Disinfection of Woodblocks of the Nguyen Dynasty of Vietnam by Low-Energy X-rays

Nguyen Thi Thuy Linh; Nguyen An Son; Masakazu Furuta; 古田雅一; Tamikazu Kume; 久米民和

doi:10.3769/radioisotopes.70.55

低エネルギーX線によるベトナム阮朝の版木の殺菌Disinfection of Woodblocks of the Nguyen Dynasty of Vietnam by Low-Energy X-rays

Nguyen Thi Thuy Linh^1,2，Nguyen An Son³，古田雅一^1,4，久米民和³Nguyen Thi Thuy Linh^1,2, Nguyen An Son³, Masakazu Furuta^1,4, Tamikazu Kume³

¹ 大阪府立大学大学院工学研究科・量子放射線系専攻Department of Quantum and Radiation Technology, Graduate School of Engineering, Osaka Prefecture University

² ダラット大学生物学部Faculty of Biology, Dalat University

³ ダラット大学物理・原子力工学部Faculty of Physics and Nuclear Engineering, Dalat University

⁴ 大阪府立大学地域連携研究機構・放射線研究センターResearch Center of Microorganism Control, Organization for Research Promotion

受付日：2020年6月25日Received: June 25, 2020

受理日：2020年10月5日Accepted: October 5, 2020

発行日：2021年2月15日Published: February 15, 2021

文化財である版木の汚染カビについて，低エネルギーX線による殺菌効果を検討した。ベトナム阮王朝の版木から分離されたカビの中で，最も放射線抵抗性の株はCladosporium sp.であった。用いたX線 F1（1 mm　アルミニウム　フィルター装着）とF0（フィルターなし）の版木表面における線量率は，1.14 及び4.64 kGy/hであった。版木の中心部（表面からの深さ8.5 mm）の線量は，表面線量に対しF1で76%，F0で20%に減少した。F1は深部の照射に適しており，版木中心部のカビは表面6.2 kGyの照射で4桁減少し，8.3 kGyで検出されなくなった。これらの結果から，版木中の汚染カビはX線（F1）を用いた両面照射により，線量10 kGy，線量均一度1.04で効果的な殺菌が可能であることが示された。

The effects of low-energy X-ray irradiation were investigated as an intervention strategy for the disinfection of fungi-contaminated woodblocks. Fungi were isolated from the woodblocks of the Nguyen dynasty of Vietnam and Cladosporium sp. was identified as the most radiation-resistant strain in the woodblock. The dose rates of the F1 (1-mm-aluminum filtered) and F0 (non-filtered) X-rays at the surface of the woodblock were 1.14 and 4.64 kGy/h, respectively. At the middle (8.5 mm from the surface) of the woodblock, the doses of the F1 and F0 X-rays decreased to 76% and 20% of the surface doses, respectively. The F1 X-rays were useful for irradiating the inside of the woodblock; the concentration of the fungi at the middle decreased by more than 4 log fractions at 6.2 kGy and the fungi were eliminated with a surface dose of 8.3 kGy. Furthermore, the contaminated fungi in the woodblock were disinfected by both-side irradiation with F1 X-rays delivering a dose of 10 kGy at a dose uniformity of 1.04.

Key words: low-energy X-ray; woodblock; fungi; disinfection; both-side irradiation

RADIOISOTOPES

原著Article

低エネルギーX線によるベトナム阮朝の版木の殺菌Disinfection of Woodblocks of the Nguyen Dynasty of Vietnam by Low-Energy X-rays