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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.
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.
Suzuki, Takahiro; Isayama, Akihiko; Ide, Shunsuke; Fujita, Takaaki; Oikawa, Toshihiro; Sakata, Shinya; Sueoka, Michiharu; Hosoyama, Hiroki*; Seki, Masami; JT-60 Team
AIP Conference Proceedings 787, p.279 - 286, 2005/09
A real-time control system of safety factor (q) profile was developed in JT-60. This system, for the first time, enables 1) real time evaluation of q profile using local magnetic pitch angle measurement by motional Stark effect (MSE) diagnostic and 2) control of current drive (CD) location (rhoCD) by adjusting the parallel refractive index 
of lower-hybrid (LH) waves through the change of phase difference (dphi) of LH waves between multi-junction launcher modules. The method for q profile evaluation was newly developed, without time-consuming reconstruction of equilibrium, so that the method requires less computational time. The system evaluates q profile within every 10ms, which is much faster than current relaxation time, typically order of 1s. Safety factor profile by the real-time calculation agreed well with that by equilibrium reconstruction with MSE. From temporal evolution of q (or current) profile, we evaluate CD location in real-time, too. The control system controls rhoCD through (or directly dphi) in such a way to minimize difference between the real-time evaluated q profile and its reference profile. The real-time control system was applied to positive shear plasmas (
), having plasma current of 0.6MA, toroidal field of 2.3T, and electron density of 
. In order to keep good coupling of LH waves to the plasma, gap between the launcher and the plasma surface was controlled to about 0.1m. The reference q profile was set to q(0)=1.3. The real-time q profile approached to the reference after application of real-time control; the controlled q profile was sustained for 3s, which was limited by injected LH power. RF experiments in JT-60U, such as stabilization of neo-classical tearing modes, plasma startup experiments, etc., are also presented.
Moriyama, Shinichi; Shinozaki, Shinichi
Japanese Journal of Applied Physics, Part 1, 44(8), p.6224 - 6229, 2005/08
Times Cited Count：1 Percentile：4.49(Physics, Applied)The control system of RF heating system in JT-60U has been improved with a concept of dispersion processing and featuring a real time waveform shaping method. It is proper that the brand-new, dispersion processing system has higher performance and reliability than old single processor system before modification, however it is worthy of mention that improvement on operation roll sharing, using the real time waveform shaping, has enabled more efficient and smooth operation. The typical roll sharing is that a simple rectangular waveform of the RF heating power is set by the experiment operator, and the waveform is re-shaped with the parameter set by the RF operator who knows deeply the condition of the RF system at that time. The simple and flexible composition of the new control system will also enable further improvement of hardware to enhance plasma performance that is inevitable to the devices for fusion experiment.
Fujii, Tsuneyuki; Seki, Masami; Moriyama, Shinichi; Terakado, Masayuki; Shinozaki, Shinichi; Hiranai, Shinichi; Shimono, Mitsugu; Hasegawa, Koichi; Yokokura, Kenji; JT-60 Team
Journal of Physics; Conference Series, 25, p.45 - 50, 2005/00
The JT-60U electron cyclotron range of frequency (ECRF) is utilized to realize high performance plasma. Its output power is 4 MW at 110 GHz. By controlling the anode voltage of the gyrotron used in the JT-60U ECRF heating system, the gyrotoron output can be controlled. Then, the anode voltage controller was developed to modulate the injected power into plasmas. This low cost controller achieved the modulation frequency 12 - 500 Hz at 0.7 MW. This controller also extended the pulse width from 5s to 16 s at 0.5 MW. For these long pulses, temperature rise of the DC break made of Alumina ceramics is estimated. Its maximum temperature becomes 
140 deg. From the analysis of this temperature rise, DC break materials should be changed to low loss materials for the objective pulse width of 30 s. The stabilization of neoclassical tearing mode (NTM) was demonstrated by ECRF heating using the real-time system in which the ECRF beams are injected to the NTM location predicted from ECE measurement every 10 ms.
gas under 1000 K by synchrotron radiation photoemission spectroscopyYoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden
Surface Science, 566-568(Part.2), p.1124 - 1129, 2004/09
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
states was formed at the early oxidation stage in the two dimiensional island regions.
Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke
Shinku, 47(4), p.301 - 307, 2004/04
Recent research results on translational kinetic energy effects of incident oxygen molecules for Si(001) oxidation are summalized and introduced. The variation of surface temperature dependence of SiO desorption yield, oxygen uptake curves, and chemical bonding states depending on translational kinetic energy of oxygen molecules is described concretely. Eapecially, the translational kinetic energy effects on chemical reaction processes of concurrent oxide-layers formation and SiO desorption are discussed.
estimatorSuzuki, Katsuo; Suzudo, Tomoaki; Nabeshima, Kunihiko
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(1), p.24 - 33, 2004/03
This paper concerns an application of digital optimal H estimator to the detection of faulty reactivity in real-time. The detection system, fundamentally based on the reactivity balance method, is composed of three modules, i.e. the net reactivity estimator, the feedback reactivity estimator and the reactivity balance circuit. H optimal filters are used for these two reactivity estimators, and the nonlinear neutronics are taken into consideration especially for the design of the net reactivity estimator. A series of performance tests of the detection system are conducted by using numerical simulations of reactor dynamics with the insertion of a faulty reactivity for an experimental fast breeder reactor JOYO. The system detects the typical artificial reactivity insertions of 1￠ within a few seconds with the accuracy of 0.1￠, and is satisfactory for its practical use.
