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JAEA Reports

Development and implementation of a real-time data analysis method for aerial radiation monitoring using satellite communication (Contract research)

Futemma, Akira; Kudo, Tamotsu; Takahashi, Fumiaki

JAEA-Research 2026-002, 51 Pages, 2026/07

JAEA-Research-2026-002.pdf:3.35MB

Rapid assessment of wide-area dose rate distributions is essential in aerial radiation monitoring during a nuclear emergency. Under contract with the Nuclear Regulation Authority, JAEA has developed a real-time data transmission system to receive gamma-ray count rates and positional information from crewed helicopters. However, the conventional system only displayed position and count-rate data on a map and did not support either real-time dose rate conversion or mapping. In this study, a real-time analysis method was developed for aerial radiation monitoring data acquired via satellite communication at approximately 30-second intervals and implemented in the existing system. The method integrates dose rate conversion at 1 m above ground level, automatic extraction of valid flightline data, and dose rate mapping. Cosmic-ray and airborne radionuclide corrections were simplified based on previous monitoring data. A machine-learning model based on aircraft flight behavior was developed to automate flight-line data extraction, which had relied on visual inspection using GIS. IDW interpolation and mapping procedures suitable for 30-second interval data were determined. Comparison with conventional post-flight analysis showed that the method reproduced the main trends of dose rate distributions. Operational testing confirmed normal operation from data reception to map display and delivery of results within several seconds. These results provide a technical basis for real-time dose rate mapping from satellite-transmitted aerial monitoring data during nuclear emergencies.

JAEA Reports

Development of real-time mapping software for wide-area radiation survey

Takahashi, Tone; Koizumi, Mitsuo; Yoshimi, Yuki*; Mochimaru, Takanori*

JAEA-Technology 2025-007, 26 Pages, 2025/11

JAEA-Technology-2025-007.pdf:1.6MB

To prevent the smuggling of nuclear and radioactive materials into event venues for the purpose of terrorism, it is common practice to individually inspect people and vehicles entering and exiting using radiation detectors. However, since there remains a risk of such inspections being bypassed, it is necessary to complement them with a wide-area radiation survey to ensure that no nuclear or radioactive materials have been brought in. Radiation mapping is an effective method for efficiently surveying large areas. In this method, a gamma-ray detector equipped with GPS is used to record location data and radiation dose rates while moving. By utilizing network connectivity, measurement data from multiple detectors can be aggregated at a central command post, allowing real-time monitoring of survey progress. This system helps to prevent both redundant and missing measurements and enables the prompt detection of suspicious radiation sources. Furthermore, by incorporating spectrometers into the gamma -ray detectors, it becomes possible to identify radioactive isotopes, thereby enabling appropriate responses. To enable such wide-area radiation surveys, we developed real-time mapping software. The developed software receives measurement data transmitted from GPS-equipped gamma-ray spectrometers, processes it sequentially in real time, and plots it onto pre -downloaded map data. Additionally, by integrating the spectral data collected from regions showing abnormal radiation levels can be displayed immediately. To enhance information security, the software is designed to function within local networks without requiring internet connectivity. In this report, we introduce an overview of the developed software and provide a simplified version of the source code as an appendix. The provided code is developed using open and free operating systems, libraries, and environments, making it freely available and usable by anyone.

Journal Articles

Real-time monitoring of oxidation processes on the Si(001) surface using O $_{2}$ gas under 1000 K by synchrotron radiation photoemission spectroscopy

Yoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden

Surface Science, 566-568(Part.2), p.1124 - 1129, 2004/09

https://doi.org/10.1016/j.susc.2004.06.069

Times Cited Count：5 Percentile：28.47(Chemistry, Physical)

The Si(001) oxidaion is an important reaction for not only semiconductor technology but also surface science. It is known that the growth mode forming oxide-layers is divided into two regions depending on surface temperature conditions. One is passive oxidation and the other is two dimensional island growth including SiO desorption. Since the oxygen uptake measurements have been measured in many reported studies, Si oxidatuion states related to the growth of oxide-layers have not been clarified yet. In order to measure the time evolution of Si oxidation states depending on the surface temperature, we have performed the real-time photoemission measurements using synchrotron radiation at SUREAC2000 in SPring-8 . We found that the Si $^{4+}$ states was formed at the early oxidation stage in the two dimiensional island regions.

Journal Articles

Real-time monitoring of oxidation on the Ti(0001) surface by synchrotron radiation photoelectron spectroscopy and RHEED-AES

Takakuwa, Yuji*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden; Yamauchi, Yasuhiro*; Mizuno, Yoshiyuki*; Tonda, Hideki*; Homma, Teiichi*

Applied Surface Science, 216(1-4), p.395 - 401, 2003/06

https://doi.org/10.1016/S0169-4332(03)00453-7

Times Cited Count：20 Percentile：64.36(Chemistry, Physical)

Real-time in-situ observation using photoelectron spectroscopy for elementary processes of Ti(0001) oxidation by O $_{2}$ molecules has been performed at the surface reaction analysis apparatus installed at the BL23SU in the SPring-8. And the real-time observation has been also performed by RHEED-AES methods at Tohoku University. The partial pressure region of oxygen was from 2x10 $^{-7}$ Torr to 8x10 $^{-8}$ Torr. The surface temperature was 473 K and 673 K. The variation from clean Ti surface toward TiO $_{2}$ was comfirmed by observation of Ti-2p and O-1s photoelectron spectra. Reflected electron intensity and O-KLL Auger electron intensity oscillated in the RHEED-AES measurements. These facts revealed that the surface morphological change of the oxidized Ti(0001) surface was associated not only with a disappearance of the surface metallic layer but also with a change of the oxidation state.