Common-mode noise analysis of silicon microstrip detectors

Silicon microstrip detectors are widely used in space astronomy experiments owing to their high spatial resolution and long-term operational stability. The silicon microstrip detector is affected by bias voltage fluctuations, causing simultaneous changes in the pedestal of all channels under the same power supply. The noise generated by this variation is referred to as common-mode noise (CN). Precisely subtracting the CN can improve the charge resolution of light nuclei. In this study, we investigate the calculation method and sources of CN using the on-orbit data from DAMPE and test beam data of HERD. Our findings confirm that the CN in DAMPE's silicon microstrip detector primarily arises from fluctuations in the power supply. Furthermore, through the combination of test beam results and SPICE simulations, we have discovered that capacitance-induced charge sharing also contributes to the CN, which increases with the particle charge.