Establishment of two-dimensional analysis method with resonance-absorption transmission utilizing pulsed neutrons

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The purpose of this study was the establishment of two-dimensional analysis method utilizing the characteristics of the pulsed neutron, focusing on the resonance absorption. Firstly, as the preparation of the proper detector system, the μPIC (Micro Projection Ion Chamber) detector developed in Kyoto University has been introduced. As the result of test experiments, it was found that μPIC was suitable for this study in viewpoint of time and spatial resolutions(～1μs, ～0.5mm), and neutron and gamma-ray separation (<10^<-6>). With this detector system, the resonance absorption experiments using pulsed neutrons were performed at beam line of the J-PARC Center NOBORU. As a sample, single materials of Co, Ta, Mo, and so on having the resonance absorption peak was used in changing of the thickness due to the confirmation of the quantitativity. As a result, the measured thickness derived with the nuclear data and no correction, it was found to be about 7% compared with the real thickness. On the other hand, it was also found that the background component affects the accuracy of quantification. As the results of the simulation and the experiment, the background is originated from the scattering neutron in the experimental room. The basic algorithm for the analysis could be established for two-dimensional resonance absorption analysis method. However, for the more precise analysis, the improvement of the detector system and the measurement method is necessary.