value measurement with Feynman- method utilizing time series data acquisition on low enriched uranium systemTonoike, Kotaro; Yamamoto, Toshihiro; Watanabe, Shoichi; Miyoshi, Yoshinori
Journal of Nuclear Science and Technology, 41(2), p.177 - 182, 2004/02
Times Cited Count：15 Percentile：66.06(Nuclear Science & Technology)As a part of the development of a subcriticality monitoring system, a system which has a time series data acquisition function of detector signals and a real time evaluation function of alpha value with the Feynman- method was established, with which the kinetic parameter (alpha value) was measured at the STACY heterogeneous core. The Hashimoto's difference filter was implemented in the system, which enables the measurement at a critical condition. The measurement result of the new system agreed with the pulsed neutron method.
estimator for VHTRC experimentSuzuki, Katsuo; Nabeshima, Kunihiko; Yamane, Tsuyoshi; Fujii, Yoshio*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(4), p.408 - 417, 2003/12
On-line and real-time estimation of time-varying reactivity in a nuclear reactor is necessary for early detection of reactivity anomaly and safe operation. Using a digital nonlinear H estimator, an experiment of real-time dynamic reactivity estimation was carried out in the VHTRC of JAERI. Some technical issues of the experiment are described, such as reactivity insertion, data sampling frequency, anti-aliasing filter, experimental circuit and digitalizing nonlinear H reactivity estimator, and so on. Then, we discussed the experimental results obtained by the digital nonlinear H estimator with sampled data of the nuclear instrumentation signal for the power responses under various reactivity insertions. Good performances of estimated reactivity were observed, with almost no delay to the true reactivity and sufficient accuracy between 0.05cent and 0.1cent. From the results of the experiment, it is concluded that the digital nonlinear H reactivity estimator can be applied as on-line real-time reactivity meter for actual nuclear plants.
Takakuwa, Yuji*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden
Kagaku Kogyo, 54(9), p.687 - 692, 2003/09
Real-time in-situ photoemission spectroscopic studies on Ti(0001) oxidation by O molecules at 473K-673K are reviewed. The Ti(0001) surface was changed from metal to oxide during exposure to oxygen gas. From the time dependent Ti-2p photoemission spectra, time evolution of each oxide component of Ti was clarified.
Yoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden
Japanese Journal of Applied Physics, Part 1, 42(7B), p.4676 - 4679, 2003/07
Times Cited Count：1 Percentile：5.41(Physics, Applied)Many studies of the thermal oxidation on Si(001) surface by O gas have been already carried out from both experimental and theoretical methods. The oxidation reaction kinetics have been studied by real time photoemission spectroscopy. Most reports, however, were performed at a fixed electron binding energy. We present the study of initial stage of thermal oxidation on Si(001) surface at the O pressure of 1x10
Pa performed by real time O-1s synchrotron radiation photoemission spectroscopy.All experiments were performed at SUREAC2000 at BL23SU in the SPring-8. The pure O gas of 1x10 Pa was fed into the reaction analysis chember through a variable leak valve. The results of oxygen uptake curves obtained by O-1s peak area intensities at the substrate temperature of 855K and 955K indicate that the Langmuir adsorption model provided the best fitting result for the 855K oxidation, whereas the oxidation at 955K was well explained by the autocatalytic reaction model.
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
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 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
Torr to 8x10
Torr. The surface temperature was 473 K and 673 K. The variation from clean Ti surface toward TiO 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.
gas on Si(0 0 1) surface by means of synchrotron radiation Si-2p photoemission spectroscopyYoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden
Applied Surface Science, 216(1-4), p.388 - 394, 2003/06
Times Cited Count：9 Percentile：44.60(Chemistry, Physical)It is well known that the initial Si(0 0 1) oxidation by O gas is an important reaction system because it is usually used to form gate-oxide films on MOSFET. With decreasing the size of ULSI, it is necessary to control the surface reaction with atomic scales. In this study, we report 
observation of thermal oxidation using O gas on Si(0 0 1) surface by means of synchrotron radiation photoemission spectroscopy at the soft x-ray beamline, BL23SU, in the SPring-8. We clarified the chemisorption processes of O on Si(0 0 1) surface over 773K regions at the initial oxidation stages from the results of Si2p core-level shifts. The fundamental understanding of surface reaction is expected to contribute the development of the future nanotechnology.
Yoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden
Japanese Journal of Applied Physics, Part 1, 42(6B), p.3976 - 3982, 2003/06
Times Cited Count：6 Percentile：27.36(Physics, Applied)It is well known that the thermal oxidation on Si(001) surface is an important reaction system to form of the gate-oxide films in MOSFET, since it is necessary to control the film thickness under a few nano-meter scale. Thus, we have studied the oxygen uptake and the Si oxidation states depending on the oxidation times by using the synchrotron radiation photoemission spectroscopy in 1
10Pa of O at the surface temperature from 870K to 1120K. We clarified the oxidation depending on the surface temperature was explained by the kinetics (Langumuir and auto-catalytic model). Using real time photoemission spectroscopy, we found that the Si sepcies was not formed at the initial oxidation stage.
Suzuki, Yoshio; Sai, Kazunori*; Matsumoto, Nobuko*; Hazama, Osamu
IEEE Computer Graphics and Applications, 23(2), p.32 - 39, 2003/04
Times Cited Count：6 Percentile：51.10(Computer Science, Software Engineering)Visualization systems PATRAS/ITBL and AVS/ITBL, which are based on visualization software PATRAS and AVS/Express respectively, have been developed on a global, heterogeneous computing environment, called Information Technology Based Laboratory (ITBL). PATRAS/ITBL allows for real-time visualization of the numerical results acquired from coupled multi-physics numerical simulations, executed on different hosts situated in remote locations. A collaborative visualization among numerous sites for this type of simulation was also made possible. AVS/ITBL allows for post processing visualization. The scientific data located in remote sites may be selected and visualized on web browser installed in a user terminal. The global structure and main functions of these systems are presented.
Hiranai, Shinichi; Shinozaki, Shinichi; Sato, Fumiaki*; Suzuki, Yasuo*; Yokokura, Kenji; Moriyama, Shinichi; Ikeda, Yoshitaka
JAERI-Tech 2003-038, 39 Pages, 2003/03
JAERI-Tech-2003-038.pdf:9.06MB
The JT-60U electron cyclotron heating (ECH) System injects a millimeteric wave at 110 GHz (EC beam) into the JT-60 Plasma, and heats the plasma or drives a current locally to enhance the confinement performance of the JT-60 plasma. The system consists of four sets of high power gyrotrons, high voltage power supplies and transmission lines, and two antennas that launch electron cyclotron (EC) beams toward the plasma. The key features of the injection control system are steering of the direction of the EC beam by driving the movable mirror in the antenna, and capability to set any combination of polarization angle and ellipticity by rotating the two grooved mirrors in the polarizers. This report represents the design, fabrication and improvements of the injection control system.
Shinozaki, Shinichi; Moriyama, Shinichi; Hiranai, Shinichi; Sato, Fumiaki*
JAERI-Tech 2003-032, 48 Pages, 2003/03
JAERI-Tech-2003-032.pdf:3.55MB
On the JT-60 radio frequency (RF) heating system, the decrease in the activity ratio was a problem because of the deterioration of the control system. To improve the reliability, we replaced CAMAC system for a power injection control system, which was a main cause of the trouble, with the microprocessor system. And, a function of computer supported programming function of RF power injection form was introduced, which contributed to reduce a load of operators. Furthermore, personal computers with network communication were introduced to improve a maintenance ability of the control system. As a result, the activity ratio of the RF heating system was improved significantly.
Maruyama, Yoichiro; Kato, Masaaki
JAERI-Research 2002-040, 15 Pages, 2003/02
JAERI-Research-2002-040.pdf:1.05MB
As a tunable laser source for the study of real time LIDAR techique to detect some trace impurities in atmosphere, a dye laser has been employed. As a dye laser is difficult to handle, it is considered that the dye laser may not be used as a practical light source. A tunable solid stat laser composed of an optical parametricc oscillaotr (OPO) which has a wider wavelength range is one of the promising tunable light sources, however, there is no OPO with high repetition rate and large pulse energy. Therefore high repetition rate lasing characteristics of OPO are studied. In this experiment, 
-Barium Borate (BBO) crystal is utilized as a gain meduim of OPO and pumped by the second harmonic of Nd:YAG laser with the pulse repetition rate of 0.5 kHz. The threshold pumping peak power for BBO-OPO is around 16 MW/cm
. Maximum OPO average output power of around 5.4 W is obtained with the power conversion efficiency of around 45%. The averege output power of OPO is increasing with the pumping power and undesirable thermal effects are not observed.
Yonekawa, Izuru; Kawamata, Yoichi; Totsuka, Toshiyuki; Akasaka, Hiromi; Sueoka, Michiharu; Kurihara, Kenichi; Kimura, Toyoaki; JT-60U Team
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.521 - 529, 2002/09
Times Cited Count：5 Percentile：33.09(Nuclear Science & Technology)The present status of JT-60 control system is reported including its original design concept, the progress of the system and various modifications since JT-60 upgrade. This control system has features of a functionally distributed and hierarchical structure, using CAMAC interfaces at the beginning, which are replaced to versatile module Europe (VME)-bus interfaces later, and a protective interlock system composed of both software and hard-wired interlock logics. Plant monitoring and control are performed by efficient data communication through CAMAC highways and Ethernet with TCP/IP protocols. Sequential control of a plasma discharges are executed by a combination of a remodeled VME-bus system and a timing system. At real-time plasma control system and a human interface system have been continuously modified corresponding to the progress of JT-60 experiments.
