Fusion Neutron Transient Effects to Charge Coupled Device Camera Images

摘要

A charge coupled device (CCD) camera's images were degraded by neutron-induced blemishes, called stars, while being irradiated with 14 MeV neutrons (n) from the Rotating Target Neutron Source. This thesis analyzed simulated images for a CCD camera operating during neutron irradiation. The simulated images were created to provide data to help determine how much shielding a CCD camera would require while being used a diagnostic tool during inertial fusion events at the National Ignition Facility. The simulated images were created from data obtained at the Rotating Target Neutron Source. The Contrast Transfer Function (CTF), autocorrelation function and visual comparisons were used as measures of the transient effects of the neutron irradiation on the simulated images. The CTF and visual image quality started to degrade significantly at neutron fluences around 10(exp 8) n/sq cm. The autocorrelation function determined that the average size of neutron-induced star was 4 x 4 pixels. Increasing neutron fluence produced image changes that could be explained by a variation in sensitivity across the camera face or (more likely) by increased Charge Transfer Inefficiency (CTI) with increasing charge loading of the CCD.