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穿透电离室用于在线监测探伤加速器输出剂量率、累计剂量,并为剂量保护提供监测和控制信号。电离室的存在不影响加速器的输出特性。该电离室的线性、工作的长期稳定性是加速器调试和运行的关键之一。电离室采用大口径双重密封结构,制作工艺难度大,要求高。电离室透射性能好,薄窗直径Φ80mm,厚0.05mm,薄窗及电极总厚度对1～4MeV Ⅹ射线强度吸收小于1％。电离室的灵敏度高,当加速器中心轴线上距靶一米处的剂量率为1Gy/min时,电离室电离电流大于0.55μA。电离室线性好、饱和特性好,当加速器中心轴线上距靶一米处的剂量率小于4.15Gy/min时,其非线性小于1％;当电离室工作电压-700V,且承受的脉冲剂量率高达2×10~5Gy/min时,其复合校正小于1.5％。电离室的重复性也好,相隔一年零七个月,前后两次测得电离室的重复性均为0.5％左右。当电离室工作电压-700V时,电离室漏电流小于5×10~(-13)A。在恶劣环境下、强干扰场中和运动及冲击条件下,电离室能长期稳定可靠地工作。
Penetration chambers are used to monitor the output dose rate of flaw detection accelerators online, accumulate doses, and provide monitoring and control signals for dose protection. The presence of an ionization chamber does not affect the output characteristics of the accelerator. The linearity of the ionization chamber, the long-term stability of the work, is one of the keys to the commissioning and operation of the accelerator. Ionization chamber with large caliber double seal structure, the production process is difficult, demanding. Ionization chamber transmission performance, thin window diameter Φ80mm, thickness 0.05mm, thin window and the total thickness of the electrode 1 ~ 4MeV X-ray intensity absorption less than 1%. The sensitivity of the ionization chamber is high. When the dose rate is 1 Gy / min from the target on the central axis of the accelerator, the ionization chamber ionization current is greater than 0.55 μA. The ionization chamber has good linearity and good saturation characteristics. The nonlinearity is less than 1% when the dose rate at one meter away from the target on the central axis of the accelerator is less than 4.15 Gy / min. When the working voltage of the ionization chamber is -700V and the pulse dose rate Up to 2 × 10 ~ 5Gy / min, the composite correction is less than 1.5%. Ionization chamber repeatability is also good, separated by one year and seven months, twice before and after the ionization chamber measured repeatability of about 0.5%. When the ionization chamber operating voltage -700V, ionization chamber leakage current is less than 5 × 10 ~ (-13) A. In harsh environment, strong interference field and exercise and impact conditions, the ionization chamber can be long-term stable and reliable work.