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Journal Articles

Radioactivity and radionuclides in deciduous teeth formed before the Fukushima-Daiichi Nuclear Power Plant accident

Takahashi, Atsushi*; Chiba, Mirei*; Tanahara, Akira*; Aida, Jun*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Murakami, Shinobu*; Koarai, Kazuma; Ono, Takumi*; Oka, Toshitaka; et al.

Scientific Reports (Internet), 11(1), p.10355_1 - 10355_11, 2021/05

 Times Cited Count:1 Percentile:65.97(Multidisciplinary Sciences)

Journal Articles

Morphological reproductive characteristics of testes and fertilization capacity of cryopreserved sperm after the Fukushima accident in raccoon (${it Procyon lotor}$)

Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.

Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03

We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.

Journal Articles

Spallation and fragmentation cross sections for 168 MeV/nucleon $$^{136}$$Xe ions on proton, deuteron, and carbon targets

Sun, X. H.*; Wang, H.*; Otsu, Hideaki*; Sakurai, Hiroyoshi*; Ahn, D. S.*; Aikawa, Masayuki*; Fukuda, Naoki*; Isobe, Tadaaki*; Kawakami, Shunsuke*; Koyama, Shumpei*; et al.

Physical Review C, 101(6), p.064623_1 - 064623_12, 2020/06

 Times Cited Count:2 Percentile:35.83(Physics, Nuclear)

The spallation and fragmentation reactions of $$^{136}$$Xe induced by proton, deuteron and carbon at 168 MeV/nucleon were studied at RIKEN Radioactive Isotope Beam Factory via the inverse kinematics technique. The cross sections of the lighter products are larger in the carbon-induced reactions due to the higher total kinetic energy of carbon. The energy dependence was investigated by comparing the newly obtained data with previous results obtained at higher reaction energies. The experimental data were compared with the results of SPACS, EPAX, PHITS and DEURACS calculations. These data serve as benchmarks for the model calculations.

Journal Articles

Comparison of heavy-ion transport simulations; Collision integral with pions and $$Delta$$ resonances in a box

Ono, Akira*; Xu, J.*; Colonna, M.*; Danielewicz, P.*; Ko, C. M.*; Tsang, M. B.*; Wang, Y,-J.*; Wolter, H.*; Zhang, Y.-X.*; Chen, L.-W.*; et al.

Physical Review C, 100(4), p.044617_1 - 044617_35, 2019/10

AA2019-0025.pdf:2.76MB

 Times Cited Count:29 Percentile:98.33(Physics, Nuclear)

International comparison of heavy-ion induced reaction models were discussed in the international conference "Transport2017" held in April 2017. Owing to their importance for safety assessment of heavy-ion accelerators and dosimetry of astronauts, various models to simulate heavy-ion induced reaction models are developed. This study is intended to clarify the difference among them to pinpoint their problems. In the comparison study, 320 protons and neutrons were packed in a 20-fm-large cube to calculate the number and energies of collisions during the time evolution. The author contributed to this study by running calculation using JQMD (JAERI Quantum Molecular Dynamics). This study showed that time step in the calculation is one of the biggest causes of the discrepancies. For example, the calculation by JQMD comprises 1-fm/c time steps, each of which is composed of transport, scattering and decay phases. Therefore a sequence of scattering, and decay followed by another scattering in 1 fm/c cannot be considered. Moreover, in JQMD particles are labeled by sequential numbers and scattering reactions are simulated by the order. Therefore scattering between low ID numbers, that between high ID numbers and that between the first (low ID) pair is overlooked in JQMD. Above indications obtained in this study must be kept in our mind for future JQMD upgrades.

Journal Articles

Comparison of heavy-ion transport simulations; Collision integral in a box

Zhang, Y.-X.*; Wang, Y,-J.*; Colonna, M.*; Danielewicz, P.*; Ono, Akira*; Tsang, M. B.*; Wolter, H.*; Xu, J.*; Chen, L.-W.*; Cozma, D.*; et al.

