Japan Atomic Energy Research Institute

About: Japan Atomic Energy Research Institute is a based out in . It is known for research contribution in the topics: Neutron & Irradiation. The organization has 7707 authors who have published 14471 publications receiving 207688 citations.

Two-dimensional radiation and neutron image detectors

Abstract: A 6 Li doped glass scintillator sheet with grooves cut at given spacings in horizontal and vertical directions. Bundles of wavelength shifting fibers placed in the vertical grooves and fluorescence reflector buried in the horizontal grooves make a group of detection pixels. Neutron detecting media are provided on the top surface and bundles of wavelength shifting fibers are arranged horizontally on the bottom surface of the scintillator. Fluorescence generated by stimulation with the neutrons entering the detection pixels and with the neutrons incident on the neutron detecting media are detected by the wavelength shifting fibers. The detected fluorescence is converted to electric signals with a multi-channel photomultiplier tube, with pulse signals for simultaneous counting generated from a retriggerable, constant time-duration pulse generator and recorded as time-series data by parallel interfaces. The recorded data are analyzed by the simultaneous counting method to produce a two-dimensional neutron image.

Study of colors and degrees of weathering of granitic rocks by visible diffuse reflectance spectroscopy

Abstract: Diffuse reflectance spectroscopy and colorimetry have been applied to study the colors of powdered granitic rocks with different degrees of weathering. As a result, FeO(OH) was considered to be the source of the yellow-brownish color of the weathered rock powders. FeO(OH) contents were determined by diffuse reflectance spectroscopy based on the Kubelka-Munk function and found to increase during weathering. The FeO(OH) contents can be hence taken as a quantitative indicator of the degree of weathering.

Effects of weak point disorder on the vortex matter phase diagram in untwinned YBa 2 Cu 3 O y single crystals

Abstract: Effects of the weak point disorder on the vortex matter phase diagram are studied by an irradiation of 2.5 MeV electrons in untwinned YBa 2Cu3Oy single crystals. We find that the point disorder lowers the critical point Hcp of the first-order vortex lattice melting line Hm(T) and has an opposite effect on the vortex glass phase boundary above and below Hcp. Below Hcp, the field-driven disordering transition line H* (T) between the Bragg glass and the vortex glass phases shifts to lower fields and the vortex glass phase is expanded after irradiation. Near the vortex liquid-to-glass transition line Hg(T) aboveHcp, on the other hand, the vortex glass phase is reduced after irradiation, indicating the enhanced vortex wandering by the point disorder in the critical region.