Investigation of reactor neutron irradiation induced dark signals increase in COTS array CCDs

Zujun Wang,Hongxia Guo,Tongding Luo,Junshan Jin,Benqi Tang,Shaoyan Huang,Zhang Wenshou

doi:10.1063/1.4896409

Abstract

The experiments of reactor neutron irradiation which induce dark signal increase in COTS array CCDs are presented. The flux of the reactor neutron beams was about 1.33 × 108 n/cm2s. The three samples were exposed to 1MeV neutron-equivalent fluences of 1 × 1011, 5 × 1011, and 1 × 1012 n/cm2, respectively. The mean dark signal (KD), dark signal non-uniformity (DSNU), and dark signal spikes (hot pixels) versus neutron fluence are investigated. The degradation mechanisms of the dark signal in CCDs are analyzed. The mean dark signal increase due to neutron displacement damage appears to be proportional to displacement damage dose. The dark images from the CCDs irradiated by neutrons are presented to investigate the generation of dark signal spike. The 1D and 2D figures which show the output signal voltage of pixels in dark images irradiated by different neutron beam fluences, are presented to compare the degradation of KD, DSNU, and dark signal spike.

Highlights

Charge-coupled devices (CCDs) are especially vulnerable to radiation damage
The mean dark signal increase due to neutron displacement damage appears to be proportional to displacement damage dose
Ionizing damage induces an increase in trapped oxide charges and bulk-oxide interface traps which cause an increase in surface dark signals and dark signal non-uniformity (DSNU) of the CCDs

Summary

Introduction

The radiation-induced damages to the CCDs can be separated into two forms: ionization damage and displacement damage. Proton displacement damage effects on CCDs have been extensively investigated.[6,7,8,9,10] Histograms of dark current in p-buried channel CCDs irradiated by 10 MeV protons are available in the literature.[6] Dark signal spikes in EEV three phase CCDs irradiated by 40 MeV protons are investigated.[7] Mean degradation of dark current and DSNU induced by proton irradiation from 17 to 100 MeV are analyzed.[10]

Objectives

Results

Conclusion