Physical Review C, 97(3), p.034625_1 - 034625_20, 2018/03

 Times Cited Count:63 Percentile:99.37(Physics, Nuclear)

International comparison of heavy-ion induced reaction models were discussed in the international conference "Transport2017" held in April 2017. Owing to their importance for safety assessment of heavy-ion accelerators and dosimetry of astronauts, various models to simulate heavy-ion induced reaction models are developed. This study is intended to clarify the difference among them to pinpoint their problems. In the comparison study, 320 protons and 320 neutrons were packed in a 20-fm-large cube to calculate the number of particle-particle collisions as well as the energies of collisions during the time evolution. In addition to the calculation, their algorithms were compared. The author contributed to this study by running calculation using JQMD (JAERI Quantum Molecular Dynamics). The results were compared with those calculated by the other 15 codes from over the world. Algorithm comparison showed that JQMD calculates collision probabilities from protons at first and collisions by neutrons are simulated later, which might be unreasonable. On the other hand, it was clarified that the calculation by JQMD agrees with those by the others. Despite the fact that some codes deviate from the average by a factor of 2, JQMD exhibited stable performance.

Journal Articles

Numerical analysis of organ doses delivered during computed tomography examinations using Japanese adult phantoms with the WAZA-ARI dosimetry system

Takahashi, Fumiaki; Sato, Kaoru; Endo, Akira; Ono, Koji*; Ban, Nobuhiko*; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Yoshitake, Takayasu*; Kai, Michiaki*

Health Physics, 109(2), p.104 - 112, 2015/08

 Times Cited Count:8 Percentile:65.81(Environmental Sciences)

A dosimetry system, named WAZA-ARI, is developed to assess accurately radiation doses to persons from Computed Tomography (CT) examination patients in Japan. Organ doses were prepared to application to dose calculations in WAZA-ARI by numerical analyses using average adult Japanese human models with the Particle and Heavy Ion Transport code System (PHITS). Experimental studies clarified the radiation configuration on the table for some multi-detector row CT (MDCT) devices. Then, a source model in PHITS could specifically take into account for emissions of X-ray in each MDCT device based on the experiment results. Numerical analyses with PHITS revealed a concordance of organ doses with human body size. The organ doses by the JM phantoms were compared with data obtained using previously developed systems. In addition, the dose calculation in WAZA-ARI were verified with previously reported results by realistic NUBAS phantoms and radiation dose measurement using a physical Japanese model. The results implied that analyses using the Japanese phantoms and PHITS including source models can appropriately give organ dose data with consideration of the MDCT device and physiques of typical Japanese adults.

Journal Articles

WAZA-ARI; A Dose assessment system for patients in CT scan

Sato, Kaoru; Takahashi, Fumiaki; Endo, Akira; Ono, Koji*; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Yoshitake, Takayasu*; Ban, Nobuhiko*; Kai, Michiaki*

RIST News, (58), p.25 - 32, 2015/01

The Japan Atomic Energy Agency (JAEA) are now developing WAZA-ARI for improvement of management of exposure doses due to CT examination under the joint research with the Oita University of Nursing and Health Sciences. The trial version of WAZA-ARI has been released on 21 December 2012. In trial version, users can perform dose assessment by using organ dose database based on the average adult Japanese male (JM-103) and female (JF-103) voxel phantoms and a 4 years old female voxel phantom (UFF4). The homepage of WAZA-ARI has been accessed over 1000 times per month and 28421 times by the end of September 2014. We are developing WAZA-ARI version 2 as the extension version of dose calculation functions of WAZA-ARI. WAZA-ARI version 2 will be released by the end of March 2015. In WAZA-ARI version 2. Users can upload dose calculation results to WAZA-ARI version 2 server, and utilize improvement of the dose management of patients and the optimization of CT scan conditions.

