Iwamoto, Yosuke; Meigo, Shinichiro; Hashimoto, Shintaro
Journal of Nuclear Materials, 538, p.152261_1 - 152261_9, 2020/09
The displacements-per-atom (dpa) is widely used as an exposure unit to predict the operating lifetime of materials in radiation environments. Because the athermal-recombination-corrected dpa (arc-dpa) model is a more realistic model than the standard Norgertt-Robinson-Torrens (NRT) model, new evaluation of radiation damage will be performed using the arc-dpa model as a standard. In this work, the recent arc-dpa model of various materials are incorporated in PHITS, and the rescaling factors (NRT-dpa/arc-dpa) over a wide energy range are reported. For neutron incidences with the energy spectrum determined in selected nuclear facilities and proton incidences with energies of 600 MeV-50 GeV, the rescaling factor for each material is independent of these irradiation conditions with almost the same value for each material. Our findings will be beneficial for rescaling the NRT-dpa model used for radiation damage applications over a wide energy region.
Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Shintaro; Minato, Futoshi; Kawabata, Masako*; Hatsukawa, Yuichi*; Hashimoto, Kazuyuki*; Watanabe, Satoshi*; Saeki, Hideya*; Motoishi, Shoji*
Journal of the Physical Society of Japan, 89(3), p.034201_1 - 034201_7, 2020/03
We found anomalously large yields of Ga, Ga, Zn and Cu by neutron irradiation on a ZnO sample in a polyethylene shield. Neutron beams are generated from the Be() reaction for 50 MeV deuterons. The yields obtained were more than 20 times larger than those in the unshielded sample. On the other hand, the yields of Ga, Ga, Zn and Cu from a metallic Zn sample and the yields of Cu, Ni and Zn from the ZnO and Zn samples were almost insensitive to the shield conditions. This finding would provide us a unique capability of accelerator neutrons to simultaneously produce a large amount of several radioisotopes, including proton induced reaction products, by using a single sample. The experimental data were compared with the yields estimated by using the Particle and Heavy Ion Transport code System and the result was discussed.
Nakayama, Shinsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Hashimoto, Shintaro
Kaku Deta Nyusu (Internet), (123), p.53 - 59, 2019/06
The 2019 International Conference on Nuclear Data for Science and Technology (ND2019) was held at the China National Convention Center on May 19-24, 2019. The series of the ND conferences are the largest conferences in nuclear data research field that are held every three years. In this paper, as a part of the conference reports of ND2019, the authors gave summaries of the presentations on nuclear data evaluation and theory conducted at the conference.
Hashimoto, Shintaro; Sato, Tatsuhiko
Journal of Nuclear Science and Technology, 56(4), p.345 - 354, 2019/04
Particle transport simulations based on the Monte Carlo method have been applied to shielding calculations. Estimation of not only statistical uncertainty related to the number of trials but also systematic one induced by unclear physical quantities is required to confirm the reliability of calculated results. In this study, we applied a method based on analysis of variance to shielding calculations. We proposed random- and three-condition methods. The first one determines randomly the value of the unclear quantity, while the second one uses only three values: the default value, upper and lower limits. The systematic uncertainty can be estimated adequately by the random-condition method, though it needs the large computational cost. The three-condition method can provide almost the same estimate as the random-condition method when the effect of the variation is monotonic. We found criterion to confirm convergence of the systematic uncertainty as the number of trials increases.
Ogawa, Tatsuhiko; Sato, Tatsuhiko; Hashimoto, Shintaro; Niita, Koji*
Physical Review C, 98(2), p.024611_1 - 024611_15, 2018/08
Particle production by nucleus-nucleus reactions in the energy range from GeV to TeV is substantially important for safety evaluation in heavy ion accelerators and evaluation of space radiation dose. A lot of models and theories have been studied. In the models developed in the past, interaction between nucleons were dependent on the reference frame; therefore the moving incident nucleus and the target nucleus at rest transferred to the common frame were disintegrated. Previously, intentional bias was introduced to the calculation algorithms to supplement stability but residual nucleus mass and secondary particle production was underestimated. In this study, a reaction model JAMQMD was developed, in which intra-nucleon interaction was described in a frame-independent way. This model can reproduce the stability of nuclei regardless of the reference frame and the yield of residual nuclei as well as secondary particles including deuterons. JQMD Ver.2 developed 3 years ago can simulate nucleus-nucleus reactions up to 3 GeV/nucleon; therefore the development of JAMQMD is the doorway to simulate nucleus-nucleus reactions regardless of the incident energy. JAMQMD is an useful model for not only radiation protection studies but also analysis of fundamental physics studies.
Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Tsai, P.-E.; Matsuda, Norihiro; Iwase, Hiroshi*; et al.
Journal of Nuclear Science and Technology, 55(6), p.684 - 690, 2018/06
We have upgraded many features of the Particle and Heavy Ion Transport code System (PHITS) and released the new version as PHITS3.02. The accuracy and the applicable energy ranges of the code were greatly improved and extended, respectively, owing to the revisions to the nuclear reaction models and the incorporation of new atomic interaction models. In addition, several user-supportive functions were developed, such as new tallies to efficiently obtain statistically better results, radioisotope source-generation function, and software tools useful for applying PHITS to medical physics. In this paper, we summarize the basic features of PHITS3.02, especially those of the physics models and the functions implemented after the release of PHITS2.52 in 2013.
Hashimoto, Shintaro; Sato, Tatsuhiko; Iwamoto, Yosuke; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Niita, Koji*
Kaku Deta Nyusu (Internet), (120), p.26 - 34, 2018/06
Particle and heavy-ion transport code system PHITS has been used for calculations of radiation shielding in accelerator facilities. PHITS describes physical phenomena induced by radiation as combination of transport and collision processes. The collision process including nuclear reactions is simulated by the three-step calculation: a generation of a reaction, pre-equilibrium, and compound processes. In the simulation, many physics models are used. This report explains roles of the models in PHITS and shows their developments we recently performed.
Ogawa, Tatsuhiko; Hashimoto, Shintaro; Sato, Tatsuhiko; Niita, Koji*; Kamae, Tsuneyoshi*
Proceedings of 3rd International Conference on Particle Physics and Astrophysics (ICPPA 2017) (Internet), p.391 - 398, 2018/04
In the reactions of cosmic-ray heavy ions producing high-energy gamma-rays, heavy ions are directed to the ground therefore prompt gamma-rays from projectile fragments are boosted by Doppler effect and observed on the ground. Recently, a lot of experiments pay attention to such high energy gamma-rays. In order to simulate such high-energy gammas, event-by-event simulation of fragmentation reaction which determines the excitation energy and angular momentum of the produced fragment, and de-excitation simulation based on the nuclear structure data. Such models are available in the general-purpose radiation transport simulation code PHITS. JAERI Quantum Molecular Dynamics model was recently updated to accurately simulate charge and mass distribution of fragments. EBITEM, which was released recently, can simulate gamma deexcitation after evaporation based on the excitation energy and angular momentum. Thus latest PHITS can accurately simulate production of -rays attributed to cosmic-ray heavy ions. This study shows a new approach to reproduce -rays by cosmic-ray heavy ions.
Minato, Futoshi; Tsukada, Kazuaki*; Sato, Nozomi*; Watanabe, Satoshi*; Saeki, Hideya*; Kawabata, Masako*; Hashimoto, Shintaro; Nagai, Yasuki*
Journal of the Physical Society of Japan, 86(11), p.114803_1 - 114803_6, 2017/11
We have measured the yield of Mo, the mother nuclide of Tc used in nuclear diagnostic procedure. Mo was produced by Mo(,)Mo using neutrons with thermal energy up to about 40 MeV, provided by C(,). The Mo yield agrees with an estimated yield with the use of the latest data of C(,) and the evaluated cross section given in the JENDL. Based on this, a new calculation was carried out to produce Mo to seek for a good economical condition. Various conditions such as the MoO sample mass, the distance between the carbon target and the sample, the radius of the deuteron beam, and the neutron irradiation time were considered. The calculated Mo yield indicates that about 30% of the Mo demand in Japan can be fulfilled with a single accelerator. The elusion of Tc from the Mo twice per day would meet about 50% of the Mo demand.
Sato, Tatsuhiko; Niita, Koji*; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Okumura, Keisuke; et al.
EPJ Web of Conferences, 153, p.06008_1 - 06008_6, 2017/09
Particle and Heavy Ion Transport code System, PHITS, has been developed under the collaboration of several institutes in Japan and Europe. It can deal with the transport of nearly all particles up to 1 TeV (per nucleon for ion) using various nuclear reaction models and data libraries. More than 2,500 researchers and technicians have used the code for a variety of applications such as accelerator design, radiation shielding and protection, medical physics, and space and geosciences. This paper briefly summarizes physics models and functions newly implemented in PHITS between versions 2.52 and 2.82.
Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Iwase, Hiroshi*; Niita, Koji*
Hoshasen, 43(2), p.55 - 58, 2017/05
Particle and Heavy Ion Transport code System, PHITS, has been developed under the collaboration of several institutes in Japan and Europe. It can deal with the transport of nearly all particles up to 1 TeV (per nucleon for ion) using various nuclear reaction models and data libraries. More than 2,500 registered researchers and technicians have used this system for various applications such as accelerator design, radiation shielding and protection, medical physics, and space- and geo-sciences. This paper summarizes the physics models and functions recently implemented in PHITS, between versions 2.52 and 2.88.
Iwamoto, Yosuke; Sato, Tatsuhiko; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Hosoyamada, Ryuji*; Niita, Koji*
Journal of Nuclear Science and Technology, 54(5), p.617 - 635, 2017/05
We performed a benchmark study for 58 cases using the recent version 2.88 of the Particle and Heavy Ion Transport code System (PHITS) in the following fields: particle production cross-sections for nuclear reactions, neutron transport calculations, and electro-magnetic cascade. This paper reports details for 22 cases. In cases of nuclear reactions with energies above 100 MeV and electro-magnetic cascade, overall agreements were found to be satisfactory. On the other hand, PHITS did not reproduce the experimental data for an incident proton energy below 100 MeV, because the intranuclear cascade model INCL4.6 in PHITS is not suitable for the low-energy region. For proton incident reactions over 100 MeV, PHITS did not reproduce fission product yields due to the problem of high-energy fission process in the evaporation model GEM. To overcome these inaccuracies, we are planning to incorporate a high-energy version of the evaluated nuclear data library JENDL-4.0/HE, and so on.
Ogawa, Tatsuhiko; Hashimoto, Shintaro; Sato, Tatsuhiko
Journal of Nuclear Science and Technology, 53(11), p.1766 - 1773, 2016/11
Nuclear resonance fluorescence (NRF) is regarded as a useful phenomenon for application to non-destructive assay of fissile nuclei because NRF cross section peak energy is specific to isotopic species and detection system can be build using conventional photon detectors. So far, experimental technique such as monochromatic photon source based on inverse Compton scattering are intensively studied. In contrast, some unofficial release of nuclear reaction models to simulate NRF based on the literature data are available; however, no general-purpose NRF model was developed. In this study, general-purpose NRF model which can simulate NRF of 1071 nuclear species including unstable nuclei from Li to Bk was developed using nuclear structure data of ENSDF (Evaluated Nuclear Structure Data File) and theoretical description of the level transitions. Moreover, the model was applied for generation of radioactive nuclei and nuclear material assay to illustrate its effectiveness. This model was incorporated to PHITS ver.2.82 released Dec. 25th 2015 and provided to users.
Iwamoto, Hiroki; Nishihara, Kenji; Iwamoto, Yosuke; Hashimoto, Shintaro; Matsuda, Norihiro; Sato, Tatsuhiko; Harada, Masahide; Maekawa, Fujio
Journal of Nuclear Science and Technology, 53(10), p.1585 - 1594, 2016/10
Iwamoto, Yosuke; Sato, Tatsuhiko; Niita, Koji*; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Iwase, Hiroshi*; et al.
JAEA-Conf 2016-004, p.63 - 69, 2016/09
A general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through the collaboration of several institutes. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. PHITS users apply the code to various research and development fields such as nuclear technology, accelerator design, medical physics, and cosmic-ray research. This presentation briefly summarizes the physics models implemented in PHITS, and introduces some new models such as muon-induced nuclear reaction model and a de-excitation model EBITEM. We will also present the radiation damage cross sections for materials, PKA spectra and kerma factors calculated by PHITS under the IAEA-CRP activity titled "Primary radiation damage cross section."
Ogawa, Tatsuhiko; Hashimoto, Shintaro; Sato, Tatsuhiko; Niita, Koji*
EPJ Web of Conferences, 122, p.04005_1 - 04005_6, 2016/06
Nucleus-nucleus reactions models are important for radiological safety in heavy ions accelerator facilities such as heavy ion cancer therapy facilities. As one of such models, JAERI Quantum Molecular Dynamics (JQMD) has been successfully used to describe production of residue and secondary particles in nucleus-nucleus collisions. However, it has been pinpointed that formulation of interactions between nucleons were unstable through time evolution therefore heavy nuclei tended to decay before interactions. Such decays could not be distinguished from decay by collisions. In this study, we revised the description of interactions between nucleons to stabilize nuclei before collisions. Moreover, an algorithm to check the stability of ground-state nuclei was introduced. Description of nucleon-nucleon scattering cross sections were improved by introducing the in-medium effects. Fragment production cross sections for heavy targets (e.g. Ag) are predicted in better accuracy by thus developed revised JQMD (JQMD 2.0).
