However, the energy spectrum measured in the experiments is not necessarily the same as that of the theoretical prediction, owing to the detection efficiency, line of sight, and shielding. In the EAST, the status of runaway electrons is routinely monitored using a gamma spectrometer . In the gamma spectrometer, a LaBr3 (Ce) scintillator detector (crystal diameter of 1.5 in. and height of 3.0 in.) is used with a fully digital data acquisition (DAQ) system based on a digitizer with Digital Pulse Processing for Pulse Shape Discrimination (DPP-PSD) algorithm.