arXiv subjects

Hiroshi Kudo

Publications and source records attributed to Hiroshi Kudo.

4 recordsLinked to original sources

arXiv2023

Transmission ERDA of ubiquitous deuterium in H-containing materials

Transmission-type elastic recoil detection analysis (T-ERDA) using 8.02 MeV He has been successfully applied to determine the concentration of ubiquitous deuterium in mylar and PPS films, both containing hydrogen as a component. The determined D/H ratios of $(1.60\pm 0.08) \times 10^{-4}$ and $(1.23\pm 0.08) \times 10^{-4}$ for mylar and PPS, respectively, are only slightly deviated from the Standard Mean Ocean Water value of $1.55\cdots \times 10^{-4}$. These results indicate potential sensitivity of T-ERDA for analysis of the variation of ubiquitous deuterium in hydrogen-containing materials. Such deuterium analysis might be useful for unique characterization of not only natural, but also synthesized hydrogen-containing materials.

cond-mat.mtrl-sci↗

arXiv2022

Determination of hydrogen concentration in solids by transmission ERDA under nuclear-elastically enhanced recoiling of H by 8 and 9 MeV He

Hydrogen concentrations in thin self-supporting samples of polyphenylene sulfide and muscovite have been determined by nuclear-elastic recoil detection analysis of transmission layout. The analysis procedure is based only on the database of stopping power and recoil cross section for material analysis, without using any reference sample of known H content. For the polyphenylene sulfide sample, the determined value of $(2.87\pm 0.26)\times 10^{22}\,{\rm H}/$cm$^{3}$ is in good agreement with the calculated value of $3.01 \times 10^{22}\,{\rm H}/$cm$^{3}$. For the muscovite sample, the H concentration originating each from bound water and absorbed water is uniform over the entire thickness of the sample. The determined concentration $(9.43 \pm 0.75) \times 10^{21}$ H$/$cm$^{3}$ of the muscovite agrees excellently with the value of $9.36 \times 10^{21}$ H$/$cm$^{3}$ obtained from other quantitative analyses typically applied for minerals. The present results demonstrate the capability of accurate determination of H contents in materials and minerals by transmission ERDA.

cond-mat.mtrl-sci↗

arXiv2013

Whispering gallery modes in hexagonal microcavities fabricated by crystal growth

We investigated the whispering gallery modes of cavities with a hexagonal cross-section. We found two different modes, namely perturbed and quasi-WGMs, of which the former exhibits the higher Q when the corner radius is large. We studied the dependence of Q on the curvature radius of the polygonal cavities and found that the coupling between the two modes determines the Q of the cavity. In addition we fabricated a cavity by employing laser heated pedestal growth and demonstrated a high Q.

physics.optics↗

arXiv2013

Fabrication of whispering gallery mode cavity using crystal growth

We developed a new method for fabricating crystalline whispering gallery mode cavities based on laser-heated pedestal growth. We fabricated sapphire cavities and obtained a Q factor of 16000 with a cavity whose diameter was about 240 um. We showed numerically that the cross-sectional shape of the cavity is sensitive to the cavity Q, and we controlled it successfully by changing the growth condition in the molten zone, without significantly degrading the crystal structure.

physics.optics↗