Enhancement of resistance against high energy laser pulse injection with chevron beam dump
シェブロン型ビームダンプによるレーザー耐力の向上
谷塚 英一; 波多江 仰紀; Bassan, M.*; Vayakis, G.*; Walsh, M.*; 伊丹 潔
Yatsuka, Eiichi; Hatae, Takaki; Bassan, M.*; Vayakis, G.*; Walsh, M.*; Itami, Kiyoshi
This paper reports our recent developments on the laser beam dump for the Edge Thomson Scattering System in ITER. The laser-induced damage on the beam dump surface is one of the most severe issues of the beam dump development to be overcome. In order to resolve the damage issue, a new type of beam dump called the chevron beam dump was proposed recently. This paper aims to verify the key concept of the chevron beam dump design. The laser irradiation tests onto flat-mirror-molybdenum sample were carried out. It was clarified that the absorbed energy density of the laser pulses should be the correct figure of the laser-induced damage. Therefore, the concept of the chevron beam dump, that minimizes the absorbed laser energy density per unit area, was validated experimentally. It was concluded that the chevron beam dump enables us to extend its lifetime drastically relative to conventional beam dumps.