Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Maurer, C.*; Galmarini, S.*; Solazzo, E.*; Ku
mierczyk-Michulec, J.*; Bar
, J.*; Kalinowski, M.*; Schoeppner, M.*; Bourgouin, P.*; Crawford, A.*; Stein, A.*; et al.
Journal of Environmental Radioactivity, 255, p.106968_1 - 106968_27, 2022/12
Times Cited Count：5 Percentile：36.02(Environmental Sciences)After performing multi-model exercises in 2015 and 2016, a comprehensive Xe-133 atmospheric transport modeling challenge was organized in 2019. For evaluation measured samples for the same time frame were gathered from four International Monitoring System stations located in Europe and North America with overall considerable influence of IRE and/or CNL emissions. As a lesion learnt from the 2nd ATM-Challenge participants were prompted to work with controlled and harmonized model set ups to make runs more comparable, but also to increase diversity. Effects of transport errors, not properly characterized remaining emitters and long IMS sampling times (12 to 24 hours) undoubtedly interfere with the effect of high-quality IRE and CNL stack data. An ensemble based on a few arbitrary submissions is good enough to forecast the Xe-133 background at the stations investigated. The effective ensemble size is below five.
Nugraha, E. D.*; Hosoda, Masahiro*; Kusdiana*; Untara*; Mellawati, J.*; Nurokhim*; Tamakuma, Yuki*; Ikram, A.*; Syaifudin, M.*; Yamada, Ryohei; et al.
Scientific Reports (Internet), 11(1), p.14578_1 - 14578_16, 2021/07
Times Cited Count：28 Percentile：84.15(Multidisciplinary Sciences)Mamuju is one of the regions in Indonesia which retains natural conditions but has relatively high exposure to natural radiation. The goals of the present study were to characterize exposure of the entire Mamuju region as a high natural background radiation area (HNBRA) and to assess the existing exposure as a means for radiation protection of the public and the environment. A cross-sectional study method was used with cluster sampling areas by measuring all parameters that contribute to external and internal radiation exposures. It was determined that Mamuju was a unique HNBRA with the annual effective dose between 17 and 115 mSv, with an average of 32 mSv. The lifetime cumulative dose calculation suggested that Mamuju residents could receive as much as 2.2 Sv on average which is much higher than the average dose of atomic bomb survivors for which risks of cancer and non-cancer diseases are demonstrated. The study results are new scientific data allowing better understanding of health effects related to chronic low-dose-rate radiation exposure and they can be used as the main input in a future epidemiology study.
Ando, Masaki; Matsuda, Norihiro; Saito, Kimiaki
Nihon Genshiryoku Gakkai Wabun Rombunshi, 20(1), p.34 - 39, 2021/03
We measured count rates and air dose rates at 11 measurement points where the influence of the Fukushima Dai-ichi Nuclear Power Plant accident could be ignored to obtain parameters for a background equation applying to KURAMA-II loaded with the high sensitivity CsI(Tl) detector, C12137-01. It was found that the sensitivity of KURAMA-II (C12137-01) was about 10 times or more for background measurement, compared with KURAMA-II loaded with the standard type CsI(Tl) detector, C12137. A background equation for the energy range of 1400-2000 keV was determined as, y (
Sv/h)=0.062 x (cps). We evaluated background air dose rates using KURAMA-II (C12137-01) for 71 municipalities and compared them with the previous study using KURAMA-II (C12137). Evaluated background air dose rates in this study were almost equal to those in the previous study. We confirmed that the background equation evaluated in this study was applicable for the KURAMA-II (C12137-01).
Hosoda, Masahiro*; Nugraha, E. D.*; Akata, Naofumi*; Yamada, Ryohei; Tamakuma, Yuki*; Sasaki, Michiya*; Kelleher, K.*; Yoshinaga, Shinji*; Suzuki, Takahito*; Rattanapongs, C. P.*; et al.
