Image reconstruction of radioactive contamination due to the Fukushima-Daiichi Nuclear Power Station Accident using a compact Compton camera

Sato, Yuki; Terasaka, Yuta; Miyamura, Hiroko; Kaburagi, Masaaki; Tanifuji, Yuta; Kawabata, Kuniaki; Torii, Tatsuo

Reactor Dosimetry; 16th International Symposium on Reactor Dosimetry (ISRD-16) (ASTM STP 1608), p.428 - 436, 2018/11

https://doi.org/10.1520/STP160820170060

Radiation imaging using a compact Compton camera inside the Fukushima Daiichi Nuclear Power Station building

Sato, Yuki; Tanifuji, Yuta; Terasaka, Yuta; Usami, Hiroshi; Kaburagi, Masaaki; Kawabata, Kuniaki; Utsugi, Wataru*; Kikuchi, Hiroyuki*; Takahira, Shiro*; Torii, Tatsuo

Journal of Nuclear Science and Technology, 55(9), p.965 - 970, 2018/09

https://doi.org/10.1080/00223131.2018.1473171

Development of compact Compton camera for 3D image reconstruction of radioactive contamination

Sato, Yuki; Terasaka, Yuta; Ozawa, Shingo*; Miyamura, Hiroko; Kaburagi, Masaaki; Tanifuji, Yuta; Kawabata, Kuniaki; Torii, Tatsuo

Journal of Instrumentation (Internet), 12(11), p.C11007_1 - C11007_8, 2017/11

https://doi.org/10.1088/1748-0221/12/11/C11007

Molecular dynamics simulation of telomeric single-stranded DNA and POT1

Kaburagi, Masaaki; Yamada, Hironao*; Miyakawa, Takeshi*; Morikawa, Ryota*; Takasu, Masako*; Kato, Takamitsu*; Uesaka, Mitsuru*

Polymer Journal, 48(2), p.189 - 195, 2016/02

https://doi.org/10.1038/pj.2015.82

We performed molecular dynamics (MD) simulations of telomeric single-stranded DNA and POT1 for 100 ns. The distance between (POT1) and O5' (telomeric ssDNA) is calculated to verify the binding system for 100 ns MD. We then calculated the distance between the bases of telomeric DNA ends and the root mean square deviation and gyration radius in single and binding states. We compared the root mean square fluctuations between single and binding states and calculated the number of hydrogen bonds between POT1 and telomeric DNA. There are many hydrogen bonds between Gln94 and the first guanine of the closest TTAGGG sequence in telomeric single-stranded DNA. These Gln94 and the guanine have a large difference in root mean square fluctuation between single and binding states. We found that Gln94 and guanine are important components of the binding system, and they are related to its stability.

Remote technology development for function advancement of research base, 7; Feasibility study of a portable Compton camera for visualizing radioactive substances

Sato, Yuki; Kishimoto, Aya*; Kaburagi, Masaaki; Kataoka, Jun*; Torii, Tatsuo

no journal, , 

no abstracts in English

Study on silicon semiconductor detector for visualization the pollution distribution in the Fukushima Daiichi Nuclear Power Plant

Yoshihara, Yuri*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Kaburagi, Masaaki; Torii, Tatsuo

no journal, , 

The accident of Fukushima Daiichi Nuclear Power Plant (FDNPP) was occurred on March 11th and the decommissioning of Unit 1-4 of FDNPP has been started since December 2011. Portable radiation imaging technologies are necessary for monitoring the pollution distribution of the inside of the reactor buildings because the measurement environment is highly contaminated and the detector should be mounted on remote-controlled robots. However, existing radiation-imaging systems mainly adopt mechanical collimation to estimate the inserted direction of ray by using lead or tungsten, which make the systems heavy and limit the operation range of the robots. We have been investigated a stacked edge-on silicon strip detector based on hetero-junction technology, which has directivity without any mechanical collimations for imaging The directivity of the 6-layer stacked silicon strip detector was evaluated. The source of 1 MBq Cs-137 was put on the distance of 10 cm from the front of the detector and rotated with the angles of 0, 15, 30, 60, 90 degree, and the detection counts of each rotate angle were measured with thresholds of 180/360 keV.

Development of radiation imaging system using small-size light-weight Compton camera mounted on remotely operated machines, 3; Study on 3D reconstruction from Compton camera data

Miyamura, Hiroko; Kaburagi, Masaaki; Sato, Yuki; Kawamura, Takuma; Idomura, Yasuhiro; Torii, Tatsuo

no journal, , 

We report the results of experiments for reconstructing three-dimensional volume data of distributions of radiation sources via two reconstruction algorithms from measurement datasets by a Compton camera. To obtain accurate distributions of radiation sources, which were released by the Fukushima Daiichi Nuclear Power Plant accident, detailed measurements of rays are necessary. In this report, as a preliminary experiment, we address three-dimensional reconstruction from measurement data under ideal conditions, using two algorithms: a three-dimensional back-projection method and a list-mode maximum likelihood estimation method. By using these methods, the radiation sources can be accurately reconstructed from the measurement datasets.

Development of radiation imaging system using small-size light-weight Compton camera mounted on remotely operated machines, 1; Visualization of radioactive substances with portable Compton camera mounted on unmanned aerial vehicle

Sato, Yuki; Ozawa, Shingo*; Izumi, Ryo*; Terasaka, Yuta; Kaburagi, Masaaki; Miyamura, Hiroko; Kawamura, Takuma; Tanifuji, Yuta; Kawabata, Kuniaki; Suzuki, Toshikazu*; et al.

no journal, , 

no abstracts in English

Remote radiation imaging system using a multicopter UAV

Sato, Yuki; Ozawa, Shingo*; Terasaka, Yuta; Kaburagi, Masaaki; Miyamura, Hiroko; Tanifuji, Yuta; Kawabata, Kuniaki; Izumi, Ryo*; Suzuki, Toshikazu*; Torii, Tatsuo

no journal, , 

no abstracts in English

Compact Compton camera for radiation distribution imaging under high dose rate environments

Sato, Yuki; Terasaka, Yuta; Kaburagi, Masaaki; Tanifuji, Yuta; Usami, Hiroshi; Miyamura, Hiroko; Ozawa, Shingo*; Izumi, Ryo*; Kawabata, Kuniaki; Suzuki, Toshikazu*; et al.

no journal, ,