20 research outputs found

    Integrated cosmic muon flux in the zenith angle range 0<cosθ<0.370 < \text{cos}\theta < 0.37 for momentum threshold up to 11.6 GeV/c

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    We have measured the cosmic muon flux in the zenith angle range<cosθ<0.37 with a detector comprising planes of scintillator hodoscope bars and iron blocks inserted between them. The muon ranges for up to 9.5 m-thick iron blocks allow the provision of muon flux data integrated over corresponding threshold momenta up to 11.6 GeV/c. Such a dataset covering the horizontal direction is extremely useful for a technique called muon radiography, where the mass distribution inside a large object is investigated from the cosmic muon distribution measured behind the object

    Detection of on-surface objects with an underground radiography detector system using cosmic-ray muons

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    We have developed a compact muon radiography detector to investigate the status of the nuclear debris in the Fukushima Daiichi Reactors. Our previous observation showed that a large portion of the Unit-1 Reactor fuel had fallen to floor level. The detector must be located underground to further investigate the status of the fallen debris. To investigate the performance of muon radiography in such a situation, we observed 2 m cubic iron blocks located on the surface of the ground through different lengths of ground soil. The iron blocks were imaged and their corresponding iron density was derived successfully

    Imaging the inner structure of a nuclear reactor by cosmic muon radiography

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    We studied the inner structure of the nuclear reactor of the Japan Atomic Power Company (JAPC) at Tokai, Japan, by muon radiography. Muon detectors were placed outside the reactor building. By detecting cosmic muons penetrating the wall of the reactor building, we could successfully identify objects such as the containment vessel, pressure vessel, and other structures of the reactor. We also observed a concentration of heavy material which can be attributed to the nuclear fuel assemblies stored in the nuclear fuel storage pool

    Prototype performance of Distributed DAQ using HORB based on Java

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    Network programming is a very important technology for next generation of distributed DAQ system. Java has powerful functionality not only in GUI but also in network programming. Execution speed of Java program is slow on Java interpreter. We have investigated various benchmark programs on Java interpreter, Java Just In Time compiler and Java compiler which generates native codes, and evaluated the performance of them in comparison with that of the C native codes. We found that the performance of the Java compiler was nearly as good as that of the C native codes. Hence, a prototype of Java-based DAQ has been developed. Our goal is to establish 3 tier (DAQ client, DAQ server and DAQ database) model for the DAQ
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