary and secondary electrons. The experimental luminescence spectra of -AlO are also analyzed in this framework for protons and helium ions in the MeV energy range. The variations of stopping power are consistent with the variation of the number of emitted VPs. The decay of luminescence yield versus ion stopping power is discussed on the basis of the variation of the computed VPS, and ionization and excitation induced by primary ions and secondary electrons. This decay is accounted for by a decrease of the yield of low-energy secondary electrons with the subsequent VP emission.
Constantini, J.-M.*; Ogawa, Tatsuhiko
Quantum Beam Science (Internet), 7(1), p.7_1 - 7_16, 2023/03
Sputtering, emission of constituent atoms or molecules of materials induced by irradiation, is regarded as one of standard engineering techniques. According to some experimental data, emission of atoms whose direction is anti-parallel to incident radiation momentum was found among the sputtered atoms. Based on the standard approach, the thermal-spike model, atoms are evaporated by equillibrated thermal canonical ensemble resulted in by heat propagation therefore emission must be isotropic. Inspired by the fact that ionizations induced by ion irradiation are arranged linearly along the ion path, and the electric repulsion force between the ionizations tend to be parallel to irradiation axis, we developed an alternative approach in this study to explain the anisotropic emission. Using the spatial configuration of the irradiation-induced positive ions calculated by track-structure calculation code RITRACKS, the momentum of ions driven by the electric force was calculated. The calculated result explains the inverse jet of ions in case of 1 MeV proton and 1 MeV/u carbon ion irradiation to water. Moreover, the calculated sputtering yield also agrees with earlier experimental data.
Iwamoto, Yosuke; Tsuda, Shuichi; Ogawa, Tatsuhiko
Frontiers in Energy Research (Internet), 11, p.1085264_1 - 1085264_11, 2023/01
Times Cited Count：1 Percentile：1.00(Energy & Fuels)This review describes experimental data useful for validation of radiation shielding design in advanced reactor systems such as nuclear fusion and accelerator-driven subcritical systems (ADS) and calculations using the PHITS code and JENDL-4.0/HE. The relevant experiments have been conducted mainly in Japan and include (1) neutron spectra in iron shields using 14 MeV neutron sources, (2) leakage neutron spectra from spherical piles of various materials using 14 MeV neutron sources, (3) neutron spectra after penetration through shields using several tens of MeV neutron sources, (4) neutron spectra produced from the target by high-energy heavy-ion bombardment, and (5) induced radioactivity in concrete using heavy-ion nuclear reaction product particles as a source. Throughout, the experimental and calculated values were agreed well. These experimental data are also useful for the validation of all radiation transport calculation codes used in the design of advanced reactor systems.
