使用高压电场的累积式^(220)Rn子体探测器的研制

Integrating high voltage electric field detector for ^(220)Rn progeny

220 Rn及其子体对人体健康危害很大。为了实现对220 Rn子体长期、有效的测量,对目前测量220 Rn子体的方法进行了分析,设计制作了一种用高压电场进行采样、用固体核径迹片(CR39)进行测量的长期测量220 Rn子体浓度的仪器。通过实验确定了仪器的各种关键参数。经测定,当高压电场为7.7×104 V·m-1时,该仪器对220 Rn子体的采集速度为(6.5×10-4±7.7×10-5)m·s-1,测量效率为0.042±0.005 4。当测量时间为1个月时,仪器的探测限为0.12~54.00Bq·m-3,相对不确定度可以控制在不超过50%。经实验验证,该仪器在不需要外接电源的情况下可以连续工作6周左右,能够实现对220 Rn子体浓度的长期测量。

The importance of 220Rn （thoron） progeny for human exposure has been widely recognized for many years. Detectors are needed for long-term measurements that directly sample and detect thoron progeny. This study presents an integrating detector based on a high voltage electric field and solid state nuclear track detector （SSNTD）. The high-voltage electric field of 7.7 X 10-4 V m 1 has precipitation velocities of the 22Rn progeny of （6.5 X 10 4 7.7 X 10 s） m s-1. The detector efficiency is measured to be 0. 042 0. 005 4. For a one month measurement time, if the detection limit is set to 0.12-54.00 Bq m , the relative uncertainty of the detector can be controlled to less than 50. Tests show that the detector can continue to work for around 6 weeks without an external power supply.