Analysis and correction of crosstalk in the side-on transition radiation detector prototype for HERD

Abstract The side-on Transition Radiation Detector (TRD) is an essential component of the High Energy cosmic-Radiation Detection (HERD) facility aboard the China Space Station (CSS). Utilizing the proportional correlation between the Lorentz factor γ and Transition Radiation (TR) intensity, the side-on TRD collaborates with the HERD calorimeter for cross-calibration in the TeV energy range while orbiting. This paper focuses on analyzing and correcting signal crosstalk in the side-on TRD prototype. A signal caused by crosstalk, referred to as the “reversed polarity signal”, affects the particle signal and biases the prototype's energy measurement. To address the issue of energy deviation and select the most suitable capacitance for the prototype to correct crosstalk, we analyze the source of the reversed polarity signal and the effectiveness of adding a decoupling capacitor to the voltage divider circuit. Additionally, we use a combination of simulation and experimentation to investigate the specific relationship between the reversed polarity signal and the decoupling capacitance. The comparison between the simulation results and the experimental results show consistent trends. Measured energy spectra shows that correcting crosstalk eliminates a maximum measurement deviation of approximately 10.79% in the prototype. Following this correction, the side-on TRD prototype completed beam experiments in 2022.