氡析出率测量中的218Po非平衡修正

通过对传统的累积法测量氡析出率模型实验验证,发现得到的氡析出率明显偏低。对测氡仪器的工作原理与集氡罩中氡的浓度变化规律进行分析,发现是由于被测介质表面析出的氡不断进入集氡罩,218Po与氡没有平衡,造成测量的氡浓度明显偏低。通过非平衡修正得到了修正后的氡析出率测量理论模型。利用修正后的该模型得到的介质表面氡析出率与参考值符合得较好,误差小于7%。此外比较优值函数的取值也可发现:修正后的理论模型优值函数的取值小于传统模型,这表明修正后的理论模型更符合实际,该理论模型可应用于氡析出率仪的研制与改进。

Non-equilibrium Correction of 218Po for Measuring Radon Exhalation Rate

By experimental verification base on traditional accumulation method,discoverd that the radon exhalation rate obtained is obviously low.Analysis of the operation principle of measuring instruments for radon and the variation of the radon concentration in the chamber,find that it is because of the radon exhaled from medium suface continuously and got into the chamber, 218Po is not in equilibrium with radon,this make the radon concentration measured by instrument obviously low.The corrected theoretical model for measuring radon exhalation rate is obtained by non-equilibrium revision.The radon exhalation rate from medium surface obtained by corrected theoretical model match the reference value well and the error is less than 7%.Moreover, compare chi-square value of different model and find that the chi-square value corrected by theoretical model is small than that of traditional model,this shows that the corrected theoretical model is more realistic.The theoretical model can be applied to develop and improve the instrument for measuring radon exhalation rate.