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Journal Articles

Estimation of I-131 concentration using time history of pulse height distribution at monitoring post and detector response for radionuclide in plume

Hirayama, Hideo*; Kawasaki, Masatsugu; Matsumura, Hiroshi*; Okura, Takehisa; Namito, Yoshihito*; Sanami, Toshiya*; Taki, Mitsumasa; Oishi, Tetsuya; Yoshizawa, Michio

Insights Concerning the Fukushima Daiichi Nuclear Accident, Vol.4; Endeavors by Scientists, p.295 - 307, 2021/10

Journal Articles

Advanced analysis technology for new material and product development

Sasaki, Hirokazu*; Nishikubo, Hideo*; Nishida, Shinsuke*; Yamazaki, Satoshi*; Nakasaki, Ryusuke*; Isomatsu, Takemi*; Minato, Ryuichiro*; Kinugawa, Kohei*; Imamura, Akihiro*; Otomo, Shinya*; et al.

Furukawa Denko Jiho, (138), p.2 - 10, 2019/02

no abstracts in English

Journal Articles

Investigation of main radiation source above shield plug of Unit 3 at Fukushima Daiichi Nuclear Power Station

Hirayama, Hideo*; Kondo, Kenjiro*; Suzuki, Seishiro*; Tanimura, Yoshihiko; Iwanaga, Kohei*; Nagata, Hiroshi*

EPJ Web of Conferences, 153, p.08010_1 - 08010_3, 2017/09

 Times Cited Count:1 Percentile:62.96

Pulse height distributions were measured using a CdZnTe detector inside a lead collimator to investigate main source producing high dose rates above the shield plugs of Unit 3 at Fukushima Daiichi Nuclear Power Station. It was confirmed that low energy photons are dominant. Concentrations of Cs-137 under 60 cm concrete of the shield plug were estimated to be between 8.1$$times$$10$$^9$$ and 5.7$$times$$10$$^{10}$$ Bq/cm$$^2$$ from the measured peak count rate of 0.662 MeV photons. If Cs-137 was distributed on the surfaces of the gaps of the shied plugs with radius 6 m and with the averaged concentration of 5 points, 2.6$$times$$10$$^{10}$$ Bq/cm$$^2$$, total amount of Cs-137 is estimated to be 30 PBq.

Journal Articles

Progress and prospects of calculation methods for radiation shielding

Hirayama, Hideo*; Nakashima, Hiroshi; Morishima, Makoto*; Uematsu, Mikio*; Sato, Osamu*

Journal of Nuclear Science and Technology, 52(11), p.1339 - 1361, 2015/11


 Times Cited Count:6 Percentile:19.79(Nuclear Science & Technology)

Progress in calculation methods for radiation shielding are reviewed based on basis of the activities of research committees related to radiation shielding fields established in the Atomic Energy Society of Japan. A technological roadmap for the field of radiation shielding, progress and prospects for specific shielding calculation methods such as the Monte Carlo, discrete ordinate Sn transport, and simplified methods, and shielding experiments used to validate calculation methods are presented in this paper.

Journal Articles

Superdeformation in $$^{35}$$S

Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Kobayashi, Motoki*; Kisamori, Keiichi*; Takaki, Motonobu*; Miya, Hiroyuki*; Ota, Shinsuke*; Michimasa, Shinichiro*; Shimoura, Susumu*; et al.

JPS Conference Proceedings (Internet), 6, p.030005_1 - 030005_4, 2015/06

Journal Articles

Estimation of I-131 concentration using time history of pulse height distribution at monitoring post and detector response for radionuclide in plume

Hirayama, Hideo*; Kawasaki, Masatsugu; Matsumura, Hiroshi*; Okura, Takehisa; Namito, Yoshihito*; Sanami, Toshiya*; Taki, Mitsumasa; Oishi, Tetsuya; Yoshizawa, Michio

Nihon Genshiryoku Gakkai Wabun Rombunshi (Internet), 13(3), p.119 - 126, 2014/09

A method of deducing the I-131 concentration in a radioactive plume from the time history of peak count rates determined from pulse height spectra obtained from an NaI(Tl)scintillation detector employed as a detector of a monitoring post was presented. The concentrations of I-131 in the plumes were estimated from the count rates using the calculated response of the NaI(Tl) detector with egs5 for a model of a plume uniformly containing I-131. This method was applied to the data from the monitoring posts at Nuclear Science Research Institutes of Japan Atomic Energy Agency (JAEA). The estimated time history variation of I-131 concentrations in plumes was in fair agreement with those measured directly by an air sampling method. The difference was less than a factor of 4 for plumes that arrived on March 15 and March 21, indicating relatively high I-131 concentrations among the plumes studied in this work.

