Nuclear Science and Techniques ›› 2019, Vol. 42 ›› Issue (1): 10401-010401.

### Study on the accuracy of detection efficiency for radioactive iodine monitor

Yin YIN1,Zihan HUANG1,Hongkun XU1,Xianfang MENG1,Changli MU1,Ge WANG2

1. 1. Beijing Research Center for Radiation Applications, Beijing 100015, China
2. Beijing Radiation Center, Beijing 100875, China
• Received:2018-07-11 Revised:2018-09-20 Online:2019-01-10 Published:2019-01-25

Abstract: Background

The monitoring of radioactive iodine has been an important part of nuclear environmental protection. Detection efficiency is the main indicator for calibrating and evaluating iodine monitor.

Purpose

Due to the environment and the form of radioactive iodine, the distribution of iodine in the activated carbon sampling box is not uniform. At present, when the detection efficiency of the iodine monitor is calibrated, the activity of the standard volumetric source used is uniform, which is different from the actual distribution. So it is necessary to verify the accuracy of detection efficiency of the environmental iodine continuous monitor.

Methods

The detection efficiency of iodine in different positions was simulated in the activated carbon sampling box using the Monte Carlo software MCNP, and the results was verified by experiments.

Results

The Monte Carlo model of detection efficiency of the iodine monitor was established, and it provided reference for improving the design of the iodine monitor and the accuracy of detection efficiency.

Conclusions

The results show that the detection efficiency of the iodine monitor is accurate calibrated with133Ba uniform source and can accurately reflect the performance of the iodine monitor.Key wordsIodine monitor,133Ba volumetric source, Detection efficiency, MCNP