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Journal Articles

Evaluation of RBE-weighted doses for various radiotherapy beams based on a microdosimetric function implemented in PHITS

Takada, Kenta*; Sato, Tatsuhiko; Kumada, Hiroaki*; Sakurai, Hideyuki*; Sakae, Takeji*

Journal of Physics; Conference Series, 1662, p.012004_1 - 012004_6, 2020/10

The University of Tsukuba has developed a treatment planning system (TPS) for boron neutron capture therapy (BNCT) that uses a Monte Carlo algorithm as a dose calculation engine. In the system, RBE-weighted dose can be also estimated using the microdosimetric function implemented in PHITS. In this study, we calculated the RBE-weighted doses for various radiation therapy beams. Comparison between the calculated results for different radiation therapy beams as well as verification of the calculated data will be presented at the meeting.

Journal Articles

Insight into Kondo screening in the intermediate-valence compound SmOs$$_4$$Sb$$_{12}$$ uncovered by soft X-ray magnetic circular dichroism

Saito, Yuji; Fujiwara, Hidenori*; Yasui, Akira*; Kadono, Toshiharu*; Sugawara, Hitoshi*; Kikuchi, Daisuke*; Sato, Hideyuki*; Suga, Shigemasa*; Yamasaki, Atsushi*; Sekiyama, Akira*; et al.

Physical Review B, 102(16), p.165152_1 - 165152_8, 2020/10

 Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)

Journal Articles

Validation of the physical and RBE-weighted dose estimator based on PHITS coupled with a microdosimetric kinetic model for proton therapy

Takada, Kenta*; Sato, Tatsuhiko; Kumada, Hiroaki*; Koketsu, Junichi*; Takei, Hideyuki*; Sakurai, Hideyuki*; Sakae, Takeji*

Journal of Radiation Research, 59(1), p.91 - 99, 2018/01

 Times Cited Count:22 Percentile:91.11(Biology)

Evaluation of the relative biological effectiveness (RBE)-weighted dose is indispensable in the treatment planning of proton and carbon ion therapies. In this study, we validate the RBE-weighted dose calculated by microdosimetric kinetic model (MKM) in tandem with the Monte Carlo particle transport code PHITS for proton therapy using the full simulation geometry for the beam line of the Proton Medical Research Center at the University of Tsukuba. The physical dose and RBE-weighted dose on the central axis for a 155 MeV monoenergetic and spread-out Bragg peak beam of 60 mm width are evaluated by the method. The calculated results generally agree with the corresponding experimental data very well, though overestimations by approximately 3.2% and 15% at the maximum are observed for the physical and RBE-weighted doses, respectively. This research completes the computational microdosimetric approach based on a combination of PHITS and MKM for all types of radiotherapy that require RBE evaluations.

Journal Articles

Outline of Japan Atomic Energy Agency's Okuma Analysis and Research Center, 2; Labolatory-1

Sugaya, Yuki; Sakazume, Yoshinori; Akutsu, Hideyuki; Inoue, Toshihiko; Yoshimochi, Hiroshi; Sato, Soichi; Koyama, Tomozo; Nakayama, Shinichi

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 8 Pages, 2017/00

The Japan Atomic Energy Agency has been developing the research and development facilities, "Okuma Analysis and Research Center", in order to ascertain the properties of radioactive wastes and fuel debris towards the decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station. This paper outlines the concept of "Laboratory-1" which will analyze low and medium level samples in the Okuma Analysis and Research Center with a focus on the research plan.

