Diagnosis of hot electron temperature by ratio of Kα lines from two-layer fluorescent target

An approach for fast ignition of laser fusion is to use hot electrons for heating, and the temperature is an important parameter to characterize the hot electrons. The temperature of the hot electrons is diagnosed by experimentally measuring the intensity ratio of Kα characteristic lines emitted from a two-layer fluorescent target in combination with a Monte-Carlo simulation. The temperature of the hot electrons measured with this method is compared with that directly measured by a magnetic spectrometer for the same shot, and a good agreement is obtained. The results show that, by choosing appropriate fluorescent layer materials and target thickness, the temperature of the hot electrons inside the target can be measured by the intensity ratio of the Kα characteristic lines.