我们研制的穿透式γ射线密度计（简称密度计）采用了

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Csγ射线放射源，其原理方枢图如图1所示。

The measurement principle of the transmission gamma ray densitometer and the accuracy analysis are described. The effect of air bubbles in pulp on measurement accuracy and its regular pattern are theoretically studied.

The necessity of developing a device for detecting bubbles in pulp within pipes

and its operation principle and structure are presented. Finally

the method of purging bubbles from pulp is reviewed and the effect of bubbles on measurement accuracy is experimentally demonstrated.