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Skobelev, I. Yu.*; Ryazantsev, S. N.*; Kulikov, R. K.*; Sedov, M. V.*; Filippov, E. D.*; Pikuz, S. A.*; Asai, Takafumi*; Kanasaki, Masato*; Yamauchi, Tomoya*; Jinno, Satoshi; et al.
Photonics (Internet), 10(11), p.1250_1 - 1250_11, 2023/11
Times Cited Count：0 Percentile：0(Optics)It is challenging to clearly distinguish the impacts of the optical field and collisional ionization in the evolution of the charge state of a plasma produced when matter interacts with high-intensity laser pulses. In this work, time-dependent calculations of plasma kinetics are used to show that it is possible only when low-density gaseous targets with sufficiently small clusters are used. In the case of Ar plasma, the upper limit of the cluster radius was estimated to be 
m.
Aizawa, Kosuke; Chikazawa, Yoshitaka; Ara, Kuniaki; Yui, Masahiro*; Jinno, Kentaro*; Hiramatsu, Takashi*
Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 7 Pages, 2019/05
Inspection technique in opaque liquid metal coolant is one of important issues for sodium-cooled fast reactors. Various under sodium viewers (USVs), including horizontal USVs for obstacle detection and imaging USVs, have been developed in several research institutes and countries. We aim practical realization of imaging USV which adopts an optical receiving system, which measures the vibration displacement of diaphragm by using a laser as a receiving sensor. This study mainly focuses on the sensitivity improvement of a receiving sensor. An issue for the sensitivity improvement of the receiving sensor is the sound pressure propagation inside the receiving sensor. Prototype tests in the water and sodium were conducted in order to resolve the issue. In addition, imaging experiments in the water and sodium were conducted using the improved receiving sensor. From the results of imaging experiments, the relation between obtained wave profile and the regeneration imaging was confirmed.
Sekiguchi, Kentaro; Jinno, Satoshi*; Tanaka, Hirotaka*; Ichinose, Kosuke*; Kanasaki, Masato*; Sakaki, Hironao; Kondo, Kiminori; Matsui, Ryutaro; Kishimoto, Yasuaki; Fukuda, Yuji
no journal, ,
The size of clusters, produced in an expansion of supercooled, high pressure molecular hydrogen gas into vacuum, has been evaluated by measuring the angular distribution of scattered light. The data are analyzed based on the Mie scattering theory. Here obtaining the size distribution of clusters reduces to solving the inverse problem. Since the scattering coefficient is a matrix, it is necessary to determine the inverse matrix. However, if you solve this equation straightforward, the size distribution often oscillates to the negative values and becomes the discrete distribution by external factors such as noise included in the measurement results. Therefore, we have built an algorithm to determine the size distribution in combination with a non-negative least square method and a Phillips-Twomey method to obtain a smooth solution.
Tanaka, Hirotaka; Jinno, Satoshi*; Kanasaki, Masato*; Sekiguchi, Kentaro; Ichinose, Kosuke*; Sakaki, Hironao; Kondo, Kiminori; Matsui, Ryutaro; Kishimoto, Yasuaki; Fukuda, Yuji
no journal, ,
The size of clusters, produced in an expansion of supercooled, high pressure molecular hydrogen gas into vacuum, has been evaluated by measuring the angular distribution of scattered light. The data are analyzed based on the Mie scattering theory. Here obtaining the size distribution of clusters reduces to solving the inverse problem. Since the scattering coefficient is a matrix, it is necessary to determine the inverse matrix. However, if you solve this equation straightforward, the size distribution often oscillates to the negative values and becomes the discrete distribution by external factors such as noise included in the measurement results. Here, the validity of the method is confirmed by performing a calibration study using the standard micro-particles.
Aizawa, Kosuke; Chikazawa, Yoshitaka; Ara, Kuniaki; Yui, Masahiro*; Jinno, Kentaro*; Hiramatsu, Takashi*
no journal, ,
Inspection in opaque liquid metal coolant is one of important issues for sodium-cooled fast reactors. To facilitate operations and maintenance activities, the under sodium viewer (USV) has been developed. JAEA works target practical use of the USV which adopts the optical receiving system. The optical receiving system measures the vibration displacement of diaphragm by using a laser as a receiving sensor. In this study, the experiments in water and in sodium focused on the improvement of elemental technology were conducted. From the experimental results, the controlling factor about the propagation behavior of sound pressure and the image reconstruction were investigated.
