Correction of dynamic error in on-line thickness measurement by gamma-ray transmission

In on-line measurement on sheet thickness by gamma-ray transmission, for the sheet thickness vibrates in counting time, and attenuation of gamma-ray which penetrates matter follows an exponential law, not a linear one. So the measured value of thickness which is taken from mean counting rate deviates from the true value. The paper analyses the causes of this deviation, describes the expression form of the dynamic error which is induced by these deviations, gives a method to diminish the dynamic error by correcting the deviation.