Science of the Total Environment, 750, p.142346_1 - 142346_11, 2021/01
Times Cited Count：34 Percentile：85.81(Environmental Sciences)The biological effects of low dose-rate radiation exposures on humans remains unknown. In fact, the Japanese nation still struggles with this issue after the Fukushima Dai-ichi Nuclear Power Plant accident. Recently, we have found a unique area in Indonesia where naturally high radiation levels are present, resulting in chronic low dose-rate radiation exposures. We aimed to estimate the comprehensive dose due to internal and external exposures at the particularly high natural radiation area, and to discuss the enhancement mechanism of radon. A car-borne survey was conducted to estimate the external doses from terrestrial radiation. Indoor radon measurements were made in 47 dwellings over three to five months, covering the two typical seasons, to estimate the internal doses. Atmospheric radon gases were simultaneously collected at several heights to evaluate the vertical distribution. The absorbed dose rates in air in the study area vary widely between 50 nGy h
and 1109 nGy h. Indoor radon concentrations ranged from 124 Bq m
to 1015 Bq m. That is, the indoor radon concentrations measured exceed the reference levels of 100 Bq m recommended by the World Health Organization. Furthermore, the outdoor radon concentrations measured were comparable to the high indoor radon concentrations. The annual effective dose due to external and internal exposures in the study area was estimated to be 27 mSv using the median values. It was found that many residents are receiving radiation exposure from natural radionuclides over the dose limit for occupational exposure to radiation workers. This enhanced outdoor radon concentration might be as a result of the stable atmospheric conditions generated at an exceptionally low altitude. Our findings suggest that this area provides a unique opportunity to conduct an epidemiological study related to health effects due to chronic low dose-rate radiation exposure.
Ando, Masaki; Mikami, Satoshi; Tsuda, Shuichi; Yoshida, Tadayoshi; Matsuda, Norihiro; Saito, Kimiaki
Journal of Environmental Radioactivity, 192, p.385 - 398, 2018/12
Times Cited Count：15 Percentile：42.34(Environmental Sciences)Car-borne surveys using KURAMA systems have been conducted over a wide area in eastern Japan since 2011. The measurement data collected until 2016 was analyzed, and decreasing trend of the dose rates in regions within 80 km of Fukushima Dai-ichi Nuclear Power Plant were examined. The averaged dose rates tended to decrease considerably with respect to the physical decay of radiocaesium, and the ecological half-lives of the fast and slow decay components were estimated. The decrease of the dose rate in the forest was slower than its decrease in other regions, and the decrease of the dose rate in urban area was the fastest. The decrease in the dose rates obtained via the car-borne survey was larger than that obtained on flat ground with few disturbances using survey meters approximately 1.5 y after the accident; hereafter, the decrease in the dose rates obtained via the car-borne survey was same as the latter measurement.
Fukunaga, Hisanori*; Yokoya, Akinari
Journal of Radiation Research, 57(1), p.98 - 100, 2016/01
Times Cited Count：10 Percentile：87.79(Biology)Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Yamaguchi, Yasuhiro
Journal of Nuclear Science and Technology, 42(9), p.768 - 778, 2005/09
Times Cited Count：17 Percentile：72.61(Nuclear Science & Technology)A new inventive radiation monitor, designated to DARWIN (Dose Assessment system applicable to various Radiations with WIde energy raNges), has been developed for monitoring doses at workspaces of high energy accelerator facilities and on ground. Characteristics of DARWIN were studied by both calculation and experiment. The calculated results indicate that DARWIN gives reasonable estimations of doses at most radiation fields. It was found from the experiment that DARWIN has an excellent property of measuring doses from all particles that significantly contribute to the background dose - photon, muon and neutron with wide energy ranges.
Nakamura, Tatsuya; Masaoka, Sei; Yamagishi, Hideshi; Sakasai, Kaoru; Soyama, Kazuhiko; Aizawa, Kazuya
IEEE Transactions on Nuclear Science, 51(4), p.1519 - 1523, 2004/08
Times Cited Count：2 Percentile：18.21(Engineering, Electrical & Electronic)A capillary plate (CP) comprising an assembly of fine glass tubes was applied as a pre-gas-amplification device for a microstrip gas chamber (MSGC) operating under high-gas pressure of helium-3 for use in neutron detection. The collection efficiency of the electrons between the CP and MSGC was maximally 17% using neutrons. The effective gas gain of the detector system was 
600 at a gas pressure of 3 atm with a 10% mixture of ethane with helium-3, confirming the feasibility of the CP as a pre-gas-amplification device. Moreover, we demonstrated that the coincidence measurement of the signals between the CP and the anodes of MSGC decreased the background levels of electronics noise, electronic discharges, and 
-rays, indicating that a detector system with a low background can be constructed using the CP.
