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

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 a pair 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.