【作者】 王立强； 王振涛； 郑健；

【Author】 WANG Li-qiang;WANG Zhen-tao;ZHENG Jian;Institute of Nuclear and New Energy Technology,Tsinghua University;

【机构】 清华大学核能与新能源技术研究院；

【摘要】 在对高压气体电离室中离子漂移速度的研究过程中,发现电离室内部绝缘材料会影响内部气体压强和离子脉冲形状,影响离子漂移速度的测量。但在气体电离室内部电极之间以及电极与外壳之间都需要绝缘材料进行隔离,绝缘材料在气体电离室内部是必不可少的,因此需要仔细研究绝缘材料对气体电离室性能的影响。首先通过测量气体电离室灵敏度随时间变化,发现聚四氟乙烯绝缘材料能够缓慢吸附电离室内部工作气体,使得电离室内部气体压强降低;通过实验验证了绝缘材料吸附和放出气体是动态可逆过程;然后通过对比实验研究了95%三氧化二铝陶瓷材料和聚四氟乙烯材料吸附气体性能,发现陶瓷材料对气体吸附平衡时间较快,一般几个小时,而且气体吸附量相对较少,而聚四氟乙烯对气体吸附平衡时间需要几天时间,而且气体吸附量较大;通过实验研究了温度对聚四氟乙烯吸附气体的影响,发现温度升高时,会放出部分气体;最后通过测量电离室在脉冲X射线下的信号脉冲形状,研究了绝缘材料的分布对电离室信号响应速度的影响。通过这些实验研究,提出了在气体电离室设计中需要注意绝缘材料的选择,在内部结构设计上需要注意绝缘材料的布置分布。更多还原

【Abstract】 The insulating material in ionization chamber affects the internal gas pressure and ionic pulse shape in the research process of the ion drift velocity in high pressure gas ionization chamber.It will affect the ion drift velocity measurement.It is required to isolate by insulating material between electrode to electrode and between electrodes to the shell of gas ionization chamber.Insulating material in gas ionization chamber is indispensable.Therefore it needs to carefully study the insulating material affecting the performance of gas ionization chamber.First of all,it is found that Teflon can slowly adsorb the working gas in ionization chamber,and the gas pressure in it is reduced when we measure the sensitivity of gas ionization chamber over time.It is verified by experiment that insulating materials absorbing and releasing gas is dynamically reversible process.Then the adsorbing gas property of 95%aluminium oxide ceramic and Teflon is studied through experimental comparision.Gas adsorption equilibrium time of ceramic material is faster,generally it is about a few hours,and the gas adsorption capacity is relatively less.Gas adsorption equilibrium time of Teflon is slower,it is about a few days,and the gas adsorption capacity is relatively more.It is found that Teflon will release part of the gas at higher temperature through experimental research on the influence of Teflon adsorbing gas.Finally it is studied that the distribution of insulation in ionization chamber affects the time response speed of ionization chamber by measuring the signal pulse shape of ionization chamber under the pulse X-ray.Through these experimental research,it is presented that it need to pay attention to select insulation material and to design the internal structure and arrangement of insulating material when we design gas ionization chamber.更多还原