spatial profile from background light in incoherent Thomson scattering diagnosticNaito, Osamu; Hatae, Takaki
JAERI-Research 2002-033, 9 Pages, 2003/03
JAERI-Research-2002-033.pdf:0.46MB
A simulation study on the feasibility of inferring spatial profile along with electron temperature and density in Thomson scattering diagnostic is presented. The background signal, which is usually discarded after subtracted from the Thomson scattered signal, is used in the reconstruction procedure. If the contribution from line radiation to the background signal is by one order of magnitude smaller than that from bremsstrahlung, a fairly accurate profile can be reconstructed.
detection system in the indoor environments of concrete buildingsTsutsumi, Masahiro; Oishi, Tetsuya; Kinouchi, Nobuyuki; Sakamoto, Ryuichi; Yoshida, Makoto
Journal of Nuclear Science and Technology, 38(12), p.1109 - 1114, 2001/12
In order to predict the indoor background spectra to gamma detection systems, the gamma radiation field in a concrete building is studied by the Monte Carlo simulations. The parameters of wall thickness, room shape and dimensions were considered in the modeling. The indoor source geometry was simulated by a spherical layer model with the intention of easy and effective calculations. The model was applied to an unshielded germanium detector and the detection system with a more complex shielding configuration. As the results, we found that the indoor radiation field in concrete buildings can be predicted well with the source geometry of a spherical concrete layer of 25cm thickness and with the source of the natural major three components of the 
U series, 
Th series and 
K that are homogeneously distributed. The simulation model is useful for designing and optimizing gamma detection systems or shielding assemblies.
U Doppler Effect using various samples in FCA XVII-1Ando, Masaki; Okajima, Shigeaki; Oigawa, Hiroyuki
JAERI-Research 2001-017, 20 Pages, 2001/03
JAERI-Research-2001-017.pdf:0.82MB
U Doppler effect measurements were carried out using 6 uranium samples with various composition or diameter varying self-shielding factors of U. Calculation accuracy of the standard analysis method for fast reactor cores at FCA was investigated.The Doppler effect were measured by the sample-heated and reactivity worth measurement method up to 800 degree in the FCA XVII-1 assembly, which simulated Na-cooled MOX fueled FBR. In the analysis, the Doppler effect was calculated using the effective cross sections obtained by the PEACO-X code. The calculated values based on the diffusion theory agreed well with the experiment for the U-metal and UO
samples. The calculation underestimated the experiment from 10% to 30% for the UO samples containing BeO. This underestimation was improved by the use of the transport calculation. The calculation, however, underestimated about 20% for the sample whose background cross section is greater than 300 barns.
Kaneko, Isamu; Muramatsu, Kazuhiro
JAERI-Data/Code 2000-020, p.16 - 0, 2000/03
JAERI-Data-Code-2000-020.pdf:0.88MB
no abstracts in English
C at FCA, 4; Investigation on calculation model for the Doppler effect measurement with a heated foil using MVP codeAndo, Masaki; Okajima, Shigeaki
JAERI-Research 97-014, 22 Pages, 1997/03
JAERI-Research-97-014.pdf:0.77MB
no abstracts in English
; Handa, Nuneo; Shiozawa, Kenichi; Hirata, Masaru;
JAERI-M 90-062, 49 Pages, 1990/03
no abstracts in English
; ; ; ;
JAERI-M 86-020, 88 Pages, 1986/02
no abstracts in English
Kikuchi, Yasuyuki;
JAERI-M 85-101, 195 Pages, 1985/07
no abstracts in English
Kikuchi, Yasuyuki;
Journal of Nuclear Science and Technology, 22(5), p.337 - 357, 1985/00
Times Cited Count：5 Percentile：59.38(Nuclear Science & Technology)no abstracts in English
experimentIijima, Tsutomu
Nukleonik, 11(3), p.157 - 159, 1968/00
no abstracts in English
; ;
Dai-2-Kai Genshiryoku Shimpojiumu Hobunshu, P. 32, 1958/00
no abstracts in English
Shibata, Kaoru
no journal, ,
The silicon crystal analyzer is an important spectroscopic device for high energy resolution neutron inelastic backscattering spectrometer. Specification of this spectroscopic device is thought to determine energy resolution and background. In order to achieve a low background spectrum without degradation of the energy resolution, it was developed new crystal analyzer which were constracted by Si wafers coated by thin film of neutron absorbers on the back side of Si wafer, and used it for the new backscattering spectrometer DNA in MLF at J-PARC which were able to achieve the desired performance.
