Statistical image analysis of high-sensitivity neutron images obtained by cooled CCD systems.

Neutron sensitivity and noise characteristics of cooled CCD NR systems were investigated. Eighteen species of neutron sensitive scintillators were tested by the use of two types of cooled CCD devices. The statistical analysis of the S/N ratio of the neutron images showed that the ZnS+LiF type was the highest sensitivity scintillator. The generation rate of the CCD noises increased with increasing exposure time, temperature of the device and dose rate of the environmental radiation. The generation rate and the pulse height distribution of the noise were quite different between the two CCD devices. Thus, the origin of the noise is considered to be strongly related to the internal structure of the CCD devices.