Journal Articles

Fano factor evaluation of diamond detectors for alpha particles

Shimaoka, Takehiro*; Kaneko, Junichi*; Sato, Yuki; Tsubota, Masakatsu*; Shimmyo, Hiroaki*; Chayahara, Akiyoshi*; Watanabe, Hideyuki*; Umezawa, Hitoshi*; Mokuno, Yoshiaki*

Physica Status Solidi (A), 213(10), p.2629 - 2633, 2016/10

 Times Cited Count:3 Percentile:20.49(Materials Science, Multidisciplinary)

JAEA Reports

A Study on the method of an equivalent continuous body modelling using crack tensor theory in the Mizunami Underground Research Laboratory Project

Sanada, Hiroyuki; Sato, Toshinori; Tanno, Takeo*; Hikima, Ryoichi*; Tada, Hiroyuki*; Kumasaka, Hiroo*; Ishii, Takashi*; Sakurai, Hideyuki*

JAEA-Research 2014-006, 124 Pages, 2014/06

JAEA-Research-2014-006.pdf:11.26MB

Japan Atomic Energy Agency has been implementing the Mizunami Underground Research Laboratory (MIU) Project in order to develop the comprehensive investigation techniques for the geological environment and the engineering techniques to construct a deep underground laboratory in crystalline rock. In the rock mechanical study in the MIU Project, the development of the evaluation method for the excavation damaged zone due to excavation of shafts and research galleries is one of the important issues. In this report, crack tensor was calculated using the tunnel wall mapping and rock mechanical test results in the shaft and research galleries in the MIU. Two dimension excavation analysis was conducted at the Ventilation Shaft and GL -500 m Sub Stage using the calculated crack tensor at GL -500 m. Based on calculated crack tensor at GL 500 m, validation of the crack tensor at GL -500 m estimated during Phase I was verified. Relative error of crack tensor was calculated in order to examine variation of relative error to the scale of observation areas.

Journal Articles

Anharmonic Pr guest modes in Pr(Os$$_{1-x}$$Ru$$_x$$)$$_4$$Sb$$_{12}$$ investigated by inelastic X-ray scattering

Tsutsui, Satoshi; Kaneko, Koji; Miyazaki, Ryoichi*; Higashinaka, Ryuji*; Aoki, Yuji*; Kobayashi, Riki*; Wakimoto, Shuichi; Baron, A. Q. R.*; Sugawara, Hitoshi*; Sato, Hideyuki*

JPS Conference Proceedings (Internet), 3, p.011060_1 - 011060_5, 2014/06

Journal Articles

Chemical state information of bulk specimens obtained by SEM-based soft-X-ray emission spectrometry

Terauchi, Masami*; Koshiya, Shogo*; Sato, Futami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Imazono, Takashi; Koeda, Masaru*; Nagano, Tetsuya*; et al.

Microscopy and Microanalysis, 20(3), p.692 - 697, 2014/06

 Times Cited Count:22 Percentile:86.04(Materials Science, Multidisciplinary)

Electron beam induced soft-X-ray emission spectroscopy (SXES) by using a grating spectrometer has been introduced to a conventional scanning electron microscope (SEM) for characterizing desired specimen areas of bulk materials. The spectrometer was designed as a grazing-incidence flat-field optics by using aberration corrected (varied-line-spacing) gratings and a multi-channel-plate detector combined with a charge-coupled-device camera, which has already applied for a transmission electron microscope. The best resolution was confirmed as 0.13 eV at Mg L-emission (50 eV), which value is comparable to that of recent dedicated electron energy-loss spectroscopy instruments. This SXES-SEM instrument presents density of states of simple metals of bulk Mg and Li. Apparent band structure effects have been observed in Si L-emission of Si-wafer, P L-emission of GaP-wafer, and Al L-emissions of intermetallic compounds of AlCo, AlPd, Al$$_{2}$$Pt, and Al$$_{2}$$Au.

Journal Articles

High power laser developments with femtosecond to nanosecond pulse durations for laser shock science and engineering

Kiriyama, Hiromitsu; Mori, Michiaki; Suzuki, Masayuki*; Daito, Izuru*; Okada, Hajime; Ochi, Yoshihiro; Tanaka, Momoko; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; et al.

