Thermal stability of BNCT neutron production target synthesized by lithium deposition and ion implantation

リチウム真空蒸着とイオン注入による窒化リチウムその場合成中性子ターゲットの熱的安定性

石山 新太郎; 馬場 祐治  ; 藤井 亮*; 中村 勝*; 今堀 良夫*

Ishiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*

癌治療用中性子源リチウムターゲットの使用時の損耗を防ぐためリチウム表面を窒化する技術を酸素や水分のない高真空状態で実施した結果、リチウム真空蒸着法並びに窒素イオン注入法により従来リチウム窒化合成に必要とされていた酸素や水分の存在なしでその合成並びに再合成に成功した。その結果リチウム表面に窒化物を合成後のリチウムターゲットの蒸発温度をリチウム単体の温度より120K高くすることに成功した。

LiN synthesis on Li deposition layer was conducted without HO and O by lithium deposition in high vacuum chamber of 10 Pa and ion implantation techniques and the thermo-chemical stability of the LiN/Li/Cu tri-layered target under laser heating and air exposure was characterized by X-ray photoelectron spectroscopy. Following conclusions were derived; (1) LiN/Li/Cu tri- layered target with very low oxide and carbon contamination was synthesized by lithium deposition and ion implantation techniques without HO and O additions and frequent synthesis of the target is possible. (2) The evaporating temperature of Li deposited layer increased by 120 K after forming the LiN layer on the surface of Li. (3) Remarkable oxidation and carbon contamination were observed on the surfaces of Li/Cu and LiN/Li/Cu after air exposure and these contaminated compositions formed on the surface of LiN/Li/Cu was not removed by Ar heavy sputtering.