Journal Articles

Cabling technology of Nb$$_3$$Sn conductor for ITER central solenoid

Takahashi, Yoshikazu; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Uno, Yasuhiro; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.4802404_1 - 4802404_4, 2014/06

 Times Cited Count:20 Percentile:73.53(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency (JAEA) is procuring all amounts of Nb$$_3$$Sn conductors for Central Solenoid (CS) in the ITER project. Before start of mass-productions, the conductor should be tested to confirm superconducting performance in the SULTAN facility, Switzerland. The original design of cabling twist pitches is 45-85-145-250-450 mm, called normal twist pitch (NTP). The test results of the conductors with NTP was that current shearing temperature (Tcs) is decreasing due to electro-magnetic (EM) load cycles. On the other hand, the results of the conductors with short twist pitches (STP) of 25-45-80-150-450 mm show that the Tcs is stabilized during EM load cyclic tests. Because the conductors with STP have smaller void fraction, higher compaction ratio during cabling is required and possibility of damage on strands increases. The technology for the cables with STP was developed in Japanese cabling suppliers. The several key technologies will be described in this paper.

Journal Articles

Effects of human model configuration in Monte Carlo calculations for organ doses from CT examinations

Takahashi, Fumiaki; Sato, Kaoru; Endo, Akira; Ono, Koji*; Yoshitake, Takayasu*; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Ban, Nobuhiko*; Kai, Michiaki*

Progress in Nuclear Science and Technology (Internet), 2, p.153 - 159, 2011/10

Computed Tomography (CT) is one of the most useful tools for medical diagnosis, and is becoming a major source of medical exposure in developed countries. Appropriate radiation protection in CT examinations is emphasized by international organizations, such as the International Atomic Energy Agency (IAEA), because the patients receive higher radiation doses than in conventional radiography. Medical staffs can acquire dose information on the conditions of some CT examinations with available dosimetry systems, which had been already developed. These systems utilize datasets of organ and tissue doses, which were derived with Monte Carlo calculations. Methods in computational analyses, however, have been improved, since these calculations had been performed. Then, our new dosimetry system for CT examination, WAZA-ARI, is being developed to estimate radiation dose based upon the state-of-art numerical analyses. Our analysis adopts Particle and Heavy Ion Transport code System (PHITS) coupled with a voxel-type phantom, JM phantom, for the organ dose calculation. PHITS has advantageous to define the model of photon emission from X-ray tube in a CT device for radiation transport calculations. The physique and mass of organs for JM phantom are similar to those for average Japanese male adults. Since the goal of WAZA-ARI is to provide dosimetric information of arbitrary patient, it is important to evaluate uncertainty due to different configurations in human bodies between JM phantom and individual patients. For this purpose, the organ doses are calculated and compared for different human models; another Japanese male adult voxel phantom and the ICRP reference voxel phantom, which is constructed on the basis of Caucasian data.

Journal Articles

Development of a web-based CT dose calculator; WAZA-ARI

Ban, Nobuhiko*; Takahashi, Fumiaki; Sato, Kaoru; Endo, Akira; Ono, Koji*; Hasegawa, Takayuki*; Yoshitake, Takayasu*; Katsunuma, Yasushi*; Kai, Michiaki*

Radiation Protection Dosimetry, 147(1-2), p.333 - 337, 2011/09

 Times Cited Count:21 Percentile:85.03(Environmental Sciences)

A web-system of WAZA-ARI is being developed to assess radiation dose to a patient in a Computed Tomography (CT) examination. The databases of organ doses for WAZA-ARI were derived by the Japanese adult Male phantom (JM phantom) combined with the Particle and Heavy Ion Transport code System, PHITS. In the Monte Carlo simulation, the phantoms were irradiated with a 5 mm-thick fan-shaped photon beam, which was moved every 5 mm along the body axis from the upper leg to the top of head. The attenuation by the beam-shaping filter (bow-tie filter) was also taken into account here. The MIRD-type phantom was also applied to the calculations. The MIRD phantom sometimes showed step changes for organ doses, while smoother curves were obtained for JM phantom. The dose data by JM phantom were incorporated into the WAZA-ARI system, which has been implemented on a Linux server. With regard to the system implementation, the system has achieved a high degree of flexibility without commercial software.

