充气电离室是较早应用于电离辐射测量的探测器，具有很好的可靠性、稳定性、耐辐照以及能够承受恶劣环境的能力，在工业核测控领域内应用十分广泛，在钴-60集装箱检测数字辐射成像系统中也选用了高压气体阵列电离室。随着扫描检测速度的提高，高压气体电离室时间响应速度的快慢将直接影响图像的清晰度和检测速度。时间响应速度又取决于电离室灵敏体积内离子的漂移速度，因此高压气体电离室中离子漂移速度是数字辐射成像系统中非常重要的参数。通过对该领域现有文献资料的调研，发现仅有针对低气压电离室或真空电离室离子漂移速度的研究，而高气压情况下离子漂移速度的研究尚无文献提及，并且在现有文献中低气压情况下离子漂移速度的研究方法并不适合于高气压电离室。在本论文中提出了一种对高压气体电离室离子漂移速度进行测量的研究方法：直接利用X光机射线在气体电离室内产生大量正负离子对，通过旋转快门瞬时改变射线束流强度，测量电离室信号电流的变化过程来研究离子漂移速度。在此方法的基础上搭建了实验研究平台，通过前后准直器和旋转快门将直流X光机射线调整为周期的脉冲X射线，脉冲的持续时间要大于离子漂移时间，且脉冲上升沿时间远小于离子收集时间，可远大于电子收集时间。使用DDC112电流积分放大器对电离室输出的脉冲电流信号进行定积分时间和变积分时间测量，使用数据采集卡将测量结果采集到计算机，将脉冲电流信号从零增加至最大值之间的实验数据进行曲线拟合，根据拟合曲线的系数得出离子从高压电极漂移到收集极的收集时间，再根据电离室电极片的结构参数计算出高压气体电离室中在一定气体压力下和不同电场强度下离子的漂移速度。实验中在一个气体探测器内设计了不同极间距离，该电离室充4MPa氙气，在加501伏正高压和987伏正高压情况下进行了实验测量，通过数据处理分析得出了离子漂移速度，也分析了它与气体压力、极间距离、电场强度之间的关系，验证了该种测量方法的可行性。

Ionization chamber was used in the earlier measurement of ionizing radiation, which was wildly used in the field of nuclear industrial measurement and control because of its advantages of high reliability, stability, resistance to radiation and the ability to withstand harsh environments. High-pressure array gas ionization chamber is also used in the Co-60 container inspection system.With the improvement of inspect speed, the time respond speed of high-pressure array gas ionization chamber affects the image clarity directly which depends on the ion drift velocity in sensitive volume of the chamber. On the basis of referring to literature, we found out that these papers studies on the drift velocity of ions in low-pressure chamber, however, they do not mention the drift velocity of ion in high-pressure gas ionization chamber, and their research method does not apply to our researches in high-pressure.A method of measuring the ion drifting velocity in high-pressure gas ionization chamber was described in the paper. In this method, large positive and negative ion-pair was produced in the gas ionization by using of X-ray radiation directly. The beam intensity was instantaneous changed by rotating shutter. Study the ion drift velocity by measuring the ionization chamber signal current change process. An experimental research bench was built for measuring the ion drift velocity based on this method. X-ray pulse period was adjusted by collimator and rotating shutter from direct-current X-ray. The X-ray pulse duration was greater than ion collection time and the pulse rise time is much smaller than ion collection. A DDC112 current integral amplifier was used to measure the output pulse current signal of ionization chamber by fixed integration time and variable integration time measurement. The data was collected to the computer by data acquisition. A curve was fitted from the experimental data that increase from zero to maximum. According to the relationship between the changes in the number of ions and the changes in output current of chambers, the velocity and the time that ions take to travel the distance between the positive and negative can be obtained by the coefficient of the curve.Especially the different distances between the electrode systems we designed in the chamber which filled with 4MPa xenon allows for the researches in the same gas pressure, different electric field strength at the same time. Based on the data of ion drift velocity, we had studied the relationship among the electrode’s structure, the type of noble gas, the pressure of gas and the electrical field strength.