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

Abstract

Displacement damage effects on the charge-coupled device (CCD) induced by neutrons at the back-streaming white neutron source (Back-n) in the China Spallation Neutron Source (CSNS) are analyzed according to an 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 measurement data. The trends of hot pixels, mean dark signal, DSNU and RTS degradation are related to the integration time and irradiation fluence. The mean dark signal, dark current and DSNU2 are nearly linear with neutron irradiation fluence when nearly all the pixels do not reach saturation. In addition, the mechanisms of the displacement damage effects on the CCD are demonstrated by combining the experimental results and technology computer-aided design (TCAD) simulation. Radiation-induced traps in the space charge region of the CCD will act as generation/recombination centers of electron–hole pairs, leading to an increase in the dark signal.