Journal Articles

The Concept of dose system for radiological protection

Hirayama, Hideo*; Nakashima, Hiroshi; Sanami, Toshiya*; Yamaguchi, Yasuhiro; Sato, Osamu*; Takagi, Shunji*; Suzuki, Toshikazu*; Iwai, Satoshi*

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 55(2), p.83 - 96, 2013/02

Since the accident at the Fukushima Daiichi Power Plant, units of radiation doses such as Sv have been frequently reported by newspapers. However, it is not exactly understood even by experts on nuclear engineering that there are two different concepts which are the protection quantity such as the effective dose related to a radiation health risk and the practical quantity such as ambient dose equivalents related to measurements. In this special issue, Radiological Protection Quantity, and Operational Quantity and Radiological Protection Quantity, explain the radiation protection dose system including the protection and practical quantities established by ICRP and ICRU. Relation between Dosimeters used at Fukushima etc. and Radiological Protection Quantity describes a method and its problems to measure radiations from Cs on surface and underground using survey meters and personal dosimeters, and convert the measured values to effective doses.

Journal Articles

Development of a resonant laser ionization gas cell for high-energy, short-lived nuclei

Sonoda, Tetsu*; Wada, Michiharu*; Tomita, Hideo*; Sakamoto, Chika*; Takatsuka, Takaaki*; Furukawa, Takeshi*; Iimura, Hideki; Ito, Yuta*; Kubo, Toshiyuki*; Matsuo, Yukari*; et al.

Nuclear Instruments and Methods in Physics Research B, 295, p.1 - 10, 2013/01

 Times Cited Count:19 Percentile:83.05(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Superdeformed band in asymmetric N $$>$$ Z nucleus, $$^{40}$$Ar and high-spin states in A = 30 $$sim$$ 40 nuclei

Ideguchi, Eiji*; Ota, Shinsuke*; Morikawa, Tsuneyasu*; Oshima, Masumi; Koizumi, Mitsuo; Toh, Yosuke; Kimura, Atsushi; Harada, Hideo; Furutaka, Kazuyoshi; Nakamura, Shoji; et al.

Progress of Theoretical Physics Supplement, (196), p.427 - 432, 2012/10

Journal Articles

Fitting method for spectrum deduction in high-energy neutron field induced by GeV-protons using experimental reaction-rate data

Kasugai, Yoshimi; Matsuda, Norihiro; Sakamoto, Yukio; Nakashima, Hiroshi; Yashima, Hiroshi*; Matsumura, Hiroshi*; Iwase, Hiroshi*; Hirayama, Hideo*; Mokhov, N.*; Leveling, A.*; et al.

Reactor Dosimetry; 14th International Symposium (ASTM STP 1550), p.675 - 689, 2012/08

Under the collaborative study project of JASMIN, shielding experiments has been carried out using the anti-proton target station (Pbar) of Fermilab. In the experiment, the multi-foil activation technique was utilized, and the neutron spectra in high-energy region between 1 and 100 MeV were deduced by using the "fitting method", which is newly developed. In this method, we made an assumption that neutron energy spectra could be expressed with a simple function. The validity of the fitting method was confirmed by comparison with the results of the unfolding method and the theoretical calculations. Finally, it was found that there are simple correlations between reaction rates and the adjusting parameters in the fitting function. The correlations are useful for estimating the adjusting parameters easily, and a neutron spectrum in the high-energy region can be deduced from a set of reaction-rate data without the complicated calculations of unfolding.

Journal Articles

Shielding experiments under JASMIN collaboration at Fermilab, 4; Measurement and analyses of high-energy neutron spectra in the anti-proton target station

Matsuda, Norihiro; Kasugai, Yoshimi; Sakamoto, Yukio; Nakashima, Hiroshi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Hirayama, Hideo*; Yashima, Hiroshi*; Mokhov, N.*; et al.