Reza Kenkyu, 42(6), p.441 - 447, 2014/06

We describe three specific high power laser systems that are being developed in our laboratory for many applications in high field science, nonlinear optics and material processing. We report on a femtosecond petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 20 J of 40 fs pulse duration, a picosecond high intensity Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 mJ of 0.5 ps pulse duration, and a nanosecond high repetition rate Nd:YAG laser system that can provide an average power of 360 W with a pulse duration of 30 ns delivered at a 1 kHz repetition rate. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.

Journal Articles

Construction of a SXES spectrometer for a conventional SEM

Terauchi, Masami*; Koshiya, Shogo*; Sato, Futami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Imazono, Takashi; Koeda, Masaru*; Nagano, Tetsuya*; et al.

Microscopy and Microanalysis, 19(Suppl.2), p.1278 - 1279, 2013/08

We have been developed and tested soft-X-ray emission spectroscopy (SXES) instruments by attaching to TEM and EPMA. The spectrometer has an energy range form 50-4000 eV by using four varied-line-spacing (aberration corrected) gratings. This SXES spectrometer inform us energy states of valence electrons (bonding electrons) form an identified specimen area by electron microscopy, which cannot be obtained by EELS and EDS. This provides not only the probing method for the energy states of valence electrons but also a sensitive tool for elemental and chemical identification. The spectrometer has applied also to a SEM (JEOL JSM-6480LV). As SEM can use a larger probe current and excitation volume of specimen than those of TEM, the detection time is about one order shorter than that of TEM. The energy resolution evaluated at AL-L$$_{3}$$edge is 0.16 eV. The spectrum of LaB$$_{6}$$ shows apparent intensity corresponds to B-K Fermi edge, showing chemical state of boron.

JAEA Reports

Environmental radiation monitoring resulting from the accident at the Fukushima Daiichi Nuclear Power Plant, conducted by Oarai Research and Development Center, JAEA; Results of ambient gamma-ray dose rate, atmospheric radioactivity and meteorological observation

Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Numari, Hideyuki*; Sato, Naomitsu*; Nemoto, Koji*; Takasaki, Hiroichi*; Shimizu, Takehiko; Takasaki, Koji

JAEA-Data/Code 2013-006, 100 Pages, 2013/06

JAEA-Data-Code-2013-006.pdf:12.04MB

This report presents the results of emergency radiation monitoring, including ambient $$gamma$$-ray dose rate, atmospheric radioactivity, meteorological observation and estimation of internal exposure resulting from the accident at the Fukushima Daiichi Nuclear Power Plant triggered by the earthquake off the pacific coast of Tohoku on 11th March 2011, conducted by Oarai Research and Development Center (ORDC), Japan Atomic Energy Agency (JAEA) from March to May, 2011. ORDC is located in the central part of Ibaraki prefecture and approximately 130 km southwest of the Fukushima Daiichi Nuclear Power Plant. From around 15th to 21st March, 2011, the ambient $$gamma$$-ray dose rate increased and many radioactive nuclides were detected in the atmosphere.

Journal Articles

Magnetic excitation in totally symmetric staggered ordered phase of PrFe$$_4$$P$$_{12}$$

Iwasa, Kazuaki*; Hao, L.*; Kogi, Masafumi*; Kuwahara, Keitaro*; Mignot, J.-M.*; Sugawara, Hitoshi*; Aoki, Yuji*; Matsuda, Tatsuma; Sato, Hideyuki*

Journal of the Physical Society of Japan, 81(9), p.094711_1 - 094711_9, 2012/09

 Times Cited Count:8 Percentile:53.03(Physics, Multidisciplinary)

Journal Articles

Suppression of time-reversal symmetry breaking superconductivity in Pr(Os$$_{1-x}$$Ru$$_x$$)$$_4$$Sb$$_{12}$$ and Pr$$_{1-y}$$La$$_y$$Os$$_4$$Sb$$_{12}$$

Shu, L.*; Higemoto, Wataru; Aoki, Yuji*; Hillier, A. D.*; Oishi, Kazuki*; Ishida, Kenji*; Kadono, Ryosuke*; Koda, Akihiro*; Bernal, O. O.*; MacLaughlin, D. E.*; et al.

