紫外超短激光驱动铜薄膜靶产生质子的实验研究

Experiment on Proton Acceleration Using Ultraviolet Ultra-short Laser Interaction With Copper Thin Foil Target

摘要: 在中国原子能科学研究院的放电泵浦的紫外KrF超短脉冲激光放大装置上，开展了紫外超短脉冲激光与铜薄膜靶相互作用加速产生质子束的实验研究。紫外超短脉冲激光输出能量为30 mJ、波长为248 nm、脉冲宽度为500 fs，采用离轴抛物面镜聚焦获得激光聚焦功率密度为1.2×10¹⁷ W/cm²。激光以45°入射5 μm厚的铜薄膜靶，质子最大能量超过300 keV。紫外超短脉冲激光的高对比度和高吸收效率是紫外激光加速的优点。

Abstract: Proton acceleration induced by ultraviolet laser interaction with a thin foil was studied on an ultra-short KrF laser amplifier called LLG50 in CIAE. The energy spectrum was recorded by a Thomson ion spectrometer. The ultraviolet laser system generated ultra-short pulses with energy of 30 mJ and pulse duration of 500 fs, and the peak focal intensity is 1.2×10¹⁷ W/cm². The maximal energy of protons recorded in the target normal direction is higher than 300 keV, and fast electrons were generated by vacuum heating or resonance absorption. The advantages of ultraviolet laser proton acceleration are high contrast in the laser pulse and high absorption rate.