Journal of the Korean Physical Society, 59(2), p.2055 - 2058, 2011/08

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

It is important to obtain neutron spectra and its intensity on shielding experiment. Deduction of high-energy neutron spectra were done using fitting and unfolding methods based on the shielding data obtained at the anti-proton (pbar) target station in Fermilab. The neutron spectra for fitting method is useful to be easily obtained and the values gave reasonable results compared with nuclear data. Therefore, that for unfolding methods included inconsistency. Furthermore, the deduced neutron spectra were verified through the calculation analyses by PHITS code.

Journal Articles

Shielding experiments at high energy accelerators of Fermilab, 2; Spatial distribution measurement of reaction rate behind the shield and its application for Moyer model

Yashima, Hiroshi*; Kasugai, Yoshimi; Matsuda, Norihiro; Matsumura, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; Vaziri, K.*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.48 - 51, 2011/02

The shielding experiment was performed at the anti-proton production target station in Fermi National Accelerator Laboratory. Aluminum, Bismath, Niobium, Copper and Indium samples were placed behind the shields. After irradiation, induced activities of samples were measured by using HPGe detector. The spatial distribution of reaction rate of samples which were placed behind the iron and concrete shields were obtained. The measured data shows that the reaction rates on the outer surfaces of the iron and concrete shields increases toward the downstream of the target. The obtained reaction rates were also fitted to Moyer's formula, and the attenuation lengths for iron and concrete shields were obtained.

Journal Articles

Shielding experiments at high energy accelerators of Fermilab, 3; Neutron spectrum measurements in intense pulsed neutron fields of the 120-GeV proton facility using a current Bonner sphere technique

Hagiwara, Masayuki*; Sanami, Toshiya*; Iwamoto, Yosuke; Arakawa, Hiroyuki*; Shigyo, Nobuhiro*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; Vaziri, K.*; Nakamura, Takashi*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.52 - 56, 2011/02

In pbar target station, the pulsed proton beam with the power of around 75 kW and the time structure of 1.6 $$mu$$s pulse width and 2.2 s cycle time bombards the pbar production target and produces high instantaneous intensity neutron (burst neutron) fields. The duration of the burst neutrons, which is less than $$mu$$s, is very severe condition to measure neutron spectra with a conventional Bonner sphere technique with pulse readout electronics because of signal pile-up problem. In this study, we have developed a current readout Bonner sphere technique to measure neutron spectra in a burst neutron field. We have measured the neutron spectra on the pbar target and graphite dump. The neutron spectra obtained with the present technique show generally good agreements with the calculation results using MARS code except difference of the thermal neutron flux due to the geometrical problem.

Journal Articles

Shielding experiments at high energy accelerators of Fermilab, 4; Calculation analyses

Matsuda, Norihiro; Kasugai, Yoshimi; Matsumura, Hiroshi*; Yashima, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Sanami, Toshiya*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.57 - 60, 2011/02

The anti-proton (pbar) production target in Fermi National Accelerator Laboratory can be produced a wide variety of secondary particles including of anti-protons, by bombarding with protons accelerated to 120 GeV. The shielding experimental data, which was obtained around the pbar target, make possible to validate the accuracies of the general-purpose Monte Carlo simulation codes. In this paper, spatial distribution of reaction rates were calculated with two-dimensional (r-z) geometry simplified the real pbar target station using the PHITS, MARS and MCNPX code. These experimental data in iron shield were compared with the calculated data. The comparison for attenuation length of iron were good agreement between the experiments and calculations.

Journal Articles

Experiments on the release of gaseous iodine from $$gamma$$-irradiated aqueous CsI solution and influence of oxygen and Methyl Isobutyl Ketone (MIBK)

Moriyama, Kiyofumi; Tashiro, Shinsuke; Chiba, Noriaki; Hirayama, Fumio*; Maruyama, Yu; Nakamura, Hideo; Watanabe, Atsushi*

Journal of Nuclear Science and Technology, 47(3), p.229 - 237, 2010/03

 Times Cited Count:16 Percentile:73.77(Nuclear Science & Technology)

The volatile iodine production due to radiation chemistry is an important uncertainty source in the source term evaluation for LWRs. The gaseous release of molecular iodine and organic iodine from $$gamma$$-irradiated ($$sim 7$$kGy/h, 2h) cesium iodide aqueous solution (1E-4M) containing methyl-isobuthyl-ketone (MIBK) was measured. The solution was buffered at pH$$sim$$7. The concentration of MIBK (up to 1E-3M) and oxygen were changed as parameters. The total iodine release fraction and the fraction released as organic iodine were 2-47% and 0.02-1.5%, respectively, at the end of the irradiation. With the same cover gas condition, the total iodine release decreased and the organic iodine release increased when the MIBK concentration increased. This behavior can be explained by branching of the reaction path of organic degradation depending on availability of dissolved oxygen and competition between iodine and organic compounds on the consumption of radicals.