Physical Review B, 83(10), p.100504_1 - 100504_4, 2011/03

 Times Cited Count:28 Percentile:75.21(Materials Science, Multidisciplinary)

Zero-field muon spin relaxation experiments have been carried out in the Pr(Os$$_{1-x}$$Ru$$_x$$)$$_4$$Sb$$_{12}$$ and Pr$$_{1-y}$$La$$_y$$Os$$_4$$Sb$$_{12}$$ alloy systems to investigate broken time-reversal symmetry (TRS) in the superconducting state, signaled by the onset of a spontaneous static local magnetic field B$$_s$$. In both alloy series B$$_s$$ initially decreases linearly with solute concentration. Ru doping is considerably more efficient than La doping, with a 50% faster initial decrease. The data suggest that broken TRS is suppressed for Ru concentration $$xgeq$$0.6 but persists for essentially all La concentrations. Our data support a crystal-field excitonic cooper pairing mechanism for TRS-breaking superconductivity.

Journal Articles

Microscopic study of antiferromagnetic ground state and possible high-field ordered state in CeOs$$_4$$Sb$$_{12}$$ using muon spin rotation and relaxation

Ito, Takashi; Higemoto, Wataru; Oishi, Kazuki*; Sato, Kazuhiko*; Aoki, Yuji*; Toda, Shizuka*; Kikuchi, Daisuke*; Sato, Hideyuki*; Baines, C.*

Physical Review B, 82(1), p.014420_1 - 014420_8, 2010/07

 Times Cited Count:7 Percentile:36.48(Materials Science, Multidisciplinary)

An antiferromagnetic (AFM) ground state and a possible high-field ordered state in magnetic fields $$H>1$$ T of a filled-skutterudite compound CeOs$$_4$$Sb$$_{12}$$ were investigated by the muon spin rotation and relaxation method. In a zero applied field, a spontaneous local filed due to the weak AFM ordering was observed below $$sim$$1.6 K. The magnetic volume fraction gradually increases below 1.6 K with decreasing temperature, suggesting that this phase is sensitive to sample quality. The magnitude of the ordered dipole moment in the AFM state was estimated to be in the range from 0.11 to 0.17 $$mu_B$$/Ce at 0.1 K. In a field of 2 T applied along the [001] direction, clear anomalies in the muon Knight shift and line width were observed at $$sim$$ 1.5 K, consistent with the phase transition scenario into the high-field ordered state suggested from specific heat, resistivity, elastic, and NMR anomalies.

Journal Articles

Pressure-induced antiferromagnetic order in filled skutterudite PrFe$$_{4}$$P$$_{12}$$ studied by single-crystal high-pressure neutron diffraction

Osakabe, Toyotaka; Kuwahara, Keitaro*; Kawana, Daichi*; Iwasa, Kazuaki*; Kikuchi, Daisuke*; Aoki, Yuji*; Kogi, Masafumi*; Sato, Hideyuki*

Journal of the Physical Society of Japan, 79(3), p.034711_1 - 034711_7, 2010/03

 Times Cited Count:14 Percentile:65.65(Physics, Multidisciplinary)

Journal Articles

Possible low-energy excitations of multipoles in SmRu$$_4$$P$$_{12}$$ probed by muon spin relaxation

Ito, Takashi; Higemoto, Wataru; Oishi, Kazuki*; Heffner, R. H.; Nishida, Nobuhiko*; Sato, Kazuhiko*; Sugawara, Hitoshi*; Aoki, Yuji*; Kikuchi, Daisuke*; Sato, Hideyuki*

Physica B; Condensed Matter, 404(5-7), p.761 - 764, 2009/04

 Times Cited Count:1 Percentile:6.65(Physics, Condensed Matter)

We report on detailed longitudinal field (LF) $$mu$$SR studies in SmRu$$_4$$P$$_{12}$$ in order to characterize magnetic fluctuations in a magnetically ordered state below $$T_{rm MI}=16.5$$ K. A magnitude and fluctuation rate of the fluctuating field are derived as functions of temperature from LF dependence of the longitudinal relaxation rate. Possible low-energy excitations of magnetic multipoles are discussed.

