Nanowires have attracted more and more interest in recent years due to their unique properties compared tobulk materials[1]. The quite different properties possessed by nanowires are mainly caused by their high surface-tovolumeratio[2]. Behaviors of nanowires under irradiation conditions have also attracted intensive attention in theseyears[3??5]. It has been proposed that nanowires may be radiation resistance because their large surface-to-volumeratio, and meanwhile the surface are the perfect sinks for defects created in the radiation process[3].