Journal Articles

Superdeformation in asymmetric $$N$$$$>$$$$Z$$ nucleus $$^{40}$$Ar

Ideguchi, Eiji*; Ota, Shinsuke*; Morikawa, Tsuneyasu*; Oshima, Masumi; Koizumi, Mitsuo; Toh, Yosuke; Kimura, Atsushi; Harada, Hideo; Furutaka, Kazuyoshi; Nakamura, Shoji; et al.

Physics Letters B, 686(1), p.18 - 22, 2010/03

 Times Cited Count:32 Percentile:85.57(Astronomy & Astrophysics)

A rotational band with five $$gamma$$-ray transitions ranging from 2$$^+$$ to 12$$^+$$ states was identified in $$^{40}$$Ar. The deduced transition quadrupole moment of 1.45 $$pm$$0.15 eb indicates that the band has a superdeformed shape. The nature of the band is revealed by cranked Hartee Fock Bogoliubov calculations and a multiparticle-multihole configuration is assigned to the band.

Journal Articles

Standard data of dose conversion coefficients in Japan

Sakamoto, Yukio; Sato, Osamu*; Hirayama, Hideo*

Proceedings of 8th Specialists' Meeting on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-8), p.25 - 33, 2010/03

no abstracts in English

Journal Articles

Generation and application of bremsstrahlung production data calculated by EGS4 code

Sakamoto, Yukio; Hirayama, Hideo*; Sato, Osamu*; Shimizu, Akinao*

Nuclear Technology, 168(3), p.585 - 590, 2009/12

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

A Bremsstrahlung production data is needed in the calculation of buildup factors included by the contribution of Bremsstrahlung as secondary photons by IE method. In this work, the emission of Bremsstrahlung is treated as possible as exactly by the introduction of EGS4 results. The Bremsstrahlung production data by pair-created electrons and Compton scattered electrons is evaluated for 26 elements and 4 compound and mixtures. The error estimation of Bremsstrahlung contribution to buildup factors by IE method coupled with this Bremsstrahlung data is coincident with fully transported results by EGS4 code within about 5%. By the introduction of this Bremsstrahlung production data into IE methods, we can calculate buildup factors included by the contribution of Bremsstrahlung with good accuracy up to deep penetration.

Journal Articles

Experimental studies of shielding and irradiation effects at high energy accelerator facilities

Nakashima, Hiroshi; Sakamoto, Yukio; Iwamoto, Yosuke; Matsuda, Norihiro; Kasugai, Yoshimi; Nakane, Yoshihiro; Masukawa, Fumihiro; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; et al.

Nuclear Technology, 168(2), p.482 - 486, 2009/11


 Times Cited Count:7 Percentile:46.15(Nuclear Science & Technology)

Experimental studies of shielding and radiation effects have been started using 120-GeV proton synchrotron at Fermi National Accelerator Laboratory (FNAL) under collaboration between FNAL and Japan. The first campaign of the experiment was carried out at the Pbar target station and Numi experimental station at FNAL, using antiproton and neutrino production targets irradiated by 120-GeV protons. The generated secondary particles passing through steel, concrete and rock were measured by activation methods as well as by other detectors such as scintillator with a veto counter, phoswich detector and a Bonner ball counter on trial. Preliminary experimental results are presented.

Journal Articles

Radiation shielding study for the J-PARC project

Nakashima, Hiroshi; Shibata, Tokushi; Nakane, Yoshihiro; Masukawa, Fumihiro; Matsuda, Norihiro; Iwamoto, Yosuke; Hirayama, Hideo*; Suzuki, Takenori*; Miura, Taichi*; Numajiri, Masaharu*; et al.

Proceedings of 14th Biennial Topical Meeting of the ANS Radiation Protection and Shielding Division (CD-ROM), p.267 - 282, 2006/00

no abstracts in English

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