Journal Articles

WAZA-ARI; Computational dosimetry system for X-ray CT examinations, 1; Radiation transport calculation for organ and tissue doses evaluation using JM phantom

Takahashi, Fumiaki; Sato, Kaoru; Endo, Akira; Ono, Koji*; Yoshitake, Takayasu*; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Ban, Nobuhiko*; Kai, Michiaki*

Radiation Protection Dosimetry, 146(1-3), p.241 - 243, 2011/07

 Times Cited Count:16 Percentile:80(Environmental Sciences)

A web-system of WAZA-ARI is being developed to assess radiation dose to a patient in a Computed Tomography (CT) examination. WAZA-ARI utilizes a set of organ and tissue doses in a database for the dose assessment, according to the given resources with a consideration of the examination condition. The organ and tissue doses in the database have been derived with the Particle and Heavy Ion Transport code System, PHITS. Modeling of the patient was a significant issue in the radiation transport calculation. JM phantom, whose height (171 cm) and weight (65 kg) are near to those averaged over Japanese male adults, was incorporated to PHITS as a human model. Since JM phantom consisted of about 1 mm$$^{3}$$ size voxel, the shapes could be realistically reproduced even for small organs such as thyroid, adrenals. Masses of most organs could be also adjusted to the averaged values of Japanese male adults. In addition, our calculations introduced a new phantom without arms based upon JM phantom, because the patient usually puts arms toward the head direction in a torso examination. Some of organ doses calculated by JM phantom were compared with results, which were derived with a MIRD-type phantom. Differences could be seen in some organ doses between the phantoms, if photon attenuations in a shaping (Bow-tie) filter were taken into account to a source model in PHITS.

Journal Articles

WAZA-ARI; Computational dosimetry system for X-ray CT examinations, 2; Development of web-based system

Ban, Nobuhiko*; Takahashi, Fumiaki; Ono, Koji*; Hasegawa, Takayuki*; Yoshitake, Takayasu*; Katsunuma, Yasushi*; Sato, Kaoru; Endo, Akira; Kai, Michiaki*

Radiation Protection Dosimetry, 146(1-3), p.244 - 247, 2011/07

 Times Cited Count:16 Percentile:80(Environmental Sciences)

We are developing a web-based system, WAZA-ARI, for the dose calculation of patients undergoing X-ray CT examinations. Tissue doses were calculated in a Japanese adult male phantom (JM phantom) using a Monte Carlo code, PHITS, and the normalized dose coefficient data are stored as XML files. The system is implemented in Java on a Linux server running Apache Tomcat, which is accessed via a web browser over a network. Users are requested to choose scanning options and to input parameters in the data entry screen. The corresponding dose data are called upon input, and they are summed over the scan range specified by the user to estimate unit tissue doses. Tissue doses are computed based on the radiographic exposure (mAs), the beam pitch and air kerma at the beam center on the axis of rotation. Users can also use their own air kerma, CTDI vol and DLP values for the dose computation instead of the default setting. Although the dose coefficients are prepared for only limited CT scanner models currently, our system has achieved high usability and easy maintenance without commercial software. Possibility of further expansion for the practical application is also discussed.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:156 Percentile:99.42(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:8 Percentile:52.71(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Analysis of organ doses from Computed Tomography (CT) examination by the radiation transport calculation to develop the dosimetry system, WAZA-ARI

Takahashi, Fumiaki; Endo, Akira; Sato, Kaoru; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Ono, Koji*; Yoshitake, Takayasu*; Ban, Nobuhiko*; Kai, Michiaki*

Progress in Nuclear Science and Technology (Internet), 1, p.517 - 520, 2011/02

Several dose assessment system were developed to avoid unnecessary exposure for a patient in a Computed Tomography (CT) examination. Most of these systems contain datasets of organ doses, which had been calculated with mathematical phantoms. The numerical analyses for radiation dosimetry and CT machines have progressed in recent years. Thus, a project is being carried out to develop a new dosimetry system, named WAZA-ARI. The basic data of organ doses are calculated with a male voxel phantom (JM phantom), which defines configurations of the human body more precisely than the mathematical model. The radiation transports in CT examination can be simulated with the Particle and Heavy Ion Transport code System, PHITS. A source model can be set up for emissions of photons from the X-ray tube with a subroutine, including the helical scanning. Thus, the WAZA-ARI system can assess radiation dose based upon the organ doses, which are calculated with the appropriate source and human models.

