为了探索飞秒脉冲激光与固体靶相互作用中高能离子的能量分布特性,在超短超强激光装置“SILEX—I”上进行了超强激光与平面薄膜Cu靶的相互作用中高能离子能谱分布的实验研究。采用固体核径迹探测器CR39和Thomson离子谱仪相结合的方式,在固体靶背表面法线方向测量了质子和C离子能量分布和产额。结果显示,同时测量到了H+质子和C1+、C2+、C3+和C4+信号,离子沿靶背法线方向发射,离子出现能量截断,离子的截止能量之比为1:2:3:4。在CR39上质子信号比C离子信号强,质子产额远高于C离子产额;在同一发打靶中,C1+、C2+、C3+和C4+随着荷质比的减小,相应的离子的截止能量也在减小。这一结果将为惯性约束聚变(ICF)“快点火”方案的可行性分析提供参考依据。
To study the distribution characteristics of high energy ions in the interaction with femtosecond pulse laser with solid targets,high energy ions behavior at the normal direction of the rear surface of the target produced from ulintencity pulse laser irradiated Cu thin film solid targets is explored on SILEX-I laser facility. The solid nuclear detector CR39 and Thomson spectrum are used to detect the energy spec- tra of protons and carbon ions. Protons H+ and carbon ions C1+ , C2+ , C3+ and C4+ have been ob- served. In addition, the results show that the ions are cut-off at a certain energy, and the ratio of the maximum cutoff energy of the C1+ ,C2+ ,C3+ and C4+ ions is about 1 : 2 : 3 : 4. Moreover,the carbon ions traces are much weaker than the protons trace, so the yields of protons can be much higher than carbon ions,and the protons have the screening effect on the carbon ions. And the cut-off energy of the carbon ion is increased with the charge-to-mass ratio in the same shot. The results will provide the refer- ence for inertial confinement fusion (ICF) "quick ignition" feasibility analysis.