Neutron imaging study of a Naginata and spears

薙刀と槍の中性子イメージング研究

及川 健一   ; 松本 吉弘*; 佐藤 博隆*; 渡辺 賢一*; Parker, J. D.*; 篠原 武尚   ; 鬼柳 善明*

Oikawa, Kenichi; Matsumoto, Yoshihiro*; Sato, Hirotaka*; Watanabe, Kenichi*; Parker, J. D.*; Shinohara, Takenao; Kiyanagi, Yoshiaki*

Our Japanese sword research team is attempting to gain insight into the secrets of sword-making techniques by conducting systematic nondestructive study from the viewpoint of crystallographic structure, mainly using the energy-resolved neutron imaging system, RADEN at MLF J-PARC. In particular, the manufacturing process of old swords "Koto" up to the end of the 16th century is not well understood because there are few written records of the sword making process, and it would be an important clue to clarify how the crystallographic structure differs compared to new swords, new-new swords, or modern swords. With the cooperation of NITROPLUS Co., Ltd., we have started the neutron imaging experiment of swords of known provenance from 2021. So far, they have provided us with a total of nine exhibition-class swords in the broad sense of the word. In this presentation, we will report on the analysis results of Bragg-edge imaging and neutron tomography of these swords, Naginata and spear, which are sword-related weapons closely related to the Japanese sword but made in different ways.