Negative-Muon Depth Profiling Reveals Near-Surface Gold Enrichment in Historical Shachihoko Scales from Nagoya Castle
Surviving fish-scale plates from the golden shachihoko (Kin-shachi) ornaments of Nagoya Castle are rare historical gold–silver (Au–Ag) materials. Recent X-ray fluorescence (XRF) analysis and color measurements indicated a discrepancy between the bulk Au concentration and the visible golden appearance. To clarify the origin of this discrepancy, we applied negative-muon depth profiling to seven surviving Kin-shachi scales. Five samples exhibited Au enrichment from the interior toward the surface; deeper regions showed lower and nearly constant Au concentrations consistent with previous XRF results. These findings suggest near-surface Au enrichment resulting from an intentional surface treatment to enhance the golden appearance of Kin-shachi.
Authors
- Izumi Umegaki (ORCID: https://orcid.org/0000-0001-9271-3574)
- Shogo Doiuchi
- Soshi Takeshita (ORCID: https://orcid.org/0000-0002-4747-1980)
- M. Tampo (ORCID: https://orcid.org/0000-0002-5708-6795)
- K. Shimomura (ORCID: https://orcid.org/0000-0002-9501-6149)
- Yasuhiro Miyake (ORCID: https://orcid.org/0000-0003-0095-0447)
- Takahiko Kutsuna
- Keisuke Murakami (ORCID: https://orcid.org/0000-0003-2844-620X)
- Akiko Hashimoto
- Souta Suzuki
- Masashi Sakai
- Keitaro Nihashi
- Misako Asahi
Institutions
- High Energy Accelerator Research Organization (JP)
- The Graduate University for Advanced Studies, SOKENDAI (JP)
- Japan Proton Accelerator Research Complex (JP)
- National Museum of Nature and Science (JP)
- Nagoya University (JP)
Publication Details
- Journal
- Journal of the Physical Society of Japan
- Published
- 2026-08-24
- DOI
- https://doi.org/10.7566/jpsj.95.093801
- Primary Topic
- X-ray Spectroscopy and Fluorescence Analysis
- Type
- article
- Field-Weighted Citation Impact
- 0.00