99 research outputs found

    Activity of Hokkaido University Neutron Source, HUNS

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    AbstractHokkaido University neutron source, HUNS was completed in 1973, and has been used actively for developments of moderators, neutron instruments, neutron devices and new methods for 40 years although its power is not so high. Recently, a pulsed neutron imaging method has been developed and a new type of small angle neutron scattering method has been also developed. The pulsed neutron imaging is a unique method that can give the physical quantities such as crystallographic quantities of materials over wide area of the real space. So far, the small angle neutron scattering (SANS) is considered to be impossible at a neutron source with a power of HUNS. However, mini focusing SANS (mfSANS) was developed and proved to be useful. Here, we present the present activities on the pulsed neutron imaging and mfSANS at HUNS

    First Imaging Experiment of a Lithium Ion Battery by a Pulsed Neutron Beam at J-PARC/MLF/BL09

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    AbstractWe obtain the transmission image of a commercial lithium ion (Li-ion) battery using a pulsed neutron beam at the beamline 09 of the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. The purpose of this study is to improve the performance of the Li-ion battery by nondestructive observation of its charging and discharging. The transmission images for three charge states (3.2V, 3.7V, and 4.2V) reveal differences between these three states, which we attribute to electrolyte migration. The transmission spectra show Bragg edges originating from the electrodes, current collectors, and battery vessel. Although the battery as a whole has the expected relation between the charge accumulation and the quantity of lithium amounts in the positive and negative electrodes, a portion of the battery deviates from this relation, which may imply a position dependent charging in the battery

    Neutron Diffraction Under High Pressure and High Temperature

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    Neutron Imaging at Compact Accelerator-Driven Neutron Sources in Japan

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    Neutron imaging has been recognized to be very useful to investigate inside of materials and products that cannot be seen by X-ray. New imaging methods using the pulsed structure of neutron sources based on accelerators has been developed also at compact accelerator-driven neutron sources and opened new application fields in neutron imaging. The world’s first dedicated imaging instrument at pulsed neutron sources was constructed at J-PARC in Japan owing to the development of such new methods. Then, usefulness of the compact accelerator-driven neutron sources in neutron science was recognized and such facilities were newly constructed in Japan. Now, existing and new sources have been used for neutron imaging. Traditional imaging and newly developed pulsed neutron imaging such as Bragg edge transmission have been applied to various fields by using compact and large neutron facilities. Here, compact accelerator-driven neutron sources used for imaging in Japan are introduced and some of their activities are presented

    Study on phase transition of Pb-Bi eutectic alloy by neutron transmission spectroscopy

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    LBE (Lead Bismuth Eutectic), which is a candidate for spallation targets, has some problems. One of them is expansion after solidification, which may bring about serious damage of an LBE loop. Two solid phases of β-phase (inter-metallic compound) and γ-phase (solid solution of Pb in Bi) appear in LBE, and it was reported that an increase of the γ-phase observed by X-ray corresponds to the volume expansion of LBE. We performed neutron spectroscopic transmission experiments using a pulsed neutron source in order to observe crystal transformation depending on the position and time for slow and rapid cooling LBE samples. It was found that the crystal structure of the slow cooling LBE varied depending on position while it was rather homogeneous for the rapid cooling sample. The re-crystallization of the γ-phase was more clearly observed for the rapid cooling sample than the slow one. We were able to obtain information of re-crystallization over the whole volume of the samples

    Pulsed neutron spectroscopic imaging for crystallographic texture and microstructure

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    A time-of-flight (TOF) spectroscopic neutron imaging at a pulsed neutron source is expected to be a new material analysis tool because this method can non-destructively investigate the spatial dependence of the crystallographic and metallographic information in a bulk material. For quantitative evaluation of such information, a spectral analysis code for the transmission data is necessary. Therefore, we have developed a Rietveld-like analysis code, RITS. Furthermore, we have applied the RITS code to evaluation of the position dependence of the crystal orientation anisotropy, the preferred orientation and the crystallite size of a welded α-iron plate, and we have successfully obtained the information on the texture and the microstructure. However, the reliability of the values given by the RITS code has not been evaluated yet in detail. For this reason, we compared the parameters provided by the RITS code with the parameters obtained by the neutron TOF powder diffractometry and its Rietveld analysis. Both the RITS code and the Rietveld analysis software indicated values close to each other, but there were systematic differences on the preferred orientation and the crystallite size
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