50~120 kV脉冲X射线参考辐射场建立及剂量率测量

Establishment of 50-120 kV Pulsed X-ray Reference Radiation Field and Dose Rate Measurement

  • 摘要: 为满足国内医疗、安检等脉冲辐射场所对剂量监测仪表准确溯源的需求,基于栅控技术建立满足规范和标准要求的50~120 kV毫秒级脉冲X射线参考辐射场,其脉冲宽度在1~6 300 ms范围内可调。通过对该辐射场的管电压稳定性、剂量线性、重复性、脉冲波形等关键参数进行研究测试,建立脉冲X射线参考波形,并使用30 cm3的圆柱电离室开展脉冲剂量率测量研究。结果表明,管电压预设60 kV时,介入法、非介入法测量管电压的相对偏差均不超过±1.5%;可输出参考波形脉冲的最小脉冲宽度为20 ms,在1 m处95%均匀辐射野直径约为5.5 cm;且N系列、RQR系列辐射质条件下的剂量率范围可分别扩展至0.002~10 mGy/s和0.03~250 mGy/s,可用于防护仪表的量值溯源。

     

    Abstract: In order to meet the needs of accurate traceability of dose monitoring instruments in domestic medical, security inspection and other pulse radiation places, a 50-120 kV millisecond pulse X-ray reference radiation field that meets the requirements of norms and standards was established, based on the gate control technology, and its pulse width can be adjustable in the range of 1-6 300 ms. The pulse X-ray reference waveform was established by studying and testing the tube voltage stability, dose linearity, repeatability, pulse waveform and other key parameters of the radiation field, and the pulse dose rate was measured using a cylindrical ionization chamber with a sensitive volume of 30 cm3, and obtained the following research results: when the tube voltage was preset to 60 kV, the relative deviation of the intervened and non-intervened measuring tube voltage did not exceed ±1.5%; the minimum pulse width of the reference waveform pulse output was 20 ms, and a 95% uniform radiation field with a diameter of about 5.5 cm could be generated at 1 m. Moreover, the dose rate range of N series and RQR series radiation quality was extended to 0.002-10 mGy/s and 0.03-250 mGy/s, respectively, which can be used for the metrological traceability of protective instruments.

     

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