レーザープラズマEUV光源用回転ドラム式固体Xeターゲットの高繰り返しレーザー照射条件下における安定性 The Stability of a Rotating-Drum Solid-Xe Target Subjected to High-Repetition Rate Laser Irradiation for Laser-Plasma EUV Generation
The stability of a continuously growing solid-Xe target (thickness 500 Em) on a rotating drum (diameter 17 cm, rotation speed 1000 rpm and up-down length 3 cm) chilled by liquid-N<SUB>2</SUB> is investigated. The thermal load and the propagation process of a laser-induced shockwave in a solid-Xe target irradiated at a high-repetition rate and a high laser power are calculated theoretically. The thermal load is calculated to be approximately 0.7 W/cm<SUP>2</SUP> for a pulse energy of 1 J, a repetition rate of 30 kHz and an average power of 30 kW. Under these conditions the solid-Xe target should be chilled to ≤ 84 K for it to attain thermal equilibrium. The target system has the ability to supply solid-Xe target sufficiently rapidly that foliation of the target due to an accumulation of shockwaves does not occur under these irradiation conditions, since the lifetimes of the shockwaves were estimated to be about 1 μs.
レーザー研究 34(8), 570-574, 2006-08-15
The Laser Society of Japan