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目的研制井型电离室,测量近距离源空气比释动能强度,与国际标准测量物理量接轨,改善源活度的测量精确度,促进国内近距离剂量学的发展。方法吸取国外先进经验,结合本国国情,设计方案,绘制图纸,对井型电离室所有材料进行筛选,加工,组装,并开展性能实验。结果用国外进口的井型电离室和研制的井型电离室在相同条件下比对,结果:井型电离室长期稳定性为0.4%,技术指标为2%;电离电荷复合率为0.9995,技术指标0.9996;井型电离室重复性为0.02%,技术指标为0.5%。井型电离室的最佳驻留位置在平坦峰值区范围内灵敏度固定没有变化,进口井型电离室的最佳驻留位置在平坦峰值5mm范围内灵敏度变化为0.1%。结论该电离室优点:测量快速准确,同时可以测量192Ir,125I和103Pd等放射源活度。测量范围从3.7MBq～7.4×105MBq。该井型电离室将填补我国现场检测仪器的空白,并能形成我国有自主知识产权的产品。
OBJECTIVE To develop a well-type ionization chamber to measure the intensity of kerma-moment of near-source air, and to meet the international standard of measuring physical quantities to improve the measurement accuracy of source activity and promote the development of domestic close-range dosimetry. The method draws on advanced foreign experience, with national conditions, design programs, drawing drawings, screening, processing, assembly, and performance tests of all well ionization chamber materials. Results The well type ionization chamber imported from abroad and the developed well ionization chamber were compared under the same conditions. The results showed that the well type ionization chamber had a long-term stability of 0.4% and a technical indicator of 2%; and the ionization charge recombination rate was 0.9995. The technique Indicator 0.9996; Well ionization chamber repeatability of 0.02%, the technical indicators of 0.5%. The optimal location of the well ionization chamber has no change in the sensitivity within the range of the flat peak area, and the best residence position of the inlet well chamber changes 0.1% in the flat peak value of 5 mm. Conclusion The advantages of the ionization chamber: rapid and accurate measurement, and can measure 192Ir, 125I and 103Pd and other radioactive source activity. Measurement range from 3.7MBq ~ 7.4 × 105MBq. The well-type ionization chamber will fill our country on-site testing equipment blank, and can form our own products with independent intellectual property rights.