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Journal Articles

Concept of radiation protection for low-dose risks

Takahara, Shogo

Hoshasen Seibutsu Kenkyu, 55(2), p.162 - 172, 2020/06

no abstracts in English

Journal Articles

Application of ion channeling for downsizing Accelerator Mass Spectrometry (AMS) systems

Matsubara, Akihiro*; Fujita, Natsuko; Ishii, Kunikazu*; Kimura, Kenji*

Hoshasen (Internet), 45(3), p.134 - 138, 2020/04

no abstracts in English

Journal Articles

Estimation of observables

Ogawa, Tatsuhiko; Iwamoto, Yosuke

Hoshasen Shahei Handobukku; Oyohen, p.68 - 74, 2020/03

Atomic Energy Society of Japan is going to compile a book entitled "The handbook of radiation shielding -Advanced Edition-" as the guideline for researchers and engineers working on radiation shielding in Japan. The authors are responsible for a chapter dedicated to "Evaluation of observables". Conventionally, in radiation shielding calculation, the quantities averaged over a lot of radiation particles are assessed; however, fluctuation around the average matters for detector response calculation, and radiation-induced damage. Therefore, algorithms to recover the details on fluctuations, such as the event generator mode of PHITS, are needed. This publication is intended to explain the significance of fluctuation evaluation in radiation transport, the principle to calculate the fluctuation, and the effect of the fluctuation on observables.

Journal Articles

Sensitivity analysis of activation

Okumura, Keisuke

Hoshasen Shahei Handobukku; Oyohen, p.78 - 83, 2020/03

no abstracts in English

Journal Articles

Prediction of scintillation light yield based on track-structure simulation

Ogawa, Tatsuhiko; Sato, Tatsuhiko; Yamaki, Tetsuya*

Hoshasen Kagaku (Internet), (108), p.11 - 17, 2019/11

Scintillators are generally used to detect various kinds of particles such as electrons, gammas, protons and heavy ions. Scintillators emit photons according to the energy deposited to the crystal. It is also known that light yield is suppressed for particles depositing energy densely owing to quenching. Moreover, it is suggested that quenching is attributed to transfer of energy from excited fluorescent molecules to damaged molecules (F$"{o}$rster mechanism or Dexter mechanism). In this study, energy deposition in a scintillator crystal by radiation was calculated using radiation transport codes to finally obtain excitation and damage of fluorescent molecules. Based on the calculation, spatial configuration of exited and damaged molecules. Then the probability that F$"{o}$rster mechanism takes place in excited molecules were estimated to obtain the number of fluorescent molecules that emit photons. As a result, light yield is proportionally increased with increase in the incident energy in case of electron incidence. On the other hand, light yield is increased non-linearly in case of proton incidence. This trend is in a good agreement with the experimental results.

Journal Articles

Radiation and spintronics

Ieda, Junichi

Hoshasen To Sangyo, (146), p.48 - 52, 2019/06

no abstracts in English

Journal Articles

Effect of H$$_{2}$$O$$_{2}$$ concentration on oxidative dissolution of U$$_{2}$$O

Kumagai, Yuta

Hoshasen Kagaku (Internet), (107), p.77 - 78, 2019/04

Reaction of hydrogen peroxide (H$$_{2}$$O$$_{2}$$) with uranium dioxide (UO$$_{2}$$) oxidizes U(IV) to water-soluble U(VI). In the concept of direct geological disposal of spent nuclear fuel, this reaction is expected to induce dissolution of UO$$_{2}$$ matrix of the spent fuel. This study investigate effect of H$$_{2}$$O$$_{2}$$ concentration on the kinetics and the yield of U(VI) dissolution of this reaction. A series of experiments of the reaction of H$$_{2}$$O$$_{2}$$ with UO$$_{2}$$ powder dispersed in water has been carried out. The experimental results reveal that increase in the H$$_{2}$$O$$_{2}$$ concentration slows down the reaction and decreases the yield of U(VI) dissolution. This observation suggests that a reaction intermediate is generated in the course of the H$$_{2}$$O$$_{2}$$ reaction on the surface of UO$$_{2}$$.

Journal Articles

Review of the performance of a car-borne survey system, KURAMA-II, used to measure the dose rate after the Fukushima Dai-ichi Nuclear Power Plant accident

Tsuda, Shuichi; Tanigaki, Minoru*; Yoshida, Tadayoshi; Saito, Kimiaki

Hoshasen, 44(3), p.109 - 118, 2018/11

JAEA has started to perform dose rate monitoring using a car-borne survey system KURAMA to rapidly produce the dose rate mappings of the deposited radionuclides in the environment after the Fukushima Dai-ichi Nuclear Power Plant accident. KURAMA is a car-borne survey system developed by Kyoto University to perform dose rate monitoring in a wide area in detail with rapidity. By improving KURAMA with continuous dose rate monitoring, the 2nd generation of KURAMA (KURAMA-II) succeeded in downsizing, durability and automated transmission of data so that enable detailed dose rate mapping in wide area in shorter period of time. This paper reports the radiation characteristics and the simulation analysis of KURAMA-II on the special issue of Hoshasen, the journal of Ionization Radiation Division in the Japan society of applied physics.

