Improvement in production yield of radioactive strontium endohedral fullerene using nuclear recoil

Miyashita, Yuka*; Akiyama, Kazuhiko*; Hatsukawa, Yuichi; Kubuki, Shiro*

Considering about the radio pharmaceutical application of metallofullerenes, the production methods using nuclear recoil phenomena is very useful because specific radioactivity of products is higher than that obtained by other methods. Due to these advantages, this production method has been attracted and examined using various nuclear reactions so far. However, reported production yields of radioactive metallofullerenes were not enough because of the radiation damages of a targeted fullerene molecule caused by incident charged particles. One of the promising method to improve the production yield of radioactive metallofullerenes is ion implantation using the nuclear recoil induced by nuclear reaction with fast neutrons. In this study, we will report the synthesis of Sr endohedral fullerene using the nuclear recoil of Sr (n, 2n) Sr reaction with 14 MeV fast neutron produced by DT reaction. As a result, the radioactivity of Sr observed in the aniline solutions derived from Sr endohedral fullerene was estimated to be about 6.8% at the best for those before extraction. Generally, production yield of metallofullerenes by the standard arc discharge method is about 0.1% or less. Therefore, observed production yield of Sr endohedral fullerene in this study is found to be extremely efficient compared to the standard methods.