Lightning γ-ray Burst Observation Based on Sodium Iodide Detector

By using a NaI(Tl) detector, a lightning high energy radiation ground observation system was set up in this paper, and a performance test was conducted. In summer of 2016, two bursts of γ-rays were recorded at ground level for the first time in China when the return strokes of a nearby negative cloud-to-ground lightning flash occurred. The first γ-ray burst has a duration of 563 μs and the second one has a duration of 353 μs. The time interval between the end time of the two bursts is 76.288 ms, and this is coincident with the time interval of return strokes revealed by the synchronous electric field signal. The analysis result shows that the signals from the stepped leader and the γ-ray have one to one correspondence, and the stepped leader of the lightning is the source of the high energy radiation.