Quantitative visualization of a radioactive plume with harmonizing gamma-ray imaging spectrometry and real-time atmospheric dispersion simulation based on 3D wind observation

Nagai, Haruyasu; Furuta, Yoshihiro*; Nakayama, Hiromasa; Satoh, Daiki

Journal of Nuclear Science and Technology, 60(11), p.1345 - 1360, 2023/11

https://doi.org/10.1080/00223131.2023.2197445

A novel monitoring method for the quantitative visualization of 3D distribution of a radioactive plume and source term estimation of released radionuclides is proposed and its feasibility is demonstrated by preliminary test. The proposed method is the combination of gamma-ray imaging spectroscopy with the Electron Tracking Compton Camera (ETCC) and real-time high-resolution atmospheric dispersion simulation based on 3D wind observation with Doppler lidar. The 3D distribution of a specific radionuclide in a target radioactive plume is inversely reconstructed from line gamma-ray images from each radionuclide by several ETCCs located around the target by harmonizing with the air concentration distribution pattern of the plume predicted by real-time atmospheric dispersion simulation. A prototype of the analysis method was developed, showing a sufficient performance in several test cases using hypothetical data generated by numerical simulations of atmospheric dispersion and radiation transport.

Gamma-ray observations at the coastal area of Japan Sea in winter seasons

Tsuchiya, Harufumi; Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Umemoto, Daigo*; Makishima, Kazuo*; GROWTH Collaboration*

Proceedings of Science (Internet), 358, p.1163_1 - 1163_6, 2021/07

https://doi.org/10.22323/1.358.1163

Photonuclear reactions in lightning, 1; Verification and modeling of reaction and propagation processes

Wada, Yuki*; Enoto, Teruaki*; Nakazawa, Kazuhiro*; Odaka, Hirokazu*; Furuta, Yoshihiro; Tsuchiya, Harufumi

Journal of Geophysical Research; Atmospheres, 125(20), p.e2020JD033193_1 - e2020JD033193_17, 2020/10

https://doi.org/10.1029/2020JD033193

Thundercloud project; Exploring high-energy phenomena in thundercloud and lightning

Yuasa, Takayuki*; Wada, Yuki*; Enoto, Teruaki*; Furuta, Yoshihiro; Tsuchiya, Harufumi; Hisadomi, Shohei*; Tsuji, Yuna*; Okuda, Kazufumi*; Matsumoto, Takahiro*; Nakazawa, Kazuhiro*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2020(10), p.103H01_1 - 103H01_27, 2020/10

https://doi.org/10.1093/ptep/ptaa115

A Remote continuous air monitoring system for measuring airborne alpha contamination

Morishita, Yuki; Usami, Hiroshi; Furuta, Yoshihiro; Aoki, Katsunori; Tsurudome, Koji; Hoshi, Katsuya; Torii, Tatsuo

Radiation Protection Dosimetry, 189(2), p.172 - 181, 2020/04

https://doi.org/10.1093/rpd/ncaa028

We developed a remote continuous air monitoring (RCAM) system. The RCAM system consisted of a personal air monitor and a robot. The personal air monitor (poCAMon, SARAD, Germany) had a 400 mm ion-injected silicon detector and a membrane air filter with 25 mm-diameter. The personal air monitor provides the alpha energy spectra for any measurement time interval. Demonstration measurements were taken underground at the Mizunami Underground Research Laboratory (MIU) and at a poorly ventilated concrete building. The RCAM system was remotely operated and successfully measured the Rn progeny even though the relative humidity (RH) was almost 100%. In the measured alpha spectra, the peaks of Po (6.0 MeV alpha) and Po (7.7 MeV alpha) were clearly identified. Our developed monitor is promising for alpha dust monitoring in a high gamma-ray environment or contaminated areas where a worker cannot safely physically enter.

Downward terrestrial gamma-ray flash observed in a winter thunderstorm

Wada, Yuki*; Enoto, Teruaki*; Nakazawa, Kazuhiro*; Furuta, Yoshihiro; Yuasa, Takayuki*; Nakamura, Yoshitaka*; Morimoto, Takeshi*; Matsumoto, Takahiro*; Makishima, Kazuo*; Tsuchiya, Harufumi

Physical Review Letters, 123(6), p.061103_1 - 061103_6, 2019/08

AA2018-0706.pdf:0.79MB

https://doi.org/10.1103/PhysRevLett.123.061103

Termination of electron acceleration in thundercloud by intracloud/intercloud discharge

Wada, Yuki*; Bowers, G. S.*; Enoto, Teruaki*; Kamogawa, Masashi*; Nakamura, Yoshitaka*; Morimoto, Takeshi*; Smith, D.*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; et al.

Geophysical Research Letters, 45(11), p.5700 - 5707, 2018/06

https://doi.org/10.1029/2018GL077784

Radiation measurements associated with lightning and thunderclouds in winter at the coastal area of the Japan Sea

Tsuchiya, Harufumi; Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Okuda, Kazufumi*; Makishima, Kazuo*; Sato, Mitsuteru*; Sato, Yosuke*; et al.

no journal, , 

no abstracts in English

Development of an estimation method of concentration distribution and release amount of radionuclide discharged to the atmosphere using gamma-ray imaging, 2; Calculation of radionuclide concentration distribution in the atmosphere

Nakayama, Hiromasa; Satoh, Daiki; Furuta, Yoshihiro; Nagai, Haruyasu

no journal, , 

We have been developing a method for estimating radionuclide concentration distributions in the atmosphere and release amount by combining atmospheric dispersion simulations with radiation measuring. This method has high potential to improve reliability of the simulation accuracy by incorporating the obtained release amount and concentration distributions near a source point into atmospheric dispersion simulations. Because there are no real data on radionuclide concentrations, we have a plan to calculate the test data on radionuclide concentration distributions in the atmosphere by computational simulation and validate the estimation method. In this study, we report the method for calculating them used for the test data.

Development of an estimation method of concentration distribution and release amount of radionuclide discharged to the atmosphere using gamma-ray imaging, 3; Simulation of detected gamma-ray images and construction of response matrices

Furuta, Yoshihiro; Satoh, Daiki; Nakayama, Hiromasa; Nagai, Haruyasu; Tanimori, Toru*

no journal, , 

In the CLADS subsidy project, we are developing an estimation method of concentration distribution and release amount of radiative nuclide by reverse-analyzing images of gamma-ray emitted by radionuclide discharged into the atmosphere obtained by an Electron Tracking Compton Camera (ETCC). It improves the estimation accuracy of atmospheric dispersion to use the concentration distribution and release amount of radionuclide calculated by this method as input data to the dispersion calculation. We simulated virtual gamma-ray images and response matrices for the development and verification of reverse analysis method. We report on simulation of these virtual gamma-ray images and construction of the response matrices.