短脉冲强激光打靶产生的质子角分布实验研究

 采用短脉冲强激光辐照固体双层薄靶的方式对质子束的产生及质子束角分布开展了实验研究。在SILEX-Ⅰ短脉冲激光装置上利用脉宽为30 fs的强激光辐照背面镀有CH膜的金膜靶，在距离靶背3.3 cm处采用CR39记录靶背出射的质子角分布。通过分析靶背出射质子的角分布,研究了激光功率密度和对比度对质子加速机制的影响。研究结果表明:占主导地位的质子产生和加速机制对激光预脉冲比较敏感。激光预脉冲较弱时,靶背壳电场加速机制占主导地位;当激光预脉冲较强时,靶前加速机制占主导地位。此外,还对导致质子环形分布的磁场大小进行了估算。

Experimental study about angular distribution of protons emitted from thin solid target irradiated by supershort laser

Proton generation and angular distribution produced by supershort laser pulse irradiating thin solid Au target were investigated. The experiment was performed on the SILEX-Ⅰ laser facility. CR39 was mounted 3.3 cm behind the target to record the protons from the target. How the laser intensity and laser contrast ratio influenced the mechanism of proton acceleration was studied by analysing the proton angular distributions. The primary acceleration mechanism of proton is sensitive to the prepulse. When the prepulse is weak, the primary proton acceleration is target normal sheath acceleration. When the prepulse is strong, most protons is primarily accelerated in the front of target.