Journal Articles

Recent progress of radiation physicochemical process (third part)

Kai, Takeshi; Yokoya, Akinari*; Fujii, Kentaro*; Watanabe, Ritsuko*

Hoshasen Kagaku (Internet), (106), p.21 - 29, 2018/11

It is thought to that the biological effects such as cell death or mutation are induced by complex DNA damage which are formed by several damage sites within a few nm. As the prediction of complex DNA damage at an electron track end, we report our outcomes. These results indicate that DNA damage sites comprising multiple nucleobase lesions with a single strand breaks can be formed by multiple collisions of the electrons within 1 nm. This multiple damage site cannot be processed by base excision repair enzymes. Pre-hydrated electrons can also be produced resulting in an additional base lesion over a few nm from the multi-damage site. This clustered damage site may be finally converted into a double strand break. These DSBs include another base lesion(s) at their termini that escape from the base excision process and which may result in biological effect. Our simulation is useful to reveal phenomena involved in radiation physico-chemistry as well as the DNA damage prediction.

Journal Articles

Introduction to radiation physics; Third revised edition

Tada, Junichiro*; Nakashima, Hiroshi; Hayano, Ryugo*; Kobayashi, Hitoshi*; Asano, Yoshihiro*

Wakariyasui Hoshasen Butsurigaku; Kaitei 3-Han, 305 Pages, 2018/03

This book is an introduction to radiation physics. Under the concept of "linking physics of high school and radiation physics" for readers with high school graduation degree, we are doing simple commentary on the basis of qualitative explanation as much as possible. This book begins with "What is Radiation Physics", and consists of 12 chapters, including introductory special relativity, introductory quantum theory, structures of atoms and nuclei, radiations, radioactivity, interactions between radiation and matter, accelerators, radiation dose and so on.

Journal Articles

Experience note of John Rogers Laboratory in Northwestern University

Sekine, Yurina

Hoshasen To Sangyo, (143), p.51 - 54, 2017/12

The author reports experience note of John Rogers laboratory in Northwestern University from January in 2017.

Journal Articles

Proceeding of 16th Annual Meeting of the Japanese Society of Radiation Management (JRSM) and the 50th Annual Meeting of Japan Health Physics Society (JHPS) (Oita); Oral session-E2 Radiation measurement-2

Mikami, Satoshi

Nippon Hoshasen Anzen Kanri Gakkai-Shi, 16(2), P. 41, 2017/11

I summarized the outline of the oral presentation session where the author served as chairman.

Journal Articles

Microfabrication of fluoropolymers using ion beam irradiation

Kitamura, Akane; Kobayashi, Tomohiro*

Hoshasen Kagaku (Internet), (104), p.29 - 34, 2017/10

no abstracts in English

Journal Articles

Research and development using the quantum beams in Japan Atomic Energy Agency

Takeda, Masayasu

Hoshasen To Sangyo, (142), p.34 - 37, 2017/06

no abstracts in English

Journal Articles

General-purpose Monte Carlo codes for neutron and photon transport calculations; MVP version 3

Nagaya, Yasunobu

Hoshasen, 43(2), p.49 - 54, 2017/05

no abstracts in English

Journal Articles

Features of PHITS version 2.88

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.

Journal Articles

Reactivity of an antioxidant, edaravone, with reactive oxygen species and its chemical repair properties against oxidative damage on DNA

Hata, Kuniki; Lin, M.*; Yokoya, Akinari*; Fujii, Kentaro*; Yamashita, Shinichi*; Muroya, Yusa*; Katsumura, Yosuke*

Hoshasen Kagaku (Internet), (103), p.29 - 34, 2017/04

Reactivity of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), which is known to show high antioxidative properties, with oxidative species, such as hydroxyl radical ($${}^{bullet}$$OH) and azide radical (N$$^{bullet}$$$$_{3}$$), was investigated by a pulse radiolysis experiment, and generation behavior of edaravone radicals produced through these reactions were observed. It was shown that OH-adducts are produced by the reaction with $${}^{bullet}$$OH in contrast to the other oxidative radicals, which react with edaravone by an electron transfer reaction. Chemical repair properties of edaravone against DNA lesions produced by reactions of DNA with oxidative species were also investigated by a pulse radiolysis experiment with deoxyguanosine monophosphate (dGMP) and a $$gamma$$-radiolysis experiment with plasmid DNA solutions. It was observed that edaravone reduced dGMP radicals just after produced in a dilute aqueous solution and inhibited some base lesions on plasmid DNA more effectively than single strand breaks. These results show that edaravone may protect living system from oxidative stress, such as radiation, by not only scavenging oxidative species but also reducing precursors of DNA leisons.

Journal Articles

Report on the stay in Norway as a secondee of OECD Halden Reactor Project

Hata, Kuniki

Hoshasen Kagaku (Internet), (103), P. 65, 2017/04

no abstracts in English

Journal Articles

What can we measure by radiation measurement instruments?

Takeyasu, Masanori

Tomioka Hoshasen Joho Matome Saito (Internet), 2 Pages, 2017/01

Some radiation measurement instruments are lent out to the residents in Tomioka-machi, Fukushima. In this paper, it is explained that the kinds of those instruments, their purposes, the attention points on their uses and the interpretation of the measurement results by those instruments.

Journal Articles

Additional information to report on site tour of the Fukushima Daiichi Nuclear Power Station

Suto, Toshiyuki

Genshiryoku, hoshasen Bukaiho (Internet), (19), P. 15, 2016/12

The Tritiated Water Task Force under METI's Committee on Countermeasures for Contaminated Water Treatment for Fukushima Daiichi Nuclear Power Plant (1F) reported that the option of post-dilution offshore release could dispose the tritiated water at a smallest cost in the shortest amount of time. The amount of tritium in the contaminated water at 1F was compared with ones released from nuclear power plants and reprocessing plants as some help for grasping its level of magnitude.

485 (Records 1-20 displayed on this page)