Dependence of Signal-to-Noise Ratio on Radiation Energy and Grey Value in Digital Industrial Radiology – (PPT)

摘要

Recent investigations showed that the overall signal-to-noise ratio (SNR) of imaging plates (IPs) is dominated by the structural noise of the sensitive layer (at the usual NDT dose range). As a consequence the standard deviation of grey values increases linear with the radiation dose at higher exposure doses. The elimination of structural noise can be achieved by the necessary calibration procedure of digital detector arrays (DDAs). This results in a square root characteristic of the SNR over grey value function dominated by the quantum noise. Experimental measurements over a broader energy range (from 80 kV uot to 7.5 MeV) showed that the SNR is independent from the radiation energy for a given gray value. The grey value is related to the efficiency of the detector which is energy dependant.