Journal Articles

Weak ferromagnetic ordering in the anomalous field-insensitive heavy-fermion state in SmOs$$_4$$Sb$$_{12}$$

Aoki, Yuji*; Higemoto, Wataru; Tsunashima, Yoshino*; Yonezawa, Yuki*; Sato, Koki*; Koda, Akihiro*; Ito, Takashi; Oishi, Kazuki; Heffner, R. H.; Kikuchi, Daisuke*; et al.

Physica B; Condensed Matter, 404(5-7), p.757 - 760, 2009/04

 Times Cited Count:4 Percentile:22.79(Physics, Condensed Matter)

Zero field (ZF) and transverse field (TF) muon spin relaxation and rotation ($$mu$$SR) study has been carried out in filled-skutterudite SmOs$$_4$$Sb$$_{12}$$ in order to investigate the magnetically robust heavy-fermion (HF) state and the weak ferromagnetic anomaly. A large-amplitude oscillating signal appears in the ZF-$$mu$$SR spectra at low temperatures, confirming that the weak ferromagnetic anomaly is an intrinsic bulk property. Analysis reveals that the weak ferromagnetic moment is carried by itinerant heavy quasiparticles.

Journal Articles

Novel features in filled skutterudites containing rare-earth elements with a plural number of 4f-electrons

Sato, Hideyuki*; Aoki, Yuji*; Kikuchi, Daisuke*; Sugawara, Hitoshi*; Higemoto, Wataru; Oishi, Kazuki; Ito, Takashi; Heffner, R. H.; Saha, S. R.*; Koda, Akihiro*; et al.

Physica B; Condensed Matter, 404(5-7), p.749 - 753, 2009/04

 Times Cited Count:4 Percentile:22.79(Physics, Condensed Matter)

Wide varieties of strongly correlated electron phenomena are performed on the stage of a filled skutterudite structure. Especially when one of the players contains a plural number of 4f electrons, the orbital degrees of freedom play a major role as a new type of nonmagnetic and/or weak-magnetic phenomena. Several examples found in Pr- and Sm-based filled skutterudites are introduced in relation to muon spin relaxation experiments.

Journal Articles

Basic characteristics of a newly developed Si/CdTe Compton camera for medical imaging

Kawachi, Naoki; Watanabe, Shigeki; Sato, Takahiro; Arakawa, Kazuo; Takeda, Shinichiro*; Ishikawa, Shinnosuke*; Aono, Hiroyuki*; Watanabe, Shin*; Yamaguchi, Mitsutaka*; Takahashi, Tadayuki*; et al.

2008 IEEE Nuclear Science Symposium Conference Record (CD-ROM), p.1540 - 1543, 2008/10

JAEA Reports

Excavation disturbance analysis based on Crack Tensor Model and Virtual Fracture Model for predicting the rock mass behavior during excavation of shafts and research galleries at the Mizunami Underground Research Laboratory

Seno, Yasuhiro; Nakama, Shigeo; Sato, Toshinori*; Goke, Mitsuo*; Tada, Hiroyuki*; Sakurai, Hideyuki*

JAEA-Research 2007-081, 120 Pages, 2008/01

JAEA-Research-2007-081.pdf:13.48MB

A 3D Crack Tensor Model analysis was carried out to predict the rock mass behavior of the complex (articulated) section at -500 m. Properties were chosen based on the Rock Mechanics Model constructed in the Surface-based Investigation Phase (Phase I). The Virtual Fracture Model was applied to analyze the change the hydraulic conductivity.

141 (Records 1-20 displayed on this page)