Ogawa, Tatsuhiko; Sato, Tatsuhiko; Hashimoto, Shintaro; Niita, Koji*
EPJ Web of Conferences, 117, p.03011_1 - 03011_8, 2016/05
Accurate prediction of fragment angular distribution in nucleus-nucleus collisions is essential for theoretical studies on nuclei and applications of particle beam. Quantum molecular dynamics is one of the approaches often adopted in general purpose radiation transport simulation codes to simulate formation of fragments, however, it is suggested that they tend to overestimate the width of fragment distribution angle. It is true for JQMD, the nucleus-nucleus reaction event generator incorporated to PHITS. By revising the description of peripheral collisions prediction of fragments angular distribution has been improved. First, spurious disintegration of nuclei before interaction is inhibited by introducing relativistic-covariant kinematics. By this improvement, one can distinguish nucleus spuriously disintegrated and nuclei interacted with other nuclei. Second, nucleon-nucleon scattering cross sections were increased by the suppression of Pauli blocking effect in the nucleus outer region to take into account for the increase in nucleon-nucleon scattering cross section. As a result, revised JQMD (RJQMD) predicts fragment angular distribution of fragments better than JQMD.
Furuta, Takuya; Hashimoto, Shintaro; Sato, Tatsuhiko
Igaku Butsuri, 36(1), p.50 - 54, 2016/00
An application of Particle and Heavy Ion Transport Code System; PHITS, for medical physics is to simulate treatment planning of radiation therapy. Treatment planning simulation is conducted by constructing patient geometry from patient CT data, calculating radiation transport of external beam, and deducing dose distribution inside patient body. However, it is not easy to extract information such as patient location and CT value distribution from patient CT data or to construct complex accelerator geometry in PHITS format. Therefore, we developed two user assistance programs, DICOM2PHITS and PSFC4PHITS. DICOM2PHITS is a program to construct the voxel PHITS simulation geometry from patient CT DICOM image data. PSFC4PHITS is a program to convert the IAEA phase-space file data to PHITS format to be used as simulation source of PHITS. We explain these two programs by showing some applications in this article.
Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Iwamoto, Yosuke; Furuta, Takuya; Noda, Shusaku; Ogawa, Tatsuhiko; Iwase, Hiroshi*; Nakashima, Hiroshi; et al.
Annals of Nuclear Energy, 82, p.110 - 115, 2015/08
The general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through a collaboration of several institutes in Japan and Europe. The Japan Atomic Energy Agency is responsible for managing the entire project. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. This paper briefly summarizes the physics models implemented in PHITS, and introduces some important functions useful for particular purposes, such as an event generator mode and beam transport functions.
Ogawa, Tatsuhiko; Sato, Tatsuhiko; Hashimoto, Shintaro; Satoh, Daiki; Tsuda, Shuichi; Niita, Koji*
Physical Review C, 92(2), p.024614_1 - 024614_14, 2015/08
For prediction of radiological impact of heavy ions in accelerator facilities, space missions and cancer therapy, nuclear reaction models play a fundamental role. As one of such models, JAERI Quantum molecular dynamics (JQMD) has been successfully used to describe production of residue and secondary particles in nucleus-nucleus collisions. However, it has been pinpointed that JQMD underestimates projectile-like fragments produced in peripheral collisions. Moreover, no cross section data systematically measured over a wide energy range are not available, which makes it difficult to benchmark the reaction models. In this study, we develop a method to measured fragmentation cross sections using a thick target and detecting fragments produced from incident ions fragmented in the target using telescope detectors. Thus we obtained fragmentation cross sections systematically over a wide energy range. We also revise the description of reaction mechanism and ground-state nuclear structure in JQMD to take into account for peripheral collisions accurately. So far, ground-state nuclei got excited and sometimes disintegrated owing to frame transform from the laboratory system to the center-of-mass system. Fragment production cross sections calculated by the revised JQMD (JQMD2.0) are in better agreement with the literature data.