Takayoshi Ito

Current Status of Engineering Materials Diffractometer at J-PARC

The Engineering Materials Diffractometer “TAKUMI” is designed and has been constructed at Materials & Life Science Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC) to conduct various kinds of studies on materials science and engineering and to promote industrial applications, related with strain measurements. The commissioning of TAKUMI has been started from September 2008, and several user programs have been done. In the commissioning, a resolution Δd/d at high resolution mode (with incident beam collimation) of less than 0.2% was achieved in a diffraction experiment using 2 mm diameter thick annealed piano wire. The d-range measured by TAKUMI with single pulse frame, i.e. standard operation, was confirmed to be 0.05 nm to 0.27 nm, showing that the optimum range for materials research is covered by this machine. TAKUMI adopted an event mode data recording method. It was found that the recording method is very useful to manipulate data as we like, for instance, detector range, time of flight binning width and time resolved data, even after the experiment has been finished.

In situ lattice strain mapping during tensile loading using the neutron transmission and diffraction methods

In this study, the change in internal lattice strain in an iron plate during tensile deformation was investigated by performing in situ measurements under applied force. The lattice strain was evaluated by neutron diffraction and Bragg-edge transmission. The neutron diffraction results showed that the averaged 110 lattice strain along the direction perpendicular to the applied force was between −422 and −109 × 10−6. The position dependence of the lattice strain and the change in the distribution of elastic strain in an iron plate with notches during tensile deformation was obtained by Bragg-edge transmission. It was also observed that, when the load increased over 30 kN, the area of plastic deformation increased around the positions of the notches.

Neutron Diffraction Measurements of Internal Strain in

The superconducting properties of Nb3Sn strands are very sensitive to strain. Measuring internal strain of Nb3Sn in Cable-In-Conduit Conductors (CICC) is important for evaluating the superconducting performance of CICC. Internal strain can be determined by neutron diffraction measurement using Takumi of J-PARC. Neutron diffraction measurement becomes a strong tool for evaluating directly the internal strain of Nb3Sn in CICC.

{\rm Nb}_{3}{\rm Sn}

The Engineering Materials Diffractometer Application Kit called EMAKi has been developed to control the Engineering Materials Diffractometer, TAKUMI, and treat data obtained by it. It is expected that TAKUMI will be widely used by not only academic users but also industrial users. We have designed EMAKi to be user-friendly interface for novice users by graphical user interface (GUI). In addition, adopting Python programming language for its development has enabled advanced users to control the diffractometer flexibly and treat the data easily. During instrumentation commissioning and running user programs, the software has demonstrated useful.

Cable-In-Conduit Conductors

We report a synchrotron X-ray study of charge density waves (CDWs) in an o-TaS3 crystal. We found that two independent CDWs coexist in the temperature range of 130 - 50 K. These waves are incommensurate and commensurate CDWs with longitudinal wave vectors qc ¼ 0:252cand 0:250c � , respectively. The temperature and electric current dependences of the intensity of the two CDW satellites were measured. We found that the commensurate CDW was converted to the incommensurate CDW at 80 K by inducing current flow. Our observation was interpreted in terms of the dynamics of topological defects. We determined the edge dislocation configuration from the electric current dependence of the intensity of the two CDWs. The result implies for the first time that discommensurations are induced in the commensurate CDW by applying an electric field.

Application Software Development for the Engineering Materials Diffractometer, TAKUMI

The construction of The Engineering Materials Diffractometer, TAKUMI of J-PARC has been finished on March 2009, and the commissioning has been started from September 2008 being parallel with the final stage of the construction. In the commissioning, after checking the validity and the stability of the detectors and the data acquisition system, powder diffraction data of an austenitic steel alloy with 10 mm diameter without beam collimation (high intensity mode) was measured, and the resolution Δd/d of 0.4% was confirmed, as designed. Further commissioning was done also with 2 mm diameter of annealed piano wire with combination of beam collimation (high resolution mode), and the resolution Δd/d of less than 0.2% was confirmed to be achieved. TAKUMI adopted an event mode data recording method. It was found that the recording method is very useful to manipulate data as we like, for instance, detector range, time of flight binning width and time resolved data, even the experiment has been finished.

Field-Induced Discommensuration in Charge Density Waves in o-TaS3

J-PARC Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan Research Center for Neutron Science and Technology, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan J-PARC Center, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan Research Reactor Institute, Kyoto University (KURRI), Kumatori, Osaka 590-0494, Japan

Aspire to Become TAKUMI - TAKUMI Present Status and Research Topics -

Simultaneous synchrotron radiation and transport measurements for the organic thyristor family compound θ-(BEDT-TTF) 2 RbZn(SCN) 4 have revealed the presence of microscopic competing domains between the twofold and 3 ×4 charge orderings in a triangular lattice. In contrast to conventional correlated electron systems, charge ordering is a unique critical parameter of phase competition. With external current, only the twofold ordering melts, which is responsible for the emergence of a nonlinear response.

The Design and q Resolution of the Small and Wide Angle Neutron Scattering Instrument (TAIKAN) in J-PARC

Zero-field muon spin relaxation experiments have been carried out in the Pr(Os

Charge Order Competition Leading to Nonlinearity in Organic Thyristor Family

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