Analysis of errors of radiation relay

Radiation relay using the radiation scaler acts at the time when the output of the scaler comes to a set value. By this action, the stop valve in infusing line (or exhausting line) is closed and the increment (or decrement) of liquid level of tank is stopped. Same as radiation relay using CR rate meter, switching time of the relay of this system varies statistically due to the statistical property of radioactivity. In this paper, the probability density function of the switching time is calculated on the assumption that the pulse train is the Poisson process. Then, the relation between the switching time and the uncertainty in the stop level is examined under a constant incremental (or decremental) velocity of liquid level. Using these results, the minimum intensity of radiation which is necessary to obtain a given accuracy is calculated and the optimum scaling time is given to minimize the uncertainty corresponding to various velocity of liquid level. (auth.)