实时单发测量的汤姆逊离子谱仪

Real-time single-shot Thomson spectrometer used for laser-driven ion acceleration

介绍一种使用闪烁体耦合电子倍增电荷耦合器件(EMCCD)的方式对离子进行记录的汤姆逊能谱仪,可实现对离子能谱的实时单发测量。同时,该谱仪利用倾斜电极板对离子进行偏转,可减少由于离子打在电极板上产生的电磁噪声,能够提高实验结果的信噪比。该谱仪在北京大学4.5 MV静电加速器和2×6MV串列加速器上进行了标定实验,测量了闪烁体将离子转化成光子后的探测效率,实验结果也验证了该谱仪的可行性和稳定性。该汤姆逊谱仪将用于北京大学激光加速器CLAPA对离子束流的测量研究。

As the fast development of ultra-short ultra-intense laser technology and mechanism research of laser ion acceleration,laser-driven ion accelerators have drawn a lot of attention for the past decades.Thomson spectrometer is one of the critical diagnostics for laser-driven ion acceleration,because of its ability to measure ions＇ energy spectrum,charge,and charge-to-mass radio parameters simultaneously.This paper presents a compact real-time single-shot Thomson spectrometer,which uses electromagnetic field to disperse ions and scintillator coupled with high performance EMCCD as a record medium.The spectrometer has apair of inclined electric plates with the advantage of avoiding electromagnetic noise caused by low energy ions＇ collision with electric plates,improving signal-to-noise ratio accordingly.Experiments were carried out on two conventional accelerators in Peking University to test the spectrometer and measure detection efficiency of ions at the same time.It turns out that the spectrometer can be used for detection of ions driven by 100 TW class femtosecond laser system,and will contribute to our understanding of laser-based high energy density physics.