Analysis of displacement damage effects on the CCD induced by neutrons at Back-n in the China Spallation Neutron Source

Abstract

Abstract Displacement damage effects on the Charge-Coupled Device (CCD) induced by neutrons at back-streaming white neutron (Back-n) in the China spallation neutron source (CSNS) are analyzed according to the online irradiation experiment. The hot pixels, random telegraph signal (RTS), mean dark signal, dark current, and dark signal non-uniformity (DSNU) induced by Back-n are presented. The dark current is calculated according to the mean dark signal at various integration times. The single-particle displacement damage and transient response are also observed based on the online measuring data. The trends of hot pixels, mean dark signal, DSNU, and RTS degradation were related to integration times and irradiation fluence. The mean dark signal, dark current, and DSNU2 are nearly linear with neutron irradiation fluence when nearly most of the pixels are not reach saturation. In addition, the mechanisms of the displacement damage effects on the CCD are demonstrated by combining the experimental results and TCAD simulation. Radiation-induced traps in the space charge region of CCD will act as generation/recombination (G/R) centers of electro-hole pairs which lead to the dark signal increase.