Journal Articles

Decommissioning program and future plan for Research Hot Laboratory, 2

Koya, Toshio; Nozawa, Yukio; Hanada, Yasushi; Ono, Katsuto; Kanazawa, Hiroyuki; Nihei, Yasuo; Owada, Isao

Dekomisshoningu Giho, (42), p.41 - 48, 2010/09

The Research Hot Laboratory (RHL) in Japan Atomic Energy Agency (JAEA) had been contributed to R&D program for fuels and nuclear materials in or out of JAEA. However, the decommissioning work of RHL has been started on April 2003 as the rationalization program for decrepit facilities in former Tokai institute. This work will be progressing, dismantling the lead cells and decontamination of concrete caves then release in the regulation of controlled area. The partial area of RHL will be used for the central storage of un- irradiated fuel and for temporary storage of radioactive device generated by J-PARC. The 18 lead cells had been dismantled and the preparing work for remained 20 lead cells has been finished including the removal of the applause from the cells, survey of the contamination revel in the lead cells and prediction of radio active waste. The future plan of decommissioning work has been prepared to incarnate the basic vision and dismantling procedure.

Journal Articles

Report on ITPA meetings, 24

Idomura, Yasuhiro; Yoshida, Maiko; Yagi, Masatoshi*; Tanaka, Kenji*; Hayashi, Nobuhiko; Sakamoto, Yoshiteru; Tamura, Naoki*; Oyama, Naoyuki; Urano, Hajime; Aiba, Nobuyuki; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 84(12), p.952 - 955, 2008/12

no abstracts in English

Journal Articles

Report on ITPA (International Tokamak Physics Activity) meeting, 22

Takenaga, Hidenobu; Ogawa, Yuichi*; Takizuka, Tomonori; Yagi, Masatoshi*; Yamada, Hiroshi*; Sakamoto, Yoshiteru; Toi, Kazuo*; Fukuda, Takeshi*; Fukuyama, Atsushi*; Fujita, Takaaki; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 84(7), p.465 - 467, 2008/07

no abstracts in English

Journal Articles

Report on ITPA (International Tokamak Physics Activity) meeting, 20

Fujita, Takaaki; Fukuda, Takeshi*; Fukuyama, Atsushi*; Sakamoto, Yoshiteru; Toi, Kazuo*; Ogawa, Yuichi*; Takenaga, Hidenobu; Takizuka, Tomonori; Yagi, Masatoshi*; Yamada, Hiroshi*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 84(1), p.70 - 72, 2008/01

no abstracts in English

Journal Articles

Report of meetings of ITPA (International Tokamak Physics Activity), 19

Sasao, Mamiko*; Kusama, Yoshinori; Kawano, Yasunori; Kawahata, Kazuo*; Mase, Atsushi*; Sugie, Tatsuo; Fujita, Takaaki; Fukuda, Takeshi*; Fukuyama, Atsushi*; Sakamoto, Yoshiteru; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 83(9), p.779 - 782, 2007/09

This is a report of highlights from 2007 spring meetings of seven Topical Groups (TG) of International Tokamak Physics Activity (ITPA). In each meeting, high priority issues in physics of International Thermonuclear Experimental Reactor (ITER) and other burning plasma experiments have been discussed and investigated. Twenty-seven scientists from Japan have participated in those meetings. Dates and places of the meetings are shown below. (1) Diagnostics TG: 26-30 March, Princeton (USA), (2) Transport Physics TG: 7-10 May, Lausanne (Switzerland), (3) Confinement Database and Modeling TG: 7-10 May, Lausanne (Switzerland), (4) Edge Pedestal Physics TG: 7-10 May, Garching (Germany) (5) Steady State Operation TG: 9-11 May, Daejeon (South Korea), (6)MHD TG: 21-24 May, San Diego (USA), (7) Scrape-off-layer and Divertor Physics TG: 7-10 May, Garching (Germany).

69 (Records 1-20 displayed on this page)